Ormeloxifene nanotherapy for cervical cancer treatment

BACKGROUND

Cervical cancer (CxCa) ranks as the fourth most prevalent women-related cancer worldwide. Therefore, there is a crucial need to develop newer treatment modalities. Ormeloxifene (ORM) is a non-steroidal, selective estrogen receptor modulator (SERM) that is used as an oral contraceptive in humans. Recent investigations suggest that ORM exhibits potent anti-cancer activity against various types of cancers. Nanoparticulates offer targeted delivery of anti-cancer drugs with minimal toxicity and promise newer approaches for cancer diagnosis and treatment. Therefore, the nanotherapy approach is superior compared to traditional chemotherapy, which is not site-specific and is often associated with various side effects.

METHODS

Pursuing this novel nanotherapy approach, our lab has recently developed ORM-loaded poly [lactic-co-glycolic acid] (PLGA), an FDA-approved biodegradable polymer, nanoparticles to achieve targeted drug delivery and improved bioavailability. Our optimized PLGA-ORM nanoformulation showed improved internalization in both dose- and energy-dependent manners, through endocytosis-mediated pathways in both Caski and SiHa cell lines. Additionally, we employed MTS and colony forming assays to determine the short- and long-term effects of PLGA-ORM on these cells.

RESULTS

Our results showed that this formulation demonstrated improved inhibition of cellular proliferation and clonogenic potential compared to free ORM. Furthermore, the PLGA-ORM nanoformulation exhibited superior anti-tumor activities in an orthotopic cervical cancer mouse model than free ORM.

CONCLUSION

Collectively, our findings suggest that our novel nanoformulation has great potential for repurposing the drug and becoming a novel modality for CxCa management.

A triphenylethylene nonsteroidal SERM attenuates cervical cancer growth

Selective estrogen receptor modulator drug molecules of triphenylethylene family have gained considerable attention as anti-cancer agents. Despite recent advances in screening and development of HPV vaccines, cervical cancer remains one of the deadliest malignancies as advanced stage metastatic disease is mostly untreatable, thus warrants newer therapeutic strategies. Ormeloxifene (ORM) is a well-known SERM of triphenylethylene family that has been approved for human use, thus represents an ideal molecule for repurposing. In this study, we for the first time have demonstrated the anti-cancerous properties of ormeloxifene in cervical cancer. Ormeloxifene efficiently attenuated tumorigenic and metastatic properties of cervical cancer cells via arresting cell cycle at G1-S transition, inducing apoptosis, decreasing PI3K and Akt phosphorylation, mitochondrial membrane potential, and modulating G1-S transition related proteins (p21, cyclin E and Cdk2). Moreover, ORM repressed the expression of HPV E6/ E7 oncoproteins and restored the expression of their downstream target tumor suppressor proteins (p53, Rb and PTPN 13). As a result, ormeloxifene induces radio-sensitization in cervical cancer cells and caused potent tumor growth inhibition in orthotopic mouse model. Taken together, ormeloxifene represents an alternative therapeutic modality for cervical cancer which may have rapid clinical translation as it is already proven safe for human use.

Abstract 3636: Generation of polymeric nanoformulation of ormeloxifene for cervical cancer treatment

Background: Cervical cancer (CxCa) is one of the most common death related cancers among women around the world and associated with poor 5-year survival rate. Therefore, there is an urgent need to develop newer treatment modalities. Ormeloxifene (ORM) is a non-steroidal, Selective Estrogen Receptor Modulator (SERM) that is used as an oral contraceptive in humans. Recent investigations suggest that ORM exhibits potent anti-cancer activity against various types of cancers. Nanoparticulates offer targeted delivery of anti-cancer drugs with minimal toxicity and promise newer approaches for cancer treatment. Therefore, nanotherapy approach outstands over traditional chemotherapy which is not site specific and often associated with various side effects. Thus, pursuing this novel nanotherapy approach, we have developed ORM nanoformulation using PLGA (poly [lactic-co-glycolic acid]); an FDA approved biodegradable polymer.

Methods: We generated ORM loaded PLGA nanoformulation (PLGA-ORM) employing nanoprecipitation method. PLGA-ORM was characterized for its physicochemical properties such as particle size, FT-IR, DSC and drug loading. We next performed cellular uptake studies in Caski and SiHa cell lines at different concentrations (5, 10, 20 and 25 µM) and temperatures (4° and 37° C) utilizing fluorescent microscope, flow cytometer and TEM. To evaluate the cellular uptake mechanism of PLGA-ORM, we did another flow cytometer experiment using various endocytosis pathways’ inhibitors. Next, we determined anti-proliferative activities of PLGA-ORM by performing MTS and colony formation assays. Furthermore, we investigated anti-tumoral functions of PLGA-ORM in an orthotopic mice model of cervical cancer.

Results: Our optimized PLGA-ORM showed particle size around 250 nm measured by DLS. ORM was completely miscible in this formulation as indicated by FT-IR and DSC spectra, which resulted in excellent drug loading of about 80% done by HPLC. PLGA-ORM nanoformulation exhibited improved internalization in dose, time and energy dependent manner through endocytosis mediated pathways in both Caski and SiHa cell lines. Additionally, we employed MTS and colony forming assays to determine the short- and long-term effects of PLGA-ORM on these cells, results showed that this formulation had an improved inhibition of cellular proliferation and clonogenic potential compared to free ORM. Furthermore, PLGA-ORM nanoformulation exhibited superior anti-tumorous activities in an orthotropic cervical cancer mouse model compared to free ORM.

Conclusion: Our findings suggest that, this PLGA-ORM nanoformulation has great potential for repurposing the drug and becoming a novel modality for cervical cancer management which needs to be developed as a lead therapy approach with appropriate clinical investigations.

Citation Format: Neeraj Chauhan, Murali M. Yallapu, Diane M. Maher, Bilal B. Hafeez, Mohammed Sikander, Meena Jaggi, Subhash Chauhan. Generation of polymeric nanoformulation of ormeloxifene for cervical cancer treatment [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 3636.

ATOH1 Promotes Leptomeningeal Dissemination and Metastasis of Sonic Hedgehog Subgroup Medulloblastomas

Medulloblastoma arising from the cerebellum is the most common pediatric brain malignancy, with leptomeningeal metastases often present at diagnosis and recurrence associated with poor clinical outcome. In this study, we used mouse medulloblastoma models to explore the relationship of tumor pathophysiology and dysregulated expression of the NOTCH pathway transcription factor ATOH1, which is present in aggressive medulloblastoma subtypes driven by aberrant Sonic Hedgehog/Patched (SHH/PTCH) signaling. In experiments with conditional ATOH1 mouse mutants crossed to Ptch1^+/- mice, which develop SHH-driven medulloblastoma, animals with Atoh1 transgene expression developed highly penetrant medulloblastoma at a young age with extensive leptomeningeal disease and metastasis to the spinal cord and brain, resembling xenografts of human SHH medulloblastoma. Metastatic tumors retained abnormal SHH signaling like tumor xenografts. Conversely, ATOH1 expression was detected consistently in recurrent and metastatic SHH medulloblastoma. Chromatin immunoprecipitation sequencing and gene expression profiling identified candidate ATOH1 targets in tumor cells involved in development and tumorigenesis. Among these targets specific to metastatic tumors, there was an enrichment in those implicated in extracellular matrix remodeling activity, cytoskeletal network and interaction with microenvironment, indicating a shift in transcriptomic and epigenomic landscapes during metastasis. Treatment with bone morphogenetic protein or SHH pathway inhibitors decreased tumor cell proliferation and suppressed metastatic tumor growth, respectively. Our work reveals a dynamic ATOH1-driven molecular cascade underlying medulloblastoma metastasis that offers possible therapeutic opportunities. Cancer Res; 77(14); 3766-77. ©2017 AACR.

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 5534: Novel pluronic F127-coated paclitaxel nanoparticles formulation for pancreatic cancer

Pancreatic cancer (PanCa) is one of the deadliest cancers which accounts for 46,420 new cancer cases and almost 39,590 deaths in the United States in 2014. There is no effective treatment modality for PanCa that can significantly improve the overall survival rate of patients. Paclitaxel is a mitotic inhibitor widely used in chemotherapy. Recent FDA approved treatment regimen of Abraxane® (paclitaxel nanoformulation) with gemcitabine has been increased overall survival of PanCa patients from 6.7 months (Gemcitabine) to 8.5 months (Abraxane® + Gemcitabine). Targeted delivery of paclitaxel may lead to significant improvement in treating pancreatic cancer. For this purpose, we have engineered a unique, pluronic F127-coated paclitaxel loaded nanoparticles (PPNPs) formulation. This formulation is composed of a PLGA core that is subsequently coated with poly(vinyl alcohol) (PVA), poly(l-lysine) (PLL), and pluronic polymer (F127) for efficient drug delivery and active tumors targeting. This formulation has several unique properties: (a) the PLGA core is capable of loading paclitaxel and its sustained release (b) pluronic-polymer layer coating provides stability and also reverses multi-drug resistance in cancer cells (c) the polyethylene glycol chains of pluronic F127 polymer act as a stealth polymer which diminishes the nonspecific uptake of formulation, and (d) amine functional groups on NPs (PLL) are useful for antibody conjugation through a PEG-linker for specific targeting of tumor/cancer cells. The PPNPs formulation was characterized for particle size, chemical composition, and thermal characteristics. The PPNPs exhibited superior dose-dependent inhibition effects on the proliferation of Colo-357, HPAF-II, BxPC-3, MiaPaca-2, Panca-1, and AsPC-1 pancreatic cancer cell lines, over free PTX and other conventional PTX nanoformulation (Abraxane®). Similar inhibition effects were also observed in colony formation assay in BxPC-3 cells. The improved anti-cancer effects of this formulation was achieved due to its accumulation in the cytosolic compartment and less presence in early endosome/late endosome/lysosome indicates their escape from lysosomal degradation. In addition, our data suggest that F127-stabilized PPNPs exhibit superior anti-cancer potential and is capable of regulating proteins associated with sonic hedgehog, multi drug resistance and miR-21 signaling pathways and inducing apoptosis which, eventually lead to the gemcitabine chemo-sensitization. Interestingly, MUC13-conjugated nanoformulation exhibited efficient targeting in HPAF-II cells. In conclusion, our data suggest that the PPNPs nanoformulation can be used for the efficient, targeted delivery of paclitaxel to tumors and may useful for treatment of pancreatic cancer alone and/or in combination with gemcitabine.

Citation Format: Murali M. Yallapu, Neeraj Chauhan, Sheema Khan, Meena Jaggi, Aditya Ganju, Diane M. Maher, Mara C. Ebeling, Subhash C. Chauhan. Novel pluronic F127-coated paclitaxel nanoparticles formulation for pancreatic cancer. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 5534. doi:10.1158/1538-7445.AM2015-5534

Ormeloxifene efficiently inhibits ovarian cancer growth

Ovarian cancer continues to be a leading cause of cancer related deaths for women. Anticancer agents effective against chemo-resistant cells are greatly needed for ovarian cancer treatment. Repurposing drugs currently in human use is an attractive strategy for developing novel cancer treatments with expedited translation into clinical trials. Therefore, we examined whether ormeloxifene (ORM), a non-steroidal Selective Estrogen Receptor Modulator (SERM) currently used for contraception, is therapeutically effective at inhibiting ovarian cancer growth. We report that ORM treatment inhibits cell growth and induces apoptosis in ovarian cancer cell lines, including cell lines resistant to cisplatin. Furthermore, ORM treatment decreases Akt phosphorylation, increases p53 phosphorylation, and modulates the expression and localization patterns of p27, cyclin E, cyclin D1, and CDK2. In a pre-clinical xenograft mouse ORM treatment significantly reduces tumorigenesis and metastasis. These results indicate that ORM effectively inhibits the growth of cisplatin resistant ovarian cancer cells. ORM is currently in human use and has an established record of patient safety. Our encouraging in vitro and pre-clinical in vivo findings indicate that ORM is a promising candidate for the treatment of ovarian cancer.

Abstract 2753: Ormeloxifene inhibits cervical cancer cell growth through intrinsic apoptotic pathway

Background: Cervical cancer (CxCa) remains the fourth leading cause of cancer related death among women worldwide. Cervical cancer is mainly (∼ 99.7%) derived from high risk Human papillomavirus (HR HPV). HPV E6/E7 oncoproteins interfere with p53 and pRb (retinoblastoma) cell cycle regulatory proteins and hinder their efficacy of controlling cell growth. Advanced stage cervical cancer is difficult to treat and patients diagnosed with metastatic disease have a poor survival rate of only 16%. Therefore, there is an urgent need to develop newer treatment modalities. Ormeloxifene is a non-hormonal, anti-estrogen, oral contraceptive for human use that effectively suppresses the proliferation of decidual cells in the endometrium to inhibit egg implantation. Growing evidences also suggest that ormeloxifene has anti-cancerous properties in breast, head and neck, and chronic myeloid leukemia cancers. Hence, considering its strong anti-proliferative/cancerous effect, we hypothesized that ormeloxifene may also inhibit the growth of cervical cancer cells and may suppress the expression of E6 and E7 HPV oncoproteins.

Methods: We performed in vitro anti-cancer studies with ormeloxifene (dose range: 5 µM to 25 µM) in the HPV positive cervical cancer cell lines (Caski and SiHa) by utilizing MTS and colony formation assays. To further determine the effects of ormeloxifene on the cellular and molecular level, immunoblotting, flow cytometry and real time PCR analyses were performed using the Caski cell line model.

Results: Ormeloxifene effectively inhibited cervical cancer cell growth as determined by proliferation and colony formation assays in a dose dependent manner. Ormeloxifene decreased mitochondrial membrane potential and induced apoptosis as shown by flow cytometry analysis of cells stained with TMRE (tetramethylrhodamine, ethyl ester) and 7AAD/Annexin V, respectively. Apoptosis was also confirmed by immunoblotting for cleaved PARP (Poly ADP ribose polymerase), Caspase 3 and Caspase 9. Additionally, ormeloxifene treatment arrested cell cycle in G1-S transition and decreased the expression of p-Akt while total Akt remained the same. Specifically relevant to cervical cancer, ormeloxifene decreased the expression of HPV E6/E7 at mRNA and protein levels as determined by quantitative PCR analysis and immunoblotting, respectively. Interestingly, ormeloxifene restored the levels of p53, Rb and PTPN 13 (Protein tyrosine Phosphatase non receptor type 13) tumor suppressor proteins as shown by immunoblotting.

Conclusion: Our findings suggest that ormeloxifene inhibits cervical cancer cell growth and decreases mitochondrial membrane potential which clearly demonstrates that apoptosis is induced via intrinsic pathway. Importantly, ormeloxifene downregulates the expression of HPV E6/E7 oncoproteins. Thus, ormeloxifene appears to be a novel treatment modality for cervical cancer.

Citation Format: Neeraj Chauhan, Mohd S. Zaman, Murali M. Yallapu, Diane M. Maher, Mara C. Ebeling, Subhash C. Chauhan, Meena Jaggi. Ormeloxifene inhibits cervical cancer cell growth through intrinsic apoptotic pathway. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 2753. doi:10.1158/1538-7445.AM2014-2753

Abstract 5411: Curcumin nanoformulation: A new therapeutic approach for cervical cancer treatment

Background: Cervical cancer is one of the most common and deadly cancers among women worldwide and is associated with persistent Human Papillomavirus (HPV) infection. Currently, Cisplatin based chemo and radio therapy is the best standard treatment for cervical cancer. While screening for cervical cancer can reduce the incidence and mortality, treatment of advanced stage cervical cancer is difficult and often unsuccessful. 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. Therefore, “we hypothesized that having targeted drug delivery, curcumin nanoparticles (NC) will show improved anti-cancerous effects on cervical cancer cells and will also overcome drug (Cisplatin) resistance when compared with free curcumin.”

Methods: The effect of NC on the proliferation of Caski cervical cancer cells was determined by MTS and colony formation assay. Annexin V/7AAD and propidium iodide (PI) staining was analyzed by flow cytometry to determine NC's effect on apoptosis and cell cycle inhibition, respectively. The expression of apoptotic markers such as poly (ADP-ribose) polymerase (PARP), Caspase 3 and Caspase 9 was determined by immunoblotting. The potential of NC to modulate the expression of miRNAs associated with drug resistance was determined by quantitative RT-PCR. In order to assess efficacy of NC to reduce tumor growth, an orthotopic mouse model was generated using Caski cells stably transfected with fluorescent gene td tomato.

Results: NC effectively inhibited Caski cell growth and also induced apoptosis as determined by staining for Annexin V/7AAD and immunoblotting for cleaved PARP, Caspase 3, and Caspase 9. PI staining clearly revealed that NC treatment arrests growth cycle of Caski cells in the G1- S phase. Additionally, NC treatment caused a marked decrease in the levels of miRNA 21, an oncomiRNA associated with chemoresistance, and enhanced miRNA 214, a tumor suppressor, when compared to free Curcumin. Moreover, NC formulation effectively reduces the tumor burden in athymic nude mice.

Conclusion: Our findings show that PLGA based NC significantly inhibits Caski cervical cancer cell growth and regulates the expression of miRNAs, associated with cervical cancer. 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 cervical cancer.

Citation Format: Mohd Saif Zaman, Neeraj Chauhan, Diane M. Maher, Murali M. Yallapu, Meena Jaggi, Subhash C. Chauhan. Curcumin nanoformulation: A new therapeutic approach for cervical cancer treatment. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 5411. doi:10.1158/1538-7445.AM2014-5411

Anti-cancer activity of curcumin loaded nanoparticles in prostate cancer

Prostate cancer is the most commonly diagnosed cancer disease in men in the Unites States and its management remains a challenge in everyday oncology practice. Thus, advanced therapeutic strategies are required to treat prostate cancer patients. Curcumin (CUR) is a promising anticancer agent for various cancer types. The objective of this study was to evaluate therapeutic potential of novel poly(lactic-co-glycolic acid)- CUR nanoparticles (PLGA-CUR NPs) for prostate cancer treatment. Our results indicate that PLGA-CUR NPs efficiently internalize in prostate cancer cells and release biologically active CUR in cytosolic compartment of cells for effective therapeutic activity. Cell proliferation (MTS), clonogenic, and Western blot analyses reveal that PLGA-CUR NPs can effectively inhibit proliferation and colony formation ability of prostate cancer cells than free CUR. PLGA-CUR NPs showed superior tumor regression compared to CUR in xenograft mice. Further investigations reveal that PLGA-CUR NPs inhibit nuclear β-catenin and AR expression in cells and in tumor xenograft tissues. It also suppresses STAT3 and AKT phosphorylation and leads to apoptosis via inhibition of key anti-apoptotic proteins, Mcl-1, Bcl-xL and caused induction of PARP cleavage. Additionally, significant downregulation of oncogenic miR21 and up-regulation of miR-205 was observed with PLGA-CUR NPs treatment as determined by RT-PCR and in situ hybridization analyses. A superior anti-cancer potential was attained with PSMA antibody conjugated PLGA-CUR NPs in prostate cancer cells and a significant tumor targeting of (131)I labeled PSMA antibody was achieved with PLGA-CUR NPs in prostate cancer xenograft mice model. In conclusion, PLGA-CUR NPs can significantly accumulate and exhibit superior anticancer activity in prostate cancer.

Abstract 3611: Benzo(a)pyrene exposure increases expression of HPV oncoproteins: a potential co-factor for increased cervical cancer among Northern Plains American Indian women

Introduction: Cervical cancer remains one of the most common and deadly cancers in women worldwide. There is a significant health disparity in the incidence and mortality of cervical cancer between American Indian and Caucasian women residing on the Northern Plains. The development of cervical cancer is closely associated with persistent infection with high risk HPV genotypes. Additionally, exposure to cigarette smoke is also a risk factor for cervical cancer. Our studies indicate that Northern Plains American Indian women have a high rate of both HPV infection and smoking. Our studies also show that American Indian women who tested positive for HPV were more likely to have an abnormal PAP test than HPV positive Caucasian women. While smoking is known to increase the risk of developing cervical cancer, the molecular interactions between HPV and smoke carcinogens are not well known. Herein, we determine the cellular and molecular effects of benzo-a-pyrene (BaP) (a carcinogen in cigarette smoke) on HPV oncoprotein expression in cervical cancer cells and elucidate the role of the aryl hydrocarbon receptor (AhR) in this process.

Methods: The effects of BaP on HPV oncoproteins and AhR mediated molecular events was determined using cervical cancer cell line models and real time PCR, immunoblotting, immunostaining and flow cytometry analyses. The level of AhR activation in normal cervix and in cervical cancer tissues was also determined with immunohistochemical analysis.

Results: Our results indicate that exposure to BaP, a tobacco carcinogen, activates the AhR pathway in a time and dose dependent manner, as determined by an increase in nuclear localization of AhR and increased expression of cytochrome p450 1A. Expsoure to BaP ultimately results in increased expression of HPV oncogenes. Importantly, curcumin, a natural compound, attenuated the BaP induced increase in the expression of HPV E7 oncoprotein. Interestingly, both cytoplasmic and nuclear localization of AhR is increased in cervical cancer tissue compared to normal cervical epithelium.

Conclusion: Taken together this data imply that a high prevalence of HPV infection and a high exposure rate to BaP may synergize to increase the incidence and mortality of cervical cancer in American Indian women residing in the Northern Plains. We have identified curcumin as a potent compound that may be effective in attenuating oncogenic HPV infection. However, increased cervical cancer screening is warranted in addition to HPV vaccine and use of chemopreventive agents, such as curcumin, to effectively decrease the cervical cancer health disparity in Northern Plains American Indian women.

Citation Format: Diane M. Maher, Maria Bell, Amanda Schaefer, Meena Jaggi, Subhash C. Chauhan. Benzo(a)pyrene exposure increases expression of HPV oncoproteins: a potential co-factor for increased cervical cancer among Northern Plains American Indian women. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 3611. doi:10.1158/1538-7445.AM2013-3611

Current status and implications of microRNAs in ovarian cancer diagnosis and therapy

Ovarian cancer is the fifth most common cancer among women and causes more deaths than any other type of female reproductive cancer. Currently, treatment of ovarian cancer is based on the combination of surgery and chemotherapy. While recurrent ovarian cancer responds to additional chemotherapy treatments, the progression-free interval becomes shorter after each cycle, as chemo-resistance increases until the disease becomes incurable. There is, therefore, a strong need for prognostic and predictive markers to help optimize and personalize treatment in order to improve the outcome of ovarian cancer. An increasing number of studies indicate an essential role for microRNAs in ovarian cancer progression and chemo-resistance. MicroRNAs (miRNAs) are small endogenous non-coding RNAs (~22bp) which are frequently dysregulated in cancer. Typically, miRNAs are involved in crucial biological processes, including development, differentiation, apoptosis and proliferation. Two families of miRNAs, miR-200 and let-7, are frequently dysregulated in ovarian cancer and have been associated with poor prognosis. Both have been implicated in the regulation of epithelial-to-mesenchymal transition, a cellular transition associated with tumor aggressiveness, tumor invasion and chemo-resistance. Moreover, miRNAs also have possible implications for improving cancer diagnosis; for example miR-200 family, let-7 family, miR-21 and miR-214 may be useful in diagnostic tests to help detect ovarian cancer at an early stage. Additionally, the use of multiple target O-modified antagomirs (MTG-AMO) to inhibit oncogenic miRNAs and miRNA replacement therapy for tumor suppressor miRNAs are essential tools for miRNA based cancer therapeutics. In this review we describe the current status of the role miRNAs play in ovarian cancer and focus on the possibilities of microRNA-based therapies and the use of microRNAs as diagnostic tools.

Abstract B60: Role of MUC1 mucin in American Indian breast cancer health disparity

Introduction: Considerable breast cancer health disparity exists among different racial/ethnic populations and geographic locations. For unknown reasons, American Indian women of the Northern Plains have a greater incidence and higher death rate due to breast cancer than Caucasian women living in the same geographical region. Additionally, American Indian women living in the Northern Plains also have a much higher incidence and death rate due to breast cancer than American Indian women living elsewhere in the United States. To investigate the potential molecular basis for breast cancer health disparity, we have initiated a study to compare the expression profiles of cancer associated proteins on breast cancer cases from American Indian and Caucasian women living on the Northern Plains. One protein of interest, MUC1, a transmembrane mucin, is known to be overexpressed in breast cancer and nuclear localization of MUC1 can have downstream effects on cell signaling and increase oncogenic phenotypes. American Indian women are exposed to cigarette smoke at rates higher than Caucasian women; therefore, we are also assessing the prevalence of aryl hydrocarbon receptor (AhR) activation in breast cancer tissues. Cigarette compounds can activate the AhR pathway and induce the expression of a variety of genes, some of which are known to be oncogenic.

Methods: We have examined the expression profiles of MUC1 in breast cancer tissue collected from American Indian (n=40) and Caucasian (n=60) women by immunohistochemical analysis. The staining was analyzed by experienced pathologists and scored according to intensity (0-4) and percent of cancer cells stained positive (0-4). A composite score was calculated by multiplying the scores of intensity and percent of cells stained. Tissues were categorized by modified Bloom-Richardson's histological grade and the mean composite scores were compared amongst American Indian and Caucasian groups. In vitro experiments have also been conducted to examine a potential link between the activation of AhR by cigarette smoke compounds and an increase in MUC1 expression or change in cellular localization.

Results and Conclusions: A differential expression/localization pattern of MUC1 was observed in American Indian breast cancer samples compared to Caucasian samples. Grade 3 breast cancer samples obtained from American Indian women showed higher nuclear MUC1 staining compared to Caucasian samples. We have also observed that breast cancer cells aberrantly express AhR and have increased AhR activation as shown by nuclear localization. We also observed a lower amount of nuclear p53 and membrane β-catenin expression. This result correlates with previous data showing that MUC1 inhibits the expression of p53 and decreases membrane β-catenin. In vitro data suggests that exposure to BaP increases the nuclear localization of MUC1. In conclusion, breast cancer tissue from American Indian women has a different expression profile of MUC1 and this finding may help to explain the cancer health disparity. Further investigation of these differences may promote understanding of the etiological differences and may identify effective treatment strategies for breast cancer in American Indian women.

Citation Format: Diane M. Maher, Emily Gaster, Phillip Stephenson, Michael Koch, Susan Eliason, Meena Jaggi, Subhash C. Chauhan. Role of MUC1 mucin in American Indian breast cancer health disparity. [abstract]. In: Proceedings of the Fifth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2012 Oct 27-30; San Diego, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2012;21(10 Suppl):Abstract nr B60.

Abstract B75: Benzo(a)pyrene exposure increases expression of HPV oncoproteins: A potential co-factor for increased cervical cancer among Northern Plains American Indian women

Introduction: Cervical cancer remains one of the most common and deadly cancers in women worldwide. There is a significant health disparity in the incidence and mortality of cervical cancer between American Indian and Caucasian women residing on the Northern Plains. The development of cervical cancer is closely associated with persistent infection with high risk HPV genotypes. Additionally, exposure to cigarette smoke is also a risk factor for cervical cancer. Our studies indicate that Northern Plains American Indian women have a high rate of both HPV infection and smoking. Our studies also show that American Indian women who tested positive for HPV were more likely to have an abnormal PAP test than HPV positive Caucasian women. While smoking is known to increase the risk of developing cervical cancer, the molecular interactions between HPV and smoke carcinogens are not well known. Herein, we determine the cellular and molecular effects of benzo-a-pyrene (BaP) (a carcinogen in cigarette smoke) on HPV oncoprotein expression in cervical cancer cells and elucidate the role of the aryl hydrocarbon receptor (AhR) in this process.

Methods: The effects of BaP on HPV oncoproteins and AhR mediated molecular events was determined using cervical cancer cell line models using real time PCR, immunoblotting, immunostaining and flow cytometry analyses. Additionally, following knockdown of AhR, cervical cancer cells lines were exposed to BaP and the levels of HPV oncoproteins and Cytochrome P450 1A (CYP1A1) were determined by flow cytometry, immunofluorescence and immunoblotting. Cervical cancer cells were also treated with curcumin to inhibit HPV oncoprotein expression. The level of AhR activation in normal cervix and in cervical cancer tissues was also determined with immunohistochemical analysis.

Results: We show for the first time that exposure to Benzo-[a]-pyrene (BaP), a tobacco carcinogen, increases the expression of HPV E7 oncoprotein in both acute and extended treatment protocols. To address the mechanism of increased HPV E7 protein expression, we determined that BaP activates AhR in cervical cancer cells which may directly or indirectly increase HPV oncoprotein expression. AhR activation is increased in cervical cancer tissue compared to normal cervical epithelium. Importantly, curcumin, natural compound, attenuated the BaP induced increase in the expression of HPV E7 oncoprotein.

Conclusion: Taken together this data imply that a high prevalence of HPV infection and a high exposure rate to BaP may synergize to increase the incidence and mortality of cervical cancer in American Indian women residing in the Northern Plains. We have identified curcumin as a potent compound that may be effective in attenuating oncogenic HPV infection. However, increased cervical cancer screening is warranted in addition to HPV vaccine and use of dietary agents, such as curcumin, to effectively decrease the cervical cancer health disparity in Northern Plains American Indian women.

Citation Format: Diane M. Maher, Maria Bell, Amanda Schaefer, Emmylu O'Donnell, Meena Jaggi, Subhash Chauhan. Benzo(a)pyrene exposure increases expression of HPV oncoproteins: A potential co-factor for increased cervical cancer among Northern Plains American Indian women. [abstract]. In: Proceedings of the Fifth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2012 Oct 27-30; San Diego, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2012;21(10 Suppl):Abstract nr B75.

Increased expression and aberrant localization of mucin 13 in metastatic colon cancer

MUC13 is a newly identified transmembrane mucin. Although MUC13 is known to be overexpressed in ovarian and gastric cancers, limited information is available regarding the expression of MUC13 in metastatic colon cancer. Herein, we investigated the expression profile of MUC13 in colon cancer using a novel anti-MUC13 monoclonal antibody (MAb, clone ppz0020) by immunohistochemical (IHC) analysis. A cohort of colon cancer samples and tissue microarrays containing adjacent normal, non-metastatic colon cancer, metastatic colon cancer, and liver metastasis tissues was used in this study to investigate the expression pattern of MUC13. IHC analysis revealed significantly higher (p<0.001) MUC13 expression in non-metastatic colon cancer samples compared with faint or very low expression in adjacent normal tissues. Interestingly, metastatic colon cancer and liver metastasis tissue samples demonstrated significantly (p<0.05) higher cytoplasmic and nuclear MUC13 expression compared with non-metastatic colon cancer and adjacent normal colon samples. Moreover, cytoplasmic and nuclear MUC13 expression correlated with larger and poorly differentiated tumors. Four of six tested colon cancer cell lines also expressed MUC13 at RNA and protein levels. These studies demonstrate a significant increase in MUC13 expression in metastatic colon cancer and suggest a correlation between aberrant MUC13 localization (cytoplasmic and nuclear expression) and metastatic colon cancer.

Abstract 3589: Comparative expression profile of transmembrane mucin MUC1 in breast cancer from American Indian and Caucasian women

Introduction: Considerable disparity exists in breast cancer incidence and mortality among different racial/ethnic populations and geographic locations. For unknown reasons, American Indian women of the Northern Plains have a greater incidence and higher death rate due to breast cancer than Caucasian women living in the same geographical region. Additionally, American Indian women living in the Northern Plains also have a much higher incidence and death rate due to breast cancer than American Indian women living elsewhere in the United States. To investigate the potential molecular basis for this cancer health disparity, we have compared the expression profile of transmembrane mucin, MUC1 on breast cancer cases from American Indian and Caucasian women living on the Northern Plains. MUC1 is known to be overexpressed in breast cancer and nuclear localization of MUC1 can have downstream effects on cell signaling and increase oncogenic phenotypes. We are also exploring the link between smoking, exposure to HPV infection, and the development of breast cancer in American Indian women. Methods: We have examined the expression profile of MUC1 in breast cancer tissue from American Indian (n=40) and Caucasian (n=60) women. The staining was analyzed by experienced pathologists and scored according to intensity (0-4) and percent of cancer cells stained positive (0-4). A composite score was calculated by multiplying the scores of intensity and percent of cells stained. Tissues were categorized by modified Bloom-Richardson's histological grade and the mean composite scores were compared amongst American Indian and Caucasian groups. Results and Conclusions: We have observed that grade 3 breast cancer samples from American Indian women had a higher percent of nuclear MUC1 staining and a lower amount of p53 expression. This result correlates with previous data showing that MUC1 inhibits the expression of p53. In conclusion, breast cancer tissue from American Indian women has a different expression profile of molecular markers and this finding may help to explain the cancer health disparity. Further investigation of these differences may promote understanding of the etiological differences and may identify effective treatment strategies for breast cancer in American Indian women.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3589. doi:1538-7445.AM2012-3589

Abstract 5325: Role of MUC13 in colon cancer progression

Colon cancer is the third most commonly diagnosed and second leading cause of cancer related deaths in the United States. Mucin 13 (MUC13), a high molecular weight glycoprotein, is a recently identified transmembrane mucin. While MUC13 is known to be over expressed in gastric and ovarian cancers, limited information about MUC13 is available in colon cancer progression. Therefore, our aim is to investigate the expression profile, potential role and possible regulatory pathways of MUC13 in colon cancer progression. We performed immunohistochemical analysis using MUC13 monoclonal antibody (ppz0020) to determine expression profile and aberrant localization of MUC13 in colon cancer cells. Our results indicate that MUC13 is over expressed in colon cancer predominantly at the apical surface. MUC13 is also aberrantly localized (cytoplasmic and nuclear) in metastasized colon cancer and in liver metastasis. We also correlated MUC13 expression levels with clinico-pathological parameters of patients. Increased MUC13 expression correlated with increased tumor size and poorly differentiated colon cancer. To determine the functional roles of MUC13 we generated stable MUC13 over expressing and MUC13 knock down cells and performed functional assays. Our results demonstrate that MUC13 increased cell proliferation, colony formation, cell migration and cell invasion characteristics of colon cancer cells. In order to investigate proteins that are affected by MUC13, we performed immunoblot assays. Immunoblot analysis revealed that MUC13 increased expression of several proteins that are associated with colon cancer progression and metastasis such as Bmi-1(B cell specific lymphoma moloney murine leukemia integration site-1), TERT (telomerase reverse transcriptase), Shh (sonic hedgehog) and GATA1 (GATA binding protein 1). We also examined potential signaling pathways that may be associated with MUC13 colon carcinogenesis. We found that MUC13 increased expression of mitogen activated kinase (MAPK) pathway members such as ERK-1 and phospho ERK-1. In order to determine potential transcriptions factors that may regulate MUC13 expression, we screened expression of various transcription factors by real time PCR. Significantly high expression of STAT5B (signal transducers and activators of transcription factor 5B) was detected in cell lines expressing endogenously high levels of MUC13. In order to confirm transcription factor STAT5B binding sites in the MUC13 promotor, we performed chromatin immunoprecipitation (CHIP). CHIP analysis revealed that STAT5B binds to the promoter of MUC13. In summary, our study revealed that MUC13 is over expressed in colon cancer and aberrantly localized in metastasis. Over expression of MUC13 increases cell proliferation, colony formation, cell migration, cell invasion and expression of metastasis associated proteins partly via MAPK pathway. MUC13 expression may be regulated through binding of STAT5B to the MUC13 promoter.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 5325. doi:1538-7445.AM2012-5325

Abstract 2882: Therapeutic effects of ormeloxifene on cervical cancer

Background: Cervical cancer is one of the most common and deadly cancers among women worldwide and is strongly associated with persistent Human Papillomavirus (HPV) infection. HPV E6/E7 oncoproteins are well known to interfere with p53 and retinoblastoma (Rb) proteins and drive the development of cervical cancer. While screening for cervical cancer can reduce the incidence and mortality, treatment of advanced stage cervical cancer is difficult and often unsuccessful. Therefore, there is an urgent need for the development of additional treatment modalities. Ormeloxifene is a non-hormonal anti-estrogen oral contraceptive for human use and it effectively suppresses the highly proliferative decidual cells in the endometrium to inhibit egg implantation. Considering its strong anti-proliferative effect, we hypothesized that ormeloxifene may inhibit the growth of cervical cancer cells and may suppress the expression of HPV oncoproteins E6/E7. Methods: The effect of ormeloxifene on the proliferation of various cervical cancer cell lines (Caski, SiHa, C33A, and HT3) was determined by MTS and colony formation assay. Annexin V/7AAD and propidium iodide (PI) staining was analyzed by flow cytometry to determine ormeloxifene's effect on apoptosis and cell cycle inhibition, respectively. The expression of apoptotic proteins such as poly (ADP-ribose) polymerase (PARP), Caspase 3 and Caspase 9 was determined by immunoblotting. The potential of ormeloxifene to repress the expression of HPV E6/E7 oncogenes was determined by quantitative RT-PCR and immunoblotting analyses. Further, the efficacy of ormeloxifene to restore tumor suppressor proteins, such as p53 and Rb, was also determined by immunoblotting. Results: In all 4 cell lines, ormeloxifene effectively inhibited cervical cancer cell growth. Ormeloxifene treatment induced apoptosis in cervical cancer cells as determined by staining for Annexin V/7AAD and immunoblotting for cleaved PARP, Caspase 3, and Caspase 9. PI staining also clearly revealed that ormeloxifene treatment arrests Caski cells in the G0-G1 phase. Additionally, ormeloxifene treatment caused a marked decrease in the levels of HPV E6 and E7 oncogenes and restored the levels of p53 and Rb proteins in Caski cells. Conclusion: Our findings show that ormeloxifene significantly inhibits cervical cancer cell growth and down-regulates HPV E6/E7 oncogenes, therefore; ormeloxifene may be novel chemo-preventive and treatment method for the management of cervical cancer.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 2882. doi:1538-7445.AM2012-2882

MUC13 mucin augments pancreatic tumorigenesis

The high death rate of pancreatic cancer is attributed to the lack of reliable methods for early detection and underlying molecular mechanisms of its aggressive pathogenesis. Although MUC13, a newly identified transmembrane mucin, is known to be aberrantly expressed in ovarian and gastro-intestinal cancers, its role in pancreatic cancer is unknown. Herein, we investigated the expression profile and functions of MUC13 in pancreatic cancer progression. The expression profile of MUC13 in pancreatic cancer was investigated using a recently generated monoclonal antibody (clone PPZ0020) and pancreatic tissue microarrays. The expression of MUC13 was significantly (P < 0.005) higher in cancer samples compared with normal/nonneoplastic pancreatic tissues. For functional analyses, full-length MUC13 was expressed in MUC13 null pancreatic cancer cell lines, MiaPaca and Panc1. MUC13 overexpression caused a significant (P < 0.05) increase in cell motility, invasion, proliferation, and anchorage-dependent or -independent clonogenicity while decreasing cell-cell and cell-substratum adhesion. Exogenous MUC13 expression significantly (P < 0.05) enhanced pancreatic tumor growth and reduced animal survival in a xenograft mouse model. These tumorigenic characteristics correlated with the upregulation/phosphorylation of HER2, p21-activated kinase 1 (PAK1), extracellular signal-regulated kinase (ERK), Akt, and metastasin (S100A4), and the suppression of p53. Conversely, suppression of MUC13 in HPAFII pancreatic cancer cells by short hairpin RNA resulted in suppression of tumorigenic characteristics, repression of HER2, PAK1, ERK, and S100A4, and upregulation of p53. MUC13 suppression also significantly (P < 0.05) reduced tumor growth and increased animal survival. These results imply a role of MUC13 in pancreatic cancer and suggest its potential use as a diagnostic and therapeutic target.

HPV infection among rural American Indian women and urban white women in South Dakota: an HPV prevalence study

Background

High-risk strains of human papillomavirus (HPV) cause cervical cancer. American Indian (AI) women in the Northern Plains of the U.S. have significantly higher incidence and mortality rates for cervical cancer than White women in the same geographical area. We compared HPV prevalence, patterns of HPV types, and infection with multiple HPV types in AI and White women living in South Dakota, U.S.

Methods

We analyzed the HPV status of cervical samples collected in 2006-2008 from women aged 18-65 years who attended two rural AI reservation clinics (n = 235) or an urban clinic in the same area serving mostly White women (n = 246). Data collection occurred before HPV vaccination was available to study participants. HPV DNA was amplified by using the L1 consensus primer system and an HPV Linear Array detection assay to identify HPV types. We used chi-square tests to compare HPV variables, with percentages standardized by age and lifetime number of sexual partners.

Results

Compared to White women, AI women were younger (p = 0.01) and reported more sexual partners (p < 0.001). A lower percentage of AI women tested negative for HPV infection compared to Whites (58% [95% CI = 51-65] vs. 77% [95% CI = 71-82]; p < 0.001), and a higher percentage of AI women were infected by oncogenic types (30% [95% CI = 25-36] vs. 16% [95% CI = 11-21]; p = 0.001). Infections among AI women showed a wider variety and very different pattern of HPV types, including a higher prevalence of mixed HPV infections (19% [95% CI = 26-38] vs. 7% [95% CI = 4-11]; p = 0.001). AI women had a higher percentage of HPV infections that were not preventable by HPV vaccination (32% [95% CI = 26-38] vs. 15% [95% CI = 11-21]; p < 0.001).

Conclusions

A higher HPV burden and a different HPV genotyping profile may contribute to the high rate of cervical cancer among AI women.

Abstract 4521: Ormeloxifene treatment inhibits growth of cisplatin-resistant ovarian cancer cells

Background: Ovarian cancer is one of the most lethal gynecological malignancies. With existing treatment options, recurrence is very common with only 30% five year survival rate. The poor survival rate is associated mainly with acquired resistance to chemotherapy drugs, such as cisplatin. Therefore, identification of novel treatment options is highly desirable. Herein, we investigated the anti-cancer potential of ormeloxifene in cisplatin-sensitive and cisplatin-resistant ovarian cancer cells.

Materials and Methods: Ovarian cancer cells SKOV-3 (semi-resistant to cisplatin), A2780-CP (cisplatin-resistant), and A2780 (cisplatin-sensitive) were treated with ormeloxifene (1-27 µM) and the effect on cell growth was determined by MTS and colony formation assays. Apoptotic cells were identified using TUNEL and propidium iodide (PI) staining. The effect of ormeloxifene treatment on the expression of apoptosis and cell survival related proteins was determined by Western blotting and Flow Cytometry. Tetramethylrhodamine (TMRE, a stain sequestered by mitochondria) staining was performed to determine the effect of ormeloxifene on mitochondrial membrane potential. For that, cells were treated with ormeloxifene (10-20 µM) at three different time points (6, 12, and 18 hours), incubated with TMRE (100 nM), and were analyzed by flow cytometry. For in vivo tumor xenograft study, athymic nude (nu/nu) mice were injected with A2780CP (5 million) cells into the peritoneum. These mice were treated with ormeloxifene (50 or 100 µg/mice/week, for 3 subsequent weeks). On day 35 after cell injection, tumor burden was recorded. Statistical significance was determined using a two-tailed student t-test with equal variance.

Results: In all three cell lines, ormeloxifene effectively inhibited cell growth in a dose-dependent manner in proliferation and colony forming assays. Further analysis using TUNEL and PI staining revealed a dose-dependent increase in percent of apoptotic cells. Immunoblotting assays showed a dose-dependent decrease in full-length caspase-9 and caspase-3 (indicating increased caspase activity), and a marked increase in cleaved Poly (ADP-ribose) polymerase (PARP). The TMRE assay also revealed a dose-and time-dependent decrease in mitochondrial membrane potential which is an early sign of the intrinsic apoptotic pathway. Interestingly, ormeloxifene treatment effectively blocked ovarian tumor growth of A2780CP ovarian cancer cells in xenograft mouse model.

Conclusions: Ormeloxifene treatment effectively inhibits growth of cisplatin sensitive and resistant ovarian cancer cell via induction of caspase-mediated apoptosis. Our data suggest that ormeloxifene induces an intrinsic apoptotic pathway by altering mitochondrial membrane potential followed by PARP cleavage. Therefore, ormeloxifene may be a potential treatment for cisplatin-resistant and cisplatin-sensitive ovarian cancer.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 4521. doi:10.1158/1538-7445.AM2011-4521

Mucin 13: structure, function, and potential roles in cancer pathogenesis

Mucin 13 (MUC13) is a high-molecular-weight transmembrane glycoprotein that is frequently and aberrantly expressed in a variety of epithelial carcinomas, including gastric, colorectal, and ovarian cancers. On the basis of the high expression of MUC13 in cancer cells as well as recent laboratory findings suggesting a malignant phenotype of MUC13-transfected cell lines, the oncogenic potential of MUC13 has emerged. The various functional domains of MUC13 may confer oncogenic potential to MUC13. For example, the bulky extracellular domain with extensive modification with glycan chains may prevent cell-cell and cell-extracellular matrix binding whereas the cytoplasmic tail containing serine and tyrosine residues for potential phosphorylation may participate in cell signaling. MUC13 exhibits the characteristics suitable as an early marker for cancer screening and presents a promising target for antibody-guided targeted therapy.

Risk factors for HPV infection among American Indian and white women in the Northern Plains

OBJECTIVE

American Indian (AI) women living in the Northern Plains have high incidence and mortality rates for cervical cancer. We assessed risk factors for human papillomavirus (HPV) infection among AI and White women.

METHODS

We tested cervical samples for HPV infection obtained from women ages 18-65 years attending 2 rural AI reservation clinics in South Dakota (n=235) and an urban clinic serving predominantly White women (n=246). Patients self-reported information on HPV risk factors. We used percentages and chi-square tests to compare risk factors, and logistic regression with HPV status as the outcome to quantify the association between HPV and risk factors.

RESULTS

AI women had more risk factors than White women, including younger age, less education, less vegetable consumption, more sexual partners, younger age at first sexual experience and first pregnancy, and more pregnancies (p values≤0.003). AI women more often endorsed recreational drug use, history of sexually transmitted diseases, and current smoking; White women reported more alcohol consumption (p values<0.001). In multivariate analysis, younger age and current smoking were associated with higher odds of HPV infection in AI women, whereas a higher number of sexual partners was associated with higher odds of HPV infection in White women.

CONCLUSIONS

AI women have a high burden of risk factors for HPV disease, and associations with HPV infection appear to differ by community. Knowledge of specific risk factors in AI populations may provide targets for public health officials to decrease HPV infection and disease.

Biotinylated PAMAM dendrimers for intracellular delivery of cisplatin to ovarian cancer: role of SMVT

AIM

The aim of this study was to prepare biotinylated PAMAM dendrimers loaded with cisplatin and to evaluate the cytotoxicity in ovarian cancer cell lines.

MATERIALS AND METHODS

Biotinylated and unconjugated dendrimer-cisplatin complexes were investigated for encapsulation efficiency, in vitro cytotoxic activity and cellular accumulation of cisplatin in OVCAR-3, SKOV-3, A2780 (wild-type) and CP70 (A2780/CP70, cisplatin-resistant) cells.

RESULTS

Encapsulation efficiency of cisplatin ranged from 5.33% to 21.10%. In vitro cytotoxic activity revealed that IC(50) values of dendrimer-cisplatin complexes were significantly lower than that of free cisplatin in OVCAR-3, SKOV-3 and CP70 cell lines. Cellular uptake data showed highest accumulation of platinum by PAMAMG(4) NH(2) dendrimer complexes of cisplatin in A2780 (19.41±0.85 μg/ml) and CP70 (25.25±1.25 μg/ml) cell lines in comparison with cisplatin uptake of only 1.77±0.351 μg/ml in A2780 and 2.31±0.421 μg/ml in CP70 cells.

CONCLUSION

In conclusion, biotinylated PAMAM dendrimers may be utilized as potential targeting agents for cisplatin delivery to ovarian cancer.

Abstract B66: Benzo(a)pyrene increases expression of HPV oncoproteins: A potential co-factor for increased cervical cancer among American Indian women living in the Northern Plains

Introduction: Cervical cancer remains one of the most common and deadly cancers in women worldwide. There is a significant health disparity in the incidence and mortality of cervical cancer between American Indian and Caucasian women, especially for American Indian women residing in the Northern Plains. The development of cervical cancer is closely associated with persistent infection with a high risk genotype of HPV. Additionally, exposure to cigarette smoke is also a risk factor for cervical cancer. Our previous and current studies indicate that American Indian women living in the Northern Plains have a high rate of both HPV infection and exposure to cigarette smoke. While smoking is known to increase the risk of developing cervical cancer, the molecular interactions between HPV and smoke carcinogens are not well known. The purpose of this study was to determine the molecular effects of benzo-a-pyrene (BaP) (a carcinogen in cigarette smoke) on the expression of HPV oncoproteins.

Methods: The effects of BaP on HPV associated molecular events was determined using cervical cancer cell lines. Following BaP exposure in either an acute or extended treatment protocol, the levels of HPV oncoproteins, activation of NFkB and AP-1 cell signaling pathways and intracellular reactive oxygen species (ROS) were determined using a combination of techniques including flow cytometry, immunofluorescence and immunoblotting. Cervical cancer cells were also treated with curcumin, a natural anti-cancer and chemopreventive compound.

Results: In cervical cancer cells, exposure to BaP increased the expression of HPV oncoproteins in both acute and extended treatment protocols. BaP exposure also increased activation of NFkB and increased levels of ROS. To address the mechanism of increased HPV E7 protein expression, we assessed the ability of BaP to activate AP1 signaling. The AP1 family of transcription factors (including c-Fos) is known to induce transcription of HPV E6/E7 through binding to the Upstream Regulatory Region (URR). We detected an increase in the amount of AP1 (c-Fos) in the nucleus of cervical cancer cells exposed to BaP, suggesting that BaP may increase HPV oncoprotein expression through modulation of AP1. Interestingly, BaP's increase in HPV oncoprotein expression was inhibited by curcumin treatment, likely through curcumin's inhibition of AP-1 and NFkB pathways.

Conclusion: Taken together this data imply that a high prevalence of HPV infection and a high exposure rate to BaP may synergize to increase the incidence and mortality of cervical cancer in American Indian women residing in the Northern Plains. Additionally, we have also identified curcumin as a potential compound that may be effective in preventing and/or treating cervical cancer. Increased cervical cancer screening is warranted for American Indian women living in the Northern Plains and additional steps, such as the use of the HPV vaccine and use of dietary agents, such as curcumin, may also be helpful to effectively decrease the health disparity associated with cervical cancer in American Indian women.

Citation Information: Cancer Epidemiol Biomarkers Prev 2010;19(10 Suppl):B66.

Curcumin induces chemo/radio-sensitization in ovarian cancer cells and curcumin nanoparticles inhibit ovarian cancer cell growth

Background

Chemo/radio-resistance is a major obstacle in treating advanced ovarian cancer. The efficacy of current treatments may be improved by increasing the sensitivity of cancer cells to chemo/radiation therapies. Curcumin is a naturally occurring compound with anti-cancer activity in multiple cancers; however, its chemo/radio-sensitizing potential is not well studied in ovarian cancer. Herein, we demonstrate the effectiveness of a curcumin pre-treatment strategy for chemo/radio-sensitizing cisplatin resistant ovarian cancer cells. To improve the efficacy and specificity of curcumin induced chemo/radio sensitization, we developed a curcumin nanoparticle formulation conjugated with a monoclonal antibody specific for cancer cells.

Methods

Cisplatin resistant A2780CP ovarian cancer cells were pre-treated with curcumin followed by exposure to cisplatin or radiation and the effect on cell growth was determined by MTS and colony formation assays. The effect of curcumin pre-treatment on the expression of apoptosis related proteins and β-catenin was determined by Western blotting or Flow Cytometry. A luciferase reporter assay was used to determine the effect of curcumin on β-catenin transcription activity. The poly(lactic acid-co-glycolic acid) (PLGA) nanoparticle formulation of curcumin (Nano-CUR) was developed by a modified nano-precipitation method and physico-chemical characterization was performed by transmission electron microscopy and dynamic light scattering methods.

Results

Curcumin pre-treatment considerably reduced the dose of cisplatin and radiation required to inhibit the growth of cisplatin resistant ovarian cancer cells. During the 6 hr pre-treatment, curcumin down regulated the expression of Bcl-X_L and Mcl-1 pro-survival proteins. Curcumin pre-treatment followed by exposure to low doses of cisplatin increased apoptosis as indicated by annexin V staining and cleavage of caspase 9 and PARP. Additionally, curcumin pre-treatment lowered β-catenin expression and transcriptional activity. Nano-CUR was successfully generated and physico-chemical characterization of Nano-CUR indicated an average particle size of ~70 nm, steady and prolonged release of curcumin, antibody conjugation capability and effective inhibition of ovarian cancer cell growth.

Conclusion

Curcumin pre-treatment enhances chemo/radio-sensitization in A2780CP ovarian cancer cells through multiple molecular mechanisms. Therefore, curcumin pre-treatment may effectively improve ovarian cancer therapeutics. A targeted PLGA nanoparticle formulation of curcumin is feasible and may improve the in vivo therapeutic efficacy of curcumin.

Abstract 2358: MUC13 mucin augments pancreatic tumorigenesis

Pancreatic cancer is one of the most lethal malignancies with extremely poor prognosis. The high death rate of pancreatic cancer is attributed to a lack of reliable methods of early diagnosis and underlying molecular mechanisms associated with aggressive pathogenesis. MUC13, a newly identified transmembrane mucin, is known to be aberrantly expressed in ovarian, gastric and colon cancer. However, the expression and functions of MUC13 in pancreatic cancer are unknown. Herein, we have investigated the expression and functions of MUC13 mucin, in pancreatic cancer to determine its potential for early cancer diagnosis and its role in pancreatic cancer pathogenesis. The expression profile of MUC13 in pancreatic cancer was investigated using a recently generated monoclonal antibody (MAb, clone PPZ0020) and pancreatic tissue microarrays. The expression of MUC13 was significantly (p&lt;0.005) higher in cancer samples compared to the normal/non-neoplastic pancreatic tissues. For the functional analyses, a full length MUC13 gene cloned in pcDNA3.1 was expressed in MUC13 null pancreatic cancer cell lines, MiaPaca and Panc1. The exogenous MUC13 expression induced morphological changes, including scattering of cells. These changes were abrogated through c-jun NH2-terminal kinase (JNK) chemical inhibitor (SP600125) or JNK2 siRNA. Additionally, a marked reduction in cell-cell adhesion and significant (p&lt;0.05) increases in cell motility, invasion, proliferation, clonogenicity and tumorigenesis in a xenograft mouse model system were observed upon exogenous MUC13 expression. These cellular characteristics were correlated with the up-regulation of HER2, p21-activated kinase1 (PAK1), extracellular signal-regulated kinase (ERK) and S100A4 (metastasin) and suppression of p53. Inhibition of MUC13 expression by MUC13 siRNA or shRNA resulted in suppression of tumorigenic characteristics in HPAFII pancreatic cancer cells. These results, for the first time, suggest that MUC13 expression augments pancreatic cancer progression and has potential as a diagnostic and/or therapeutic target.

Note: This abstract was not presented at the AACR 101st Annual Meeting 2010 because the presenter was unable to attend.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2358.

Combined staining of TAG-72, MUC1, and CA125 improves labeling sensitivity in ovarian cancer: antigens for multi-targeted antibody-guided therapy

Single antigen-targeted intraperitoneal radioimmunotherapy for ovarian cancer has shown limited success. Due to the heterogeneous expression of tumor antigens on cancer cells, a multi-antigen targeting approach appears logical to augment the therapeutic efficacy of antibody-guided therapy. In the interest of developing this novel approach, ovarian cancer tissue microarray slides containing cancer and benign/non-neoplastic tissue samples (n=92) were processed for single-, double-, and triple-antigen labeling using antibodies for the tumor-associated antigens TAG-72, MUC1, and CA125. Among all ovarian cancer types, 72%, 61%, and 50% of the samples showed immunolabeling for TAG-72, MUC1, and CA125, respectively. Expression level of these antigens was significantly (p<0.005) higher in advanced stage carcinomas compared with early stage. Of the 48 epithelial ovarian cancer samples, individual anti-TAG-72, MUC1, and CA125 antibody probing showed labeling in 89.5%, 87.5%, and 73.0% of the cases, respectively. In the majority of the cancer samples (>70%), a heterogeneous labeling pattern was observed (only 30-40% of the cancer cells within the sample were labeled). However, upon combining the three antigens (triple-antigen labeling), 98% of the epithelial ovarian cancer samples were labeled and >95% of the cancer cells within each sample were labeled. Our data indicate that the heterogeneous expression of cancer antigens appears to be a major obstacle in antibody-guided therapy, and this can be overcome by multiple antigen targeting. Therapeutic efficacy of antibody-guided therapy for ovarian cancer treatment will be enhanced by the combined targeting of TAG-72, MUC1, and CA125.

Expression of HIV receptors, alternate receptors and co-receptors on tonsillar epithelium: implications for HIV binding and primary oral infection

Background

Primary HIV infection can develop from exposure to HIV in the oral cavity. In previous studies, we have documented rapid and extensive binding of HIV virions in seminal plasma to intact mucosal surfaces of the palatine tonsil and also found that virions readily penetrated beneath the tissue surfaces. As one approach to understand the molecular interactions that support HIV virion binding to human mucosal surfaces, we have examined the distribution of the primary HIV receptor CD4, the alternate HIV receptors heparan sulfate proteoglycan (HS) and galactosyl ceramide (GalCer) and the co-receptors CXCR4 and CCR5 in palatine tonsil.

Results

Only HS was widely expressed on the surface of stratified squamous epithelium. In contrast, HS, GalCer, CXCR4 and CCR5 were all expressed on the reticulated epithelium lining the tonsillar crypts. We have observed extensive variability, both across tissue sections from any tonsil and between tonsils, in the distribution of epithelial cells expressing either CXCR4 or CCR5 in the basal and suprabasal layers of stratified epithelium. The general expression patterns of CXCR4, CCR5 and HS were similar in palatine tonsil from children and adults (age range 3–20). We have also noted the presence of small clusters of lymphocytes, including CD4⁺ T cells within stratified epithelium and located precisely at the mucosal surfaces. CD4⁺ T cells in these locations would be immediately accessible to HIV virions.

Conclusion

In total, the likelihood of oral HIV transmission will be determined by macro and micro tissue architecture, cell surface expression patterns of key molecules that may bind HIV and the specific properties of the infectious inoculum.

Ex vivo modeling of oral HIV transmission in human palatine tonsil

The majority of newly acquired HIV infections are believed to occur following transmission of virus infectivity across mucosal surfaces, although many mechanistic details still remain unresolved. We have used human ex vivo organ cultures and primary cell populations to analyze the cellular and molecular basis for mucosal HIV transmission. By using human palatine tonsil from routine tonsillectomies and semen from HIV-positive donors, we have created an experimental equivalent to oral HIV transmission. HIV infection was readily transferred into tonsillar lymphocytes, but this transmission into lymphocytes was dramatically reduced when the exposed lymphocyte populations were protected by intact mucosal surfaces. In this study, we consider the impact that leukocyte activation and morphological aberrations in surface structure may have on susceptibility to primary HIV infection and introduce novel time-lapse confocal microscopy procedures that begin to reveal the dynamic complexity associated with cell-mediated HIV transmission.

Inner-Shell Electron Spectroscopy for Microanalysis

The transmission electron energy-loss spectrum shows characteristic "edges" corresponding to the excitation of inner-shell electrons of atoms in a thin sample. Analysis of these edges provides detailed chemical, structural, and electronic data from the radiated volume. By combining electron spectroscopy and electron microscopy, this microanalytical technique can be performed in conjunction with highresolution imaging of the sample. It is shown that this approach has advantages of sensitivity, spatial resolution, and convenience over other comparable techniques.

Fluorinated molecule as a tracer: difluoroserotonin in human platelets mapped by electron energy-loss spectroscopy

The intracellular distribution of fluorine has been delineated in human platelets incubated with 4,6-difluoroserotonin, utilizing a scanning-transmission electron microscope equipped with an energy-loss spectrometer. Discrete intracellular structures corresponding in location to dense bodies contained high concentrations of fluorine. Electron energy-loss spectroscopy, which apparently can detect less than 10(-20) gram of fluorine in an area of 10 square nonometers, can thus localize fluorinated tracer molecules with biological activity.

The formation and interpretation of defect images from crystalline materials in a scanning transmission electron microscope

The technique of scanning transmission electron microscopy (STEM) has been employed usefully in studies of amorphous materials, and the theory of image formation and interpretation in this case has been well developed. Less attention has been given to the practical and theoretical problems associated with the use of STEM for the examination of crystalline materials. In this case the contrast mechanisms are dominated by Bragg diffraction and so they are quite different from those occurring in amorphous substances. In this paper practical techniques for the observation and interpretation of contrast from defects in crystalline materials are discussed. It is shown that whilst images of defects are obtained readily under all typical STEM operating conditions, the form of the image and the information it contains varies with the angle subtended at the specimen by the detector. If this angle is too large significant image modifications relative to the "conventional" transmission electron microscope case may occur and the resolution of the image may degrade. If this angle is too small, then signal to noise considerations make an interpretation of the image difficult. In this paper we indicate how the detector angle may be chosen correctly, and also present techniques for setting up a STEM instrument for imaging a crystalline material containing lattice defects.

Topographical contrast in the transmission electron microscope

An adaptation of the Foucault method for topographical imaging in the transmission electron microscope is described in detail. The image contrast is produced by selection of electrons which have suffered differential phase retardations in the specimen inner potential. Surface or interface displacements produce bright or dark image contrast, and the ultimate resolution approaches that of the atomic scale. The imaging method is applied in studies of both amorphous and crystalline objects. The possibility of performing quantitative measurements is demonstrated by the estimation of the inner potential of crystalline MgO.