bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 4005: HDAC inhibitors regulate M2 tumor-associated macrophage function through histone acetylation
Authors: Groot Amber E. de , Zarif Jelani C. , Pienta Kenneth J.
Published: July 2017

Macrophage tumor infiltration in metastatic prostate cancer is a predictor of patient prognosis. Macrophages influence tumors in contrasting ways depending on their polarization: M1 macrophages have anti-tumor functions while M2 macrophages are pro-tumor. The external stimuli influencing macrophage differentiation and M2 polarization have been largely elucidated but the resulting downstream changes remain unknown. There are a number of epigenetic differences between M1 and M2 macrophages that act as important functional determinants. Recent work studying these epigenetic changes has implicated histone deacetylases (HDACs), as critical regulators in macrophage differentiation and in maintaining M1 or M2 function. Pan-HDAC inhibitors (HDIs) such as the clinically utilized suberanilohydroxamic acid (SAHA) target a wide range of HDACs and provide a means for manipulating macrophage histone acetylation. Though HDIs have been found to attenuate inflammatory functions in M1 macrophages, the field has yet to explore effects of histone acetylation in M2 macrophages. Using M2 macrophages derived from human CD14+ monocytes, we found that SAHA regulates M2 macrophage polarization and function through alteration of histone acetylation. Work is ongoing to test expression levels of canonical M2 markers such as the mannose receptor CD206 and scavenger receptor CD163 in M2 macrophages exposed to SAHA either during or after M2 polarization. Additionally, investigation into the ability of these populations to secrete M2 cytokines such as IL-10 and VEG-FA and induce EMT in prostate cancer cells is also being pursued. These results contribute to scientific knowledge of epigenetic regulation in macrophage function and elucidate strategies to decrease the pro-tumor function of tumor-infiltrating M2 macrophages. This work lays the foundation for using epigenetic regulators to modulate the tumor microenvironment and advance cancer medicine.

Citation Format: Amber E. de Groot, Jelani C. Zarif, Kenneth J. Pienta. HDAC inhibitors regulate M2 tumor-associated macrophage function through histone acetylation [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 4005. doi:10.1158/1538-7445.AM2017-4005
Abstract 4027: Developing biophysical platforms to study KRAS membrane interaction in artificial membranes
Authors: Jean-Francois Frantz L. , Stephen Andrew G.
Published: July 2017

In our studies, we leverage the techniques that we believe will allow us to better understand and tackle KRAS membrane interaction. RAS proteins are small GTPases that oscillate between an active GTP-bound and inactive GDP-bound state to function as plasma membrane localized molecular switches in growth factor regulated signaling pathways. Mutation in HRAS, KRAS and NRAS are present in nearly 30% of human tumors. In particular, KRAS is mutated in almost 90% of pancreatic adenocarcinomas. Considering the requirement of the plasma membrane for KRAS activity, we are setting up ‘screenable’ biophysical platforms to understand the importance of lipids and find small molecules that could prevent KRAS membrane association in reconstituted systems. The two main techniques that are being developed are Surface Plasmon Resonance and Confocal Imaging in model membranes. Using these two techniques, we have been able to better understand the main lipids that drive KRAS membrane association and set up platforms that can be screened by small/large molecules. Biophysical techniques are frequently used by pharmaceutical companies as primary or secondary screening platforms. Developing such platforms for KRAS membrane interaction could enable the discovery of anti-cancer tool compounds.

Citation Format: Frantz L. Jean-Francois, Andrew G. Stephen. Developing biophysical platforms to study KRAS membrane interaction in artificial membranes [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 4027. doi:10.1158/1538-7445.AM2017-4027
Abstract 4117: Mechanisms of acquired resistance to c-Src kinase inhibitor in triple negative breast cancer
Authors: Gilani Rabia A. , Lachacz Eric J. , Phadke Sameer , Bao Li Wei , Cheng Xu , Jiagge Evelyn M. , Soellner Matthew B. , Merajver Sofia D.
Published: July 2017

Triple negative breast cancers (TNBCs) are especially lethal due to their high metastatic potential and propensity to recur. TNBCs comprise the only subset of breast cancer for which there are no FDA-approved targeted therapies. We have developed a mechanistically novel dual c-Src/p38 inhibitor, UM-164, that has potent in vivo anti-TNBC activity. However, single-agent targeted therapies are prone to resistance and rational drug combinations can overcome or prevent resistance. We developed TNBC cells lines that are resistant to UM-164. Significant morphology and cell signaling changes occurred in the drug-resistant cell lines. Most crucial is the observation that in drug-resistant cell lines the activation of c-Src and/or p38 does not return in the presence of UM-164, suggesting that resistance is not occurring via constitutive activation enabling mutations of c-Src and/or p38 kinases. However, compared to their drug-sensitive counterparts, the UM-164-resistant cells have significantly hyperactivated MEK1/2 and ERK1/2 signaling when treated with UM-164. Thus, we tested combinations of UM-164 + MEK1/2 inhibitors in several TNBC cell lines and patient derived xenografts. We found that trametinib (Mekinist®, an FDA-approved inhibitor of MEK1/2) is synergistic (Chou-Talalay CI at ED90 = 0.4, CI < 1 denotes synergy) with UM-164 to inhibit the growth of UM-164-resistant MDA-MB-231 and SUM-149 cell lines. These results support our hypothesis that activation of MEK/ERK signaling can act as an escape mechanism that leads to resistance to UM-164. Future research into rational combinations of targeted therapies delivered in data driven schedules may hold the key to improving survival in TNBC.

Citation Format: Rabia A. Gilani, Eric J. Lachacz, Sameer Phadke, Li Wei Bao, Xu Cheng, Evelyn M. Jiagge, Matthew B. Soellner, Sofia D. Merajver. Mechanisms of acquired resistance to c-Src kinase inhibitor in 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 4117. doi:10.1158/1538-7445.AM2017-4117
Abstract 4125: Comparison between knockdown of Pim-1, Pim-2 and Pim-3 identifies Pim-2 as the most relevant Pim oncogene in hepatocellular carcinoma
Authors: Weirauch Ulrike , Kürz Pia , Aigner Achim M.
Published: July 2017

Introduction Pim-Kinases (Pim - proviral integration site for moloney murine leukemia virus; Pim-1, -2, -3) are a family of serine/threonine kinases with oncogenic potential. They are overexpressed in various solid tumors including hepatocellular carcinoma (HCC) and have been found responsible for malignant transformation, induction of cell proliferation and inhibition of apoptosis. While the main focus has been on Pim-1 so far, the other Pim kinases, esp. Pim-2, have not been explored in detail.

Objectives The aim of this study was to compare the tumor-inhibitory effects of the single and combined of Pim family members in HCC, for evaluating their individual contributions and potential as therapeutic target. To this end, RNA interference (RNAi) for specific gene knockdown was employed.

Materials and methods Different HCC cell lines were transfected with small interfering RNAs (siRNAs) for inducing RNAi and transient target gene downregulation. Various cellular and molecular effects were analysed.

Results Transient siRNA transfection led to robust and specific knockdown of the selected Pim kinase(s) on mRNA and protein level. This resulted in anti-proliferative and pro-apoptotic effects. Most profound consequences on cell growth, cell cycle and apoptosis were observed upon Pim-2 knockdown, with little additive effects upon combined inhibition. These cellular changes were paralleled by alterations of various genes involved in cell cycle, cell survival, EMT and other important cellular processes.

Conclusion In hepatocellular carcinoma, Pim-2 represents a functionally relevant oncogene. We demonstrate its higher potential as compared to the other Pim family members, and analyze various consequences of its inhibition or knockdown on the cellular and molecular level. Taken together, this identifies Pim-2 as a potentially relevant target gene for therapeutic intervention.

Citation Format: Ulrike Weirauch, Pia Kürz, Achim M. Aigner. Comparison between knockdown of Pim-1, Pim-2 and Pim-3 identifies Pim-2 as the most relevant Pim oncogene in hepatocellular carcinoma [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 4125. doi:10.1158/1538-7445.AM2017-4125
Abstract 4127: Targeting MDM4 in hepatocellular carcinoma to reactivate p53 signaling
Authors: Woodfield Sarah E. , Shi Yan , Patel Roma H. , Chen Zhenghu , Ibarra Aryana M. , Vasudevan Sanjeev A.
Published: July 2017

Objective: New therapeutic strategies are desperately needed for hepatocellular carcinoma (HCC), the fourth most common cause of cancer-related deaths worldwide. Most patients with HCC lack mutations in the p53 tumor suppressor gene. Therefore, we hypothesized that targeting MDM4 or MDM2 to reactivate p53 signaling could be effective in this disease.

Methods: HCC cell lines (SK-Hep1, Huh-7, Hep3B) were profiled for gene and protein expression of MDM4 with qPCR and immunoblotting assays, respectively. The effects of MDM4 inhibitor NSC207895 on the same cell lines were analyzed with MTT assays for cytotoxicity and qPCR experiments to look at changes in expression of p53 downstream targets, in comparison to the effects of MDM2 inhibitor Nutlin-3a. Effects of MDM4 on targets other than p53, including family members p63 and p73, were examined in cells with mutant or null p53 for changes in expression with qPCR experiments.

Results: Three HCC cell lines showed expression of MDM4. Inhibition of MDM4 showed cytotoxic (high dose, 0.16-15.0 μM) and anti-proliferative (low dose, 0.05-0.3 μM) effects in all three cell lines, including p53 mutant Huh-7 and p53 null Hep3B cells. The same cell lines were strongly resistant to Nutlin-3a. Gene expression analyses were conducted with cells exposed to NSC207895 to examine effects of MDM4 inhibition on p53 targets Bax, Puma, and p21. In SK-Hep1 cells, NSC207895 treatment led to 2.5-fold overexpression of Bax, 27.4-fold of Puma, and 23.1-fold of p21. Huh-7 showed 11.8-fold upregulation of Puma and 12.4-fold of p21, and Hep3B exhibited a very strong 58.4-fold increase in p21 gene expression with the same treatment. Interestingly, Hep3B showed 5.9-fold overexpression of p63 and 1.99-fold of p73 gene expression with NSC207895 exposure, suggesting novel interactions between MDM4 and p63/p73 in the absence of p53.

Conclusions: Inhibition of MDM4 shows efficacy in in vitro models of HCC through upregulation of p53, p63, and p73 to activate p53 tumor suppressive signaling. Thus, targeting MDM4 may be a viable option for all HCC patients, no matter the p53 mutation status.

Citation Format: Sarah E. Woodfield, Yan Shi, Roma H. Patel, Zhenghu Chen, Aryana M. Ibarra, Sanjeev A. Vasudevan. Targeting MDM4 in hepatocellular carcinoma to reactivate p53 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 4127. doi:10.1158/1538-7445.AM2017-4127
Abstract 4135: Inactivation/loss of PTPRS promotes ERK activation that sensitizes colorectal cancer cells to ERK inhibitors
Authors: Davis Thomas B. , Yang Mingli , Schell Michael J. , Wang Heiman , Ma Le , Pledger W. Jack , Yeatman Timothy J.
Published: July 2017

The RAS pathway is a driver of many cancers, and has been targeted for the development of a variety of therapeutic inhibitors of BRAF, MEK, and more recently ERK. One of challenging issues is to predict response to targeted therapies. Here we report identification of PTPRS, a receptor-type protein tyrosine phosphatase, as a regulator/biomarker of ERK activation and inhibitor response in colorectal cancer. To identify the genes with high frequency mutations that might be predictive of RAS pathway dependence (“addiction”), we used a gene expression signature score to stratify 468 colorectal cancer tumors that also underwent targeted exome sequencing for 1321 cancer-associated genes. We found that, when the masking effects caused by mutant KRAS, BRAF and NRAS was iteratively removed, mutant PTPRS was strongly correlated with RAS pathway activation, with a mutation rate of 10.4% (22 out of 211 remaining tumors). This led us to inactivate PTPRS in vitro using a specific peptide inhibitor, siRNA or CRISPR approaches in various colorectal cancer cell lines. Inhibition/loss of PTPRS significantly elevated phosphorylation of ERK and AKT and substantially sensitized cancer cells to the treatment of ERK inhibitors, which was enhanced by an AKT inhibitor. Surprisingly, PTPRS did not modulate the activity of EGFR and the ERK kinase, MEK. Our data indicate that PTPRS negatively regulates ERK signaling downstream of the EGFR/RAS/RAF/MEK pathway in a mechanism independent of AKT and DUSP6. As a result, inactivation/loss of PTPRS promotes ERK activation and “addiction”, thereby contributing to increased sensitivity to ERK inhibitors.

Citation Format: Thomas B. Davis, Mingli Yang, Michael J. Schell, Heiman Wang, Le Ma, W. Jack Pledger, Timothy J. Yeatman. Inactivation/loss of PTPRS promotes ERK activation that sensitizes colorectal cancer cells to ERK inhibitors [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 4135. doi:10.1158/1538-7445.AM2017-4135
Abstract 4137: Second generation alpha-helical stapled peptides efficiently reduce lymphoma cell viabilityby inhibiting LUBAC and NF-κB activity
Authors: Aguilar-Alonso Francisco A. , Whiting Amanda L. , Marshall Erin , Bernal Federico
Published: July 2017

The linear ubiquitin chain assembly complex (LUBAC) is the only known linear ubiquitin ligase whose function is dependent on the interaction of three proteins: HOIL, HOIP and SHARPIN. The activity of this ubiquitin ligase has been linked to a malignant phenotype associated with the activated B-cell (ABC) subtype of diffuse large B-cell lymphoma (ABC-DLBCL) through constitutive activation of the NF-κB pathway. A first generation of stapled peptides designed to inhibit LUBAC by intracellular disruption of the complex have been shown to reduce cell viability and NF-κB activity in ABC-DLBCL cells modestly. We have developed a second generation of stapled peptides based on the alpha-helical interaction interface of HOIP to enhance their ability to reduce LUBAC formation and, consequently, NF-κB activity as well as ABC-DLBCL cell viability. Live cell imaging showed that some of the second generation HOIP stapled peptides are cell permeable. Biochemical assays revealed that these peptides compromised cell viability, disrupted LUBAC complex formation and inhibited the NF-κB canonical pathway in ABC-DLBCL cell lines. Many of these new peptides were far more potent than any of the previously generated compounds that target the HOIL-HOIP binding interface. These findings support the hypothesis that these second generation peptides may be a useful tool as coadjuvants or therapeutic agents for the treatment of ABC-DLBCL.

Citation Format: Francisco A. Aguilar-Alonso, Amanda L. Whiting, Erin Marshall, Federico Bernal. Second generation alpha-helical stapled peptides efficiently reduce lymphoma cell viabilityby inhibiting LUBAC and NF-κB activity [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 4137. doi:10.1158/1538-7445.AM2017-4137
Abstract 4206: A high-throughput 3D tumor spheroid screening method for drug discovery using imaging cytometry
Authors: Chan Leo Li-Ying , Cribbes Scott , Kessel Sarah , McMenemy Scott , Qiu Jean
Published: July 2017

There have been 1600 FDA approved drugs since their inception in 1938. Currently it costs approximately 883 million dollars to bring a drug candidate to the market, and often times the potential candidate fails at the beginning of the clinical phase. Therefore, it is important to develop drug screening methods that are more clinically relevant or predictable. The current 2D methods for cancer drug discovery have had some difficulty in identifying potential drug candidates that can be used for clinical testing. To overcome this challenge, there has been an increase in research of 3D tissue culture that facilitated the development of new in-vitro tumor model assays. Traditional 3D spheroid analysis method relied heavily on visual observation using standard microscopy, which is time-consuming and has high operator variations. In the recent years, high-throughput image-based cytometers, such as Celigo, have demonstrated the ability to perform bright-field and fluorescence cell-based assays. Celigo imaging cytometer can be employed to rapidly analyze and characterize 3D tumor spheroids, which can be used to generate both quantitative and qualitative results. In this work, we demonstrate a high-throughput 3D tumor spheroid screening method using the Celigo imaging cytometer to screen the effects of 14 drug compounds (NIH/NCAT) on U87MG spheroid size, matrigel invasion, and tumor spheroid viability. First, a dose response experiment is performed to screen the growth inhibitory effects of the drug compounds. In addition to direct spheroid size analysis, dose inhibitory responses of tumor invasion into the matrigel are also examined. Finally, the use of specific fluorescent dyes such as Calcein AM, PI, and Caspase 3/7 were used to screen drug induced cytotoxicity on the tumor spheroids. The results showed that Celigo imaging cytometer can quickly generate accurate growth inhibitory data to identify potential drug candidates. Furthermore, tumor invasion were clearly observed and quantified in the captured images, as well as fluorescent analysis of tumor spheroid viability. By utilizing the 3D spheroid screening method, researchers can rapidly characterize and quantify drug effects on tumor spheroids in a high-throughput format, which can improve the efficiency of identifying more qualified cancer drug candidates.

Citation Format: Leo Li-Ying Chan, Scott Cribbes, Sarah Kessel, Scott McMenemy, Jean Qiu. A high-throughput 3D tumor spheroid screening method for drug discovery using imaging cytometry [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 4206. doi:10.1158/1538-7445.AM2017-4206
Abstract 4208: Inhibition of proliferation and induction of apoptosis by a novel phytobiological mixture against breast cancer cell lines
Authors: Alqarni Afnan A. , Alamoudi Aliaa A. , Ajabnoor Ghada M. , Al-Abd Ahmed M. , Niedwiecki Aleksandra , Rath Matthias , Harakeh Steve
Published: July 2017

Breast cancer remains a leading cause of women’s death worldwide with progressive emergence of resistance towards approved chemotherapies. For this reason, new complementarytreatments have been sought. One of those includethe use of a phytobiological mixture against different types of malignancies, including but not limited to breast cancer. Herein, we investigated the anti-proliferative effects of a novel phytobiological mixture (PB)against two breast cancer cell lines :MDA-MB-231 and MCF-7.The PB mixture is composed of the following: quercetin, resveratrol, cruciferex, epigallocatechin-3-gallate and curcumin at different proportions. Theanti-proliferative and pro-apoptotic effects of PB were evaluated at non-cytotoxic concentrations as determined usingthe Sulfa-Rhodamine B assay (SRB).The effects of PB on the induction of apoptosis were valuated using Annexin-V and flow cytometry to measure the resultingDNA fragments. The results showed that at 72hrs, PB had cytotoxic effects against MDA-MB-231 and MCF-7 cells with an IC50’s of 25.8±5.4 µg/ml and 56.9±4.2 µg/ml, respectively. Exposure of MDA-MB-231 to PB for 72hrs resulted in the induction of apoptosis in a dose-dependent manner. PB concentrations of 10 µg/ml and 30 µg/ml, resulted in early programmed cell death of 9.1±1.5% and 22.1±1.8% respectively. Exposure to PB (10 µg/ml for 24 hrs) resulted in mild cell cycle arrest at the G2/M phase20.3±0.3% ;while higher dosesshowed a significant cell cyclearrest at theS-phaseas compared to the control untreated cells (p<0.001). However, exposure to PB for 48 hrs at both doses,10 µg/ml and30 µg/ml,resulted in a significant cell cycle arrest at the S-phase 25.3±1.6% and 20.5± 0.4%respectivelyas compared to the control untreated cells 12.4±1.5% (p<0.001). In conclusion, PB was found to have a promising anti-proliferative and pro-apoptotic effect in breast cancer cell lines. Further studies are needed to address the underlying mechanism of action of PB against breast cancer cell lines.

Citation Format: Afnan A. Alqarni, Aliaa A. Alamoudi, Ghada M. Ajabnoor, Ahmed M. Al-Abd, Aleksandra Niedwiecki, Matthias Rath, Steve Harakeh. Inhibition of proliferation and induction of apoptosis by a novel phytobiological mixture against 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 4208. doi:10.1158/1538-7445.AM2017-4208
Abstract 4236: Gene expression profiling of prostate tissue identifies biological pathways associated with TMPRSS2:ERG gene fusion
Authors: Ebot Ericka , Isikbay Masis , Gerke Travis , Ahearn Thomas U. , Kelly Rachel S. , Tyekucheva Svitlana , Pettersson Andreas , Penney Kathryn L. , Mucci Lorelei A.
Published: July 2017

Background: TMPRSS2:ERG, a hormonally regulated gene fusion present in about half of prostate tumors, is the most common somatic event in prostate cancer. There is intriguing evidence to suggest that TMPRSS2:ERG-positive tumors may define a distinct subgroup of prostate cancer. In this study we compared gene expression profiles according to fusion status to identify genes and biological pathways differential expressed by TMPRSS2:ERG.

Methods: The study included men with prostate cancer in the Health Professionals Follow-up Study and the Physicians’ Health Study diagnosed between 1982 and 2004 and followed through 2012. Tumor biomarker data was available for archival tumor tissue from 380 cases, 191 of whom also had gene expression data for adjacent normal tissue. Whole genome mRNA expression profiling (20,254 genes) was performed using the Affymetrix 1.0 ST array. TMPRSS2:ERG tumor status was assessed by a genetically validated IHC assay for ERG. To relate expression of individual genes to ERG we used linear regression. Gene Set Enrichment Analysis (GSEA) was used to identify pathways of genes associated with ERG in both tumor and adjacent normal tissue. Data from The Cancer Genome Atlas (TCGA) was used to validate these findings.

Results: Among 380 cases, 186 (49%) of tumors were positive for the gene fusion.

Genome-wide differential expression analysis identified 492 genes upregulated and 369 genes downregulated in tumor tissue comparing ERG+ to ERG- tumors (FDR p-value < 0.05). No genes were identified in the adjacent normal tissue at this significance level. 772 of the 861 genes (90%) identified in the HPFS/PHS dataset were confirmed in TCGA (448 upregulated and 324 downregulated). The top ten genes included ERG, WNK2, CACNA1D, HES1, SEPT9, PLA2G7, TDRD1, ANTXR2, SORBS2, and MYO6. Enrichment analysis identified a number of metabolic pathways associated with ERG tumor status including pathways involved in amino acid and fatty acid metabolism.

Conclusions: We identified significant differences in gene expression profiles in prostate tumor tissue according to TMPRSS2:ERG status, providing supportive evidence of this fusion as a unique subtype.

Citation Format: Ericka Ebot, Masis Isikbay, Travis Gerke, Thomas U. Ahearn, Rachel S. Kelly, Svitlana Tyekucheva, Andreas Pettersson, Kathryn L. Penney, Lorelei A. Mucci. Gene expression profiling of prostate tissue identifies biological pathways associated with TMPRSS2:ERG gene fusion [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 4236. doi:10.1158/1538-7445.AM2017-4236
Abstract 4241: Circulating microRNAs in plasma of men screened for prostate cancer
Authors: Mcdonald Alicia C. , Shen Jing , Vira Manish , Sanda Martin , Liao Jason , Lesser Martin L. , Patil Dattatraya , Raman Jay D. , Taioli Emanuela
Published: July 2017

Introduction: Although microRNAs (miRNAs) have been linked to prostate cancer risk, their role as a screening biomarker for prostate cancer (PC) has yet to be determined. We examined whether circulating miRNAs in plasma could be potential biomarkers for the early detection of PC among men undergoing prostate needle biopsy. Methods: Men who had a prostate biopsy due to an abnormal screening test were recruited. Demographics, medical history, clinical information, and blood processed into plasma were collected. TaqMan Low Density Arrays were used for the expression profiling of 733 miRNAs in plasma. Wilcoxon test was used to compare expression levels between men with and without a PC diagnosis. Logistic regression was used to examine the association between miRNAs and PC status, after adjusting for age and Bonferroni-correction. Results: There were 131 men, aged 46 to 86 years, included in the final analysis, with 66 men diagnosed with PC on prostate biopsy and 65 men without a PC diagnosis. Majority were white (72.5%) followed by black race (13.5%). Men with PC were older (median: 64 vs. 62 years; p-value = 0.16) and had statistically significantly higher serum PSA (median: 5.8 vs. 5.1 ng/mL; p-value = 0.01) compared to men without a PC diagnosis. The most statistically significant PC circulating miRNAs in plasma were miR-381, miR-523, miR-450B-5p, miR-34a, miR-34b, miR-639, and miR-365, after adjusting for age (p-values ≤ 0.05). The detection rate of these miRNAs in plasma ranged from 23.7% to 83.2%. These miRNAs were no longer statistically significant with PC diagnosis, after adjusting for multiple comparison (FDR q-value = 1.00). Conclusion: Among the 733 miRNAs evaluated, there was no miRNA found to be associated with PC diagnosis after adjusting for multiple comparison. Studies that examine a larger number of miRNAs which include the discovery of new miRNAs and their relationship with PC risk are warranted.

Citation Format: Alicia C. Mcdonald, Jing Shen, Manish Vira, Martin Sanda, Jason Liao, Martin L. Lesser, Dattatraya Patil, Jay D. Raman, Emanuela Taioli. Circulating microRNAs in plasma of men screened for 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 4241. doi:10.1158/1538-7445.AM2017-4241
Abstract 4243: Epigenome-wide association study of metabolic syndrome in African-Americans
Authors: Akinyemiju Tomi
Published: July 2017

Background: The epidemic of obesity among US adults has resulted in significant increases in associated metabolic disorders such as diabetes, dyslipidemia and high blood pressure. Together, these disorders constitute metabolic syndrome, a clinically defined condition highly prevalent among African-Americans. Identifying epigenetic alterations associated with metabolic syndrome, including DNA methylation changes may provide information on biological pathways that are dysregulated and may potentially act as early biomarkers in cancer.

Methods: Data on cardio-metabolic risk factors and DNA methylation was assessed on 606 African-Americans from the Hypertension Genetic Epidemiology Network (HyperGEN) study. Metabolic syndrome was defined using the joint harmonized criteria of at least three of: elevated waist circumference, high triglycerides, low HDL-cholesterol, high fasting blood glucose and high blood pressure. DNA methylation was assessed using the Illumina HumanMethylation 450K Bead Chip assay on DNA extracted from buffy coat. Linear mixed effects regression models were used to examine the association between CpG methylation and metabolic syndrome in crude and adjusted (for age, alcohol, smoking, sex) analyses. Replication using DNA from 76 African-Americans in the REason for Geographic and Racial Disparities in Cancer (REGARDS) study, as well as meta-analysis combining both cohorts was conducted.

Results: Two differentially methylated CpG sites in the IGF2BP1 gene on chromosome 17 (cg06638433; β =0.01, p-value=3.10x10-7) and the ABCG1 gene on chromosome 21 (cg06500161; β: 0.018, p-value=2.60x10-8) were identified in models adjusted for age, sex, alcohol and smoking. Methylation of CpG sites on the TXNIP gene on chr 1 (p=2.83 x 10-9), and CPT1A gene on chr 11 (p=1.39 x 10-4) were also significantly associated with metabolic syndrome in unadjusted models. Results for the ABCG1 gene remained statistically significant in the replication set and meta-analysis.

Conclusion: Metabolic syndrome was consistently associated with focal DNA hypermethylation in the ABCG1gene, a region of the chromosome that encodes proteins in the ATP-binding cassette transporter family, and is involved intra- and extra- cellular signaling. Alterations in the ABCG1 gene was observed in 40% of invasive breast cancer tumors in the TCGA, providing a potential epigenetic link between metabolic syndrome and breast cancer that deserves further study.

Note: This abstract was not presented at the meeting.

Citation Format: Tomi Akinyemiju. Epigenome-wide association study of metabolic syndrome in African-Americans [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 4243. doi:10.1158/1538-7445.AM2017-4243
Abstract 4257: Dietary nutrient intake, ethnicity, and epigenetic silencing of lung cancer genes detected in sputum in New Mexican smokers
Authors: Leng Shuguang , Picchi Maria , Filipczak Piotr , Gilliland Frank , Belinsky Steven A.
Published: July 2017

Promoter hypermethylation of lung cancer (LC) genes detected in sputum assesses field cancerization and predicts LC risk. Hispanic smokers have greater risk for methylation than non-Hispanic Whites (NHW). We aimed to identify novel dietary nutrients affecting methylation of LC genes in sputum and determine the degree of ethnic disparity explained by diet. A cross-sectional population-based study was conducted with dietary intake assessed using a validated Harvard food frequency questionnaire in 327 Hispanics and 1502 NHWs from the Lovelace Smokers cohort (LSC). Twelve LC genes with diverse cellular functions whose concomitant methylation strongly predicted LC risk were studied. A global association was identified between dietary intake and gene methylation (Ppermutation=0.003). Seventeen nutrient measurements were associated with methylation with magnitude greater than seen for folate and these nutrients together accounted for 36% of the variance in methylation. Six protective nutrients were identified and their insufficient intake in Hispanics explained approximately 42% of ethnic disparity in methylation. Functional validation of protective nutrients that also explained ethnic disparity was provided by showing an enhanced DNA repair capacity towards double-strand DNA breaks, a mechanistic biomarker strongly linked to acquisition of LC gene methylation in smokers. Dietary intake is a major modifiable factor for preventing promoter methylation of LC genes in smokers’ lungs. Altering the diet in Hispanics may alleviate ethnic disparity for methylation. Complex dietary supplements could be developed based on these protective nutrients for LC chemoprevention in smokers. This study was funded by NIH R01 CA097356, NIH/NCI P30 CA118100, and the State of New Mexico as a direct appropriation from the Tobacco Settlement Fund.

Citation Format: Shuguang Leng, Maria Picchi, Piotr Filipczak, Frank Gilliland, Steven A. Belinsky. Dietary nutrient intake, ethnicity, and epigenetic silencing of lung cancer genes detected in sputum in New Mexican smokers [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 4257. doi:10.1158/1538-7445.AM2017-4257
Abstract 4271: Population-wide vs. carrier-probability-based BRCA1/2 mutation testing in the Washington Ashkenazi Study
Authors: Best Ana F. , Tucker Margaret A. , Katki Hormuzd A.
Published: July 2017

Background: Currently, women are referred for BRCA1/2 mutation testing if their family history of breast and ovarian cancer indicates they have sufficient probability of carrying mutations. In contrast, calls have intensified for population-wide testing for BRCA1/2 founder mutations among Ashkenazi Jews, due to relatively high mutation prevalence (2.5%) and decreasing genotyping costs. However, population-wide testing would strain genetic counseling resources and incur costs from testing mostly mutation-negative women. We compared the performance of population-wide vs. carrier-probability-based BRCA1/2 testing in the community-based Washington Ashkenazi Study (WAS).

Methods: BRCA1/2 carrier-probabilities based on reported family histories were calculated using BRCAPRO for 4589 probands (102 BRCA1/2 mutation-carriers) in WAS. For each carrier-probability threshold, we compared the percent of mutations found (sensitivity) vs. the percent of women requiring mutation testing, overall and by proband age. At example carrier-probability thresholds, undetected and detected carriers’ attributes were compared using nonparametric tests.

Results: A 1.2% carrier-probability threshold identified 80% of BRCA1/2 mutations in the 35% of women with highest carrier-probability. For women under age 40, 94% of BRCA1/2 mutations were identified in the 50% of women with highest carrier-probability. Compared to identified mutation-carriers, missed mutation-carriers had no personal cancer history, no affected first- and second-degree relatives (p<0.0001), more unaffected first-degree relatives (p=0.0002), and were older (p=0.012; median age=53).

Conclusion: Carrier-probability-based BRCA1/2 mutation testing identified large majorities of mutation-carriers and would have avoided testing for many mutation-negative women. Missed mutation-carriers were older and cancer-free and would gain minimal benefit from risk-reducing interventions. A cost-effective carrier-probability threshold could acceptably tradeoff identifying BRCA1/2 mutation carriers before they get cancer while testing as few women as possible.

Citation Format: Ana F. Best, Margaret A. Tucker, Hormuzd A. Katki. Population-wide vs. carrier-probability-based BRCA1/2 mutation testing in the Washington Ashkenazi 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 4271. doi:10.1158/1538-7445.AM2017-4271
Abstract 4300: Thymoquinone Inhibits Proliferation and induces apoptosis in leukemic cells
Authors: Harakeh Steve , Semaan Josiane , Sabban Marwan El , Jaouni Soad K. Al , Diab-Assaf Mona , Azar Rania
Published: July 2017

Introduction: Adult T-cell leukemia (ATL) is caused by human T-cell lymphotropic virus 1 (HTLV-1) and is an aggressive form of malignancy. So far, there is no effective treatment for ATL. Thymoquinone has been reported to exhibit many useful effects including anti-cancerous properties. Objective: The aim of this study is to investigated the effects of TQ on proliferation, apoptosis induction and the underlying mechanism of action in both HTLV-1 positive (C91-PL and HuT-102) and HTLV-1 negative (CEM and Jurkat) malignant T-lymphocytes. Materials and methods: Cells were treated with various concentrations of thymoquinone for 24h. Cell cytotoxicity was assayed using the CytoTox 96® Non-Radioactive Cytotoxicity Assay Kit. Cell proliferation was determined using CellTiter 96® Non-Radioactive Cell Proliferation. Cell cycle analysis was performed using staining with propidium iodide. Apoptosis was assessed using cell death ELISA kit. The effect of TQ on p53, p21, Bcl-2 protein expression was determined using Western blot analysis while TGF mRNA expression was determined by RT-PCR. Results: At non-cytotoxic concentrations of TQ, it resulted in inhibition of proliferation in a dose dependant manner. Flow cytometric analysis revealed a shift in the cell cycle distribution to the PreG1 phase which is a marker of apoptosis. Also TQ increased DNA fragmentation. TQ mediated its anti-proliferative effect and apoptosis induction by an up-regulation of TGFβ1, p53 and p21 and a down-regulation of TGF-α and Bcl-2α. Conclusion: Thymoquinone showed antiproliferative and proapoptotic potentials in ATL cells. For this reason, further research is required to investigate its possible application in the treatment of ATL.

Citation Format: Steve Harakeh, Josiane Semaan, Marwan El Sabban, Soad K. Al Jaouni, Mona Diab-Assaf, Rania Azar. Thymoquinone Inhibits Proliferation and induces apoptosis in leukemic 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 4300. doi:10.1158/1538-7445.AM2017-4300
Abstract 4309: Mode of action of LTX315-induced cell death
Authors: ZHOU HENG , Sauvat Allan , Durand Sylvère , Forveille Sabrina , Yamazaki Takahiro , Souquere Sylvie , Sica Valentina , Rekdal Øystein , Kepp Oliver , Kroemer Guido
Published: July 2017

The experimental anticancer agent LTX-315 is an amphipathic cationic peptide that efficiently eradicates cancer cells in vitro and in vivo. Attracted by its efficacy we launched an in depth mechanistic study on LTX-315. First we focused on the mode of action of LTX-315 and found that the agent failed to induce morphological signs of apoptosis but evoked necrotic phenotypes. Accordingly, LTX-315 failed to stimulate the activation of caspases, and the pan-caspase inhibitor Z-VAD-fmk was unable to reduce cell killing. We then studied its subcellular localization by fractionation of LTX-315-treated cells, and revealed that the agent was enriched in mitochondria and caused an immediate arrest of mitochondrial respiration without any major uncoupling effect. LTX-315 disrupted the mitochondrial network, dissipated the mitochondrial inner transmembrane potential, and caused the release of mitochondrial intermembrane proteins into the cytosol. Cells lacking the two pro-death multidomain proteins BAX and BAK, were less susceptible to LTX-315-mediated killing. Moreover, cells engineered to lose their mitochondria were resistant against LTX-315, underscoring the importance of this organelle for LTX-315-mediated cytotoxicity. Further, we observed that LTX-315 induced all known characteristics of immunogenic cell death, including calreticulin exposure, ATP secretion, HMGB1 exodus and type-1 interferon induction. When injected into established cancers, LTX-315 caused a transiently hemorrhagic focal necrosis that was accompanied by massive release of HMGB1 (from close-to-all cancer cells), as well caspase-3 activation in a fraction of the cells. Collectively, these results support the idea that LTX-315 triggers unregulated necrosis, and kills cancer cells by virtue of its capacity to permeabilize mitochondrial membranes. In addition, LTX-315 can induce ICD, hence explaining its capacity to mediate immune-dependent therapeutic effects.

Citation Format: HENG ZHOU, Allan Sauvat, Sylvère Durand, Sabrina Forveille, Takahiro Yamazaki, Sylvie Souquere, Valentina Sica, Øystein Rekdal, Oliver Kepp, Guido Kroemer. Mode of action of LTX315-induced cell death [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 4309. doi:10.1158/1538-7445.AM2017-4309
Abstract 4311: Targeting specific regulatory subunits of protein phosphatase 1 phenocopies estrogen-induced apoptosis
Authors: Sevigny Catherine , Sengupta Surojeet , Bouker Kerrie B. , Clarke Robert
Published: July 2017

The growth of estrogen receptor positive (ER+) breast cancers is considered to be dependent on estrogen and its actions can be blocked by selective estrogen receptor modulators (SERMS), like tamoxifen, or by inhibiting the synthesis of estrogen, by aromatase inhibitors (AIs). Both of these classes of drug are used to treat ER+ breast cancers in the clinic. Paradoxically, before the discovery of SERMs and AIs, high dose estrogen was the choice of endocrine therapy to treat post-menopausal breast cancers. Recent clinical trials have confirmed a 30% clinical benefit rate with high, as well as low, doses of estrogen therapy in AI- resistant breast cancers. However, the underlying mechanism by which estrogen triggers the tumor regression remains unknown. Using an in vitro cell model MCF7:5C cells, that undergo estrogen-induced apoptosis, we demonstrate that sustained phosphorylation of eukaryotic initiation factor 2-alpha (eIF2-α), a downstream target of PERK activation, is crucial in estrogen-induced apoptosis. Growth arrest and DNA damage inducible-34 (GADD34) and constitutive repressor of eIF2α phosphorylation (CReP) are two regulatory subunits of protein phosphatase 1 (PP1) complex, that provides substrate specificity towards eIF2α, and are responsible for its de-phosphorylation. Our results show that pharmacological inhibition of GADD34 and CReP, or their genetic depletion, can enhance the phospho-eIF2α (p-eIF2α) levels and promote apoptosis. Elevated levels of p-eIF2α attenuated global translation but preferentially allowed high expression of activating transcription factor 4 (ATF4) and C/EBP homologous protein (CHOP) that are involved in apoptosis. Both estrogen and inhibition of GADD34 and CReP promote apoptosis by an identical mechanism. Importantly, inhibition of GADD34 and CReP induced apoptosis in another estrogen-independent breast cancer cell line, LCC9, which is resistant to both tamoxifen and fulvestrant but does not undergo estrogen mediated apoptosis. Overall, our study provides crucial evidence that inhibiting specific regulatory subunits (GADD34 and CReP) of PP1 complex, can mimic estrogen-induced apoptosis in breast cancer cells that are not susceptible to estrogen mediated apoptosis. Therefore, GADD34 and CReP can be targeted for potential therapeutic intervention in endocrine therapy resistant breast cancers.

Citation Format: Catherine Sevigny, Surojeet Sengupta, Kerrie B. Bouker, Robert Clarke. Targeting specific regulatory subunits of protein phosphatase 1 phenocopies estrogen-induced apoptosis [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 4311. doi:10.1158/1538-7445.AM2017-4311
Abstract 4312: Targeting FoxM1 in inducing anticancer effects in triple-negative breast cancer cells
Authors: Bu Rong , Siraj Abdul K. , Ahmed Maqbool , Al-Dayel Fouad , Al-Kuraya Khawla S.
Published: July 2017

Triple-negative breast cancer (TNBC) is highly aggressive and a major threat to survival due to absence of molecular targets. Invasion, metastasis and chemoresistance are the greatest obstacles to the successful tumor treatment in breast cancer patients. In this study, over-expression of Forkhead box transcription factor M1 (FoxM1) was observed in 79% (770/975) of breast cancers from Saudi Arabia. FoxM1 over-expression was found to be an independent prognostic marker in multivariate analysis in late stage (Stage 3 and 4) breast cancer (p=0.0110). Our in vitro results show that treatment with thiostrepton, a dual FoxM1 and proteasome inhibitor caused cell viability loss and induce apoptosis in a dose dependent manner in triple-negative breast cancer cell lines. Thiostrepton treatment also inhibited colony formation and invasion/migration capabilities of triple-negative breast cancer cells. In vivo, thiostrepton treatment regressed TNBC cells; MDA-MB-231 generated xenografts via down-regulation of FoxM1 and its downstream targets. Altogether, our results suggest that FoxM1 and its associated signaling pathway may be a potential target for therapeutic intervention in the treatment of aggressive breast cancer.

Key words: Triple-negative breast cancer, FoxM1, Apoptosis and Invasion

Citation Format: Rong Bu, Abdul K. Siraj, Maqbool Ahmed, Fouad Al-Dayel, Khawla S. Al-Kuraya. Targeting FoxM1 in inducing anticancer effects in triple-negative 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 4312. doi:10.1158/1538-7445.AM2017-4312
Abstract 4317: EGLN1/c-Myc induced lymphoid-specific helicase inhibits ferroptosis through lipid metabolic gene expression changes
Authors: Tao Yongguang , Liu Shuang , Jiang Yiqun
Published: July 2017

Ferroptosis has emerged as a new form of non-apoptotic cell death in multiple human diseases. However, the epigenetic mechanisms of ferroptosis remain poorly defined. We demonstrate that Lymphoid-specific helicase (LSH), a DNA methylation modifier, interacts with WDR76 to inhibit ferroptosis by activating lipid metabolism-associated genes, including GLUT1, and ferroptosis related genes SCD1 and FADS2. These effects are dependent on iron and lipid reactive oxygen species. We further show that EGLN1 and c-Myc directly activate LSH expression by inhibiting HIF-1α. Finally, we demonstrate that LSH functions as an oncogene in lung cancer in vitro and in vivo. Therefore, our study elucidates the molecular basis for a c-Myc/EGLN1-mediated induction of LSH expression to inhibit ferroptosis, which can be exploited for the development of therapeutic agents to target ferroptosis in cancer.

Note: This abstract was not presented at the meeting.

Citation Format: Yongguang Tao, Shuang Liu, Yiqun Jiang. EGLN1/c-Myc induced lymphoid-specific helicase inhibits ferroptosis through lipid metabolic gene expression changes [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 4317. doi:10.1158/1538-7445.AM2017-4317