bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 2226: Sildenafil suppresses tumorigenesis in ApcMin/+ mouse model
Authors: Sharman Sarah K. , Islam Bianca N. , Hou Yali , Bridges Allison , Singh Nagendra , Sridhar Subbaramiah , Berger Frankin G. , Browning Darren D.
Published: July 2017

The cGMP signaling pathway regulates homeostasis in the colon epithelium and has been implicated in the suppression of colorectal cancer. Exisulind is a weak phosphodiesterase-5 (PDE5) inhibitor that was previously shown to reduce polyp formation in familial adenomatous polyposis (FAP) patients. Despite this validation of PDE5 as a therapeutic target, the failure of Exisulind due to toxicity halted further trials of cGMP elevating agents. The present study tested the effect of the PDE5 inhibitor sildenafil, and the receptor guanylyl-cyclase C (GCC) agonist linaclotide on tumorigenesis in the ApcMin/+ mouse model of colon cancer. Administration of either sildenafil or linaclotide to both wild type and ApcMin/+ mice caused dramatic effects on homeostasis that included reduced proliferation and increased goblet cell differentiation. With treatment beginning at 4 weeks, sildenafil and linaclotide caused a 50% and 67% (respectively) reduction in the number of polyps per mouse. Furthermore, the polyps in sildenafil and linaclotide treated animals exhibited a reduced proliferative index and increased mucus density compared to polyps from untreated mice. The mean polyp size was not changed by treatment with either drug. In support of a tumor-suppressive role for cGMP signaling in the intestine, the ApcMin/+ mice showed reduced levels of endogenous GCC agonists in the intestinal mucosa compared to wild type animals. This suggests that part of the tumor preventative effects observed here could be due to compensation for this deficit by augmenting cGMP signaling with PDE5 inhibitors or GCC agonists. While the tumor suppressive mechanism is not fully understood, the results presented here demonstrate in a preclinical model, that increasing intestinal cGMP levels by targeting PDE5 or GCC may be a viable chemoprevention strategy for human FAP patients.

Citation Format: Sarah K. Sharman, Bianca N. Islam, Yali Hou, Allison Bridges, Nagendra Singh, Subbaramiah Sridhar, Frankin G. Berger, Darren D. Browning. Sildenafil suppresses tumorigenesis in ApcMin/+ mouse model [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2226. doi:10.1158/1538-7445.AM2017-2226
Abstract 2249: Integrated multi-level omics-based biomarker models for ovarian cancer survival
Authors: Fu Alan , Chang Shen-Chih , Baecker Aileen , Chang Helena R. , Zhang Zuo-Feng
Published: July 2017

Background: Although a number of prognostic biomarkers for ovarian cancer have been proposed, the pool of clinically useful biomarkers remains small. While the predictive power of individual biomarkers may be weak, the advent of more affordable high-throughput technologies and readily available “omics” level data point toward the possibility of high performance biomarker panels. In this study, we used tumor-based somatic mutation, mRNA and miRNA expression, and DNA methylation data from The Cancer Genome Atlas (TCGA) to construct integrated biomarker models for overall and progression-free survival.

Methods: The somatic mutations, mRNA expression, and DNA methylation of 451 candidate genes, as well as the expression of the miRNAs targeting them, were individually analyzed for association with overall and progression-free survival in 488 TCGA serous cystadenocarcinoma patients of predominantly Caucasian descent. Following correction for multiple comparisons, molecular variations associated with survival were combined to construct integrated cross-validated prediction models for overall and progression-free survival. The discriminative power of these models was then evaluated for 1-, 3-, and 5-year overall and progression-free survival using ROC analysis.

Results: Our cross-validated integrated molecular models were demonstrated to predict 5-year overall survival in the total patient pool with a ROC AUC of 0.801 and 5-year overall and progression-free survival in Caucasian patients with ROC AUCs of 0.866 and 0.809, respectively.

Conclusions: Our findings suggest the potential utility of our multi-omics-based biomarker models in helping to inform clinical decisions following ovarian cancer diagnosis. Although extensive efforts were made to maximize the predictive potential of our models, further retrospective and prospective validation efforts are necessary before their clinical utility can be accurately assessed.

Citation Format: Alan Fu, Shen-Chih Chang, Aileen Baecker, Helena R. Chang, Zuo-Feng Zhang. Integrated multi-level omics-based biomarker models for ovarian cancer survival [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2249. doi:10.1158/1538-7445.AM2017-2249
Abstract 2303: Entacapone and prostate cancer in patients with Parkinson’s disease: A large Veterans Health Administration study
Authors: Major Jacqueline M. , Cunningham Francesca , Dong Diane , By Kunthel , Hur Kwan , Shih David C. , Pinheiro Simone P. , Podskalny Gerald D. , Graham David J.
Published: July 2017

Background: An increased risk of prostate cancer was observed in Parkinson’s disease (PD) patients treated with entacapone during a pre-approval randomized clinical trial.

Objective: To investigate a potential association between entacapone use and prostate cancer in an ambulatory setting.

Methods: Using data from the Department of Veterans Affairs (VA) healthcare system, new-user cohorts were created of PD patients treated with add-on entacapone or add-on dopamine agonist/monoamine oxidase B inhibitors between January 2000 and December 2014. Patients were followed on-treatment for occurrence of prostate cancer, identified via VA cancer registry linkage. Cox proportional hazards regression with time-dependent exposure was used to calculate hazard ratios (HR) and 95% confidence intervals (CI). Confounding was controlled by using inverse probability treatment weighting calculated from propensity scores.

Results: Mean follow-up time was 3.1 and 4.0 years in the entacapone and control cohort, respectively. There were 17,666 subjects meeting study criteria (mean age, 74 (SD 8.6) years); the group treated with entacapone comprised 5,257 subjects. Twenty-three prostate cancers occurred in the entacapone cohort and 97 in the control cohort. The overall incidence of prostate cancer was 1.8 per 1000 person-years of risk. There was no difference in risk of prostate cancer between the cohorts for increased duration of entacapone intake (adjusted HR: 1.08; 95% confidence interval: 0.46-2.51 for cumulative exposure of ≥2 years). Time since starting drug therapy and cumulative dose (mg) were also examined.

Conclusion: In this cohort of PD patients, extended duration of entacapone use was not associated with an increased incidence of prostate cancer.

Note: This abstract was not presented at the meeting.

Citation Format: Jacqueline M. Major, Francesca Cunningham, Diane Dong, Kunthel By, Kwan Hur, David C. Shih, Simone P. Pinheiro, Gerald D. Podskalny, David J. Graham. Entacapone and prostate cancer in patients with Parkinson’s disease: A large Veterans Health Administration study [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2303. doi:10.1158/1538-7445.AM2017-2303
Abstract 2312: Feasibility study of a fractionation method in the treatment of tumor treating fields
Authors: Jo Yunhui , Sung Jiwon , Song Hyo Sook , Kim Eun Ho , Yoon Myonggeun
Published: July 2017

Tumor treating fields (TTFs) treatment has been reported to have great potential to treat various cancers. Inspired by a similarity between TTFs and radiotherapy in electromagnetic property, TTFs using a fractionated treatment scheme originally designed for radiotherapy were applied to cancer (Human glioblastoma, U373) and normal cells (intestinal epithelial, IEC-6) for three days with durations of 3, 6, 9, or 24 hours/day. As the treatment time of TTFs increases from 3 to 24 hours/day, the relative cancer cell growth rates in both cell lines were reduced. While the difference in cancer cell growth rate compared to control was ~25% (decreased from 100% to ~75%) for the treatment time of 6 hours/day, the growth rates of cells treated for additional 6 hours (i.e., 12 hours/day) and additional 18 hours (i.e., 24 hours/day) differed only ~5% and ~8% from that of cells treated for 6 hours/day, respectively. Our results suggested that the dependence on treatment time in cancer cell inhibition is weakened distinctly at treatment times over 6 hours/day. For normal cells, the relative growth rates corresponding to the treatment time of TTFs was not decreased much for the treatment time of 3, 6, 12 hours/day revealing 93.3%, 90.0%, 89.3% of cell growth rates compared to control, respectively, but it suddenly reduced to ~73% for 24 hours/day of treatment. The experimental results indicated that the effects of TTFs on growth rates of cancer cells are higher than the effects of TTFs on growth rates of normal cells for treatment times of 3-12 hours/day, but the difference became minimal for treatment times of 24 hours/day. Our results suggest that the fractionated scheme in the treatment of tumor treating fields may reduce treatment time while maintaining efficacy, suggesting that this method can increase patients’ quality of life.

Citation Format: Yunhui Jo, Jiwon Sung, Hyo Sook Song, Eun Ho Kim, Myonggeun Yoon. Feasibility study of a fractionation method in the treatment of tumor treating fields [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2312. doi:10.1158/1538-7445.AM2017-2312
Abstract 2313: Promoting caspase-8-dependent apoptosis signaling using 17-beta-hydroxywithanolides
Authors: Brooks Alan D. , Xu Ya-ming , Wijeratne E. M. Kithsiri , Henrich Curtis J. , Tewary Poonam , Gunatilaka Leslie , Sayers Thomas J.
Published: July 2017

We have previously reported that withanolide E (WE), a steroidal lactone from Physalis peruviana, was highly active in sensitizing various human carcinoma cell lines to TRAIL-mediated apoptosis. Therefore, over 100 natural and semi-synthetic withanolides were evaluated for their ability to promote caspase-8-dependent cancer cell death. Our studies identified several withanolides that were 4-8 fold more potent than WE in sensitizing the renal carcinoma cells and melanoma cells to caspase-8-dependent apoptosis in response to either TRAIL or the TLR3 ligand poly (I:C). All active withanolides were 17-beta-hydroxywithanolides (17-BHW). The highly active 17-BHWs were more efficient than withanolide E at reducing cellular levels of both cFLIPL and cFLIPS and enhancing caspase-8 activation. Furthermore, immunoprecipitation of the TRAIL death-inducing signaling complex (DISC), or the related ripoptosome, demonstrated enhanced levels of both FADD and RIP1 in these macromolecular apoptosis signaling complexes following treatment with active 17-BHWs. The 17-BHWs used in this work were obtained by the application of an efficient method of plant biomass production involving our innovative and patented soil-less aeroponic cultivation of P. crassifolia and P. peruviana and by chemical modification of natural withanolides produced by these plants. Preliminary structure activity relationship (SAR) studies suggested that the enone moiety in ring A was essential for activity. In addition, acetoxylation at C-18, an alpha orientation of the side-chain lactone group and the double bond at C-24(25) of the lactone ring played important roles in determining the activity of 17-BHWs as apoptosis sensitizers. This suggests that the 17-BHW scaffold is amenable to optimization by a medicinal chemistry approach, which could lead to the identification of highly active natural product-based sensitizers of cancer cells to caspase-8-dependent apoptosis. The cellular molecular target(s) of active 17-BHWs are currently under further investigation. Funded by FNLCR Contract HHSN261200800001E.

Citation Format: Alan D. Brooks, Ya-ming Xu, E. M. Kithsiri Wijeratne, Curtis J. Henrich, Poonam Tewary, Leslie Gunatilaka, Thomas J. Sayers. Promoting caspase-8-dependent apoptosis signaling using 17-beta-hydroxywithanolides [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2313. doi:10.1158/1538-7445.AM2017-2313
Abstract 2317: Prostanoid EP4 receptor induces cleavage of HSP90 via ROS generation in human colon cancer cells
Authors: Chae In Gyeong , Yu Mi-hee , Chun Kyung-Soo
Published: July 2017

Prostaglandin E2 (PGE2) has been reported to play critical roles in cell fate decision by interacting with four types of G protein-coupled membrane receptors such as EP1, EP2, EP3 and EP4. We previously reported that EP4 stimulation by treatment with its agonist CAY10598 induced apoptosis via reactive oxygen species (ROS) formation in colon cancer HCT116 cells. Moreover, treatment with CAY10598 diminished the phosphorylation of JAK2 and induced degradation of this oncoprotein, leading to the attenuation of STAT3 activation in HCT116 cells. In the present study, we attempted to delineate the molecular mechanisms underlying the degradation of JAK2 by activation of EP4. HSP90, a member of the heat shock protein family, is a molecular chaperone that supports stability of client proteins, such as, EGFR, MET, Akt and JAK2. HSP90-mediated stabilization/activation of these client proteins contributes to the acquisition of cancer cell hallmarks, including proliferation, survival, angiogenesis and invasion. It has been recently reported that the chaperoning function of HSP90 may be disrupted by post-translational modification induced by oxidative stress. Treatment of human colon cancer HCT116 cells with CAY10598 down-regulated expression of HSP90 client proteins in a concentration- and time-dependent manner and the down-regulation was restored by pretreatment with ROS scavenger N-acetyl cysteine (NAC) or proteasome inhibitor MG132. However, cotreatment with cycloheximide, protein synthesis inhibitor, accelerated the CAY10598-induced degradation of HSP90 client proteins. These data suggest that CAY10598-induced HSP90 client protein degradation may be caused by ROS generation. In renal carcinoma Caki cells, CAY10598 also down-regulated expression of HSP90 client proteins, suggesting that EP4 stimulation may regulate HSP90 activity in colon cancer cells as well as renal cancer cells. We found that HSP90α was cleaved to 40 or 55 kDa, while HSP90β cleaved to 25 kDa by CAY10598 treatment and the cleavage of HSP90α and β was blocked by NAC treatment. Furthermore, EP4 inhibition by treatment with antagonist GW627368x attenuated not only degradation of HSP90 client proteins but also cleavage of HSP90 in CAY105998-treated HCT116 cells. In conclusions, EP4 agonist CAY10598 induces degradation of HSP90 client proteins via ROS-dependent HSP90 cleavage, leading to apoptosis in HCT116 cells. This is a novel mechanism by which EP4 activation induces apoptosis of cancer cells that involved inhibiting HSP90 function.

Citation Format: In Gyeong Chae, Mi-hee Yu, Kyung-Soo Chun. Prostanoid EP4 receptor induces cleavage of HSP90 via ROS generation in human colon cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2317. doi:10.1158/1538-7445.AM2017-2317
Abstract 2323: The inhibitory role of Kaempferol-3-O-rutinoside induced AMPK activation on the growth of human breast cancer cell lines
Authors: Kim Chea Ha
Published: July 2017

Solidago virga-aurea, herbaceous perennial plant of the family Asteraceae, has astringent, diuretic, and antiseptic assets. In our current study, we found that kaempferol-3- O -rutinoside (KR) from Solidago virga-aurea extract prompted cellular apoptosis in breast cancer cells. The present study was conducted to investigate its effects on MCF-7 cells with respect to the induction of inhibitory effect on cell viability against MDA-MB-231 and MCF-7 breast cancer cell lines. In addition, apoptotic protein, especially Bim, was also increased in KR treated MDA-MB-231 and MCF-7 cell line. However, an anti-apoptotic protein, Bcl-xL, was not changed by KR. To find out positive regulator of Bim

expression, FOXO (forkhead-box transcription factor, group O) 3a and AMPK (5' AMP-activated protein kinase) protein expressions were examined in KR treated cells. Immunoblot analysis showed dramatically increased expressions of FOXO3a and AMPK in KR treated MDA-MB-231 and MCF-7 cells. In addition, cell cycle analysis indicated that G0/G1 arrest was intensely increased in KR treated MDA-MB-231 and MCF-7 cells. Moreover, phospho-AMPK (pT172) and phospho-FOXO3a (S472) expression were also increased in KR treated MDA-MB-231 and MCF-7 cells. Our results suggest that KR induces apoptosis by AMPK-FOXO3a mediated Bim expression. The mechanisms of KR

mediated AMPK and FOXO3a regulation is not fully elucidated yet, but further studies about these molecular mechanisms between two proteins will give some ideas for cancer therapies for certain breast cancer patients.

Citation Format: Chea Ha Kim. The inhibitory role of Kaempferol-3-O-rutinoside induced AMPK activation on the growth of human breast cancer cell lines [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2323. doi:10.1158/1538-7445.AM2017-2323
Abstract 2327: Apoptosis of melanoma induced by non-thermal atmospheric pressure bio-compatible plasma activated media
Authors: Han Ihn , Li Ying , Choi Eun Ha
Published: July 2017

Melanoma is the most dangerous type of skin cancer, which mostly related with the exposure of ultraviolet (UV), and especially happened to those who have low skin pigment levels. Epidemiological studies showed Europeans and North Americans have a high incidence of melanoma, while it is less common in Asia and Africa. Therefore, the new and more effective methods to treat melanoma are still necessarily needed.

Non-thermal atmospheric pressure bio-compatible plasma (NBP) is defined as a partially ionized gas with electrically charged particle, which has been reported have cytotoxicity on various cancer cells induce DNA damage and apoptosis other than normal cells. Reactive oxygen and/or nitrogen species (RONS) were proved to play the most important role during this process, by inducing oxidative stress and depolarization of mitochondria membrane potential with the consequence of various cancer cells apoptosis.

The plasma activated media (PAM), which the media treated directly by NBP with different time, containing mostly long-live secondary species such as hydrogen peroxide (H2O2) which have been confirmed anti-microorganism and cytotoxic activity. Researches already investigated that PAM also effective in cancer therapy via inducing apoptosis. However, the underlying molecular mechanisms of apoptosis are remaining elusive.

The purpose of this study was to evaluate the potential of PAM as an effective tool to induce apoptosis in melanoma cells. Our results showed that PAM has a killing effect to melanoma cells in a time-dependent manner, for 3minutes treatment could induce almost 40% cells entry death, after treated by 5 minutes more than 60%, and 10 minutes treatment reduced the cell viability to approximately 30%. Annexin-V/PI staining demonstrated that PAM kills these cells via apoptosis pathway. We also found that with a manner of treatment time PAM significantly increased the concentration of intracellular NO and H2O2, reflecting an influx of extracellular RONS may result in melanoma cells apoptosis. Besides, western blot assay showed that P53 and caspase 3 increased after PAM treatment. Taken together, PAM is effective to induce the apoptosis in melanoma cells in vitro, further in vivo experiments will be performed to investigate the functional effects in the animals.

Citation Format: Ihn Han, Ying Li, Eun Ha Choi. Apoptosis of melanoma induced by non-thermal atmospheric pressure bio-compatible plasma activated media [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2327. doi:10.1158/1538-7445.AM2017-2327
Abstract 2328: Race specific hyper-activation of CCR9-mediated survival signals and its impact on efficacy of docetaxel in prostate cancer
Authors: Kapur Neeraj , Mir Hina , Sonpavde Guru , Singh Shailesh
Published: July 2017

Current approaches to treat and manage prostate cancer (PCa) have failed to reduce racial disparity primarily due to undefined molecular mechanism. We have shown higher expression of chemokine receptor-9 in PCa cells and CCR9 expression was higher in PCa cells (MDA-PCa-2b) derived from African American (AA) patient compared to PCa cells derived form European American (EA) patients (LNCaP and PC3). Using antibody microarray we observed hyper activation of survival molecules and down-regulation of apoptotic molecules in AA PCa cells compared to EA PCa cell lines, following CCL25 stimulation. Comparative heat map analysis showed significant increase (~2-3 fold) in phosphorylation of pro-survival proteins in AA cells compared to EA cells treated with CCL25, which was further confirmed by western blot analysis. Furthermore, CCL25 treated PCa cells showed decreased expression of pro-apoptotic proteins (Bim, Bid, Bak), which was significantly abrogated by CCR9 shRNA. This effect was more pronounced in AA cells compared to EA cells. Efficacy of docetaxel (DTX) was higher after CCR9 blockade in presence of CCL25 compared to cells treated with CCL25 without blocking CCR9. Improvement in efficacy of DTX was due to inhibition of cell survival and activation of pro-apoptotic signals following CCR9 blockade. These observations suggest potential involvement of CCR9 mediated molecular pathways in disparity associated with outcome of PCa.

Citation Format: Neeraj Kapur, Hina Mir, Guru Sonpavde, Shailesh Singh. Race specific hyper-activation of CCR9-mediated survival signals and its impact on efficacy of docetaxel in prostate cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2328. doi:10.1158/1538-7445.AM2017-2328
Abstract 2347: MicroRNA mediated CDK4/6 inhibitor resistance via extracellular signaling
Authors: Cornell Liam , Shapiro Geoffrey I.
Published: July 2017

Multiple potent and highly selective inhibitors of the cell cycle kinases - CDK4 and CDK6 are in development. One such inhibitor, palbociclib, was recently approved for use in combination with letrozole for the treatment of estrogen receptor positive (ER+) breast cancer. Cyclin D-dependent kinase activity is a driving factor for ER+ breast carcinogenesis, irrespective of CCND1 amplification, making CDK4/6 inhibition a promising approach for this breast cancer subset. However, as with all cancer treatments, resistance will be a major issue limiting the efficacy of this approach. To date, mechanisms of palbociclib resistance have not been extensively investigated.

Through interrogation of the generated CDK4/6 inhibition resistant cells we discovered overexpression of CDK6, specifically, mediates resistance. CDK6 depletion reversed resistance and overexpression caused resistance, whereas the same was not true when CDK4 or D cyclin protein levels were manipulated. Interestingly, when generating and analyzing resistant cell populations, we observed a “bystander effect”, by which resistance was transmissible between cells. The “resistant bystander” cells display all characteristics of the drug exposure induced resistant cells, however became resistant in just 48 hours as oppose to 14 weeks. Analysis of conditioned medium revealed that the transmission of resistance is dependent on exosomes, but not protein or DNA. We identified a specific miRNA, present in the exosomes of resistant cells, by microarray which caused resistance when excreted. Additionally, overexpression and inhibition of the miRNA confirmed that it is responsible for causing resistance. miRNA overexpressing cells exhibited the same phenotype as drug induced resistant cells, and furthermore, could cause resistance in neighboring cell populations by exosome mediated signaling. Using Biotin labelled miRNA-mRNA pulldown followed by RNA-seq, we identified the TGFβ pathway as the miRNA target. Downregulation of the TGFβ caused a decrease in the CDK inhibitors, p15 and p21, resulting in an increased CDK6 protein level and palbociclib resistance. We subsequently confirmed these data in patient samples by comparing before treatment and post relapse biopsies.

These findings highlight a novel mechanism of conferred drug resistance as well as new insights into acquired CDK4/6 inhibitor resistance.

Citation Format: Liam Cornell, Geoffrey I. Shapiro. MicroRNA mediated CDK4/6 inhibitor resistance via extracellular signaling [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2347. doi:10.1158/1538-7445.AM2017-2347
Abstract 2355: Palbociclib enhances the antitumor activity of taxanes by abrogating cell cycle checkpoints and alleviating hypoxia in squamous cell lung cancer
Authors: Cao Joan , Zhu Zhou , Wang Hui , Nichols Tim , Rosfjord Edward , Hopf Christine , Upeslacis Erik , Rejto Paul , Weinrich Scott , Vanarsdale Todd , Hardwick James , Wei Ping
Published: July 2017

Lung cancer remains one of the leading causes of cancer-related mortality. Squamous cell lung cancer (SqCLC) is the second most common subtype of non-small cell lung cancer (NSCLC) and is responsible for ~100,000 deaths in the US and EU. Most SqCLC patients receive chemotherapy as 1st line treatments and have a high un-met medical need for new therapies. Therapeutic approaches that enhance the efficacy of chemotherapy would therefore improve clinical outcomes for this patient population. CDK inhibitors comprise a class of drugs that target the dysregulated cell cycle in malignant cells. Treatment of tumor cells with the CDK4/6 inhibitor palbociclib inhibits tumor growth by decreasing retinoblastoma (RB) protein phosphorylation and inducing cell cycle arrest at the G1/S phase transition. Based on promising clinical trial results, palbociclib in combination with letrozole was granted accelerated approval by the US FDA for the treatment of postmenopausal women with ER-positive, HER2-negative advanced breast cancer. Like hormone receptor positive breast cancer patients, the vast majority of SqCLC patients harbor wild type RB and thus may also benefit from palbociclib treatment. Previously, we reported robust cytotoxicity and antitumor effects of palbociclib plus taxanes, including nanoparticle albumin-bound paclitaxel (Nab-PTX) or docetaxel (DTX), in several preclinical models of SqCLC. In the present study, we extended our efficacy studies of this combination to additional RB+ SqCLC models with diverse molecular genetic backgrounds. In search of mechanisms of action underlying the observed combinatorial effects, we identified several novel mechanisms, including cell cycle checkpoint abrogation as well as reduction of hypoxia-inducible factor 1 alpha (HIF-1α). Decrease in HIF-1α protein led to strong modulation of downstream genes involved in angiogenesis, resulting in reduced blood vessel size in tumor vasculature. Our results suggest that palbociclib enhances the antitumor activity of taxanes by abrogating cell cycle checkpoints and alleviating hypoxia in SqCLC.

Citation Format: Joan Cao, Zhou Zhu, Hui Wang, Tim Nichols, Edward Rosfjord, Christine Hopf, Erik Upeslacis, Paul Rejto, Scott Weinrich, Todd Vanarsdale, James Hardwick, Ping Wei. Palbociclib enhances the antitumor activity of taxanes by abrogating cell cycle checkpoints and alleviating hypoxia in squamous cell lung cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2355. doi:10.1158/1538-7445.AM2017-2355
Abstract 2357: CDK4/6 inhibition in early stage triple negative breast cancer
Authors: Kietzman William B. , Ory Virginie , Saenz Fransisco , Sharif Ghada , Wellstein Anton , Riegel Anna T.
Published: July 2017

Palbociclib (PD), a CDK4/6 inhibitor, has recently been approved for use in advanced ER positive breast cancer, demonstrating significant benefit in combination with endocrine therapies. Ductal carcinoma in situ (DCIS) is an inobligate precursor to invasive ductal carcinoma with anywhere from 14-53% of cases progressing. Progression is unpredictable and driven by poorly understood mechanisms. In this study, we assess the efficacy of PD in the context of this early stage disease using a triple negative DCIS model(MCF10DCIS), not only in inhibiting cell cycle but also in hindering the progression from in situ to invasive lesion. We demonstrate similar efficacy of PD in 2D on MCF10DCIS and immortal mammary epithelial cells (MCF10As) in preventing proliferation, inhibiting phosphorylation of RB and stopping cell cycle progression. Yet in 3D, MCF10DCIS cells form smaller, more organized spheres in the presence of drug while MCF10As appear unaffected, highlighting potential disease selectivity in vivo. Interestingly, when a cDNA array is performed on MCF10DCIS cells grown in 3D +/- PD, the most regulated genes are not well characterized cell cycle genes as one might predict based on previously published data and 2D response to treatment, suggesting alternative CDK4/6 targets may be responsible for the phenotype observed in 3D. We also demonstrate in a nude mouse xenograft model of MCF10DCIS that PD is able to significantly reduce overall tumor burden while simultaneously delaying the progression of lesions to invasive disease. Though the growth of PD treated MCF10DCIS lesions is delayed we demonstrate that proliferation is unaffected in vivo by the presence of the drug, based on equivalent Ki67 signal within the lesions. This reiterates the possibility that in 3D and in vivo contexts PD targets mechanisms outside of cell cycle regulation in order to slow tumor growth and delay invasive transition. We believe that investigation into alternative targets of CDK4/6 altered by PD in 3D and in vivo may provide insights on important mechanisms of DCIS progression in DCIS models and human patients.

Citation Format: William B. Kietzman, Virginie Ory, Fransisco Saenz, Ghada Sharif, Anton Wellstein, Anna T. Riegel. CDK4/6 inhibition in early stage triple negative breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2357. doi:10.1158/1538-7445.AM2017-2357
Abstract 236: Stearoyl-CoA desaturase-1, a novel target of omega-3 fatty acids for reducing breast cancer risk in obese postmenopausal women
Authors: Manni Andrea , Richie John P. , Schetter Susann E. , Calcagnotto Ana , Trushin Neil , Aliaga Cesar , El-Bayoumy Karam
Published: July 2017

Preclinical and epidemiologic data suggest that a unique feature of lipogenesis in cancer cells which has received limited attention is the accumulation of monounsaturated fatty acids (MUFA) which are largely derived from saturated fatty acids (SFA) by the action of stearoyl-Co-A desaturase (SCD-1). Activation of SCD-1, a delta-9 fatty acid desaturase, is considered to be an important factor in the development of obesity and several types of cancer including breast cancer. However, no data are available on how changes in SCD-1 activity induced by potential chemopreventive agents relate to established biomarkers of breast cancer risk. To address this issue, we measured the activity of SCD-1, expressed as the ratios of palmitoleic acid (C16:ln7) to palmitic acid (C16:0) (SCD-16) and oleic acid (C18:ln9) to steric acid (C18:0) (SCD-18) in plasma samples of postmenopausal women enrolled in our recently published clinical trial (Sandhu N, et al Cancer Prev Res 9:275, 2016) designed to test the individual and combined effect of the antiestrogen Raloxifene and the omega-3 preparation Lovaza on breast density, a validated biomarker of breast cancer risk. We observed that daily administration of Lovaza (1,860 mg eicosapentaenoic [EPA] + 1,500 mg docosahexaenoic [DHA]) significantly reduced SCD-1 activity, an effect which was sustained for the two-year duration of the trial. Raloxifene, on the other hand, did not significantly alter SCD-1 activity in our subjects. SCD-1 activity was positively correlated with BMI (for SCD-16, r=0.45, p<01; for SCD-18, r=0.23, p<0.01) and paralleled changes in BMI in the same direction over the two years of the study. These findings support the role of this enzyme in the development of obesity. Importantly, decreasing levels of SCD-1 were found to be associated with a progressive reduction in breast density in obese women (BMI≥30) (for SCD-16; r=0.47, p<0.01; for SCD-18; r=0.36, p<0.05). No correlation between breast density and SCD-1 was observed in non-obese subjects (r=0.02 for SCD-16 and 0.04 for SCD-18). Our results suggest that BMI-related factors play an important role in the reduction of breast density by omega-3 fatty acids. They also indicate that SCD-1 may be a useful biomarker in future clinical trials testing the benefit of nutritional interventions in reducing obesity associated breast cancer risk.

Citation Format: Andrea Manni, John P. Richie, Susann E. Schetter, Ana Calcagnotto, Neil Trushin, Cesar Aliaga, Karam El-Bayoumy. Stearoyl-CoA desaturase-1, a novel target of omega-3 fatty acids for reducing breast cancer risk in obese postmenopausal women [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 236. doi:10.1158/1538-7445.AM2017-236
Abstract 2387: Overexpression of NSUN2 by DNA hypomethylation is associated with metastatic progression in human breast cancer
Authors: Yi Jie , Chen Yu , Gao Ran , Yang Zhuo , Wang Jinhua , Xu Yingchun
Published: July 2017

NSUN2 is a RNA methyltransferase that has been shown to be implicated in development of human cancer. However, the functional role of NSUN2, mechanism of NSUN2 overexpression and its association with clinicopathologic features in breast cancer remain unclear. To investigate alterations in the expression and functional role of NSUN2 in breast cancer, NSUN2 expression was assessed in breast cancer cells and tissues obtained from cancers at different American Joint Committee on Cancer (AJCC) stages, and its functions were investigated using breast cancer cells. NSUN2 expression was shown to be significantly higher in breast cancer cells and tissues than in normal breast epithelial cells and tissues, at both mRNA and protein levels. Overexpression of NSUN2 was shown to promote cell proliferation, migration, and invasion while NSUN2 knockdown inhibited these processes in vitro and in vivo. NSUN2 expression level was associated with the methylation level of its promoter. Our results demonstrated that the overall expression of NSUN2 significantly correlated with clinical stage (P=0.027), tumor classification (P=0.012), pathological differentiation (P=0.023), as well as with the expression levels of estrogen receptor (P<0.001), progesterone receptor (P=0.001), and Ki-67 (P<0.001). Our findings provide a unique insight into the roles and effects of NSUN2 overexpression in breast cancer cells, and highlight the necessity of the investigation of novel therapeutic targets, such as NSUN2, for the improvement of breast cancer treatments.

Citation Format: Jie Yi, Yu Chen, Ran Gao, Zhuo Yang, Jinhua Wang, Yingchun Xu. Overexpression of NSUN2 by DNA hypomethylation is associated with metastatic progression in human breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2387. doi:10.1158/1538-7445.AM2017-2387
Abstract 2388: Low grade gliomas exhibit distinct patterns of epigenetic aging associated with prognostic molecular subtype
Authors: Liao Peter , Barnholtz-Sloan Jill
Published: July 2017

Background: Low grade gliomas make up a significant proportion of malignant brain tumors and possess a high degree of heterogeneity, highlighting a need for clinically useful markers for prognosis and further biologic investigation. We used an existing model of biological age based upon DNA methylation to characterize epigenetic age in low grade gliomas (LGG) according to existing molecular classifications and assessed the prognostic utility of epigenetic age.

Methods: We analyzed the full TCGA LGG cohort consisting of 516 patients; 216 grade 2 and 241 grade 3 tumors. Age at diagnosis ranged from 14-87 years with median age 43. We calculated “DNA methylation age” (DNAm age) based upon 353 CpG probes according to the epigenetic clock developed by Steve Horvath, and calculated age acceleration according to the DNAm age of tumor tissue relative to reported chronological age of patient at diagnosis. DNAm age was assessed for prognostic value using Cox proportional hazards regression. Age acceleration differences were assessed across LGG molecular classification methods using the Wilcoxon Ranked Sum test.

Results: DNAm age remained highly correlated with chronological age in LGG tumor tissue (cor=0.58, p<0.001), with an average age acceleration of 33.5y. DNAm age was weakly positively correlated with mutational burden (cor=0.12, p=0.01). Higher DNAm age was positively associated with survival independent of chronologic age and Karnofsky Performance Score (p=0.003), but not when IDH mutation status was included into the Cox proportional hazards model. Further investigation showed that DNAm age acceleration was associated with IDH mutation status and was significantly increased in IDH-mutant compared to IDH-wt tumors (95% CI= 18.6-28.8y) as well as MGMT-promoter methylated versus unmethylated cases (95%CI= 18.1- 28.9y). No significant DNAm changes were observed across histological subtype or grade.

Conclusions: Although the regulation of DNAm age in cancers remains poorly understood, significant association of DNAm age acceleration with prognostically useful molecular subtypes in LGGs underscores biological differences that cannot be discerned in LGGs based upon histological classification. This association suggests that LGGs may provide an avenue for investigating DNAm age, molecular subtype, and their relation to tumor behavior and clinical prognosis.

Citation Format: Peter Liao, Jill Barnholtz-Sloan. Low grade gliomas exhibit distinct patterns of epigenetic aging associated with prognostic molecular subtype [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2388. doi:10.1158/1538-7445.AM2017-2388
Abstract 239: Associations of polyunsaturated fat, bile acids, and gut microbiota on colorectal adenoma risk
Authors: Wang Tengteng , Brown Nicole M. , McCoy Amber N. , Sandler Robert S. , Keku Temitope O.
Published: July 2017

Background: Intestinal microbiota, and their metabolites are increasingly recognized as important players in the genesis of colorectal adenomas and cancer. Epidemiological studies have also shown that polyunsaturated fat intake is associated with decreased risk of colorectal adenomas. This study examined the association between adherent gut microbiota and mucosal bile acids, and total polyunsaturated fat intake in relation to colorectal adenomas in a case-control study.

Methods: Participants were 217 adenoma cases and 218 adenoma-free controls who underwent screening colonoscopies and completed food frequency questionnaires. The mucosal adherent microbiota was characterized by bacterial 16S rRNA sequencing. Global metabolomics of colonic mucosal tissue was conducted by gas chromatography and mass spectrometry on a subset of samples. Genus level microbiota and bile acids were compared between cases and controls using t-test with correction for multiple comparison. Logistic regression and Pearson correlations were used to estimate adjusted odds ratios (ORs) and 95% confidence intervals (CIs), and correlation coefficients for the association among microbiota abundance, bile acids concentration, and total polyunsaturated fat intake.

Results: Adenoma subjects had a significantly higher bacterial abundance of Sphingomonas, Marinomonas and Ralstonia, but lower abundance of Adlercreutzia compared to controls. The concentration of eleven bile acids (Chenodeoxycholate, Cholate, Deoxycholate, Glycochenodeoxycholate, Glycocholenate sulfate, 7-ketodeoxycholate; 12-dehydrocholate, Taurochenodeoxycholate, Taurocholate, Taurodeoxycholate, Taurolithocholate 3-sulfate, and Tauroursodeoxycholate) were significantly elevated in cases compared to controls. Subjects with increased abundance of Sphingomonas and Ralstonia were significantly more likely to have adenomas (OR 2.17, 95% CI 1.31-3.57; OR 1.19, 95% CI 1.02-1.38) respectively. Subjects with increased abundance of Adlercreutzia were less likely to have adenomas (OR 0.44, 95% CI 0.21-0.93). The multivariable adjusted OR for those in the high relative to the low level of total polyunsaturated fat intake was 0.46 (95% CI 0.27-0.80). The correlations between bacterial diversity and eleven bile acids also significantly differed by case control status.

Conclusion: The interactions of the gut microbiota, bile acids and consumption of polyunsaturated fat are associated with colorectal adenoma risk.

Citation Format: Tengteng Wang, Nicole M. Brown, Amber N. McCoy, Robert S. Sandler, Temitope O. Keku. Associations of polyunsaturated fat, bile acids, and gut microbiota on colorectal adenoma risk [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 239. doi:10.1158/1538-7445.AM2017-239
Abstract 24: HMBD001, a novel anti-ErbB3 antibody with a unique mechanism of action, effectively inhibits tumor growth in pre-clinical models of ErbB3+ solid tumors
Authors: Boyd-Kirkup Jerome D. , Thakkar Dipti , Ingram Piers J.
Published: July 2017

Gastric cancer is the second highest cause of cancer mortality in Asia. Over-expression of ErbB3, a cell surface RTK, occurs in ~60% of mGC patients where it is significantly associated with poorer survival. Ligand binding to ErbB3 triggers heterodimerization and downstream signaling through Akt. Neutralizing antibodies that inhibit ligand binding show poor efficacy in clinical trials, likely due to high levels of ligand independent activation in many tumor types. Directly inhibiting heterodimerization could be more effective, however, current methods of antibody isolation offer limited control over the site of antibody binding and, therefore, mechanism of action, requiring extensive screening of antibodies and posing significant challenges to identifying suitable candidates for therapeutic development.

Hummingbird Bioscience has used its proprietary Rational Antibody Development Platform for the design and development of novel therapeutic antibodies against ErbB3. Computational sequence and structural analyses predicted highly specific surface epitopes, with strong antigenicity and good safety profiles, where antibody binding would inhibit dimerization. Subsequently, Hummingbird’s directed evolution mouse immunization strategy efficiently isolated monoclonal antibodies that bound with low nM (Kd < 5nM) affinity to these epitopes on native folded ErbB3. Furthermore, these mAbs showed ELISA cross-reactivity to ErbB3 in model organisms (mouse, rat, monkey) but no binding to other EGFR family proteins.

Antibody HMBD001 was found to strongly inhibit the phosphorylation of ErbB3 and decrease downstream signaling through the Akt pathway (90% decrease in p-ErbB3 and 60% decrease in p-AKT observed at 24 hrs) resulting in the inhibition of tumor cell proliferation in models of ErbB3+ gastric cancer (over 90% inhibition of NCI-N87 proliferation after 5 days) and breast cancer (up to 85% inhibition of BT474 proliferation after 5 days). In mouse NCI-N87 gastric cancer CDX models, weekly doses of HMBD001 achieved greater than 90% inhibition of tumor growth (at 25 days) with no observable adverse toxicity.

The first in-human trial of HMBD001 is planned for 2018.

Citation Format: Jerome D. Boyd-Kirkup, Dipti Thakkar, Piers J. Ingram. HMBD001, a novel anti-ErbB3 antibody with a unique mechanism of action, effectively inhibits tumor growth in pre-clinical models of ErbB3+ solid tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 24. doi:10.1158/1538-7445.AM2017-24
Abstract 2400: Identification of histone modifying enzymes associated with tamoxifen resistance in MCF7 breast cancer cells
Authors: Lee Min-Ho , Lee Mi-Ock
Published: July 2017

Tamoxifen is widely used to treat estrogen receptor-alpha positive breast cancer. However, resistance to tamoxifen often prevent the success of endocrine therapy. Epigenetic change in tumors are associated with cancer development and progression. Although altered histone modification has been implicated in tumorigenesis, their role in endocrine resistance was little known. To identified tamoxifen-resistance associated histone methylation modifying enzyme, we examined the global histone H3 methylation patterns in tamoxifen-resistance MCF7 breast cancer cells. Our results show that, the levels of methylated histone H3 lysine 4 (H3K4) and histone H3 lysine 9 (H3K9) was upregulated in tamoxifen resistance MCF7 breast cancer cells. Next, we analysis expression levels of H3K4 and H3K9 methylation modifying enzyme in tamoxifen resistance breast cancer cells. qRT-PCR results show that H3K4 methyltransferases (KMT2A and KMT2C) is upregulated in tamoxifen resistance breast cancer cells. Moreover, we observed that si-RNA mediated knockdown of KMT2C was more susceptible to tamoxifen-induced growth inhibition. Finally, Analyses of publicly available patient data sets indicated that KMT2A and KMT2C levels are higher in patients after endocrine therapy failure (recurrence), compared to those of responders (non-recurrence). Our study indicates that elevated levels of KMT2A and KMT2C in the tamoxifen-resistance breast cancers may contributed tamoxifen resistance.

Citation Format: Min-Ho Lee, Mi-Ock Lee. Identification of histone modifying enzymes associated with tamoxifen resistance in MCF7 breast cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2400. doi:10.1158/1538-7445.AM2017-2400