bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 1753: XIAP maintains the characteristics of cancer stem cells and is a therapeutic target in nasopharyngeal carcinoma
Authors: ji jiao , Deng Rong , Chen Wen-Dan , Feng Gong-Kan , Zhu Xiao-Feng , Yang Da-Jun
Published: August 2015

Nasopharyngeal carcinoma (NPC) is a common malignancy in South China. Cancer stem cells (CSCs) are thought as the key players in the resistance to chemo- or radio-therapy and are response for tumor recurrence and metastasis, while their ability to escape from the apoptosis pathway may render them the resistant property to the therapies. We show that XIAP is overexpressed in the NPC cell line S18, which have the higher SP populations and CD44+ populations and the stronger abilities of sphere-formation and metastasis. Importantly, XIAP knockdown decreases SP and CD44+ populations, prevents sphere-formation and reduces the ability of invasion and migration. What more, loss of XIAP enhances the sensitivity of cells to conventional chemotherapy drugs CDDP and 5-FU. The primary xenograft tumor formation in vivo found there is a dramatic reduction in tumor formation in the XIAP KD group. They all indicate that XIAP plays an important role in nasopharyngeal cancer stem cell. Further studies show that XIAP limits MAPK signaling and thereby restricts differentiation and maintains the characteristics of cancer stem cells. We designed and synthesized a novel Smac mimetic compound APG-1387 that promotes the rapid degradation of cIAP1/2 and XIAP, and it exerts an antitumor effect on nasopharyngeal carcinoma cancer stem cells. Further studies show that APG-1387 enhances the chemosensitivity and promotes apoptosis in combination with CDDP and 5-FU of NPC in vitro and vivo.

Citation Format: jiao ji, Rong Deng, Wen-Dan Chen, Gong-Kan Feng, Xiao-Feng Zhu, Da-Jun Yang. XIAP maintains the characteristics of cancer stem cells and is a therapeutic target in nasopharyngeal carcinoma. [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 1753. doi:10.1158/1538-7445.AM2015-1753
Abstract 1769: Rottlerin induces ER stress-mediated cell death in pancreatic stellate cells
Authors: Su Hsin-Yuan , Waldron Richard , Gong Raymond , Pandol Stephen , Lugea Aurelia
Published: August 2015

Pancreatic ductal adenocarcinoma (PDAC) is a deadly disease with a 5-year survival rate under 5%. Whereas activated pancreatic stellate cells (PaSC) are important players in PDAC stroma, simultaneously targeting both cancer and stromal cells can be beneficial for cancer therapy. We previously reported that the phytochemical rottlerin dose-dependently reduces PaSC viability through dysregulation of autophagy and induction of apoptosis, and attenuates tumor progression in PDAC experimental models. Interestingly, both rottlerin and metformin have been shown to affect mitochondrial function, and metformin has been demonstrated to induce AMPK-dependent, CHOP-mediated cell death. Here we further studied the mechanisms underlying cell death and autophagy in rottlerin-treated mouse PaSC. Rottlerin rapidly depolarized mitochondrial membrane, increased oxygen consumption and decreased cellular ATP levels and the expression of the mitochondrial transmembrane protein TOM20, suggesting mitochondrial damage. Rottlerin dysregulated autophagy as indicated by rapid and prolonged increasing in LC3I-LC3II conversion and p62/SQSTM1 accumulation. However, rottlerin-induced LC3II did not further change in the presence of inhibitors of autophagic flux, suggesting that rottlerin blocks autophagy progression in PaSC. In addition, rottlerin induced marked AMPK activation and inhibited mTOR signaling. In contrast to metformin, AMPKα1/2 knockdown had no effect on rottlerin-induced inhibition of mTOR signaling and cell viability. Furthermore, rottlerin induced ER stress as manifested by persistent activation of the PERK pathway and upregulation of proapoptotic transcription factor CHOP. Importantly, rottlerin-induced apoptosis was greatly reduced in PaSC isolated from CHOP null mice. In summary, these data indicate that rottlerin reduces PaSC viability through impairing mitochondrial function, inhibiting mTOR signaling and inducing prolonged ER stress. Specifically, CHOP induction plays an important role in determining cell-fate in mitochondria-targeting agents, such as rottlerin and metformin.

Citation Format: Hsin-Yuan Su, Richard Waldron, Raymond Gong, Stephen Pandol, Aurelia Lugea. Rottlerin induces ER stress-mediated cell death in pancreatic stellate cells. [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 1769. doi:10.1158/1538-7445.AM2015-1769
Abstract 1770: A role of nicotinamide phosphoribosyltransferase in growth of KRAS mutant non-small cell lung cancer
Authors: Okumura Shunsuke , Sasaki Takaaki , Ohsaki Yoshinobu
Published: August 2015

Background:

KRAS mutations are frequently found in non-small cell lung cancer (NSCLC). The KRAS mutations could be predictive of resistance to targeted therapy like epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) or a prognostic factor in NSCLC. No successful targeted therapy currently exists to treat patients with KRAS mutant NSCLC, and novel therapeutic strategies are needed to prolong survival in patients with KRAS mutant NSCLC. Nicotinamide phosphoribosyltransferase (nampt) is a rate-limiting enzyme in NAD+ salvage, and we previously reported that nampt is a potent therapeutic target in NSCLC. Based on the analysis result of GEO database, we found that expression of nampt is associated with RAS-MAPK signaling pathway in NSCLC, and we therefore, conducted an in vitro study to evaluate a role of nampt in growth of KRAS mutant NSCLC.

Methods: We used a panel of KRAS mutant NSCLC cell lines (A427, A549, H157, H23, H1792, H2009, H358, H441, Calu6, Calu1). The cells were treated with a nampt inhibitor, FK866, and acid phosphatase (APH) assay (Thermo SCIENTIFIC) was used to evaluate cell viability of the KRAS mutant cells. Changes in expression of MAPK signaling pathway and BCL2 family proteins (antibodies from Cell Signaling and Santa Cruz) were evaluated by western blot. Apoptosis of the cells treated with FK866 was detected using an Annexin V FITC apoptosis detection kit (BD Biosciences). FACS analysis was performed using a BD FACSAria II cytometer (BD Bioscience). Autophagic proteolysis was studied by Cyto-ID autophagy detection kit (Cosmo Bio), and the expression of the fluorescent signal was visualized by a FV1000 confocal microscope (OLYMPUS JAPAN).

Results:

We found that the sensitivity to FK866 was different among the KRAS mutant cell lines, and for instance, A427 cells were sensitive while H157 cells were resistant. FK866 suppressed growth of KRAS mutant NSCLC and decreased expression of p-ERK expression in the cell line sensitive to FK866. We will report alteration of apoptosis and autophagy in the KRAS mutant NSCLC treated with FK866.

Conclusion:

Nampt could be a potent therapeutic target in KRAS mutant NSCLC.

Citation Format: Shunsuke Okumura, Takaaki Sasaki, Yoshinobu Ohsaki. A role of nicotinamide phosphoribosyltransferase in growth of KRAS mutant non-small cell lung 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 1770. doi:10.1158/1538-7445.AM2015-1770
Abstract 1774: The effects of diarylthiourea analogs on triple negative breast cancer cell growth
Authors: Nambi Deborah , Louie Maggie C. , Liu Shengquan
Published: August 2015

Breast cancer is the most common cancer occurring in women and the second leading cause of cancer death in women after lung cancer. Breast cancer is often classified at the molecular level in terms of whether the cancer expresses the estrogen receptor, progesterone receptor and human epidermal growth factor 2 receptor. Hormone receptor positive breast cancer accounts for 75-80% of all breast cancer and the remaining 20-25% accounts for the most aggressive types of cancer which are negative for all three receptors– known as triple negative breast cancer (TNBC). The current treatment used to manage TNBC is chemotherapy. Although chemotherapy has been effective in improving patients’ prognosis, a significant number of patients either relapse or develop resistance to these drugs. There is a significant interest in developing new therapeutic drugs aimed at improving outcomes in TNBC patients. Many studies have shown that flexible heteroarotinoids (Flex-Het) are a promising new class of drugs due to their ability to regulate growth, differentiation and apoptosis in a variety of cancer cells without activating the nuclear retinoic acid receptors. Previous studies have shown ShetA2 as the leading Flex-Het anti-cancer drug with the greatest efficacy in treating various types of cancer cells (Liu et al. 2004, Benbrook et al. 2005, and Liu et al. 2007). Some of the limitations of the ShetA2 are its high lipophilicity, toxic side effects and the low yields associated with the laborious synthesis. Therefore, efforts have been made to develop 2nd generation diarylthiourea compounds that retain anti-cancer activity, but with minimal side effects. The objective of this study was to examine the effects of two 2nd generation drugs SL1-18 and SL1-09 on various TNBC cell lines including MDA-MB-453, MDA-MB-231 and MDA-MB-468. Our preliminary data shows that exposure to micromolar levels of the diarylthiourea compounds effectively inhibited cancer cell growth in all three TNBC cell lines; however additional studies are necessary to understand the molecular mechanism of how SL1-18 and SL1-09 work to block cell growth and whether these anti-cancer drugs are promising therapeutic leads for the treatment of triple negative breast cancer.

Citation Format: Deborah Nambi, Maggie C. Louie, Shengquan Liu. The effects of diarylthiourea analogs on triple negative breast cancer cell growth. [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 1774. doi:10.1158/1538-7445.AM2015-1774
Abstract 1781: G1 phase melanoma cells escape proteasome inhibitor cytotoxicity
Authors: Daignault Sheena M. , Hill David S. , Beaumont Kimberley A. , Anfosso Andrea , Lovat Penny E. , Weninger Wolfgang , Haass Nikolas K.
Published: August 2015

Utilising the fluorescent ubiquitination-based cell cycle indicator (FUCCI), which facilitates real-time cell cycle tracking, we have demonstrated in vitro and in vivo that melanomas are composed of differentially cycling tumour cells in a subcompartment-specific distribution. Further, we have shown that targeting the endoplasmic reticulum with fenretinide (synthetic retinoid) or bortezomib (26S proteasome inhibitor) induces cell cycle arrest and apoptosis of metastatic melanoma cells in vitro and in vivo.

This study aims to investigate the effect of ER stress-inducing agents on the dynamics of cell division and cell death of individual melanoma cells within the complex tumor microenvironment, and to develop combination strategies that increase the efficacy of ER stress-inducing agents for melanoma therapy.

FUCCI-melanoma cells were grown as 3D spheroids and implanted into a collagen matrix to mimic tumor architecture and microenvironment. Utilising the F-XBP1ΔDBD-venus reporter construct, which labels the cytoplasm in response to ER stress, we found that bortezomib induced ER stress, delayed cell cycle progression, and combination with fenretinide increased cell death in 2D and 3D culture. Flow cytometry and confocal microscopy indicated that treatment of FUCCI-melanoma cells with bortezomib induced G2 accumulation in 2D and 3D culture over the course of 24 h. In contrast, by 72 h the majority of cells were in G1 phase. Analysis of 2D and 3D real-time cell cycle imaging movies revealed that bortezomib induced both G1- and G2 arrest, but preferentially killed G2-phase cells. Consequently, pretreatment with temozolomide or fenretinide, leading to G2-arrest, sensitised melanoma cells to bortezomib cytotoxicity. In contrast, pretreatment with MEK inhibitors, leading to G1 arrest, inhibited bortezomib cytotoxicity in all melanoma cells, as did selective BRAF inhibitors in BRAF mutant melanoma cells.

Our data suggest that bortezomib combined with fenretinide or temozolamide is a strategy worth exploring for the treatment of BRAF-inhibitor insensitive or resistant melanoma. Importantly, melanoma cells arrested in G1 are protected from bortezomib cytotoxicity, which excludes MAPK pathway inhibitors as combination partners.

Citation Format: Sheena M. Daignault, David S. Hill, Kimberley A. Beaumont, Andrea Anfosso, Penny E. Lovat, Wolfgang Weninger, Nikolas K. Haass. G1 phase melanoma cells escape proteasome inhibitor cytotoxicity. [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 1781. doi:10.1158/1538-7445.AM2015-1781
Abstract 1786: Role of Euphorbia tirucalli terpenes cocktail extracts in the regulation of molecular cell death: implications in gynecological cancer progression
Authors: Choene Mpho , Motadi Lesetja
Published: August 2015

Gynaecological cancers are increasingly becoming the cause of death in females in developing countries. This type of cancers, especially cervical cancer is in the increase due to co-infection with HIV. Many of these people are solely dependent on traditional remedies, as conventional treatment might be expensive or inaccessible to them. In this study we characterised butanolic, hexane and methanolic extracts of Euphorbia tirucalli using both TLC and LC-MS spectroscopy. Following extract analysis, we looked at the effects of the extracts in regulating cell death in breast (MDA-MB 231), ovarian (RMG-1) and cervical (SiHa) cancer cell lines. The cells were treated with varying concentrations of the cocktailed extracts for up to 48 hours. A real time cell analyzer (xCELLigence) was used to monitor cell growth and to determine IC50. MTT assay was used to assess cell viability 24 hours post treatment with extracts. To determine if the extracts had an effect on cell cycle arrest, cell cycle distribution was determined by staining treated cancer cells with propidium iodide and the percentages of G0/G1, S, G2/M cell populations were analysed using flow cytometry. To determine the type of cell death induced, flow cytometry using annexin V was employed. At IC50, molecular analysis was performed to evaluate the effect cocktailed extracts had on apoptotic and cell cycle genes. Cocktailed extracts were found to inhibit cell proliferation in a concentration and cell type dependent manner. Cells were also found to have been arrested at G0/G1 and in some cases apoptosis induced. In general most pro-apoptotic genes like Bax and caspase-8 were upregulated this included the cell cycle gene p21 which was found to be significantly up-regulated in cells treated with extracts. These results suggest that the 3 cocktailed extracts might induce apoptosis or arrest cells at G0/G1 with the molecular mechanism that suggest activation of caspase-8 and Bax.

Note: This abstract was not presented at the meeting.

Citation Format: Mpho Choene, Lesetja Motadi. Role of Euphorbia tirucalli terpenes cocktail extracts in the regulation of molecular cell death: implications in gynecological cancer progression. [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 1786. doi:10.1158/1538-7445.AM2015-1786
Abstract 1789: Drug repurposing: Sulfasalazine sensitizes gliomas to gamma knife surgery by blocking cystine uptake through System XC−, leading to gluthatione depletion
Authors: Sleire Linda , Skeie Bente Sandvei , Netland Inger Anne , Førde Hilde Elise , Dodoo Ernest , Selheim Frode , Leiss Lina , Wang Jian , Heggdal Jan , Pedersen Paal-Henning , Enger Per Øyvind
Published: August 2015

Glioblastomas (GBMs) are lethal cancers and inherently resistant to radiotherapy. Established treatments including surgery, radio- and chemotherapy have a limited efficacy, and the median survival is approximately 14.6 months. Thus, treatment resistance represents a major challenge in the clinical management of these patients, and new therapies are urgently needed.

We hypothesized that the Xc−-inhibitor sulfasalazine (SAS) could potentiate the efficacy of radiotherapy against gliomas. Expression of the catalytic subunit of system Xc−, xCT, was found in a panel of 30 human GBM biopsies. Sections from normal brain tissue displayed only weak immunopositivity, thus our findings therefore suggest that xCT expression is common to most GBMs, which together with its low expression in normal brain tissue could provide a therapeutic window. SAS treatment dramatically reduced cysteine-uptake and glutathione (GSH) levels in glioma cells in vitro and markedly increased the levels of reactive oxygen species (ROS). Furthermore, SAS and radiation synergistically increased DNA double-strand breaks and increased glioma cell death, whereas adding the antioxidant N-acetyl-L-cysteine (NAC) reversed cell death. Moreover, SAS and gamma knife radiosurgery (GKRS) synergistically prolonged survival in nude rats harboring human GBM xenografts, compared to controls or either treatment alone. In conclusion, SAS effectively blocks cystine uptake in glioma cells in vitro, leading to GSH depletion and increased ROS levels, DNA damage and cell death. Moreover, it potentiates the anti-tumor efficacy of GKRS in rats with human GBM xenografts, providing a survival benefit. Thus, SAS may have a role as a radiosensitizer to enhance the efficacy of current radiotherapies for glioma patients. We are currently preparing a clinical trial for patients with GBM recurrences combining pre-treatment with SAS and GKRS.

Citation Format: Linda Sleire, Bente Sandvei Skeie, Inger Anne Netland, Hilde Elise Førde, Ernest Dodoo, Frode Selheim, Lina Leiss, Jian Wang, Jan Heggdal, Paal-Henning Pedersen, Per Øyvind Enger. Drug repurposing: Sulfasalazine sensitizes gliomas to gamma knife surgery by blocking cystine uptake through System XC−, leading to gluthatione depletion. [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 1789. doi:10.1158/1538-7445.AM2015-1789
Abstract 181: miR-134 targets programmed cell death 7 (PDCD7) gene to modulate the pathogenesis of head and neck carcinoma
Authors: Peng Shih-Yuan , Chang Kuo-Wei , Lin Shu-Chun , Tu Hsi-Feng
Published: August 2015

Head and neck squamous cell carcinoma (HNSCC) is one of the prevalent malignancies in the world. microRNAs (miRNAs) are involved in the neoplastic process of various malignancies including HNSCC to mediate post-transcriptional down-regulation of target genes. This study shows that miR-134 enhances the proliferation, migration and invasion of HNSCC cells. In silico modules predict that programmed cell death 7 (PDCD7) gene could be one of the targets of miR-134. In stable HNSCC cell subclones, ectopic miR-134 expression decreased PDCD7 expression; while the ectopic miR-134Zip expression increased PDCD7 expression. Reporter assays confirmed the binding of miR-134 to the wild type 3′UTR of PDCD7, which decreased reporter activity. The targeting of miR-134 to the 3′UTR of PDCD7 was abolished by the mutations in targeted sequences. Moreover, miR-134Zip expression increased the activity of wild type reporter. Down-regulation of PDCD7 was identified in around 70% of HNSCC tumors, which was significantly opposite to miR-134 expression. A trend of reverse expression between miR-134 and PDCD7 was also present in HNSCC cell lines. PDCD7 was up-regulated following the apoptosis induced by cis-platin. Ectopic PDCD7 expression decreased the proliferation and migration of HNSCC cells, but it was unable to affect apoptosis or drug resistance status. Moreover, miR-134 associated oncogenicity was attenuated by PDCD7 expression. Taking together, this study concludes that the oncogenic potential of miR-134 in head and neck carcinoma is able to be mediated by targeting PDCD7.

Citation Format: Shih-Yuan Peng, Kuo-Wei Chang, Shu-Chun Lin, Hsi-Feng Tu. miR-134 targets programmed cell death 7 (PDCD7) gene to modulate the pathogenesis of head and neck carcinoma. [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 181. doi:10.1158/1538-7445.AM2015-181
Abstract 1825: Carbonylation and degradation of cardiac myosin binding protein C serves as an indicator of doxorubicin-induced cardiotoxicity
Authors: Aryal Baikuntha P. , Jeong Jinsook , Rao V. Ashutosh
Published: August 2015

Dose-dependent oxidative stress by the anthracycline doxorubicin (Dox) and other chemotherapeutic agents causes irreversible cardiac damage, restricting their clinical effectiveness. We hypothesize that irreversible protein oxidation caused by oxidative stress could be correlated with physiological functional impairment. We focused our study on protein carbonylation as an indicator of severe oxidative damage. We identified a specific cardiac protein that showed selective carbonylation under Dox-induced cardiotoxic conditions in a spontaneously hypertensive rat (SHR) model and this protein was confirmed to be a 140 kDa cardiac myosin binding protein C (MyBPC) using mass spectrometry. We further analyzed and confirmed the carbonylation and degradation of this protein using HL-1 cardiomyocytes under Dox-induced oxidative stress, and a purified recombinant rat cardiac MyBPC under metal-catalyzed oxidative stress conditions. Using HL-1 cells we demonstrated that carbonylated MyBPC undergoes proteasome-mediated degradation under Dox-induced oxidative stress. Using immunoprecipitation, co-sedimentation, and actin-binding assays we confirmed the functional impairment of MyBPC as a consequence of carbonylation. Carbonylation of recombinant MyBPC showed significant impairment in its actin binding properties with a dissociation constant of 7.35±1.9 μM compared to 2.7±0.6 μM for native MyBPC. Overall, our findings indicate that MyBPC carbonylation serves as a critical determinant of cardiotoxicity. We are currently investigating the interaction of MyBPC with divalent metal ions and sites of carbonylation under oxidative stress conditions.

Citation Format: Baikuntha P. Aryal, Jinsook Jeong, V. Ashutosh Rao. Carbonylation and degradation of cardiac myosin binding protein C serves as an indicator of doxorubicin-induced cardiotoxicity. [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 1825. doi:10.1158/1538-7445.AM2015-1825
Abstract 1847: AR-V7 regulation during epithelial plasticity
Authors: Ware Kathryn E. , Schaeffer Daneen , Zhang Tian , Garcia-Blanco Mariano A. , Armstrong Andrew J.
Published: August 2015

Background: The androgen receptor (AR) is a key gene involved in prostate cancer (PC) biology, including disease development, response to initial hormonal therapies, and subsequent resistance to hormonal therapies. AR variants lacking the ligand-binding domain, such as AR-V7, have been observed and enriched in metastatic castration resistant prostate cancer. These variants contribute to resistance mechanisms against agents that target hormonal regulation of the AR, including anti-androgens, such as enzalutamide. In addition to AR variants, epithelial plasticity, including an epithelial-to-mesenchymal transition (EMT), has been implicated in PC metastatic dissemination during castration-resistance. In response to androgen deprivation therapy, PC xenografts have been found to display an acute and reversible up-regulation of both EMT phenotypic markers and AR variants.

Methods: To explore the mechanism by which an EMT program may regulate AR variant expression and metastatic disease, we used pre- and post- EMT cells to compare AR expression, migration, invasion and enzalutamide resistance. To induce EMT, we stably transfected LNCaP95 PC cells with a plasmid encoding inducible Snail, a master regulator of EMT. In addition, LNCAP95 cells were serially passaged under increasing enzalutamide conditions and we assessed biomarkers of EMT and invasion/growth in resistant cells.

Results: We found that Snail activation was sufficient to induce an EMT and increased expression of both AR-FL and AR-V7 as compared to pre-EMT cells. Nuclear localization of AR, migration and invasion were also increased in post-EMT cells. Importantly, cells were more resistant to enzalutamide treatment. Likewise, in a second model of acquired enzalutamide resistance, we found that Snail, AR-FL and AR-V7 were upregulated in enzalutamide resistant vs. sensitive cell lines.

Conclusion: Our study suggests that Snail activation promotes both an aggressive and therapy resistant tumor cell through the induction of EP and both AR-FL and AR-V7 isoforms.

Citation Format: Kathryn E. Ware, Daneen Schaeffer, Tian Zhang, Mariano A. Garcia-Blanco, Andrew J. Armstrong. AR-V7 regulation during epithelial plasticity. [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 1847. doi:10.1158/1538-7445.AM2015-1847
Abstract 1848: PPARγ function is attenuated by full length androgen receptor and the AR-V7 variant in human prostate cancer cells
Authors: Olokpa Emuejevoke , Stewart Lamonica V.
Published: August 2015

The peroxisome proliferator activated receptor gamma (PPARγ) is a ligand-activated transcription factor that regulates in vitro and in vivo growth of castration-resistant human prostate cancer (PCa) cells. However, the factors that control expression of PPARγ within human PCa have not been characterized. We have previously shown that the androgen dihydrotestosterone decreases PPARγ levels and transcriptional activity in human PCa cells. Dihydrotestosterone serves as a high affinity ligand for the 110 kD form of the androgen receptor (AR-FL). Recent studies have shown the development of castration-resistant forms of prostate cancer is not only due to reactivation of AR-FL but also results from the expression of androgen receptor splice variants (ARVs) that lack the ligand-binding domain of the receptor. The goal of this study is to define the extent to which AR-FL and an ARV found in castration-resistant prostate cancer, AR-V7, regulate PPARγ expression and function. We first examined the role of AR-FL in the AR-positive C4-2 cell line. siRNA-mediated knockdown of endogenous AR-FL within C4-2 cells increased PPARγ protein and transcriptional activity. We next used reporter assays to further define the role of AR-FL and AR-V7 in PPARγ function. In these experiments, we first transfected plasmid vectors that express the AR-V7 or AR-FL into the AR null PC-3 prostate cancer cell line. A luciferase-based reporter assay was then used to measure alterations in PPARγ transcriptional activity within transfected cells. The addition of AR-FL to PC-3 cells resulted in reduced basal PPARγ luciferase activity. The ability of the ligand rosiglitazone to increase PPARγ activation was also suppressed in AR-FL positive PC-3 cells. A comparable decrease in ligand-induced PPARγ activation was detected in PC-3 cells that expressed AR-V7. The reduction in PPARγ activity produced by AR-FL and AR-V7 was likely not due to alterations in PPAR gamma expression, for we did not detect a consistent reduction in PPARγ mRNA and protein in transfected cells. Overall these data suggest that both AR-FL and AR-V7 are negative regulators of PPARγ function. Moreover, the AR-V7 stimulated reduction in PPARγ activity does not require the presence of AR-FL. Studies currently are underway to define the effect of endogenous AR-V7 on PPARγ expression and activity. This project was supported by NIGMS RISE grant (2R25GM059994-13), a NCI Mentored Career Development Award (K01CA114253), and the Vanderbilt CTSA grant UL1 RR024975-01 from NCRR/NIH.

Citation Format: Emuejevoke Olokpa, Lamonica V. Stewart. PPARγ function is attenuated by full length androgen receptor and the AR-V7 variant in human prostate cancer cells. [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 1848. doi:10.1158/1538-7445.AM2015-1848
Abstract 1850: Evaluation of Pim-1 kinase inhibition in a preclinical model of mouse prostate cancer
Authors: De Velasco Marco A. , Oki Takashi , Kura Yurie , Ando Naomi , Fukushima Emiko , Davies Barry R. , Huszar Dennis , Yamamoto Yutaka , Hatanaka Yuji , Shimizu Nobutaka , Yoshimura Kazuhiro , Nozawa Masahiro , Yoshikawa Kazuhiro , Nishio Kazuto , Uemura Hirotsugu
Published: August 2015

Pim-1 is a serine/threonine kinase that is in involved in the transcription of genes that regulate apoptosis and cell cycle progression. Pim-1 has been shown to be overexpressed in a variety of cancers and has been implicated in human prostate tumorigenesis. The aim of our study was to clarify the role of Pim-1 during the prostate tumorigenesis and determine its potential as a molecular target for therapy. To accomplish this goal, we carried out a series of experiments using a genetically engineered mouse model of prostate cancer driven by the conditional inactivation of PTEN. High levels of Pim-1 were observed during the early stages of the tumorigenesis process which decreased as tumors progressed. Expression of Pim-1 was localized in the nucleus and cytoplasm of prostatic intraepithelial neoplasia (PIN), well-differentiated, and moderately-differentiated tumors. In poorly-differentiated tumors, Pim-1expression was heterogeneously expressed at lower levels and was predominantly localized to the cytoplasm of cancer cells. Levels of Pim-1 expression were increased in tumors from mice after surgical castration. To evaluate the therapeutic potential of Pim-1as a target for prostate cancer, we tested the antitumor effects of AZD1208, a highly potent Pim kinase inhibitor, on a panel of cell lines derived from castration-naïve and castration-resistant mouse prostate cancer. AZD1208 inhibited the tumor cell growth of several cell lines and demonstrated higher sensitivity to those derived from castration resistant tumors. In vivo, drug intervention studies show that treatment with AZD1208 reduced tumor growth of castration-naïve and castration-resistant prostate tumors by 12.1 (P = 0.162) and 24.3% (P<0.001), respectively. These findings provide further support for a role of Pim-1 during prostate tumorigenesis and could thus serve as a rational target for the development of novel combination strategies.

Citation Format: Marco A. De Velasco, Takashi Oki, Yurie Kura, Naomi Ando, Emiko Fukushima, Barry R. Davies, Dennis Huszar, Yutaka Yamamoto, Yuji Hatanaka, Nobutaka Shimizu, Kazuhiro Yoshimura, Masahiro Nozawa, Kazuhiro Yoshikawa, Kazuto Nishio, Hirotsugu Uemura. Evaluation of Pim-1 kinase inhibition in a preclinical model of mouse prostate 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 1850. doi:10.1158/1538-7445.AM2015-1850
Abstract 1864: Selective estrogen receptor degrader (SERD) activity in ESR1 mutant models
Authors: Zhou Wei , Blake Robert A. , Nonomiya Jim , Qian Jing , Kategaya Lorna , Wertz Ingrid , Daemen Anneleen , O'Brien Thomas , Sensintaffar John , Moon Michael , Nannini Michelle A. , Oeh Jason , Sampath Deepak , Wang Xiaojing , Smith Nicholas , Brigham Daniel , Joseph James , Hager Jeffrey H. , Friedman Lori S.
Published: August 2015

The majority of breast cancers express and rely on ERα for tumor growth, thus endocrine therapy is the mainstay of ER-positive breast cancer treatment. Despite the effectiveness of current therapies, many patients relapse with tumors still dependent on ER for growth via both estrogen-dependent and estrogen-independent mechanisms. Acquired mutations in ESR1 were recently identified in the ligand-binding domain of ERα in patients who progressed after aromatase inhibitors and tamoxifen. It is estimated that more than 20% of relapsed ER-positive breast cancer patients acquire activating mutations in ESR1. We created a variety of model systems to study the functional consequences of ESR1 mutations. In stable overexpressing cell lines, the mutant ER protein eventually becomes down-regulated, thus we generated cell lines with dox-inducible and CRISPR engineered ESR1 hotspot mutations. We confirmed ligand-independent transcriptional activity of ESR1 hotspot mutations including Y537S and D538G. Cell lines and patient derived xenograft (PDX) models were utilized in ER ChIP-seq studies. Additionally, we investigated therapeutic response and resistance in the context of ESR1 activating mutations for tamoxifen, fulvestrant, and next generation oral SERDs including ARN-810, also known as GDC-0810. ARN-810 is efficacious in MCF7 ESR1 Y537S xenografts and WHIM20 Y537S PDX tumors, indicating that SERDs may be effective for ER mutants.

Citation Format: Wei Zhou, Robert A. Blake, Jim Nonomiya, Jing Qian, Lorna Kategaya, Ingrid Wertz, Anneleen Daemen, Thomas O'Brien, John Sensintaffar, Michael Moon, Michelle A. Nannini, Jason Oeh, Deepak Sampath, Xiaojing Wang, Nicholas Smith, Daniel Brigham, James Joseph, Jeffrey H. Hager, Lori S. Friedman. Selective estrogen receptor degrader (SERD) activity in ESR1 mutant models. [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 1864. doi:10.1158/1538-7445.AM2015-1864
Abstract 1887: Calcium intake and milk product consumption in association with risk for colorectal adenomas
Authors: Um Caroline , Fedirko Veronika , Flanders W Dana , Bostick Roberd M.
Published: August 2015

Calcium intake has been consistently, albeit modestly associated with lower risk of colorectal cancer and adenomas, and supplemental calcium reduced adenoma recurrence in large randomized controlled trials. Milk-based dairy products are the major source of dietary calcium in the US, but the association between milk product consumption and colorectal cancer is unclear. Conventionally produced milk contains significant levels of insulin-like growth factor 1 (IGF-1) from the use of bovine somatotropin hormone. Calcium intake has been positively associated with IGF-1 and IGF-1 binding protein 3 (IGFBP-3) levels. Higher circulating levels of IGF-1 and the IGF-1:IGFBP-3 ratio have been associated with higher risk of certain cancers, including breast, prostate, and colorectal, as well as with adenomatous polyps.

To investigate associations of calcium and milk product intakes with risk for colorectal neoplasms, we pooled data from three colonoscopy-based case-control studies of incident, sporadic colorectal adenoma (n = 786 cases, 2,020 controls) conducted between 1991 and 2002, and analyzed the data using multivariable unconditional logistic regression. Dietary and supplemental intakes in all three studies were assessed using Willett food frequency questionnaires. For indirect indicators of IGF-1 intake from milk products, dietary calcium-adjusted residuals were calculated for total milk products and non-fat milk. For total, dietary, and supplemental calcium intakes, the multivariable-adjusted odds ratios (ORs) comparing the highest to the lowest quintiles of intake were 0.87 (95% confidence interval [CI] 0.63-1.20), 0.91 (95% CI 0.65-1.28), and 0.96 (95% CI 0.70-1.31), respectively. The corresponding ORs for consumption of total milk products, total milk, non-fat milk, total milk product residuals, and non-fat milk residuals were, 1.01 (95% CI 0.74-1.36), 0.97 (95% CI 0.73-1.29), 0.95 (95% CI 0.71-1.25), 0.92 (95% CI 0.70-1.22), and 0.97 (95% CI 0.70-1.34), respectively. For those who consumed any whole milk relative to those who consumed none, the OR was 1.15 (95% CI 0.89-1.50).

These results are consistent with previous findings of modestly lower risk with higher total (dietary plus supplemental) calcium intakes, but suggest that neither the consumption of specific milk products nor all milk products combined, nor the non-calcium components of milk products are associated with risk for sporadic colorectal adenoma.

Citation Format: Caroline Um, Veronika Fedirko, W Dana Flanders, Roberd M. Bostick. Calcium intake and milk product consumption in association with risk for colorectal adenomas. [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 1887. doi:10.1158/1538-7445.AM2015-1887
Abstract 1912: Reduction of microRNA-21 by vitamin D compounds during ductal carcinoma in situ transition to invasive ductal carcinoma
Authors: Wahler Joseph , Cheng Larry C. , Maehr Hubert , Uskokovic Milan , Suh Nanjoo
Published: August 2015

MicroRNAs (miRNAs) are small RNA molecules of approximately 22 nucleotides in lengths that can negatively control target gene expression post-transcriptionally. There are currently more than one hundred known human miRNAs. miRNAs have been shown to play an important role in the development and progression of various types of cancer. In breast cancer, ductal carcinoma in situ (DCIS) is an early non-invasive precursor, which is known to progress to invasive ductal carcinoma (IDC) if left untreated. The involvement of miRNAs in the breast cancer progression from DCIS to IDC is still not well understood, and potential regulation of miRNAs by vitamin D compounds during the progression has not been tested. We have previously reported that a novel Gemini vitamin D analog, 1α,25-dihydroxy-20R-21(3-hydroxy-3-deuteromethyl-4,4,4-trideuterobutyl)-23-yne-26,27-hexafluoro-cholecalciferol (BXL0124), inhibits the progression of DCIS to IDC in vivo. To identify miRNAs that could potentially be involved in DCIS progression to IDC, we utilized the MCF10DCIS.com xenograft tumors. MCF10DCIS.com cells (10^6 cells/mouse) were injected subcutaneously into the rear flanks of nu/nu mice. The mice were then treated with BXL0124 (0.1 μg/kg) for 5 weeks. The critical DCIS to IDC transition occurred between weeks 3 and 4 in the in vivo lesions, and several microRNAs were assessed with respect to the DCIS to IDC transition at weeks 3 and 4. Among many miRNAs analyzed, miR-21, miR-24, and miR-140 were up-regulated in IDC lesions compared to DCIS lesions, whereas no marked changes were observed with respect to miR-200c, miR-let-7a, miR-26a, miR-34a, and miR-182. One of the miRNAs identified miR-21, is a well-known oncomir and overexpressed in breast carcinoma, mediating cell survival, proliferation, and metastasis. The increased expression of miR-21 was significant when DCIS lesions progressed to IDC, and this effect was diminished by the treatment with Gemini vitamin D, BXL0124, at week 4. In conclusion, vitamin D compounds reduce the levels of miR-21 during DCIS transition to IDC, potentially contributing to its preventive effects in breast cancer progression. Further investigation of the mechanisms of action by which vitamin D compounds regulate miR-21 should be considered. (This work was supported in part by the National Institutes of Health National Cancer Institute R01-CA127645 and the National Institute of Environmental Health Sciences Grant ES005022).

Citation Format: Joseph Wahler, Larry C. Cheng, Hubert Maehr, Milan Uskokovic, Nanjoo Suh. Reduction of microRNA-21 by vitamin D compounds during ductal carcinoma in situ transition to invasive ductal carcinoma. [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 1912. doi:10.1158/1538-7445.AM2015-1912
Abstract 1917: Targeting wildtype and L858R/T790M mutant EGFR by isoliquiritigenin induces apoptosis and Inhibits tumor growth of NSCLC
Authors: Lee Mee-Hyun , Jung Sung Keun , Lim Do Young , Cho Yong-Yeon , Lee Cheol-Jung , Song Ji-Hong , Kim Myoung Ok , Kim Sung-Hyun , Bode Ann M. , Dong Zigang
Published: August 2015

Genetic alteration of epidermal growth factor receptor (EGFR) is a high risk factor of non-small-cell lung cancer (NSCLC). Isoliquiritigenin (ILQ), a chalcone derivative, reported anti-cancer activities. In this study, we investigated the effects of ILQ on the growth of tyrosine kinase inhibitor -sensitive and -resistant NSCLC cells and elucidated its molecular mechanisms. Treatment with ILQ inhibited growth and induced apoptosis in both tyrosine kinase inhibitor-sensitive (HCC827, H1650; delE746-A750 EGFR) and -resistant (H1975; L858R/T790M EGFR) NSCLC cells. However, ILQ didn't showed the inhibitory effects of cell growth and induction of apoptosis in Met amplified-HCC827GR or K-ras mutated-A549 cells. ILQ induced apoptotic markers, the cleavage of caspase-3 and poly-(ADP ribose)-polymerase, increased expression of Bim and reduced expression of Bcl-2. ILQ inhibited the catalytic activity of both wildtype and double mutant (L858R/T790M) EGFR by kinase assay. Treatment with ILQ inhibited the anchorage-independent growth of NIH3T3 cells stably transfected with either wildtype or double-mutant EGFR with or without EGF stimulation. ILQ also reduced the phosphorylation of Akt and ERK1/2 in both TKI-sensitive and -resistant NSCLC cells in the western blotting analysis. ILQ directly bound both wildtype and double-mutant EGFR by ATP-competitive manner. Computational docking model expected that ILQ interacted with Glu762 and Met793 sites of wildtype EGFR and Lys745, Met793 and Asp855 of mutant EGFR. ILQ attenuated the tumor growth of H1975 cell xenografted athymic mice in vivo, which was caused by decreased expression of Ki-67 and diminished phosphorylation of Akt and ERK1/2. Taken together, ILQ suppresses NSCLC cell growth by directly targeting wildtype or mutant EGFR.

Citation Format: Mee-Hyun Lee, Sung Keun Jung, Do Young Lim, Yong-Yeon Cho, Cheol-Jung Lee, Ji-Hong Song, Myoung Ok Kim, Sung-Hyun Kim, Ann M. Bode, Zigang Dong. Targeting wildtype and L858R/T790M mutant EGFR by isoliquiritigenin induces apoptosis and Inhibits tumor growth of NSCLC. [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 1917. doi:10.1158/1538-7445.AM2015-1917
Abstract 1919: Warfarin-dependent gamma-carboxylation regulates androgen receptor activity
Authors: Tew Ben Yi , Hong Teresa , Pal Sumanta K. , Kalkum Markus , Jones Jeremy
Published: August 2015

The anti-coagulant warfarin prevents the gamma-carboxylation (gla) of target proteins by interfering with the vitamin K cycle through its inhibition of the vitamin K epoxide reductase (VKOR). Most known gla proteins are found in the blood clotting cascade, but we demonstrate using immunoprecipitation and mass spectrometry that the androgen receptor (AR) can also be gamma-carboxylated. This modification occurs at amino acid 2E and can be prevented by warfarin treatment. This residue has been found to be mutated in partial androgen insensitivity syndrome patients. Warfarin, likely through its ability to control carboxylation, alters AR conformation and inhibits AR transcriptional activity, as does siRNA-mediated knockdown of VKOR, the target of warfarin. We further demonstrate that warfarin treatment reduces AR target gene expression in benign mouse prostate tissue in vivo. Interestingly, retrospective studies have shown that prolonged use of warfarin reduces the incidence of prostate cancer, an effect that is not observed for other cancers. In a small series of patients at our institution, we found that one allele of a functional SNP in VKOR is found at a significantly higher rate in prostate cancer patients than would be expected in the general population. We also found that VKOR is highly expressed in normal human prostate epithelia but is lost in cancerous tissue, a pattern of expression that appears to be unique to prostate cancer. We hypothesize that the lower prostate cancer incidence observed in men taking warfarin is due to the ability of warfarin to reduce AR activity, similar to the effect of 5-alpha reductase inhibitors. Importantly, we show for the first time that a nuclear receptor and transcription factor can be regulated by gamma-carboxylation.

Citation Format: Ben Yi Tew, Teresa Hong, Sumanta K. Pal, Markus Kalkum, Jeremy Jones. Warfarin-dependent gamma-carboxylation regulates androgen receptor activity. [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 1919. doi:10.1158/1538-7445.AM2015-1919