Tannic Acid Induces Endoplasmic Reticulum Stress-Mediated Apoptosis in Prostate Cancer

Endoplasmic reticulum (ER) stress is an intriguing target with significant clinical importance in chemotherapy. Interference with ER functions can lead to the accumulation of unfolded proteins, as detected by transmembrane sensors that instigate the unfolded protein response (UPR). Therefore, controlling induced UPR via ER stress with natural compounds could be a novel therapeutic strategy for the management of prostate cancer. Tannic acid (a naturally occurring polyphenol) was used to examine the ER stress mediated UPR pathway in prostate cancer cells. Tannic acid treatment inhibited the growth, clonogenic, invasive, and migratory potential of prostate cancer cells. Tannic acid demonstrated activation of ER stress response (Protein kinase R-like endoplasmic reticulum kinase (PERK) and inositol requiring enzyme 1 (IRE1)) and altered its regulatory proteins (ATF4, Bip, and PDI) expression. Tannic acid treatment affirmed upregulation of apoptosis-associated markers (Bak, Bim, cleaved caspase 3, and cleaved PARP), while downregulation of pro-survival proteins (Bcl-2 and Bcl-xL). Tannic acid exhibited elevated G₁ population, due to increase in p18INK4C and p21WAF1/CIP1 expression, while cyclin D1 expression was inhibited. Reduction of MMP2 and MMP9, and reinstated E-cadherin signifies the anti-metastatic potential of this compound. Altogether, these results demonstrate that tannic acid can promote apoptosis via the ER stress mediated UPR pathway, indicating a potential candidate for cancer treatment.

Protein kinase D1 regulates subcellular localisation and metastatic function of metastasis-associated protein 1

BACKGROUND

Cancer progression and metastasis is profoundly influenced by protein kinase D1 (PKD1) and metastasis-associated protein 1 (MTA1) in addition to other pathways. However, the nature of regulatory relationship between the PKD1 and MTA1, and its resulting impact on cancer metastasis remains unknown. Here we present evidence to establish that PKD1 is an upstream regulatory kinase of MTA1.

METHODS

Protein and mRNA expression of MTA1 in PKD1-overexpressing cells were determined using western blotting and reverse-transcription quantitative real-time PCR. Immunoprecipitation and proximity ligation assay (PLA) were used to determine the interaction between PKD1 and MTA1. PKD1-mediated nucleo-cytoplasmic export and polyubiquitin-dependent proteosomal degradation was determined using immunostaining. The correlation between PKD1 and MTA1 was determined using intra-tibial, subcutaneous xenograft, PTEN-knockout (PTEN-KO) and transgenic adenocarcinoma of mouse prostate (TRAMP) mouse models, as well as human cancer tissues.

RESULTS

We found that MTA1 is a PKD1-interacting substrate, and that PKD1 phosphorylates MTA1, supports its nucleus-to-cytoplasmic redistribution and utilises its N-terminal and kinase domains to effectively inhibit the levels of MTA1 via polyubiquitin-dependent proteosomal degradation. PKD1-mediated downregulation of MTA1 was accompanied by a significant suppression of prostate cancer progression and metastasis in physiologically relevant spontaneous tumour models. Accordingly, progression of human prostate tumours to increased invasiveness was also accompanied by decreased and increased levels of PKD1 and MTA1, respectively.

CONCLUSIONS

Overall, this study, for the first time, establishes that PKD1 is an upstream regulatory kinase of MTA1 status and its associated metastatic activity, and that the PKD1-MTA1 axis could be targeted for anti-cancer strategies.

Abstract 3216: Attenuation of pancreatic tumor growth by a small molecule tubulin inhibitor

Introduction: Pancreatic cancer (PanCa) is one of the most fatal cancers and is ranked as the fourth common cause of cancer-related deaths among both men and women in the US. The management of PanCa is exceptionally difficult due to the extremely poor response to available chemotherapeutic drugs. Microtubules are dynamic structures composed of α-β-tubulin heterodimers that are essential in cell division and are important targets for several clinical drugs (paclitaxel, docetaxel and vinblastine). However, clinical use of these tubulin-targeting drugs have toxicity and drug resistance issues in cancer patients. Thus, identification of more potent non-toxic inhibitors of β-tubulin is urgently required for cancer therapy purposes. In this study, we have identified a synthetic compound (ABI-231) which is a potent inhibitor of β-tubulin and evaluated its therapeutic efficacy against PanCa in vitro, and in vivo model systems.

Methods: ABI-231 ((2-(1H-indol-3-yl)-1H-imidazol-4-yl) (3, 4, 5-trimethoxyphenyl)) - methanone was synthesized and characterized in our department. Effect of ABI-231 on proliferation, migration and invasion of human PanCa cells (ASPC1, HPAFII, and PANC1) was performed by in vitro functional assays (MTS, wound healing, and Boyden chamber migrations). Effect of ABI-231 on the expression of β-tubulin isoforms was determined and compared with other clinical inhibitors of β-tubulin by Western blot, and qRT-PCR. Moreover, the effect of ABI-231 on the expression of β-tubulin III in PanCa cells was determined by confocal microscopy. Therapeutic efficacy of ABI-231 against PanCa was evaluated in an ectopic xenograft mouse model.

Results: ABI-231 treatment inhibited cell proliferation, invasion, migration and colony formation abilities of PanCa cells in a dose-dependent manner (1-100 nM) compared to vehicle treated group. Aberrant expression of β-tubulin III is involved in aggressiveness and drug resistance of various type of cancers including PanCa. ABI-231 effectively inhibited the protein levels and mRNA expression of total β-tubulin (TBB), TBB1, TBB2c, TBB3 and TBB4 in PanCa cells via destabilization. Our confocal microscopy results further showed inhibition of β-tubulin in ABI-231 treated PanCa cells. Upregulation of micro RNA 200c (miR-200c) has been shown to inhibit the expression of β-tubulin III in cancer cells. ABI-231 treatment of PanCa cells showed significant (p<0.01) induction of miR-200c as determined by qRT-PCR. ABI-231 administration (intra-tumoral; 50μg/mouse), three times/week significantly (p<0.01) inhibited the growth of ASPC1 cells derived xenograft tumors in athymic nude mice.

Conclusion: Taken together, our results suggest that ABI-231 is a potent β-tubulin inhibitor and chemotherapeutic agent which could be used for the treatment of pancreatic cancer.

Citation Format: Vivek K. Kashyap, Bilal B. Hafeez, Qinghui Wang, Saini Setua, Andrew Massey, Aditya Ganju, Murali M. Yallapu, Duane D. Miller, Wei Li, Meena Jaggi, Subhash C. Chauhan. Attenuation of pancreatic tumor growth by a small molecule tubulin inhibitor [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 3216. doi:10.1158/1538-7445.AM2017-3216

Abstract 3224: Cucurbitacin D inhibits prostate tumor growth via targeting glucose metabolism

Background: Emergence of hormone-refractory PrCa (HRPC) after the anti-androgen therapy, cancer metastasis and chemo-resistance are the major hurdle for the treatment of prostate cancer (PrCa) patients. Accumulative evidence suggests that altered glucose metabolism is one of the mechanisms for metastatic PrCa cell survival and chemo-resistance. Therefore, identification and generation of natural/or synthetic pharmacological agents that can limit altered glucose metabolism might be highly useful for the treatment of metastatic and chemo-resistant PrCa. Cucurbitacins have shown potent anti-cancer and glucagonostic activities along with severe liver toxicity. Thus, a focus on developing different analogues of cucurbitacin is being pursued by scientific community. Herein, we report that Cucurbitacin D, an analogue of cucurbitacin, suppresses the growth of metastatic PrCa cells in vitro and in vivo via targeting glucose metabolism and its associated molecular targets.

Methods: HRPC cells (PC3 and DU145) was used as a model system. Effect of Cucurbitacin D on PrCa cell proliferation and apoptosis was performed by MTS, xCELLigence and Annexin V assays. Effect of Cucurbitacin D on clonogenic potential of PrCa cells was examined by colony formation assay. In silico analysis was performed to study if Cucurbitacin D interacts with GLUT1 receptor. Effect of Cucurbitacin D on glucose metabolism of PrCa cells was performed by metabolic shift, glucose and lactate uptake assays. Effect of Cucurbitacin D treatment on key molecules of cell survival and glucose metabolism signaling pathways in PrCa cells was analyzed by Western blot and qRT-PCR analyses. Therapeutic efficacy of Cucurbitacin D against PrCa was evaluated in an ectopic PrCa xenograft mouse model.

Results: Cucurbitacin D (0.1 to 1 µM) treatment significantly (P<0.01) inhibited the growth and metastatic potential of PrCa cells in a dose-dependent manner. Cucurbitacin D effectively induced apoptosis in PrCa cells as shown by enhanced Annexin V staining and PARP protein cleavage and arrested cells in G2/M phase via modulation of cell cycle regulatory proteins (inhibition of cyclin D1/E and Mcl-1 and induction of p21 and p27). Cucurbitacin D treatment dose-dependently decreased the lactate production, glucose uptake in PrCa cells which was correlated by suppressed expression of GLUT1 and its proficient docking with GLUT1 (with binding energy for this complex is -8.5 kcal mol-1). It has been reported that miR-132 targets the GLUT1, interestingly, Cucurbitacin D replenished the expression of miR-132 in PrCa cells. These growth inhibitory effects of Cucurbitacin D were confirmed in PrCa xenograft mouse model while administered intra-tumorally (1 mg/kg body weight thrice/week).

Conclusion: Our results suggest that Cucurbitacin D is a novel modulator of glucose metabolism which could be a promising therapeutic modality alone or in combination of conventional chemotherapeutic agents for PrCa.

Citation Format: Mohammed Sikander, Bilal Bin Hafeez, Shabnam Malik, Aditya Ganju, Fathi T. Halaweish, Murali Mohan Yallapu, Subhash C. Chauhan, Meena Jaggi. Cucurbitacin D inhibits prostate tumor growth via targeting glucose metabolism [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 3224. doi:10.1158/1538-7445.AM2017-3224

Abstract 2101: Ormeloxifene suppresses the growth of prostate tumor via inhibition of β-catenin induced AR signaling

Background: Prostate cancer (PrCa) first manifests as an androgen-dependent disease and can be treated with androgen-deprivation therapy. Despite the initial success of androgen ablation therapy, resistance to anti-androgen therapy displays by progression to hormone refractory (androgen-independent) advanced stage PrCa which is primary cause of patient’s death. Main underlying cause for the onset of hormone refractory cancer is ligand independent activation of AR signaling in PrCa cells. It has been shown that β-catenin acts as a non-androgen activator of AR which enhances AR transactivation in PrCa cells. Thus, identification of agents with excellent pharmacokinetics and pharmacodynamics parameters that can inhibit ligand independent activation of AR signaling might be highly useful for the treatment of advanced stage PrCa. Herein, we identified a synthetic molecule, ormeloxifene (ORM), which efficiently represses β-catenin mediated ligand independent activation of AR signaling, thus, inhibits growth and metastatic features of PrCa cells.

Methods: Androgen-refractory but AR positive PrCa cell (C4-2) was used as an in vitro and in vivo model systems. Effect of ORM on AR and PSA protein levels was determined by Western blot analysis. Effect of ORM treatment was analyzed on AR and PSA luciferase activities by transiently transfecting the C4-2 cells by AR and PSA luciferase plasmids. Renilla construct was used as an internal control. C4-2 cells nuclear and cytoplasmic lysates were prepared using Active Motif kit. Immunoprecipitation analysis was performed to determine if ORM inhibits physical interaction of β-catenin with AR. Therapeutic efficacy of ORM was evaluated in cell lines and PrCa xenograft mouse models.

Results: ORM dose-dependently (10, 15 and 20 µM) inhibited the protein levels of AR and its downstream target protein PSA. ORM (10 and 20μM) treatment also inhibited AR transactivation as determined by decreased promoter activities of AR and its target gene PSA. ORM (10 and 20μM) treatment inhibited protein levels of nuclear β-catenin and physical interaction of β-catenin with AR in PrCa cells. ORM administration dose- dependently (intra-peritoneal; 100 and/or 500µg/mouse; thrice/week) significantly (P<0.01) inhibited growth of C4-2 cells derived xenograft tumors in athymic nude mice. ORM treatment significantly (P<0.01) inhibited the expressions of nuclear AR and β-catenin expressions in xenograft tumor tissues. These ORM treated mice did not show any apparent toxicity in our study.

Conclusion: Our study demonstrates that ORM is a potent inhibitor of β-catenin-mediated activation of AR signaling. Based on its safety profile, ORM might be an ideal candidate for repurposing to treat advanced stage PrCa alone or in combination with other therapies.

Citation Format: Aditya Ganju, Bilal Bin Hafeez, Mohammed Sikander, Vivek Kumar Kashyap, Murali Mohan Yallapu, Subhash C. Chauhan, Meena Jaggi. Ormeloxifene suppresses the growth of prostate tumor via inhibition of β-catenin induced AR signaling [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 2101. doi:10.1158/1538-7445.AM2017-2101

Abstract LB-070: Nano self-assemblies of paclitaxel for breast cancer treatment

Objectives: Breast cancer (BC) is second leading cause of cancer-related deaths in the United States. Paclitaxel (Ptx) is an FDA-approved and frequently used chemotherapeutic agent against various cancers, including BC. However its adverse side effects and chemoresistance against it, limits its use in the clinic. Minimizing the toxicity issues of Ptx through nanoparticle technology (such as Ptx bound to human serum albumin nanoformulation, i.e., Abraxane®) is feasible and has displayed encouraging outcomes. With this background, we aim to generate Ptx self-assemblies (PSAs) using various biocompatible polymers and surfactants, and to evaluate its efficacy against BC cells.

Methods: PSAs composed of Ptx dispersion or a core formation with a polymer at a weight ratio of 1:50. The extent of Ptx assembly/binding efficiency was determined using a fluorescence quenching study. FT-IR spectral study was employed to confirm the presence of Ptx in PSAs. The optimal polymers for forming PSAs were identified through measurement of particle size, zeta potential and TEM. Another check point of generating a better PSAs was evaluated by its extent of cellular internalization in BC cells and through hemolytic assay. Finally, the finalized PSAs were examined for in vitro activity in BC cells using proliferation, colony formation, and immunoblotting assays.

Results: We screened 22 biocompatible polymers for PSA formation, out of which 8 were finalized due to excellent Ptx binding profiles, appropriate particle size ranges (40-300 nm), zeta potentials (-14.0 to -4.0 mV), and superior internalization in BC cells. The optimized PSAs exhibited enhanced anti-cancer capability in MCF-7 and MDA-MB-231 BC cells in proliferation and colony formation assays, compared to free Ptx. This was further affirmed through tubulin stabilization studies. Further, PSA treatment in BC cells demonstrates a distinct induction of the expression of apoptosis-associated proteins and distinct downregulation of anti-apoptotic proteins.

Conclusion: Overall this study suggests a simple and feasible Ptxl self-assembly approach for achieving superior anti-cancer activity with Ptx.

Citation Format: Prashanth Kumar Bhusetty Nagesh, Pallabita Chowdhury, Sumeeth S. Chauhan, Elham Hatami, Sheema Khan, Bilal Hafeez, Subhash C. Chauhan, Meena Jaggi, Murali M. Yallapu. Nano self-assemblies of paclitaxel for breast cancer treatment [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 LB-070. doi:10.1158/1538-7445.AM2017-LB-070

Abstract 4399: MUC13 induced NFκB activation regulates metabolic reprograming by promoting its crosstalk with GLUT-1 receptor

Objective: Pancreatic cancer (PanCa) is the fourth most common cause of cancer-related deaths in the US. MUC13, mucin is aberrantly expressed in PanCa and promotes tumor growth and progression. Herein, we investigate the fundamental role of MUC13 in glucose metabolism and delineate the molecular interplay of various molecules governing MUC13 mediated metabolic reprograming that may be involved in pancreatic tumor maintenance.

Methods: MUC13 expressing (Panc-1) and knockdown PanCa cells (HPAF-II) were generated for the study. Immunoblotting and qRT-PCR assays were performed to assess the expression of protein and mRNA levels, respectively, of key signaling molecules involved in glucose metabolism of PanCa. MUC13 and Glut-1 interaction was studied using reciprocal co-immunoprecipitation, immunofluorescence, proximity ligation, Western blotting, co-capping assays in cell lines. Lactate and glucose assays were performed using commercially available kits. In vitro functional assays using wound healing scratch assay (migration), and cell Matrigel assay (invasion) were performed in presence or absence of Lactate and 2DG supplementation.

Results: Our results demonstrate that MUC13 expression leads to the TNF-induced activation/nuclear translocation of NFκB p-65 and phosphorylation of IkB which in turn upregulates additional key proteins, Glut-1, c-Myc, Bcl-2. This recruits the Glut-1 to MUC13, wherein MUC13 functionally interacts with Glut-1 and stabilizes it, initiating downstream events that result in altered glucose metabolism. MUC13 expression in PanCa cells increases glucose uptake, lactate secretion which is reduced upon MUC13 knockdown. Additionally, MUC13 mediates increased cell migratory and invasion potential which can be potentiated by supplementing the culture media with lactate, an end product of aerobic glycolysis. However, treatment of cells with NFκB inhibitor, Sulfasalazine, inhibits the MUC13 and Glut-1 interaction and abrogates all these events associated with glucose metabolism.

Conclusion: These outcomes from our study suggest that MUC13 plays an important role in metabolic reprogramming of PanCa cells metabolism to induce cancer growth and enhanced cellular invasion and motility. NFκB acts downstream of MUC13 to coordinate the events leading to its interation with Glut-1 and metabolic reprogramming. Overall, these findings illustrate mechanisms by which MUC13 coordinates the shift in metabolism to sustain cancer growth and invasion in PanCa.

Citation Format: Sonam Kumari, Sheema Khan, Subash C. Gupta, Vivek K. Kashyap, Murali M. Yallapu, Subhash C. Chauhan, Meena Jaggi. MUC13 induced NFκB activation regulates metabolic reprograming by promoting its crosstalk with GLUT-1 receptor [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 4399. doi:10.1158/1538-7445.AM2017-4399

Abstract 3427: Targeting MUC13 to overcome the survival mechanisms for improved response to chemotherapy

Background: Pancreatic cancer (PanCa) is a third leading cause of cancer-related deaths in the US due to late diagnosis and development of chemoresistance. Therefore, understanding molecular mechanisms that confer survival benefit to PanCa cells may offer new therapeutic strategies for PanCa treatment.Mucin, MUC13 aberrantly expressed in PanCa,promoting cancer growth and progression and these effects are abrogated by microRNA-145 (miR-145) restoration. Unlike other cancer types, PanCa is highly resistant to Tumor necrosis factor (TNF)-related apoptosis inducing ligand (TRAIL) that emerges as one of the most promising experimental cancer therapeutic drugs.Herein, we demonstrate the integration of novel approach to overcome chemoresistance and offer TRAIL-based therapeutic strategies.

Methods: MUC13 expressing and null stable PanCa cells were generated to investigate the role of MUC13 in cell survival.miR-145 mimics were used to investigate the effect of MUC13 silencing in promoting survival and inhibiting apoptosis in presence of TRAIL using Western blotting, cell proliferation (MTT), Acridine orange staining and flow cytometry apoptosis assays(cell cycle, Annexin V/7AAD staining). Various distinct domain specific constructs of MUC13 were constructed such as the mucin (α), Beta (β) sea urchin sperm protein enterokinase arginine (SEA) domain and cytoplasmic (CD) domains and transfected into MUC13 null Panc-1 cells to identify the role of different domains in eliciting survival benefit to PanCa cells.

Results: Results demonstrate that MUC13 expression blocks activation of caspase-8 and death receptor-mediated apoptosis in PanCa cells in response toTRAIL treatment as observed through Western blotting and flow cytometer. Inhibition of MUC13 using shRNA knockdown or miR-145 restoration resulted in the TRAIL-mediated increase in apoptotic cell death as evidenced by AnnexinV/ 7AAD and sub G0 population, as well as rendered PanCa cells sensitive to treatment with drugs, such as paclitaxel. Additionally, cells treated with TRAIL in combination with paclitaxel or Abraxane showed enhanced apoptosis on inhibition of MUC13 expression using miR-145 restoration. Further investigation showed that cytoplasmic domain of MUC13 (MUC13-CD) is indispensable for blockingcaspase-8 activation and PARP cleavage, indicating that the MUC13-CD blocks TRAIL-induced signaling upstream to Bid by inhibiting caspase-8 activation.

Conclusion: These observations suggest that MUC13 contributes to the survival advantage in PanCa cells in response to treatment with drugs or death inducing ligands such as, Tumor necrosis factor related apoptosis-inducing ligand (TRAIL) which can be strategically overcome by miR-145 replenishment. These findings indicate that MUC13 silencing sensitizes PanCa cells towards TRAIL therapy and counteracts chemoresistance mechanisms in PanCa that may lead to novel combination therapies for PanCa treatment.

Citation Format: Saini Setua, Sheema Khan, Murali M. Yallapu, Stephen W. Behrman, Nadeem Zafar, Meena Jaggi, Subhash C. Chauhan. Targeting MUC13 to overcome the survival mechanisms for improved response to chemotherapy [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 3427. doi:10.1158/1538-7445.AM2017-3427

Ormeloxifene Suppresses Prostate Tumor Growth and Metastatic Phenotypes via Inhibition of Oncogenic β-catenin Signaling and EMT Progression

Ormeloxifene is a clinically approved selective estrogen receptor modulator, which has also shown excellent anticancer activity, thus it can be an ideal repurposing pharmacophore. Herein, we report therapeutic effects of ormeloxifene on prostate cancer and elucidate a novel molecular mechanism of its anticancer activity. Ormeloxifene treatment inhibited epithelial-to-mesenchymal transition (EMT) process as evident by repression of N-cadherin, Slug, Snail, vimentin, MMPs (MMP2 and MMP3), β-catenin/TCF-4 transcriptional activity, and induced the expression of pGSK3β. In molecular docking analysis, ormeloxifene showed proficient docking with β-catenin and GSK3β. In addition, ormeloxifene induced apoptosis, inhibited growth and metastatic potential of prostate cancer cells and arrested cell cycle in G₀-G₁ phase via modulation of cell-cycle regulatory proteins (inhibition of Mcl-1, cyclin D1, and CDK4 and induction of p21 and p27). In functional assays, ormeloxifene remarkably reduced tumorigenic, migratory, and invasive potential of prostate cancer cells. In addition, ormeloxifene treatment significantly (P < 0.01) regressed the prostate tumor growth in the xenograft mouse model while administered through intraperitoneal route (250 μg/mouse, three times a week). These molecular effects of ormeloxifene were also observed in excised tumor tissues as shown by immunohistochemistry analysis. Our results, for the first time, demonstrate repurposing potential of ormeloxifene as an anticancer drug for the treatment of advanced stage metastatic prostate cancer through a novel molecular mechanism involving β-catenin and EMT pathway. Mol Cancer Ther; 16(10); 2267-80. ©2017 AACR.

Disparity in rates of HPV infection and cervical cancer in underserved US populations

There is a higher rate of HPV infection and cervical cancer incidence and mortality in underserved US population who reside in Appalachian mountain region compared to Northern Plains. Social and behavioral factors such as smoking and alcohol consumption are for such a high incidence. However, by and large, the reasons for these discrepancies lie in the reluctance of the underserved population to adopt preventive measures such as prophylactic Human papilloma virus (HPV) vaccines and Pap smear screening that have significantly reduced the incidence and mortality rate of cervical cancer in Caucasian women. Thus, it is clear that drastic change in social behavior and implementation of preventive measures is required to effectively reduce the incidence and mortality from cervical cancer in this underserved population.

miR-145: Revival of a Dragon in Pancreatic Cancer

Emergence of the role of MicroRNA-145 (miR-145) as a tumor suppressor in pancreatic cancer, offers its potential for novel therapeutic interventions. Our recently published studies demonstrate clinical significance of miR-145 in pancreatic cancer and suggest that the dysregulation of miR-145 in human pancreatic tumors draws in parallel with the aberrant expression of an oncogenic mucin, MUC13. These studies also present a novel therapeutic strategy of restoring the downregulated levels of miR-145 in pancreatic cancer via nanoparticle mediated efficient delivery system.

Restitution of Tumor Suppressor MicroRNA-145 Using Magnetic Nanoformulation for Pancreatic Cancer Therapy

INTRODUCTION

The functional significance of lost microRNAs has been reported in several human malignancies, including pancreatic cancer (PC). Our prior work has identified microRNA-145 (miR-145) as a tumor suppressor microRNA (miRNA) in pancreatic cancer. The restoration of miR-145 downregulates a number of oncogenes including mucin MUC13, a transmembrane glycoprotein that is aberrantly expressed in pancreatic cancer, thus efficiently inhibiting tumor growth in mice. However, lack of an effective tumor-specific delivery system remains an unmet clinical challenge for successful translation of microRNAs.

METHODS

We developed a miRNA-145-based magnetic nanoparticle formulation (miR-145-MNPF) and assessed its anti-cancer efficacy. Physico-chemical characterization (dynamic light scattering (DLS), transmission electron microscopy (TEM) and miR-binding efficiency), cellular internalization (Prussian blue and confocal microscopy), miR-145 restitution potential (quantitative reverse-transcription PCR (qRT-PCR), and anti-cancer efficacy (proliferation, colony formation, cell migration, cell invasion assays) of this formulation were performed using clinically relevant pancreatic cancer cell lines (HPAF-II, AsPC-1).

RESULTS

miR-145-MNPF exhibited optimal particle size and zeta potential which effectively internalized and restituted miR-145 in pancreatic cancer cells. miR-145 re-expression resulted in downregulation of MUC13, HER2, pAKT, and inhibition of cell proliferation, clonogenicity, migration, and invasion of pancreatic cancer cells.

CONCLUSIONS

miR-145-MNPF is an efficient system for miR-145 delivery and restitution in pancreas cancer that may offer a potential therapeutic treatment for PC either alone or in conjunction with conventional treatment.

miRNA nanotherapeutics for cancer

MicroRNAs (miRNAs) are noncoding RNA molecules that regulate gene expression through diverse mechanisms. Increasing evidence suggests that miRNA-based therapies, either restoring or repressing miRNA expression and activity, hold great promise. However, the efficient delivery of miRNAs to target tissues is a major challenge in the transition of miRNA therapy to the clinic. Cationic polymers or viral vectors are efficient delivery agents but their systemic toxicity and immunogenicity limit their clinical usage. Efficient targeting and sustained release of miRNAs/anti-miRNAs using nanoparticles (NPs) conjugated with antibodies and/or peptides could reduce the required therapeutic dosage while minimizing systemic and cellular toxicity. Given their importance in clinical oncology, here we focus on the development of miRNA nanoformulations to achieve enhanced cellular uptake, bioavailability, and accumulation at the tumor site.

Probing mucin interaction behavior of magnetic nanoparticles

In this study, we developed iron oxide based magnetic nanoparticles (MNPs) by precipitation of iron salts in the presence of ammonia and created four different formulations: without functionality (plain MNPs, no coating), with β-cyclodextrin (MNPs+β-CD) or pluronic 127 polymer (MNPs+F-127), and both β-cyclodextrin and pluronic 127 polymer (MNPs+β-CD-F-127) functionality for its efficient use in mucosal delivery. We studied the interaction and/or binding behavior of these MNPs formulations with porcine stomach mucin using steady-state fluorescence spectroscopy, and then quantified the bound mucin from absorption studies. Toxicity of these MNPs against cervical cancer cells and red blood cells was evaluated. Ex-vivo studies were performed using freshly collected gastrointestinal, ovarian, pancreas and colon organ tissues of pig to evaluate binding and uptake phenomenon of MNPs. Transport studies of these MNPs in mucin was evaluated using Boyden's chamber assay. All these studies together suggest that the MNPs+β-CD-F-127 formulation was strongly interacted with mucin and interestingly transported through mucin compared to other MNPs formulations. Hence, MNPs+β-CD-F-127 formulation could be a good candidate for the mucoadhesive biopharmaceuticals and drug delivery system.

Abstract 3862: Ormeloxifene, a novel pharmacological activator of PKD1 enhances docetaxel sensitivity in prostate cancer

Background: Prostate cancer (PrCa) is the second leading cause of cancer-related deaths in American Men. Docetaxel (DTX) is a standard first-line treatment for metastatic castration-resistant PrCa after the failure of hormone therapy. However, most PrCa patients who receive DTX experience only transient benefits and rapidly develop incurable drug resistance. Protein Kinase D1 (PKD1), one of the serine threonine kinases from PKD family is highly expressed in normal prostate tissues and is suppressed during PrCa progression. Accumulative evidence suggest a tumor suppressive role of PKD1 in PrCa, while other isoforms of PKD (PKD2 and PKD3) act as oncogene. In this study, we identified pharmacological agent Ormeloxifene (ORM) which selectively activates PKD1 and inhibits metastasis associated protein 1 (MTA1), thus induces sensitivity to DTX treatment in PrCa cells.

Materials and Methods: We have used androgen-independent human PrCa cells (C4-2) which show low PKD1 expression compared to other PrCa cell lines. Cells were treated with 10 and 15 μM doses of ORM for 24 hrs and various functional assays (cell proliferation, colony formation, motility and invasion) were performed. In a parallel experiment, cells were treated with ORM (10 and 15 μM) for 24 hrs protein and RNA samples isolation. Protein lysates were used to investigate the effect of ORM on PKD1, PKD2, PKD3 and MTA1 protein levels. qRT-PCR was performed to investigate the effect of ORM on PKD1, PKD2 and PKD3 expression at mRNA levels. To investigate if ORM treatment sensitizes the effects of DTX, cells were treated with ORM and DTX alone or in combination. In-silico docking studies were performed to determine the putative molecular interaction of ORM with MTA1.

Results: ORM treatment inhibits proliferation and clonogenic potential of C4-2 cells. We observed that ORM significantly induces PKD1 expression at protein and mRNA level in C4-2 cells. To determine whether this PKD1 inducing effects of ORM in PrCa cells is specific, we examined the effects of ORM on PKD2 and PKD3 at mRNA and protein levels. Interestingly, we observed that ORM treatment inhibits expression of oncogenic PKD3 isoform, however, no effect PKD2 was observed. MTA1 is involved in DTX resistance and ORM treatment effectively inhibited the expression of MTA1. However, there was no effect of DTX treatment on the expression of MTA1. We also observed that ORM treatment significantly potentiates the effect of DTX on cell viability and colony formation of C4-2 cells. In-silico docking studies between ORM and MTA1 showed four potential binding sites with best score at serine 270.

Conclusion: Overall, our study defines ORM as a novel PKD1 activator/modulator which also inhibits a key metastasis associated protein, MTA1 and sensitizes the PrCa cells to DTX. Based on these results, it appears that ORM may be a novel therapeutic modality for advanced stage metastatic PrCa alone or in combination with DTX.

Citation Format: Aditya Ganju, Bilal Bin Hafeez, Fathi Halaweish, Wei Li, Man Mohan Singh, Murali Mohan Yallapu, Subhash Chauhan, Meena Jaggi. Ormeloxifene, a novel pharmacological activator of PKD1 enhances docetaxel sensitivity in prostate cancer. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 3862.

Abstract 3081: Novel cucurbitacin analogue Cuc D exhibits potent anti-cancer activity in cervical cancer

Background: Cervical cancer is one of the leading cause of mortality among women in US. Naturally occurring dietary compounds have gained increasing attention for their anticancer effects. Cucurbitacins, tetracyclic triterpenoid compound, belong to a family of Cucurbitaceae have shown promising anti-cancer activity. Herein, we investigated the potential anti-cancer effects of a novel analogue of cucurbitacin D (Cuc D) against cervical cancer in in vitro and in a xenograft mouse model.

Methods: In our study, we used human cervical cancer cells (CaSki and SiHa). Cells were treated with Cuc D (0.05 to 1μM) for 48 and 72 hrs. MTS and colony formation assays were performed to investigate the effects of Cuc D on cell viability and proliferation. Western Blot analysis was performed to investigate the effects of Cuc D on cell proliferation and apoptotic markers. To determine the therapeutic effects of Cuc D, we used female athymic nude mice and injected CaSki cells (4 × 106) into the cervix to develop orthotopic xenograft tumors. Cuc D (1 mg/kg body weight) was administered through intratumoral injection four weeks post-tumor cell injection. Tumor volume in these mice were recorded bi-weekly.

Results: Cuc D inhibited cell viability of cervical cancer cells in a dose-dependent manner. IC50 of Cuc D was observed 400 nM and 250 nM in Caski and SiHa cells, respectively. Cuc D treatment effectively inhibited growth of cervical cancer cells which was determined by decreased cell proliferation and colony formation assays. Cuc D treatment induced apoptosis in cervical cancer cells as measured by enhanced Annexin V staining. Western blot result also illustrated cleavage in PARP protein in Cuc D treated cells which further confirms apoptosis induction. Cuc D treatment also inhibited PI3K and c-Myc protein levels and phosphorylation of STAT3 and Rb proteins. In addition, Cuc D treatment induced the cell cycle inhibitory proteins (p21 and p27) and PTEN and the expression of a tumor suppressor microRNA, miR-145, as determined by qRT-PCR. In an orthotopic tumor xenograft mouse model, Cuc D treatment effectively inhibited tumor growth as compared to vehicle control treated mice.

Conclusion: Taken together, our results demonstrate potent anti-cancer efficacy of Cuc D in cervical cancer cells via modulation of key onco/tumor suppressor proteins. Thus, Cuc D could be a useful therapeutic agent for cervical cancer treatment.

Citation Format: Mohammed Sikander, Bilal Bin Hafeez, Fathi T. Halaweish, Murali M. Yallapu, Meena Jaggi, Subhash C. Chauhan. Novel cucurbitacin analogue Cuc D exhibits potent anti-cancer activity in cervical cancer. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 3081.

Abstract 4592: MUC13 interaction with receptor tyrosine kinase HER2 drives pancreatic ductal adenocarcinoma progression

Background: Pancreatic Ductal Adenocarcinoma (PDAC) is the fourth leading cause of cancer related death in the United States and has a very poor survival rate due to late diagnosis. MUC13 is a recently identified high molecular weight glycoprotein that is upregulated in PDAC and its progression is allowed via alterations of multiple signaling pathways. MUC13 is aberrantly expressed in PDAC and generally correlates with increased expression of HER2, however, the underlying mechanism remains poorly understood. MUC13 consists of three EGF-like domains that may serve as a ligand for EGF receptors, such as HER2, and modulate EGFR signaling pathways. We sought to better characterize the interaction of MUC13 with HER2 in PDAC.

Methods: MUC13 and HER2 interaction was studied using reciprocal co-immunoprecipitation, immunofluorescence, proximity ligation, Western blotting, co-capping assays in human PDAC cell lines and immunohistofluorescence techniques in human tissues. Tissue microarrays prepared from formalin-fixed, paraffin-embedded specimens of PDAC were assessed for expression of MUC13 and HER2 using our own laboratory generated anti-MUC13 mouse monoclonal antibody (MAb) through confocal immunofluorescence. The association of MUC13 and HER2 co-localization with nuclear chromatin organization was analyzed to study the stage or degree of aggressiveness of the pancreatic cancer using Dapi stained confocal images of tissues.

Results: MUC13 co-localizes and interacts with HER2 in PDAC cell lines. The results from this study demonstrate that MUC13 functionally interacts and activates HER2 at Tyrp1248 in PDAC cells, leading to stimulation of HER2 signaling cascade including, ERK1/2, FAK, AKT and PAK1 as well as regulation of the growth, cytoskeleton remodeling, motility and invasion of PDAC cells - all collectively contributing to PDAC progression. The interaction between MUC13-HER2 binding resulting in their tumorigenic characteristics likely occurs at the 1st and 2nd but not the 3rd domains of MUC13 as the EGF 1 and 2 deletion mutant constructs of MUC13 failed to promote proliferation and invasion of cells. These phenotypic effects of MUC13-HER2 co-localization could be effectively compromised by depleting MUC13. MUC13-HER2 co-localization also held true in PDAC human tissues with a strong functional correlation that contributed to an increased degree of disorder and cancer aggressiveness.

Conclusions: 1) MUC13 can be detected in formalin-fixed paraffin-embedded tissues using our anti-MUC13 MAb. 2) MUC13 co-localizes and activates HER2 and its downstream signaling cascade promoting PDAC progression in both cell lines and human tissue. 3) This process is reversed by depletion of MUC13. 4) This MUC13-HER2 interaction may potentially be manipulated for targeted therapeutics in patients harboring PDAC.

Citation Format: Sheema Khan, Mara C. Ebeling, Mohammad Sikander, Murali M. Yallapu, Tomoko Ise, Satoshi Nagata, Stephen W. Behrman, Nadeem Zafar, Jim Y. Wan, Hemendra M. Ghimire, Peeyush Sahay, Prabhakar Pradhan, Meena Jaggi, Subhash C. Chauhan. MUC13 interaction with receptor tyrosine kinase HER2 drives pancreatic ductal adenocarcinoma progression. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4592.

Abstract 51: Role of MUC13 as non-hypoxic stimuli inducing HIF-1α in pancreatic cancer under normoxia

Objective: Pancreatic cancer is the fourth most common cause of deaths occurring due to cancer, with an overall survival rate of just 5%. MUC13, a transmembrane mucin, is aberrantly expressed in pancreatic cancer, while an altered glucose metabolism is known to facilitate cancer cell survival and proliferation. Hypoxia-inducible factor 1 α (HIF-1 α) plays an important role in reprogramming of cancer cell metabolism by activating the transcription of genes which encode glucose transporters and enzymes involved in glycolysis. Recent reports suggest that several non-hypoxic stimuli such as lipopolysaccharides, thrombin, and angiotensin II can also increase HIF-1α under normoxia. Herein, we investigated the effects of MUC13 expression on glucose metabolism and elucidated underlying signaling mechanisms that might be involved in this process.

Methods: MUC13 null pancreatic cancer Panc-1 cells were used for the study. Glucose and Lactate assay were performed in Panc-1 cells stably expressing MUC13 (Panc-1-M13) and vector (Panc-1-V). Cell culture media after 48 hrs was collected to measure the amount of unused glucose and L-lactate concentration using glucose and Lactate assay kits. Immunoblot and semi-quantitative PCR analyses were performed to check the expression of protein and mRNA levels, respectively. Cell proliferation and colony forming assays were performed to determine the effect of MUC13 on cellular growth and cell survival.

Results: Our results demonstrate that MUC13 acts as a modulator of the glucose metabolism in pancreatic cancer cells by regulating the expression and activity of hypoxia-inducible factor-1α (HIF-1α) and its downstream targets. We observed increased amount of L-lactate production and glucose consumption in Panc-1-M13 cells as compared to Panc-1-V cells. This facilitates metabolic alterations and help tumor cells survive and proliferate under these conditions as indicated by increased cellular growth pattern in Panc-1-M13 cells. Our results demonstrate increased expression of the downstream targets of HIF-1α, such as cell regulatory (c-Myc), and cell survival (Bcl-2) proteins, while decreased the expression of tumor suppressor/cell cycle inhibitor (p-27) proteins in Panc-1M13 cells. Additionally, an increase in the expression of a critical downstream target of HIF-1α, Glut-1 was observed in Panc-1-M13 cells.

Conclusion: Our studies indicate that MUC13 acts as a key regulator of the metabolic process and facilitates metabolic alterations in the non-hypoxic environment that help tumor cells survive and proliferate under these conditions. However, further studies are required to elucidate detailed molecular mechanisms that are involved in MUC13 mediated metabolic remodeling in pancreatic cancer cells.

Citation Format: Sonam Kumari, Sheema Khan, Subhash Chauhan, Meena Jaggi. Role of MUC13 as non-hypoxic stimuli inducing HIF-1α in pancreatic cancer under normoxia. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 51.

Abstract 1071: Mir-145 based magnetic nanoformulation for pancreatic cancer therapy

Background: Pancreatic cancer (PanCa) is the fourth leading cause of cancer related deaths in the USA, with a 5-year survival rate of less than 5%. MicroRNAs have been identified as attractive targets for therapeutic intervention. The functional significance of lost microRNAs have been reported in several human malignancies, including PanCa. Therefore, restoring lost miRNA function can provide a potential therapeutic benefit. Prior work has identified microRNA-145 (miR-145) as a tumor suppressor miRNA in pancreatic cancer. The restoration of miR-145 downregulates a number of oncogenes including mucin MUC13, a glycoprotein that is aberrantly expressed in PanCa, and efficiently inhibits tumor growth in mice. The main challenge for successful translation of microRNAs into clinical practice remains an effective in vivo delivery system. The focus of this study was to develop and assess the efficacy of a miR-145 based nanoparticle formulation for PanCa treatment.

Methods: Magnetic nanoparticle (MNP) based nanoformulation of miR-145 (miR-145-MNPF) was developed for the intracellular delivery and sustained release of miR-145. The positively charged polyethyleneimine molecules were used to increase the loading efficiency of miR-145. MUC13 expressing pancreatic ductal adenocarcinoma cell lines (HPAF-II and AsPC-1) were used for the study. Following transfection of miR-145-MNPF, Western blotting and immunofluorescence techniques were used to investigate the effects of miR-145 restoration on number of proteins including MUC13. Additionally, functional studies of the effects of miR-145 restitution using miR-145-MNPF included cell proliferation, colony formation, cell migration, and cell invasion assays.

Results: miR-145 expression was progressively suppressed over the course of development from PanIN I-III to late stage poorly differentiated PDAC. Treatment of cells with miR-145-MNPF led to efficient intracellular delivery of miR-145 mimics as observed through prussian blue staining. This led to the simultaneous upregulation of miR-145 levels in cells as confirmed by qRT-PCR. miR-145 restitution resulted in significant downregulation of target oncogenes including MUC13, HER2, P-AKT and p53 as observed through Western blotting and immunofluorescence techniques. miR-145-MNPF inhibited cell proliferation, clonogenicity, migration, and invasion of PanCa cells. MNPF mediated restitution of miR-145 effectively sensitizes PanCa cells for paclitaxel and TRAIL therapy.

Conclusions: 1) MNP based delivery systems can be efficiently used for microRNA replacement therapy in order to restore lost microRNAs in cancer. 2) miR-145-MNPF efficiently restores miR-145 in pancreatic cancer cells and inhibits growth and invasion of PanCa. 3) miR-145 restitution using miR-145-MNPF may offer a potential therapeutic strategy for pancreatic cancer treatment alone or in combination with other therapies.

Citation Format: Saini Setua, Sheema Khan, Murali Mohan Yallapu, Mohammed Sikander, Stephen W. Behrman, Meena Jaggi, Subhash C. Chauhan. Mir-145 based magnetic nanoformulation for pancreatic cancer therapy. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 1071.

Abstract 2197: Mucopenetrating magnetic nanoparticles for drug delivery

Objectives: Cervical cancer (CxCa) is one of the most common cancers among women worldwide. Current standards of care for cervical cancer includes surgery, radiation, and chemotherapy. However, systemic chemotherapy fails to elicit therapeutic responses and causes severe systemic toxicity due to limited concentration of drug reaching to mucosal tissue and blocking of drug penetration through the epithelial mucus surface of the cervix. Mucus in general functions as a protective barrier to for viruses and bacteria, but in cervical cancer condition it poses a serious issue for drug delivery modalities. Therefore, our study was aimed to develop a nanoparticle formulation that can effectively bind and penetrate the mucin barrier of the tissues for effective drug delivery applications.

Methods: Iron oxide based magnetic nanoparticles (MNPs) were prepared by precipitation of iron salts in the presence of ammonia with subsequent coating with β-cyclodextrin (β-CD) and/or pluronic polymer (F127). Four different compositions of MNP formulations, plain MNPs, MNPs with β-CD (MNP+βCD), MNPs with F127 (MNP+F127), and MNPs with β-CD and F127 (MNP+βCD-F127) were formulated for this study. Particle size, distribution, and zeta potential of MNPs and MNP-mucin were measured using the Zetasizer based on dynamic light scattering technique, mucin binding ability of MNPs was measured using SpectraMax M2e plate reader, migration of MNPs in the presence of mucin was measured using Boyden chamber assay, and tissue uptake/internalization was measured by Prussian blue staining and fluorescence techniques.

Results: Among four different formulations (MNPs, MNPs+βCD, MNP+F127, and MNP+βCD-F127), MNP+βCD-F127 formulation is unique due to its triple layered composition. This MNP formulation was prevented from aggregation in particle size anaysis in solution, indicating its dispersive nature along with penetration compatibility in mucus network. Instantaneous and long term mucin binding experiments suggest that MNP+βCD-F127 nanoparticles strongly interacted with mucin layer. Further, our mucin incubated nanoparticles effectively pass through membrane in Boyden chamber migration assay. Moreover, tissue uptake/internalization studies demonstrated an efficient penetration of MNP+βCD-F127 nanoparticles through mucin layer.

Conclusion: All above biophysical properties of MNP+βCD-F127 nanoparticles demonstrate that our unique formulation can bind and penetrate the mucus barrier. This study suggest that this unique nanoparticle formulation could a good candidate for local drug delivery applications for overcoing problems associated with cervical cancer treatment.

Citation Format: Viajayakumar N. Boya, Renn Lovett, Saini Satua, Vaibhav Gandhi, Prashanth K.B. Nagesh, Meena Jaggi, Subhash C. Chauhan, Murali M. Yallapu. Mucopenetrating magnetic nanoparticles for drug delivery. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 2197.

Abstract 1745: Comorbidity factors associated with human papillomavirus infectivity: Implications in cervical cancer health disparity

Objective: High-risk strains of human papillomavirus (HPV), HPV E6/E7 cause cervical cancer (CxCa). Certain underserved populations in the United States, such as American Indian and African American women disproportionately suffer from CxCa compared to their Caucasian counter parts. However, precise etiology and comorbidity factors associated with CxCa health disparity are not fully uncovered. Understanding of these factors at molecular level will entail developing novel strategies to reduce this health disparity. In this study, we have investigated the molecular interplay existing between various comorbidity factors, namely, smoking, alcohol and HIV co-infection on the HPV infectivity which are primarily known for the progression of CxCa.

Method: In order to define a molecular association of smoking, alcohol and HIV co-infection with CxCa, Caski and SiHa (HPV infected cervical cancer cells) cells were treated with a smoking carcinogens Benzo[a]Pyrene (BaP) or alcohol (EthOH) or both for different time periods. Effects of these treatment was analyzed on cell proliferation, clonogenicity, cell migration, cell cycle and the expression of HPV E6/E7 was determined by qRT-PCR, immunoblotting and confocal microscopy. The effect of HIV co-infection on the expression of HPV E6/E7 was also investigated by incubating CxCa cells with conditioned medium derived from HIV infected U937 monocytic cells (U1). Additionally, we examined effect of these cofactors on the expression enzymes associated with cellular oxidative stress using immunoblotting and confocal microscopy analyses.

Result: Our results show that the exposure of BaP or EthOH or their combination enhances the expression of HPV E6/E7 oncogenes. Additionally, cells treated with BaP and EthOH alone or in combination show higher oncogenic phenotypes as evident by increased cell proliferation, clonogenicity and cell migration andinvasion. These cofactors in presence of HIV co-infection also augment the expression of HPVE6/E7 oncogenes. Exposure of these cofactors alter cellular oxidative stress via modulation of the expression of PRDX6 enzyme. Interestingly, curcumin and its nanoparticle formulation (Nano-Cur) effectively inhibits BaP/EthOH induced expression of E6/E7 oncogenes, growth, migration of CxCa cells and induces apoptosis.

Conclusions: The study suggests a molecular link between smoking, alcohol and HIV infection with HPV infectivity and their potential association with CxCa health disparity. These events however, can be effectively attenuated by curcumin/nano-curcumin treatment, implying its role in CxCa prevention/treatment. This provides hope for developing a feasible approach to effectively reduce CxCa health disparity among underserved populations.

Citation Format: Vivek K. Kashyap, Sheema Khan, Mohammad Sikander, Diane M. Maher, Santosh Kumar, Namita Sinha, Murali M. Yallapu, Nadeem Zafar, Meena Jaggi, Subhash C. Chauhan. Comorbidity factors associated with human papillomavirus infectivity: Implications in cervical cancer health disparity. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 1745.

Abstract 2208: Novel nanoparticle formulation of Plumbagin for pancreatic cancer treatment

Pancreatic cancer (PanCa) is one of the most fatal of all cancers and is ranked as the fourth most common cause of cancer related deaths among both men and women in the US. The management of PanCa, is exceptionally difficult due to the extremely poor response to available therapeutic modalities. Highly desmoplastic microenvironment in pancreatic tumor causes suboptimal drug delivery and increases chemo-resistance. Plumbagin (PL), a naturally occurring napthoquinone derived from the root of Plumbago zeylanica L., has showed potent cancer preventive and therapeutic activity against variety of cancers. However, the clinical translation of PL has been significantly hampered due to its toxicity and suboptimal bioavailability. To address these clinically relevant issues, we have developed and characterized a novel PL-loaded magnetic nanoparticle (MNP-PL) formulation. This MNP-PL formulation was prepared using Magnetic nanoparticles (MNPs) composed of an iron oxide core which has distinct advantages in i) bio/hemo-compatibility, ii) biodegradation, iii) higher drug loading capacity and iv) improved bioavailability. Our novel MNP-PL formulation provided average size of 125 nm in dynamic light scattering (DLS) and exhibited -9.42 to -10.79 mV zeta potential with an outstanding PL loading efficiency. We have evaluated anti-cancer potential of MNP-PL formulation in human PanCa cells (HPAF-II, AsPc1 and Panc-1). We first performed MTS and colony formation assays to determine the effects of free PL and MNP-PL formulation on growth of PanCa cells. In this experiment, cells were treated with various concentrations of free PL (1-15 μM) or MNP-PL (1-15 μM) for 24 hrs. Results exhibited efficient internalization of the MNP-PL formulation in a dose-dependent manner. As a result, the MNP-PL formulation showed four fold dose advantage over free PL. IC50 of free PL was recorded 10 μM which was significantly reduced to 2.5 μM in MNP-PL. MNP-PL also showed four fold inhibition in colony formation compared to free PL. MNP-PL treatment more efficiently inhibited oncogenic CXCL12/CXCR4 signaling pathway in both PanCa and patient derived stromal fibroblast cells. MNP-PL treatment also showed decreased expression of CXCR4 protein levels in PanCa cells. Moreover, MNP-PL treatment inhibited stromal derived factor 1 (SDF-1)/CXCL12 expression in stromal fibroblasts. These results suggest that our novel MNP-PL formulation has more anti-cancer potential than free PL against PanCa. In conclusion, MNP-PL formulation may reduce the toxicity and improve the bioavailability of free PL and could be used for the treatment of PanCa.

Citation Format: Bilal B. Hafeez, Vivek K. Kashyap, Vijayakumar N. Boya, Aditya Ganju, Mohammad Sikander, Murali M. Yallapu, Meena Jaggi, Subhash C. Chauhan. Novel nanoparticle formulation of Plumbagin for pancreatic cancer treatment. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 2208.

PSMA targeted docetaxel-loaded superparamagnetic iron oxide nanoparticles for prostate cancer

Docetaxel (Dtxl) is currently the most common therapeutic option for prostate cancer (PC). However, adverse side effects and problems associated with chemo-resistance limit its therapeutic outcome in clinical settings. A targeted nanoparticle system to improve its delivery to and activity at the tumor site could be an attractive strategy for PC therapy. Therefore, the objective of this study was to develop and determine the anti-cancer efficacy of a novel docetaxel loaded, prostate specific membrane antigen (PSMA) targeted superparamagnetic iron oxide nanoparticle (SPION) (J591-SPION-Dtxl) formulation for PC therapy. Our results showed the SPION-Dtxl formulation exhibits an optimal particle size and zeta potential, which can efficiently be internalized in PC cells. SPION-Dtxl exhibited potent anti-cancer efficacy via induction of the expression of apoptosis associated proteins, downregulation of anti-apoptotic proteins, and inhibition of chemo-resistance associated protein in PC cell lines. J591-SPION-Dtxl exhibited a profound uptake in C4-2 (PSMA(+)) cells compared to PC-3 (PSMA(-)) cells. A similar targeting potential was observed in ex-vivo studies in C4-2 tumors but not in PC-3 tumors, suggesting its tumor specific targeting. Overall, this study suggests that a PSMA antibody functionalized SPION-Dtxl formulation can be highly useful for targeted PC therapy.

Abstract A57: Curcumin nanoformulation: A new therapeutic approach for cervical cancer treatment

Underserved populations such as African Americans (AA) and American Indians (AI) are experiencing increasing prevalence and mortality rates of cervical cancer (CxCa) as compared to Caucasians (CA). CxCa is one of the most common and deadly cancers among women worldwide and is associated with persistent Human Papillomavirus (HPV) infection. A persistent oncogenic HPV infection itself is not enough to immortalize and transform the epithelial host cell, as over a course of time only a small proportion of women with chronic HPV infection progress to develop disease. Additional factors are needed to acquire an immortal, malignant and invasive phenotype. In addition to HPV infection, cigarette smoking is a known risk factor. Polycyclic aromatic hydrocarbons (PAHs), such as Benzo[a]pyrene (BaP), are among the numerous carcinogens associated with cigarette smoking. The level of BaP has been found to be elevated in the cervical mucus of women who smoke. Moreover, a number of studies have implicated BaP to affect both the viral life cycle and the cellular environment. BaP has been shown to stimulate high levels of virion synthesis in cell lines prolifically infected with HPV. Furthermore, in other cancers the primary metabolite of BaP, benzo(a)pyrene diol epoxide increases the expression of oncogenic transcription factors like NFκB and oncogenic cytokines such as Interleukin-6 (IL-6). IL-6 in turn is known to activate transcription factors such as STAT3 and enhance the malignant transformation of cells. This is achieved through the transcriptional activation of oncogenic microRNAs (miRNA) like miRNA-21. MiRNAs are small non-coding RNAs that regulate gene expression and their aberrant regulation/function has been reported in a large majority of cancers. miRNA-21 has been shown to enhance chemoresistance to established regimens of chemotherapy and radiation therapy. This resistance to chemo-radio therapy with prolonged treatment, resulting in an invasive form of cancer, requires the development of novel therapeutic modalities to conquer chemo resistance and improve overall life expectancy of patients. Nanotechnology provides targeted delivery of anti-cancer drugs and indicates a new approach for cancer diagnosis and treatment. Our lab has developed PLGA (poly [lactic-co-glycolic acid]), an FDA approved polymer coated nanoparticle(s) using a well-known anti-cancer drug Curcumin (Cur) for the enhanced bioavailability and improved therapeutic efficacy of Cur, known as nano-curcumin (NC).

In comparison to pure Cur, NC effectively inhibited Caski/ SiHa cell growth and also induced apoptosis as determined by staining for Annexin V/7AAD. PI staining revealed that NC treatment arrests growth cycle of Caski/SiHa cells in the G2-M phase. Additionally, NC treatment caused a marked decrease in the levels of miRNA 21, an oncomiRNA associated with chemoresistance, and enhanced by BaP, with a concomitant increase in the tumor suppressor miRNA-214 (decreased by BaP). It was found to down-regulate the expression of oncogenic proteins and cytokines such as IL-6 and enhance the expression of tumor suppressor entities as evident from Western blots. Moreover, NC formulation effectively reduced the tumor burden in Non SCID gamma mice. Furthermore, it decreased the expression of oncogenic miRNA-21 in in vivo experiments as observed through ISH. Our findings show that PLGA based NC significantly inhibits Caski/SiHa CxCa cell tumorigenicity and regulates the expression of miRNAs, associated with CxCa. In vivo experiments show that NC is efficacious in reducing the tumor burden. Therefore, NC may be a novel chemo-preventive and therapeutic modality for the overall management of CxCa.

Citation Format: Mohd Saif Zaman, Neeraj Chauhan, Diane Maher, Rishi Gara, Mohammed Sikander, Murali Mohan Yallapu, Sheema Khan, Meena Jaggi, Subhash Chauhan. Curcumin nanoformulation: A new therapeutic approach for cervical cancer treatment. [abstract]. In: Proceedings of the Seventh AACR Conference on The Science of Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; Nov 9-12, 2014; San Antonio, TX. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2015;24(10 Suppl):Abstract nr A57.

Therapeutic Applications of Curcumin Nanoformulations

Curcumin (diferuloylmethane) is a bioactive and major phenolic component of turmeric derived from the rhizomes of curcuma longa linn. For centuries, curcumin has exhibited excellent therapeutic benefits in various diseases. Owing to its anti-oxidant and anti-inflammatory properties, curcumin plays a significant beneficial and pleiotropic regulatory role in various pathological conditions including cancer, cardiovascular disease, Alzheimer's disease, inflammatory disorders, neurological disorders, and so on. Despite such phenomenal advances in medicinal applications, the clinical implication of native curcumin is hindered due to low solubility, physico-chemical instability, poor bioavailability, rapid metabolism, and poor pharmacokinetics. However, these issues can be overcome by utilizing an efficient delivery system. Active scientific research was initiated in 2005 to improve curcumin's pharmacokinetics, systemic bioavailability, and biological activity by encapsulating or by loading curcumin into nanoform(s) (nanoformulations). A significant number of nanoformulations exist that can be translated toward medicinal use upon successful completion of pre-clinical and human clinical trials. Considering this perspective, current review provides an overview of an efficient curcumin nanoformulation for a targeted therapeutic option for various human diseases. In this review article, we discuss the clinical evidence, current status, and future opportunities of curcumin nanoformulation(s) in the field of medicine. In addition, this review presents a concise summary of the actions required to develop curcumin nanoformulations as pharmaceutical or nutraceutical candidates.