Publications

@misc{singh2019abstract,

title = {Abstract A104: Nanoformulations of PARP and CDK inhibitors for cancer therapy},

author = {Bijay Singh and Shicheng Yang and Paige Baldwin and Anne van de Ven and Srinivas Sridhar},

year  = {2019},

date = {2019-01-01},

publisher = {American Association for Cancer Research},

abstract = {Poly(ADP-ribose) polymerase (PARP) inhibitors have been majorly utilized in cancers with BRCA1/2 mutations that have deficiencies in the homologous recombination (HR) DNA repair pathway. Traditionally, PARP inhibitors have been administered through oral route in the clinic but they have resulted in poor bioavailability, low tumor accumulation and high systemic toxicity. Moreover, tumors develop resistance to PARP inhibitors necessitating the development of strategies to re-sensitize these resistant tumors. To overcome these limitations, nanoparticle drug formulation has demonstrated a great potential to increase the drug concentration and accumulation at tumor sites with low systemic toxicities. Here we report the development of several nanoformulations of PARP inhibitors and observe their efficacies by systemic administration to treat various cancer diseases. We used two FDA approved PARP inhibitors (Olaparib or Talazoparib) for nanoformulations of NanoOlaparib and NanoTalazoparib, decorated with EpCAM or EGFR antibody, and tested on breast, ovarian, prostate and lung cancer with or without irradiation. In HR deficient models, the nanoformulations showed significant inhibition of tumor cell growth in vitro and in vivo. Above all, combination of PARP inhibitor with irradiation resulted in greater efficacy in lung and prostate cancer models. To overcome PARP inhibitor resistance, we formulated nanoparticles, NanoDinaciclib of cyclin-dependent kinase 12 (CDK12) inhibitor (dinaciclib) and used in combination with nanoformulation of PARP inhibitor to arrest the tumor growth in animal model. Our current research reveals that the use of CDK12 inhibitor in PARP resistant tumors further arrests tumor growth compared with monotherapy alone. Further studies will help clarify to achieve clear understanding of the mechanism of action CDK12 inhibitor to determine the best way to use PARP inhibitors beyond HR deficiency.



Citation Format: Bijay Singh, Shicheng Yang, Paige Baldwin, Anne van de Ven, Srinivas Sridhar. Nanoformulations of PARP and CDK inhibitors for cancer therapy [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference on Molecular Targets and Cancer Therapeutics; 2019 Oct 26-30; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2019;18(12 Suppl):Abstract nr A104. doi:10.1158/1535-7163.TARG-19-A104



©2019 American Association for Cancer Research.},

keywords = {Nanomedicine},

pubstate = {published},

tppubtype = {misc}

}

@misc{zhang2018developing,

title = {Developing a nanoformulation of the PARP inhibitor talazoparib as a novel delivery for treatment of BRCA-deficient breast cancer},

author = {Di Zhang and Paige Baldwin and Srinivas Sridhar and Karen Liby},

year  = {2018},

date = {2018-01-01},

urldate = {2018-01-01},

publisher = {American Association for Cancer Research},

abstract = {BRCA mutations are the leading cause of hereditary breast cancer. PARP inhibitors have shown promising activities in clinical trials for breast cancer by inducing synthetic lethality, particularly in patients with BRCA deficiency. Moreover, the utility of PARP inhibitors could potentially extend beyond BRCA mutations by targeting defects in homologous recombination, and thus impact up to 33% of breast cancer patients overall. However, conventional oral delivery of PARP inhibitors is hindered by limited bioavailability and significant off-target toxicities, thus compromising the therapeutic benefits and quality of life in patients. Therefore, we developed a new nanoparticle delivery system for PARP inhibitors and hypothesize that nanoformulated Talazoparib can enhance efficacy by increasing drug concentrations in the tumor and reduce off-target toxicities. The nanoparticle formulation includes polymer brushes to prolong the circulation time, enabling tumor accumulation through the enhanced permeability and retention effect. The therapeutic efficacy of Nano-Talazoparib (Nano-TLZ) was assessed after i.v. injection in Brca1Co/Co;MMTV-Cre;p53+/- mice with established tumors and compared to vehicle control (saline, i.v.), empty nanoparticles (i.v.), free Talazoparib (i.v.), and free Talazoparib (gavage). Treatment was started when the tumor was 4 mm in diameter and ended when the tumor size reached defined IACUC endpoints. Nano-TLZ significantly (p<0.05) prolonged the life span of BRCA deficient mice from 11.6±2.6 days with saline injection to 82.2±10.5 days with i.v. Nano-TLZ. Nano-TLZ induced growth arrest in 100% of the tumors and regression (> 50% reduction in tumor volume) in 80% of the tumors. Established tumors regressed more rapidly, and therefore progression free survival significantly improved in the nanoformulated Talazoparib group (p<0.05). Moreover, Nano-TLZ is better tolerated than free Talazoparib with no significant weight lost. In a biomarker study following 10 days of treatment, Nano-TLZ increased double strand DNA breaks (γ-H2AX) and decreased proliferation (PCNA) compared to controls. Interestingly, Nano-TLZ significantly (p<0.05) decreased myeloid derived suppressor cells in both the tumor (41.6±4.7% to 11.2±2.9%) and spleen (10.0±3.2% to 3.7±0.6%) compared to the saline control. Nano-TLZ also significantly (p<0.05) decreased the percentage of tumor-associated macrophages in the mammary gland from 7.4±2.0% in the saline control group to 2.5±0.2% in the Nano-TLZ group. The changes in immune populations suggest potential immunomodulatory effects of Talazoparib. These results demonstrate that the delivery of Talazoparib as a nanoformulation induces superior treatment outcomes with reduced off-target toxicity in BRCA deficient mice, and provides a novel delivery strategy for PARP inhibitors in patients.



Citation Format: Di Zhang, Paige Baldwin, Srinivas Sridhar, Karen Liby. Developing a nanoformulation of the PARP inhibitor talazoparib as a novel delivery for treatment of BRCA-deficient breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 3874.



©2018 American Association for Cancer Research.},

keywords = {Nanomedicine},

pubstate = {published},

tppubtype = {misc}

}

@misc{vazquez2018nanoparticle,

title = {Nanoparticle-mediated concomitant radiation dose amplification and PARP inhibition in lung cancer},

author = {Ana G Vazquez-Pagan and Paige Baldwin and Ravina M Ashtaputre and Sijumon Kunjachan and Srinivas Sridhar and Rajiv Kumar and Ross Berbeco},

year  = {2018},

date = {2018-01-01},

publisher = {American Association for Cancer Research},

abstract = {Introduction: More than 50% of cancer patients receive radiation therapy at some point during their care. Gold nanoparticles (GNPs) can amplify the radiation dose by facilitating the ejection of low-energy photoelectrons, resulting in increased DNA damage. One of the main challenges of radiation therapy in cancer is to sustain this damage for longer durations. DNA single-strand breaks (SSBs) are repaired by base excision repair, which utilizes Poly(ADP-ribose) polymerase (PARP). PARP inhibition during radiotherapy provides an attractive alternative in maximizing treatment outcomes. Here, we explore a strategy to combine the radiosensitizing effect of GNPs with the DNA-repair inhibiting ability of NanoTalazoparib (nTLZ), a liposomal formulation of the PARP inhibitor, talazoparib (TLZ).



Methods: GNPs were synthesized by reducing AuCl4 using Tetrakis(hydroxymethyl)phosphonium chloride and further PEGylating using heterobifunctional PEGs. A liposomal formulation of TLZ was synthesized using the Nanoassemblr, a microfluidics-based device. Physicochemical characterization of GNPs and nTLZ was carried out using TEM, DLS and release kinetics studies. In vitro studies were carried out to assess the toxicity of the GNPs using MTT assay in non-small cell lung cancer (NSCLC) cell line Calu-6. The therapeutic efficacy of combination treatment using GNPs, nTLZ and radiation was done using clonogenic survival assays. Clonogenic assay was carried out using Calu 6 cells, which were sequentially treated with GNPs (1mg/mL), TLZ (0.5 uM) and nTLZ (0.5 uM) with and without radiation. The radiation doses varied from 0-10Gy for each set of treatments.



Results: PEGylated GNP's showed a hydrodynamic diameter of ~10-12 nm with a spherical morphology whereas nTLZ size was 70 nm encapsulating TLZ at a concentration of ~200 ug/ml. MTT assay showed no toxicity for PEGylated GNPs treated upto a concentration of 3.0 mg/mL. Cells treated with either GNPs, TLZ or nTLZ did not show significant reduction in colony formation, but were reduced with increasing doses of radiation. The survival plots showed a highly additive antiproliferative effect for the GNP + nTLZ combination at all radiation doses, while the free TLZ + GNPs combination was not as effective at inhibiting colony formation. In vivo experiments assessing the combination therapy in a subcutaneous xenograft mice model using Calu 6 are currently under way.



Conclusions: The preliminary in vitro results indicate that the combination of radiosensitizing GNPs with a potent DNA repair enzyme inhibitor, TLZ, has an immense potential as a complimentary combination therapy in conjunction with radiation therapy in treatment of lung cancer.



This work is supported by the CaNCURE program (grant #1CA174650-02), American Lung Association, Dana-Farber Cancer Institute and Brigham and Women's Hospital.



Citation Format: Ana G. Vazquez-Pagan, Paige Baldwin, Ravina M. Ashtaputre, Sijumon Kunjachan, Srinivas Sridhar, Rajiv Kumar, Ross Berbeco. Nanoparticle-mediated concomitant radiation dose amplification and PARP inhibition in lung cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 3710.



©2018 American Association for Cancer Research.},

keywords = {Nanomedicine},

pubstate = {published},

tppubtype = {misc}

}

@misc{baldwin2018targeted,

title = {Targeted nanotherapy using the PARP inhibitor talazoparib for breast cancer treatment},

author = {Paige Baldwin and Rajiv Kumar and Srinivas Sridhar},

year  = {2018},

date = {2018-01-01},

publisher = {American Association for Cancer Research},

abstract = {Introduction: PARP inhibitors exploit defects in DNA repair pathways to selectively target cancerous cells. These drugs are currently delivered orally, but Talazoparib, the most potent PARP inhibitor, exhibits greater toxicity than the others. Systemic administration of nanoparticles bypasses the first-pass metabolism of oral drugs and nanoparticles preferentially accumulate in tumors due to the leaky tumor vasculature. Additionally, nanoparticles can be actively targeted to tumors by conjugating different moieties such as antibodies that recognize overexpressed markers on the tumor cells. NanoTalazoparib (NanoTLZ) has been previously formulated and extensively characterized in breast, ovarian, and lung cancer models. Here we describe further characterization of NanoTLZ and the development of a next generation fluorescently labeled EPCAM targeted formulation of NanoTLZ for the treatment of triple negative breast cancer (TNBC).



Methods: Animals with orthotopic TNBC xenografts were injected with NanoTLZ and at various time points tumor biopsies were taken to assay tumor PAR levels. Blood was collected at various time points and plasma separated for drug extraction and quantification. Pharmacokinetic modeling is underway. Fluorescently labeled NanoTLZ was developed with the addition of Cy5, followed by further improvement via conjugation of anti-EPCAM antibodies. Targeting capability was assessed via laser scanning confocal microscopy after treatment of the TNBC cell line MDA-MB-231 with either non-targeted or targeted NanoTLZ. Therapeutic efficacy studies with targeted NanoTLZ alone and in combination with radiation are underway in an MDA-MB-231 xenograft model.



Results: Pharmacodynamics indicated PAR suppression in tumors within 30 minutes of NanoTLZ treatment. Tumor PAR levels began to increase 24 hours after a single dose but remained significantly lower than control levels up to 72 hours (P<0.005). Characterization of NanoTLZ after the addition of Cy5 and after anti-EPCAM targeting indicated that the formulation remained under 100 nm in diameter with a charge of ~10 mV and equivalent drug loading and release. Cy 5 labeling allowed for visualization of nanoparticle uptake and intracellular fluorescence was 70% greater in cells when treated with EPCAM targeted NanoTLZ compared to non-targeted.



Conclusions: The sustained release of Talazoparib from the nanoformulation decreases tumor PAR levels for up to 72 hours after a single dose, allowing for less frequent administration than the current daily regime used for oral Talazoparib. The targeted formulation of NanoTLZ shares the same physicochemical properties as the untargeted formulation, but is taken up much faster in vitro, suggesting it will allow for greater accumulation at the tumor site making it more effective than the previously tested untargeted NanoTLZ. Supported by ARMY/W81XWH-16-1-0731 and Rivkin Foundation.



Citation Format: Paige Baldwin, Rajiv Kumar, Srinivas Sridhar. Targeted nanotherapy using the PARP inhibitor talazoparib for breast cancer treatment [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 3715.



©2018 American Association for Cancer Research.},

keywords = {Nanomedicine},

pubstate = {published},

tppubtype = {misc}

}

@misc{faegh2018sensor,

title = {Sensor system utilizing piezoelectric microcantilever coupled with resonating circuit},

author = {Samira Faegh and Nader Jalili and Srinivas Sridhar},

year  = {2018},

date = {2018-00-01},

abstract = {An interchangeable sensor system is described, including: a microcantilever including a beam anchored at a first end, the beam being free to vibrate on another end, wherein a piezoelectric layer is deposited on a surface of the beam; an input configured to receive a voltage from a voltage source for applying voltage to the piezoelectric layer; and a resonating circuit including: the piezoelectric layer, configured as a capacitor of the resonant circuit; and one or more additional electrical elements; wherein the voltage source is configured to apply a first AC voltage under a first condition for actuating the microcantilever at a first mechanical resonating frequency of the microcantilever and a second AC voltage under a second condition for actuating the microcantilever at a second electrical resonating frequency of the resonating circuit. Method of using the sensor system is also described.},

note = {US Patent 9,921,226},

keywords = {Sensors},

pubstate = {published},

tppubtype = {misc}

}

@misc{wilfred2018biomaterials,

title = {Biomaterials for combined radiotherapy and immunotherapy of cancer},

author = {NGWA Wilfred and Rajiv Kumar and Gerassimos Makrigiorgos and Srinivas Sridhar and Stephanie Dougan},

year  = {2018},

date = {2018-00-01},

abstract = {Compositions and methods for the radiological and immunotherapeutic treatment of cancer are provided. Metallic nanoparticles conjugated with an immunoadjuvant are dispersed within a biodegradable polymer matrix that can be implanted in a patient and released gradually. The implant may be configured as, or be a component of, brachytherapy spacers and applicators, or radiotherapy fiducial markers. The composition may be combined with marginless radiotherapy, allowing for lower doses of radiation and enhancing the immune response against cancer, including at non-irradiated sites.},

note = {US Patent App. 15/752,099},

keywords = {Nanomedicine},

pubstate = {published},

tppubtype = {misc}

}

@misc{paro2017abstract,

title = {Abstract B44: Biological mechanisms involved in nanoparticle-enhanced radiation therapy for pancreatic cancer},

author = {Autumn D Paro and Ilan Shanmugam and Anne van de Ven and Rajiv Kumar and Thomas J Webster and Srinivas Sridhar},

year  = {2017},

date = {2017-01-01},

publisher = {American Association for Cancer Research},

abstract = {Introduction: The objective of this project is to study the biological pathways activated in irradiated pancreatic cancer cells pre-treated with gold nanoparticles. Metallic nanoparticles emit Auger electrons and photoelectrons upon exposure to X-rays. When selectively delivered to tumors, these nanoparticles can locally enhance<?__anchored_object__ "ro_u170cins1e758"?><?__anchored_object__ "ro_u170cins1e759"?> the effects of radiation therapy. Previous in vitro work has primarily studied the effectiveness of nanoparticle-enhanced therapy, without elucidating the underlying biological mechanisms. Understanding the biological mechanisms (such as changes in gene expression) of how nanoparticles enhance radiation therapy can help in the further design of more effective nanoparticles.



Methods: Gold nanoparticle sensitization was tested using a human based pancreatic cancer cell line, Capan-1. Nanoparticle toxicity was tested using a combination of MTS and Alamar Blue assays after 24 hours of treatment. Gene expression was tested using immunofluorescence and western blot techniques. Cells were pretreated with 0.8 mg gold nanoparticles 24 hours prior to radiation. Cells were then harvested at various time points to determine how gene expression changes over time. Radiosensitization was carried out using a clonogic cell survival assay where cells were pretreated with 0.8 mg gold nanoparticles 24 hours prior to radiation and then re-plated at various densities 4 hours post radiation, and allowed to incubate for 14 days. Statistical differences were determined using ANOVA followed by student t-tests.



Results: The MTS and Alamar blue assays showed low gold nanoparticle toxicity towards cells up to a dose of 1mg for Capan-1 cells. Capan-1 cells pretreated with 0.8 mg gold nanoparticles for 24 hours prior to radiation showed lower cell survival than cells only treated with radiation. Western blots and immunofluorescence data showed that certain genes, such as γ-H2AX, were upregulated when pretreated with gold nanoparticles and irradiated compared to cells treated with radiation alone. It was also shown that γ-H2AX expression peaked around 30 minutes post radiation and then returned to basal levels after 24 hours.



Conclusions: Capan-1 cells experience more DNA damage when pretreated with gold nanoparticles than when only treated with radiation. γ-H2AX, which is a DNA damage-related protein, was upregulated in the combined dose showing that there was more DNA damage in the combined treatment. It was also shown that protein and gene expression analysis needs to be carried out at various time points post radiation to obtain a better understanding of the mechanisms involved in radiation induced damage to pancreatic cancer cells.



Supported by NSF-DGE- 0965843 and CA188833-02.



Citation Format: Autumn D. Paro, Ilan Shanmugam, Anne van de Ven, Rajiv Kumar, Thomas J. Webster, Srinivas Sridhar. Biological mechanisms involved in nanoparticle-enhanced radiation therapy for pancreatic cancer. [abstract]. In: Proceedings of the AACR Special Conference on Engineering and Physical Sciences in Oncology; 2016 Jun 25-28; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2017;77(2 Suppl):Abstract nr B44.



©2016 American Association for Cancer Research.},

keywords = {Nanomedicine},

pubstate = {published},

tppubtype = {misc}

}

@misc{baldwin2017abstract,

title = {Abstract B29: Nanoformulations and sustained delivery systems for the PARP inhibitors Olaparib and Talazoparib},

author = {Paige Baldwin and Anders Ohman and Jodi Belz and Jeremy Thong and Noelle Castilla Ojo and Karen Liby and Daniela Dinulescu and Srinivas Sridhar},

year  = {2017},

date = {2017-01-01},

publisher = {American Association for Cancer Research},

abstract = {Introduction: Poly(ADP-ribose) Polymerase (PARP) plays an important role in a number of DNA repair pathways. PARP inhibitors (PARPi) such as Olaparib and Talazoparib exploit the concept of synthetic lethality by selectively targeting cancer cells with defective DNA repair pathways. These drugs are currently only available in oral form which results in limited bioavailability, poor tumor accumulation, and systemic toxicity, specifically when combined with other DNA damaging agents. Here we report the development of two different delivery techniques including nanoformulations of Olaparib and Talazoparib and a biodegradable implant for localized delivery of Talazoparib. The nanoformulations allow for intravenous or intraperitoneal delivery, providing greater bioavailability and tumor accumulation, while limiting systemic toxicities and the implant provides a sustained release for intratumoral delivery to enhance the dose at the tumor site thereby limiting systemic toxicity.



Methods: Nanoparticle formulations of Olaparib and Talazoparib were synthesized and characterized via TEM, DLS, and HPLC to elucidate size, loading, and release before testing in vivo. In vitro experiments for testing nanoformulations include dose response with a panel of ovarian cancer cell lines. In vivo, NanoOlaparib was tested in an IP spread model using 404 cells derived from BRCA2-/-, TP53-/-, PTEN-/- genetically engineered mouse models. Animals were treated IP with NanoOlaparib alone, and in combination with cisplatin. The 1-2 mm long Talazoparib implant was characterized with SEM and HPLC for structure, loading, and release. A spontaneous tumor forming breast cancer model was used to test the Talazoparib implant. Implants were directly injected into the tumor of Brca1Co/Co;MMTV-Cre;p53+/- mice for a one time treatment.



Results: PA1 demonstrated high sensitivity to NanoOlaparib which may be attributed to genetic instability at 11/13 polymorphic loci. Both PTEN and BRCA deficiencies resulted in comparable IC50's likely due to synthetic lethality attributed to dysfunctional homologous recombination pathways. NanoTalazoparib is more potent than NanoOlaparib, resulting in a similar relationship in cell line sensitivity with overall lower IC50's. Bioluminescence images illustrated that NanoOlaparib administered IP daily in the ovarian cancer model resulted in a greater inhibition of tumor growth than those treated with oral Olaparib daily. The Talazoparib implant released therapeutically relevant doses of Talazoparib over multiple weeks. In vivo the implant reduced tumors 50% following the one time treatment, while untreated tumors increased significantly in size.



Conclusions: Robust nanoparticle formulations of NanoTalazoparib and NanoOlaparib have been successfully developed and characterized. These results show that NanoOlaparib and NanoTalazoparib amplify the efficacy of PARP inhibitors in vivo. The Talazoparib implant provides a safe strategy for sustained local delivery of Talazoparib directly to the tumor. These strategies provide opportunities to increase the efficacy of PARP inhibitors via tailored delivery to the type of tumor.



This work was supported by the DOD Ovarian Cancer Research Program under Army- W81XWH-14-1-0092 and IGERT grant NSF-DGE- 0965843.



Citation Format: Paige Baldwin, Anders Ohman, Jodi Belz, Jeremy Thong, Noelle Castilla Ojo, Karen Liby, Daniela Dinulescu, Srinivas Sridhar. Nanoformulations and sustained delivery systems for the PARP inhibitors Olaparib and Talazoparib. [abstract]. In: Proceedings of the AACR Special Conference on Engineering and Physical Sciences in Oncology; 2016 Jun 25-28; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2017;77(2 Suppl):Abstract nr B29.



©2016 American Association for Cancer Research.},

keywords = {Nanomedicine},

pubstate = {published},

tppubtype = {misc}

}

@misc{codi2017abstract,

title = {Abstract B22: Quantitative tumor imaging using magnetic nanoparticles},

author = {Gharagouzloo Codi and Ju Qiao and Liam Timms and Anne van de Ven and Srinivas Sridhar},

year  = {2017},

date = {2017-01-01},

publisher = {American Association for Cancer Research},

abstract = {Introduction: We have developed a new method of Quantitative MRI named QUTE-CE MRI that yields images of the vasculature with unparalleled clarity and definition and is quantitative. QUTE-CE MRI can produce contrast enhanced magnetic resonance angiograms (CE-MRA) using super paramagnetic iron-oxide nanoparticle (SPION), including the FDA approved ferumoxytol, with high contrast in cardiovascular, cerebral, and tumor imaging.



Based upon principles of magnetic nanoparticle interactions with neighboring water molecules, the method achieves robust, reproducible results by utilizing rapid signal acquisition at ultra-short time-to-echo (UTE) to produce positive-contrast images with pure T1 weighting and little T2* decay. The spoiled gradient echo equation (SPGR) is used to transform UTE intensities directly into concentration using experimentally determined relaxivity constants and image acquisition parameters.



Methods: All animal experiments were conducted in accordance with the Northeastern University Division of Laboratory Animal Medicine and Institutional Animal Care and Use Committee. MRI images were obtained at ambient temperature (∼25°C) using a Bruker Biospec 7.0T/20-cm USR horizontal magnet (Bruker, Billerica, Massachusetts, USA) equipped with a 20-G/cm magnetic field gradient insert (ID =12 cm, Bruker) and the same quadrature 300 MHz, 30 mm Mouse MRI coil was used for all in vivo work as previously utilized for mouse experiments in Section 3.8 (Animal Imaging Research, LLC, Holden, Massachusetts, USA).



PC 3 cells were injected into the right flank of immunocompromised FoxNu1 mice (n=5, Charles River Laboratories). After tumors reached about 0.5-1.0cm3, animals underwent three separate imaging sessions: Session 1 - pre-contrast T1, T2 and QUTE-CE measurements, Session 2 - immediate post-contrast QUTE-CE measurement and Session 3 - 24h post-contrast T1, T2 and QUTE-CE measurements. For contrast, 100μl of ferumoxytol diluted to 6mg/ml was injected i.v. to render a blood concentration of ~200μg/ml Fe (2x clinical dose).



Results: Contrary to more standard MRI techniques, QUTE-CE pre-contrast images render a nearly homogenous signal with a Gaussian distribution in the tumor. The immediate post-contrast images render the vasculature clearly and skew the distribution of voxels within the whole tumor to the left, however also increases the overall mean of the signal intensity because the movement of voxels within the tumor is to the right, leaving a long bright tail with the brightest voxels represented by those containing 100% blood. 24h after the initial administration of ferumoxytol the vasculature is no longer visible, but the locations within the tumor that have passively accumulated SPIONs resulting from the EPR effect becomes apparent. While the distribution of voxels within the tumor becomes less skewed, the overall shape is still slightly skewed to the left and the mean of the distribution has moved to the right. Nanoparticle accumulation in the post-contrast image is heterogeneous and unambiguous.



Angiography and TBV in tumors Assuming a partial 2-volume model of blood and tissue, we determine the tumor blood volume (TBV) across the entire tumor volume. The resultant TBV heatmaps show a clear range of TBV values are apparent, delineating areas of the tissue with high contrast in regard to overall vascular health, including apparently necrotic tissue.



Nanoparticle accumulation Next, a unique feature of the methodology to produce high-contrast images of purely T1-weighted signal is employed to unambiguously delineate nanoparticle accumulation in a PC3 subcutaneous tumor model with ferumoxytol accumulation 24 hours after just one dose. From this, contrast efficiency was produced compared to standard techniques with the additional benefit that pre-contrast images are not necessitated. A major advantage of delineating SPION accumulation using QUTE-CE, compared to ΔT2 or ΔT1 imaging, is that the post-contrast image contains sufficient information for nanoparticle localization, eliminating the need for pre-contrast images.



Conclusion: QUTE-CE MRI exploits physical principles of magnetic relaxation modulated by SPIONs to achieve quantitative MRI yielding exceptional vascular images. This ability to longitudinally quantify blood pool CA concentration is unique to the QUTE-CE method, and makes QUTE-CE MRI competitive with nuclear imaging. Quantitative tumor blood volume distributions are obtained at short times, while nanoparticle accumulation maps are obtained at long times. QUTE-CE MRI is a new method that can be used to study tumor properties longitudinally. The technique is immediately translatable to the clinic using the FDA approved contrast agent ferumoxytol and is expected to have a major impact on clinical tumor imaging.



Work supported by NSF-DGE- 0965843.



Citation Format: Gharagouzloo Codi, Ju Qiao, Liam Timms, Anne van de Ven, Srinivas Sridhar. Quantitative tumor imaging using magnetic nanoparticles. [abstract]. In: Proceedings of the AACR Special Conference on Engineering and Physical Sciences in Oncology; 2016 Jun 25-28; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2017;77(2 Suppl):Abstract nr B22.



©2016 American Association for Cancer Research.},

keywords = {MRI},

pubstate = {published},

tppubtype = {misc}

}

@misc{van2017abstract,

title = {Abstract B48: Prostate cancer pre-treatment with nanoformulated Olaparib overcomes radiation resistance},

author = {Anne L van de Ven and Shifalika Tangutoori and Paige Baldwin and Ju Qiao and Codi Gharagouzloo and Nina Seitzer and John Clohessy and Houari Korideck and Mike G Makrigiorgos and Robert Cormack and others},

year  = {2017},

date = {2017-01-01},

publisher = {American Association for Cancer Research},

abstract = {Prostate cancers with PTEN deletions are promising candidates for DNA repair inhibitors such as olaparib and talazoparib. Here we show that radiation-resistant cells and tumors derived from Ptenpc-/-;Trp53pc-/- mice are rendered radiation-sensitive following pre-treatment with liposomal nanoOlaparib. This enhancement in radiosensitivity is accompanied by radiation dose-dependent changes in γ-H2AX expression and is specific to nanoformulated Olaparib alone. In animals, twice-weekly intravenous administration of nanoOlaparib alone results in significant tumor growth inhibition. When nanoOlaparib is administered prior to radiation, we find that a single dose of radiation is sufficient to increase mouse survival time by as much as 10 weeks (study duration = 13 weeks). Using ferumoxytol as a surrogate nanoparticle, magnetic resonance imaging (MRI) studies revealed that nanoOlaparib administration enhances the ability of nanoparticles to accumulate in tumors. Compared to untreated and radiation-only controls, nanoOlaparib-treated tumors showed 18-fold higher nanoparticle accumulation, suggesting that the in vivo efficacy of nanoOlaparib may be potentiated by its ability to enhance its own accumulation in tumors.



Citation Format: Anne L. van de Ven, Shifalika Tangutoori, Paige Baldwin, Ju Qiao, Codi Gharagouzloo, Nina Seitzer, John Clohessy, Houari Korideck, G. Mike Makrigiorgos, Robert Cormack, Pier Paolo Pandolfi, Srinivas Sridhar. Prostate cancer pre-treatment with nanoformulated Olaparib overcomes radiation resistance. [abstract]. In: Proceedings of the AACR Special Conference on Engineering and Physical Sciences in Oncology; 2016 Jun 25-28; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2017;77(2 Suppl):Abstract nr B48.



©2016 American Association for Cancer Research.},

keywords = {Nanomedicine},

pubstate = {published},

tppubtype = {misc}

}

@misc{kumar2017abstract,

title = {Abstract B41: Gold nanoparticles based platforms for localized radiosensitization in cancer radiation therapy},

author = {Rajiv Kumar and Wilfred Ngwa and Vinit Joshi and Sijumon Kunjachan and Ross Berbeco and Mike Makrigiorgos and Srinivas Sridhar},

year  = {2017},

date = {2017-01-01},

publisher = {American Association for Cancer Research},

abstract = {The use of nanoparticles with high atomic (Z) number have been known to attenuate X-rays and the unique properties associated with gold nanoparticles makes them as potent radiosensitizers for enhancing Radiotherapy (RT) treatments. The interaction of high Z materials with the X-rays results in photoelectric absorption which leads to generation of photoelectrons. These low energy photoelectrons can deliver lethal energy in the close proximity. The success of cancer radiation therapy relies heavily on the effective delivery of radiation dose to the tumor site sparing the surrounding normal tissues. To overcome the limitations associated with increasing the radiation dose, due to normal tissue toxicities, the feasibility of radiosensitizing the tumor using gold nanoparticles provide a promising alternative. Targeting gold nanoparticles based formulations to the tumor prior to radiation therapy will result in radiation dose enhancement, by generating secondary photoelectrons, locally inside the tumor and thereby minimizing the dose dependent toxicity to non-specific neighboring tissues. Here, we have developed different Gold nanoparticles based formulations to locally radiosensitize the tumor cells in three different cancer models.



For targeting pancreatic cancers, we have fabricated a new generation of GNPs formulation which are 3-4 nm in diameter and surface passivated with hetero-bifunctional PEG, fluorophore AlexaFlour 647 and peptide RGD. This formulation showed a 2.8-fold in vitro cell kill enhancement with X-rays, as demonstrated by clonogenic survival assays. In vivo studies confirmed the highly specific tumor uptake in tumor endothelial cells in orthotopic pancreatic tumor mice model. The combined treatment in animals treated with GNPs and radiation (10Gy) showed the maximum endothelial cells damage, as confirmed with confocal imaging of the tumor sections and CD31 immunostaining.



For targeting the lung cancer, we have used the same GNPs formulation but adopted a inhalation/instillation (INH) route for administering the nanoparticles in vivo in transgenic lung cancer mice model as opposed to customary intravenous (i.v) route. Fluorescence imaging and ex-vivo electron microcopy results showed a 4.7 times higher concentration of GNPs in the lung tumors of mice when using INH delivery compared to i.v. approach. The survival studies with these animals are currently underway.



For using these radiosensitizing nanoparticles in brachytherapy applications, we have incorporated GNPs in modified brachytherapy spacers to enhance radiation dose locally in tumor without any additional surgical intervention. These spacers are normally placed inside the tumor to spatially distribute the radioactive seeds. The incorporation of GNPs in these spacers allowed for enhancing the radiation dose by the GNPs released from the spacers. These spacers have same morphology (5 mm in length and 0.8 mm in diameter) as commercial spacers with additional radiosensitizing properties because of doped GNPs. We have shown the time dependent release of the GNPs as a function of size of GNPs from the spacers into the tumor by optical imaging. We have further incorporated the GNPs based brachytherapy spacer with the immunoadjuvants, anti-CD40 to combine the radiation and immunotherapy in a single platform. The preliminary results indicate that gold nanoparticles based nanoplatform shows promise as a potential theranostic radiosensitizer which allows for combining multiple therapies in a single platform.



This work is supported by ARMY/ W81XWH-12-1-0154, NSF DGE 0965843, HHS/5U54CA151881-02, NCI R03CA164645, NCI1 K01CA17247801, the Electronics Materials Research Institute at Northeastern University, and Brigham and Women's Hospital.



Citation Format: Rajiv Kumar, Wilfred Ngwa, Vinit Joshi, Sijumon Kunjachan, Ross Berbeco, Mike Makrigiorgos, Srinivas Sridhar. Gold nanoparticles based platforms for localized radiosensitization in cancer radiation therapy. [abstract]. In: Proceedings of the AACR Special Conference on Engineering and Physical Sciences in Oncology; 2016 Jun 25-28; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2017;77(2 Suppl):Abstract nr B41.



©2016 American Association for Cancer Research.},

keywords = {Nanomedicine},

pubstate = {published},

tppubtype = {misc}

}

@misc{belz2017abstract,

title = {Abstract B30: Sustained release of PARP inhibitor Talazoparib and chemotherapeutic Docetaxel from modified brachytherapy spacers for treatment of breast and prostate cancer},

author = {Jodi Belz and Noelle Castilla Ojo and Paige Baldwin and Rajiv Kumar and Anne van de Ven and Karen Liby and Robert Cormack and Mike Makrigiorgos and Srinivas Sridhar},

year  = {2017},

date = {2017-01-01},

publisher = {American Association for Cancer Research},

abstract = {Sustained localized delivery of cancer therapeutics is a safe and effective unique option for local control of tumors. Here we report a novel biodegradable implant with the capability to encapsulate different therapeutics, molecular agents, or nanoparticles for local intratumoral delivery. We have successfully demonstrated in vivo the delivery of PARP inhibitor Talazoparib to treat Brca1-mutated cancers and Docetaxel to treat localized or recurring prostate cancers. This one-time intratumoral injection provides a safe vehicle for the sustained release of PARP inhibitor Talazoparib and chemotherapeutic Docetaxel in contrast to low bioavailability and toxicity associated with oral or systemic delivery.



Methods: Biodegradable implants of 1-2mm length and 0.8mm diameter were loaded with ~50μg Talazoparib for BRCA1-mutated breast cancer studies and ~500μg Docetaxel (DTX) for prostate cancer studies. The implants were characterized in vitro using SEM and HPLC, and the release kinetic studies were carried out in PBS buffer (pH 6.0) at 37°C. The IC50's were determined using an MTS assay in breast cancer cell lines derived from Brca1 Co/Co; MMTV-Cre; p53+/−mice, W0069 and W780, and human-derived prostate cancer, PC3. In vivo studies were carried out in Brca1 Co/Co; MMTV-Cre; p53+/− spontaneous tumored mice for breast cancer studies. Subcutaneous PC3 tumors were xenografted in nude mice. Prostate cancer studies were done with and without radiation. Drug-loaded implants were injected once intratumorally using an 18G brachytherapy needle.



Results: The release profile of the drug from the implant in buffer showed a highly sustained release for multiple weeks at therapeutically relevant doses for both docetaxel and Talazoparib loading implants. Breast cancer cell lines W0069 and W780 were highly sensitive to Talazoparib, most likely due to Brca1 mutation. Following a one-time intratumoral implantation of Talazoparib, tumors reduced in size by an average of 50%, while untreated tumors increased ~5X in size. Talazoparib dosing appeared to be well tolerated by the mice. Docetaxel implants proved to be an effective method for prostate cancer in vivo with no significant weight loss observed. The local docetaxel spacer group showed sustained tumor inhibition compared to empty implants and an equivalent DTX dose given systemically. At 40 days 89% survival was observed for mice treated with localized DTX implants compared with 0% in all other treatment groups. Histology samples were taken from sacrificed mice and immunohistochemistry are currently underway.



Conclusions: Sustained local release of therapeutically relevant doses of Talazoparib and Docetaxel were observed in vitro and in vivo. Therapeutics-loaded implants represent a novel delivery route that are well-tolerated. Sustained release of Talazoparib appears to amplify the therapeutic efficacy of PARP inhibition in BRCA1 mutated breast cancers and sustained release of Docetaxel is an effective chemotherapy option alone or in combination with radiation therapy. These results laid a strong foundation for the use of localized biodegradable implants for the treatment of breast and prostate cancer.



This work was supported by the Army- W81XWH-14-1-0092, Breast Cancer Research Foundation and Northeastern University–Dana Farber Cancer Institute collaborative grant.



Citation Format: Jodi Belz, Noelle Castilla Ojo, Paige Baldwin, Rajiv Kumar, Anne van de Ven, Karen Liby, Robert Cormack, Mike Makrigiorgos, Srinivas Sridhar4. Sustained release of PARP inhibitor Talazoparib and chemotherapeutic Docetaxel from modified brachytherapy spacers for treatment of breast and prostate cancer. [abstract]. In: Proceedings of the AACR Special Conference on Engineering and Physical Sciences in Oncology; 2016 Jun 25-28; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2017;77(2 Suppl):Abstract nr B30.



©2016 American Association for Cancer Research.},

keywords = {Nanomedicine},

pubstate = {published},

tppubtype = {misc}

}

@misc{baldwin2017abstractb,

title = {Abstract NTOC-080: NANOOLAPARIB: AN INTRAPERITONEAL PARP INHIBITOR THERAPY FOR OVARIAN CANCER},

author = {Paige Baldwin and Anders Ohman and Daniela Dinulescu and Srinivas Sridhar},

year  = {2017},

date = {2017-01-01},

publisher = {American Association for Cancer Research},

abstract = {PURPOSE: PARP inhibitor therapy for ovarian cancer exploits the concept of synthetic lethality by taking advantage of defects in DNA damage repair pathways. Currently Olaparib is the only FDA-approved PARP inhibitor and is available as an oral dosage, which has plenty of advantages, but requires the drug to undergo first pass metabolism, inactivating a significant fraction of the dose. We have developed a nanoparticle delivery system to allow for local delivery of Olaparib directly to the intraperitoneal cavity.



METHODS: NanoOlaparib was characterized in vitro in regards to size, charge, drug loading and release before testing on a panel of ovarian cancer cell lines, including KURAMOCHI, SKOV3, OVSAHO, JHOS2, PA1, COV318, 403 and 404, derived from tumors of Brca2-/-, Pten-/-, Tp53-/- mice, and 4306 and 4412, developed from conditional KrasLSL-G12D/+, Pten-/- mice, to elucidate sensitivity profiles and ensure comparable activity to the free drug. 404 cells, derived from Brca2-/-, Tp53-/-, Pten-/- genetically engineered mouse models, were utilized to develop an IP spread xenograft model to test NanoOlaparib in vivo. Animals were treated with NanoOlaparib or oral Olaparib daily for 4 weeks. Tumor burden was monitored weekly via bioluminescence imaging.



RESULTS: NanoOlaparib shows comparable efficacy in vitro to free Olaparib. The murine cell lines were the most sensitive to the treatment regardless of BRCA status, suggesting that Pten deletions are just as susceptible to PARP inhibitor therapy as the BRCA mutations. The average fold change in bioluminescence for NanoOlaparib decreased, while it increased for oral Olaparib. The oral Olaparib animals had widely varied responses, with some animals' tumors shrinking and others never responding. All NanoOlaparib tumors shrank initially, however, severe toxicity was noted after 3 weeks of treatment.



CONCLUSIONS: NanoOlaparib toxicity in vivo was observed with daily dosing likely due to the sustained release of the drug in comparison to the much more rapid clearance of the oral drug. While the NanoOlaparib was toxic, it provided a much more uniform response to the treatment than the oral Olaparib. It is clear that because this strategy provides 100% of the dose to the disease site with a sustained delivery it is no longer necessary to administer daily. This suggests that NanoOlaparib changes the pharmacokinetics to allow for a lower dose to be administered. A modified dosing regime is to be tested with the goal of lowering the toxicity while still maintaining therapeutic efficacy.



Citation Format: Paige Baldwin, Anders Ohman, Daniela Dinulescu, Srinivas Sridhar. NANOOLAPARIB: AN INTRAPERITONEAL PARP INHIBITOR THERAPY FOR OVARIAN CANCER [abstract]. In: Proceedings of the 11th Biennial Ovarian Cancer Research Symposium; Sep 12-13, 2016; Seattle, WA. Philadelphia (PA): AACR; Clin Cancer Res 2017;23(11 Suppl):Abstract nr NTOC-080.



©2017 American Association for Cancer Research.},

keywords = {Nanomedicine},

pubstate = {published},

tppubtype = {misc}

}

@misc{baldwin2017nanoformulated,

title = {Nanoformulated Talazoparib and Olaparib for enhanced delivery},

author = {Paige Baldwin and Rajiv Kumar and Edward Favours and Karen Liby and Raushan Kurmasheva and David Kozono and Srinivas Sridhar},

year  = {2017},

date = {2017-01-01},

publisher = {American Association for Cancer Research},

abstract = {Introduction: PARP inhibitors such as Talazoparib and Olaparib exploit deficiencies in DNA repair pathways, making them attractive candidates for treatment of a number of different cancers. These drugs are particularly effective when used in combination with other DNA damaging agents such as chemotherapeutics and radiation therapy. Combination trials, however, have resulted in severe toxicities, necessitating either dose reduction or delay. Dose reduction leads to suboptimal dosing and provides little therapeutic benefit compared to monotherapy. Systemically administered nanoparticles offer a more effective way to selectively accumulate drugs in tumors and bypass toxicities associated with oral delivery. We have developed nanoparticle delivery systems for both Olaparib and Talazoparib in order to improve tumor accumulation while bypassing the toxicity associated with oral administration.



Methods: Lipid nanoformulations of Olaparib and Talazoparib have been developed and characterized in regard to size, surface charge, drug loading, release, and stability. NanoTalazoparib has been tested in vitro in breast cancer cell lines including W0069, W780, and HCC1937 which exhibit BRCA1 and 2 mutations, and NanoOlaparib in the lung cancer cell line Calu-6 which also has a defective FA-BRCA pathway. Mice have been treated with NanoOlaparib and NanoTalazoparib alone and in combination with radiation or temozolomide in order to evaluate toxicity. Therapeutic efficacy studies are currently underway.



Results: The nanoformulations have been formulated to encapsulate a clinically relevant dose of either Talazoparib or Olaparib and release at 37°C over a period of days, while remaining stable during storage at 4°C. In vitro, both nanoformulations show the same activity as free drug with IC50s in the nanomolar range for these cell lines with varying deficiencies in the BRCA pathway. Mice have shown no appreciable weight loss during treatment with either nanoformulation alone or in combination with other treatment modalities.



Conclusion: Nanoformulations of Talazoparib and Olaparib have been developed and characterized to demonstrate activity in vitro and tolerable doses in vivo. We have found that mice tolerate NanoTalazoparib at higher doses when combined with Temozolomide than when given oral Talazoparib. The sustained release from the nanoparticles allows for the nanoformulation to be administered less often than the daily administration for oral drug and the improved tolerability opens the door for combination therapy with both chemotherapeutics and radiation therapy. Therapeutic efficacy studies are underway and we expect that as a monotherapy NanoTalazoparib will be more effective at lower doses than oral Talazoparib, based on the longer circulation time and more selective accumulation in tumors. We also anticipate that combination therapy will be more effective with the nanoformulation, as the maximum tolerated dose is higher than that of the oral drug.



Citation Format: Paige Baldwin, Rajiv Kumar, Edward Favours, Karen Liby, Raushan Kurmasheva, David Kozono, Srinivas Sridhar. Nanoformulated Talazoparib and Olaparib for enhanced delivery [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 3100. doi:10.1158/1538-7445.AM2017-3100



©2017 American Association for Cancer Research.},

keywords = {Nanomedicine},

pubstate = {published},

tppubtype = {misc}

}

@misc{baig2017nanoformulation,

title = {Nanoformulation of talazoparib to increase efficacy when combined with temozolomide for the treatment of Ewing sarcoma xenografts},

author = {Nabeela Baig and Rostislav Likhotvorik and Paige Baldwin and Srinivas Sridhar and Raushan Kurmasheva},

year  = {2017},

date = {2017-01-01},

publisher = {American Association for Cancer Research},

abstract = {Ewing Family of tumors (EFT) comprises the fourth most common highly malignant childhood cancer. Although sustained event-free survival (EFS) can be achieved with intensive chemo-radiation therapy for patients with local-regional disease, this therapy is relatively ineffective in the treatment of metastatic disease with EFS of 12% at 5 years. Ewing sarcoma is characterized by a reciprocal translocation between chromosomes 11 and 22 that encodes a chimeric oncoprotein resulting from the fusion of EWSR1 to the FLI1 transcription factor in ~85% of tumors. Therapy for patients with EFT comprises surgery, intensive use of cytotoxic agents and radiation therapy. Dose intensification and dose compression has resulted in some improvement in outcome, but patents with advanced or metastatic disease at diagnosis still represent a challenge. Further, patients alive at 5 years from diagnosis still have a high probability of subsequent relapse. Further, long-term consequences of treatment included cardiac dysfunction, and secondary malignancies. Thus, more effective and less toxic therapies are required to treat patients with advanced disease.



Our studies, as part of the Pediatric Preclinical Testing Program (PPTP), identified the combination of the PARP inhibitor, talazoparib, with the DNA damaging agent temozolomide, as being highly synergistic in xenograft models of Ewing sarcoma, but not against other tumor types. In this study 5 of 10 Ewing tumor xenografts models showed dramatic regressions to the combination, while administered as single agents neither talazoparib or temozolomide were active. We have studied the talazoparib-temozolomide synergy in vitro, and results indicate that in models where there is no synergy as xenografts, the cell lines have either intrinsic resistance to talazoparib, temozolomide or both drugs. In mice, and in the clinical trial (NCT02116777), the talazoparib-temozolomide combination is toxic requiring a reduction in temozolomide dose to ~15% of its single maximum-tolerated dose.



We are exploring the use of nanoparticle-formulated talazoparib (npTLZ) developed by Nanomaterials Synthesis Laboratory at Northeastern University without tumor targeting or with antibody-mediated targeting to increase the tumor-drug delivery, reduce normal tissue toxicity (mainly thrombocytopenia), and potentially allow escalation of temozolomide dose. In the PPTP study, the MTD for temozolomide combined with free talazoparib (0.25 mg/kg PO BID daily x 5) was 12 mg/kg. Our recent data showed no toxicity of temozolomide at 66 mg/kg (PO daily x 5) in mice treated with npTLZ (0.5 mg/kg IV daily x 5), suggesting that npTLZ does not potentiate TMZ toxicity to normal mouse tissues. We anticipate that nanoparticle delivery of talazoparib combined with temozolomide will allow reduced toxicity while increasing the response rate for this combination in preclinical models of Ewing sarcoma.



Citation Format: Nabeela Baig, Rostislav Likhotvorik, Paige Baldwin, Srinivas Sridhar, Raushan Kurmasheva. Nanoformulation of talazoparib to increase efficacy when combined with temozolomide for the treatment of Ewing sarcoma xenografts [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 5054. doi:10.1158/1538-7445.AM2017-5054



©2017 American Association for Cancer Research.},

keywords = {Nanomedicine},

pubstate = {published},

tppubtype = {misc}

}

@misc{gharagouzloo2017quantitativeb,

title = {Quantitative magnetic resonance imaging of the vasculature},

author = {Codi Gharagouzloo and Srinivas Sridhar},

year  = {2017},

date = {2017-01-01},

abstract = {A quantitative, ultrashort time to echo, contrast-enhanced magnetic resonance imaging technique is provided. The technique can be used to accurately measure contrast agent concentration in the blood, to provide clear, high-definition angiograms, and to measure absolute quantities of cerebral blood volume on a voxel -by- voxel basis.},

keywords = {MRI},

pubstate = {published},

tppubtype = {misc}

}

@misc{kumar2017biopolymer,

title = {Biopolymer-Nanoparticle Composite Implant for Tumor Cell Tracking},

author = {Rajiv Kumar and Srinivas Sridhar and NGWA Wilfred and Robert Cormack and Gerassimos Makrigiorgos},

year  = {2017},

date = {2017-00-01},

abstract = {A method of detecting migration of tumor cells is provided by implanting in a region of tumor cells one or more implants having a matrix material of a biocompatible and biodegradable polymer, and a plurality of nanoparticles dispersed within the matrix material and functionalized to bind tumor cells. Nanoparticles bound to the tumor cells that have migrated out of the region can be detected by various imaging modalities. The implant can be in the shape of a brachytherapy spacer or radiotherapy fiducial maker or can be a coating on a brachytherapy spacer or fiducial marker. A method of treating cancer is provided by implanting one or more brachytherapy spacers or fiducial markers including the matrix material and an anti-cancer therapeutic agent dispersed within the matrix material.},

note = {US Patent App. 15/328,711},

keywords = {Nanomedicine},

pubstate = {published},

tppubtype = {misc}

}

@misc{sridhar2016electric,

title = {Electric field encephalography: electric field based brain signal detection and monitoring},

author = {Srinivas Sridhar and Yury Petrov and Ozgur Yavuzcetin},

year  = {2016},

date = {2016-03-01},

abstract = {Systems and methods for measuring brain activity of a subject are disclosed, comprising: positioning a plurality of electric field sensors at multiple positions on the exterior of a skull of the subject; measuring one to three components of a plurality of instantaneous electric field vectors generated by a plurality of electric field sources, the electric field vectors being measured by the plurality of electric field sensors; and determining brain activity of the subject based on the measurement of the plurality of instantaneous electric field vectors.},

note = {US Patent App. 14/420,613},

keywords = {Neurotechnology},

pubstate = {published},

tppubtype = {misc}

}

@misc{baldwin2016abstract,

title = {Abstract A03: PARP inhibitor nanotherapy for ovarian cancer.},

author = {Paige Baldwin and Anders Ohman and Jeremy Thong and Shifalika Tangutoori and Daniela Dinulescu and Srinivas Sridhar},

year  = {2016},

date = {2016-01-01},

publisher = {American Association for Cancer Research},

abstract = {Introduction: Poly-ADP-Ribose Polymerase (PARP) inhibitor therapy exploits a synthetic lethality strategy in ovarian cancers specifically endowed with inherent damage in DNA repair or transcription pathways. Talazoparib and Olaparib are potent PARP inhibitors that are currently indicated for oral inhibitor therapy in several clinical trials for a variety of cancers. Oral administration of these inhibitors typically results in poor bioavailability and tumor accumulation. Here we report the first novel nanoformulations NanoTalazoparib and NanoOlaparib, thus enabling a platform which provides a safe vehicle for parenteral administration specifically targeted to the tumor, thereby increasing the bioavailability while reducing systemic toxicity.



Methods: Three nanoparticle (~120nm size) formulations NanoOlaparib, NanoOlaparibPt and NanoTalazoparib, have been successfully formulated and tested in vitro on several cancer cell lines. KURAMOCHI, SKOV3, and OVSAHO were cultured in RPMI + 10% FBS. JHOS2 was cultured in RPMI + 10% FBS +1% Non-Essential Amino Acids. PA1, COV318, 403, 404, 4412, and 4306 were all cultured in DMEM + 10% FBS. 403 and 404 were derived from tumors of BRCA2-/-¬, PTEN-/-, and TP53mut mice. 4306 and 4412 4306 were developed from conditional LSL-K-rasG12D/+/PTENloxP/loxP mice.



Dose Response: Cell lines were exposed to either Olaparib or NanoOlaparib concentrations ranging from 0 to 100 µM. Each cell line was treated for a total of four doubling cycles to ensure that the percent viability for each cell line was comparable. Cell viability was ascertained with an MTS assay, to measure the metabolic activity of the cells.



Pt synergism: The synergism due to chemosensitization using cisplatin was studied for both therapies using isobolograms developed from a delayed viability assay.



Results: In vitro studies PA1 is highly sensitive to NanoOlaparib which may be attributed to genetic instability at 11/13 polymorphic loci, each containing (CA)¬n microsatellites. Microsatellite instability has the potential to cause mutations in critical genes that contain coding repeat sequences. This suggests that the genetic instability in PA1 leads to downstream mutations conferring sensitivity to PARP inhibitors.



The murine cell lines, 403, 404 are the next most sensitive group to this treatment due to there triply mutated genomic profile. The high sensitivity of 4412 and 4306 cell lines suggests that PTEN deletion confers similar sensitivity to PARP inhibitors as a BRCA2 deletion. Loss of PTEN has been shown to lead to spontaneous DSBs, chromosomal instability, and defects in homologous recombination. While it was expected that cell lines with BRCA1/2 mutations would be some of the most sensitive to these treatments, the results indicate that BRCA mutations and deletions are just as susceptible as PTEN deletions while high genetic instability shows the greatest sensitivity.



NanoTalazoparib is 10-100 times more potent than Olaparib. The cell line dependence is similar to Olaparib except for the overall lower magnitudes.



In vivo studies A pilot study was carried out in an endometrial OvCa murine model with KRaS-PTEN deletion to test the nanoformulations for biocompatibility and therapeutic efficacy. Bioluminescence images show tumor suppression of more than a nearly a factor of 3. All formulations were well tolerated. Studies in BRCA2-/-¬/ PTEN-/-/TP53mut GEMM also showed good therapeutic response to i.p. administration.



Conclusions: Robust nanoparticle formulations of NanoTalazoparib and NanoOlaparib have been successfully demonstrated for in vitro and in vivo administrations. These results show that NanoOlaparib and NanoTalazoparib amplify the therapeutic efficacy of PARP inhibition and imply a very promising role for the nanoformulation in ovarian and other cancers.



This work was supported by the DOD Ovarian Cancer Research Program under Army- W81XWH-14-1-0092.



Citation Format: Paige Baldwin, Anders Ohman, Jeremy Thong, Shifalika Tangutoori, Daniela Dinulescu, Srinivas Sridhar. PARP inhibitor nanotherapy for ovarian cancer. [abstract]. In: Proceedings of the AACR Special Conference on Advances in Ovarian Cancer Research: Exploiting Vulnerabilities; Oct 17-20, 2015; Orlando, FL. Philadelphia (PA): AACR; Clin Cancer Res 2016;22(2 Suppl):Abstract nr A03.



©2016 American Association for Cancer Research.},

keywords = {Nanomedicine},

pubstate = {published},

tppubtype = {misc}

}

@misc{sridhar2016sensor,

title = {Sensor system and process for measuring electric activity of the brain, including electric field encephalography},

author = {Srinivas Sridhar and Yury Petrov and Ozgur Yavuzcetin and Kaushik Chowdhury},

year  = {2016},

date = {2016-01-01},

abstract = {A sensor system and process for measuring electromagnetic activity of a brain are provided. The system and process employ a sensor assembly having a plurality of electrodes arranged in a closely spaced arrangement and a processor to determine a weighted average of the signals indicative of an electric field generated by electromagnetic activity of the brain. The system provides a medical body area network of a subject including one or more of the sensor assemblies and one or more additional sensors, which may be within a smartphone or other wearable device.},

note = {US Patent App. 14/896,511},

keywords = {Nanomedicine},

pubstate = {published},

tppubtype = {misc}

}