Citations

Abstract Multiple myeloma (MM) is twice as common in African Americans (AA) compared to European Americans (EA). The reported familial clustering and the elevated MM risk among first-degree relatives of cases implicate genetic susceptibility. Previous genome-wide association studies (GWAS) in EA have identified 16 novel risk loci. In this study, we tested the generalizability of the established risk alleles to AA and conducted a meta-GWAS analysis using two sets of AA to identify additional novel common MM risk variants. In the first study, we genotyped 1,305 incident AA MM cases from the African American Multiple Myeloma Study (AAMMS) using the Illumina HumanCore GWAS array and compared them to 7,078 AA controls from the African Ancestry Prostate Cancer Consortium (AAPC) and African Ancestry Breast Cancer Consortium (AABC) using the Illumina 1M-Duo. In the second study, 95 additional AAMMS cases and 435 AA MM cases from the University of Arkansas for Medical Sciences (UAMS) were genotyped using the Illumina MegaBead Chip and compared to 2,390 AA controls from the Multiethnic Cohort. The Haplotype Reference Consortium (HRC) was used to impute the overlapping typed SNPS from each GWAS case and control set together. Per-allele risk associations were tested for 8,715,278 overlapping genotyped and imputed variants with >1% frequency and >0.8 imputation score using unconditional logistic regression in both sets, and the combined effects were estimated using a fixed-effect meta-analysis. Of the 16 reported risk loci discovered in EA, directional consistency was present for 15 variants; eight of these replicated at nominal significance p<0.05, with the most statistically significant variant being rs4487645 at 7p15.3 (OR=1.38, p=3.56×10-6). AA individuals with polygenic risk scores from these 16 variants (PRS) in the top 10% stratum had a 1.44-fold increased MM risk compared to those with a PRS in the 25th -75th percentiles. Additionally, we identified three suggestive novel loci located at 12q12, 9p24.3 and 9p13.1 at p<1×10-6, with ORs ranging from 1.25-1.55, but none reached genome-wide significance. The variant at 9p24.3 is located in an intron in the KANK1 gene and a correlated SNP in EAs (r2=0.5) is strongly associated with gene expression in neoplastic plasma cells (unpublished, Weinhold and Morgan). Our study replicated most of the reported risk loci discovered among EA, demonstrated that a PRS constructed using the 16 reported risk alleles was associated with MM risk, and provides suggestive evidence for additional loci associated with MM risk in AAs. Citation Format: Zhaohui Du, Chi Song, Kristin Rand, Niels Weinhold, David Van Den Berg, Amie Hwang, Xin Sheng, Victor Hom, Sikander Ailawadhi, Ajay K. Nooka, Seema Singhal, Karen Pawlish, Edward S. Peters, Cathryn Bock, Ann Mohrbacher, Alexander Stram, Sonja I. Berndt, William Blot, John David Carpten, Antoinette Stroup, Andrew Olshan, Wei Zhang, African Ancestry Breast & Prostate Consortium, Stephen Chanock, Jayesh Mehta, Graham A. Colditz, Jeffrey Wolf, Thomas G. Martin, Michael Tomasson, Mark A. Fiala, Howard Terebelo, Nalini Janakiraman, Laurence Kolonel, Loic LeMarchand, Elad Ziv, Daniel Stram, Ravi Vij, Leon Bernal-Mizrachi, Gareth J. Morgan, Jeffrey A. Zonder, Carol Ann Huff, Sagar Lonial, Robert Z. Orlowski, David V. Conti, Christopher A. Haiman, Wendy Cozen. A meta-analysis of genome-wide association studies of multiple myeloma among African Americans [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 223.

Abstract Background: We previously identified 5 SNPs at 4 susceptibility loci for diffuse large B-cell lymphoma (DLBCL) in individuals of European ancestry through a large genome-wide association study (Cerhan et al, Nat Gen 2014;46:1233-8); however, much of the heritability remains unexplained. To further elucidate genetic susceptibility to DLBCL, we sought to validate 2 loci at 3q13.33 and 3p24.1 that were suggestive in the original report. Methods: We selected two SNPs rs9831894 (3q13.33) and rs6773363 (3p24.1) for de novo replication from studies at the Mayo Clinic, MD Anderson, and Memorial Sloan Kettering. Logistic regression was used to estimate odds ratios (ORs), using a log-additive model, and adjusting for age, gender and significant eigenvectors for each genotyping center separately. For both SNPs, we then conducted a meta-analysis of all replication studies (n=3) and our original GWAS studies (n=4), encompassing in total 5662 cases and 9237 controls for rs9831894, and 5510 cases and 12,817 controls for rs6773363. Meta-analysis was conducted using the fixed-effects inverse variance method based on the β estimates and standard errors from each study. Results: In a meta-analysis of the 4 original GWAS scans (3856 cases and 7666 controls), rs9831894 (MAF=0.40) was associated with DLBCL risk (OR=0.84, P=4.52 x 10-9) and this replicated in a meta-analysis of the 3 studies with de novo genotyping (OR=0.80, P=4.17 x 10-5); the overall meta-analysis showed a strong association with DLBCL risk (OR=0.83, P=3.62 x 10-13). This locus maps near a plausible candidate gene, CD86, a protein coding gene and a member of the immunoglobulin superfamily that encodes a type I membrane protein. Binding of CD86 with cytotoxic T-lymphocyte-associated protein 4 negatively regulates T-cell activation and diminishes the immune response, while binding of CD86 with CD28 antigen is a costimulatory signal for activation of the T-cell. In a meta-analysis of the same 4 GWAS scans, rs6773363 (MAF=0.45) was tentatively associated with DLBCL risk (OR=1.17, P= 3.68 x 10-7) and this replicated in a meta-analysis of the studies with de novo genotyping (OR=1.27, P=3.78 x 10-7); the overall meta-analysis showed a strong association with DLBCL risk (OR=1.20, P=2.31 x 10-12). This locus also maps near a plausible candidate gene, eomesodermin (EOMES), a transcription factor crucial for embryonic development of the central nervous system and also putatively involved in T-cell differentiation in viral infection defense. Conclusion: In this follow-up analysis of our initial GWAS, we have identified two additional loci associated with risk of DLBCL, the most common lymphoma subtype. These loci provide additional evidence for the role of immune function in the etiology of DLBCL. Citation Format: Geffen Kleinstern, Michelle Hildebrand, Vijai Joseph, Sonja I. Berndt, Hervé Ghesquières, James McKay, Sophia S. Wang, Alexandra Nieters, David Cox, Alain Monnereau, Angela R. Brooks-Wilson, Qing Lan, Mads Melbye, Rebecca D. Jackson, Lauren R. Teras, Mark P. Purdue, Claire M. Vajdic, Demetrius Albanes, Anne Zeleniuch-Jacquotte, Simon Crouch, Yawei Zhang, Susan L. Slager, Xifeng Wu, Karin E. Smedby, Gilles Salles, Christine F. Skibola, Nathaniel Rothman, Stephen J. Chanock, James R. Cerhan. Inherited variants at 3q13.33 and 3p24.1 influences risk of diffuse large B-cell lymphoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 221.

Abstract Objective Genome-wide association studies (GWAS) identify associations of individual SNPs with cancer risk but usually only explain a fraction of the inherited variability. Pathway analysis of genetic variants has been shown for many disorders to be a powerful tool in discovering novel networks of susceptibility genes. Design We have conducted a large agnostic pathway-based meta-analysis of GWAS data using the summary-based adaptive rank truncated product (sARTP) method to identify novel gene sets and pathways associated with pancreatic ductal adenocarcinoma (PDA) in 9,040 cases and 12,495 controls. We performed expression quantitative trait loci (eQTL) analysis and functional annotation of the top SNPs in genes identified in PDA-associated gene sets and pathways. Results We identified 14 gene sets and pathways associated with PDA at FDR < 0.05. Five of the strongest signals (P-value ≤ 1.3x10-5 Bonferroni corrected) were in genes from KEGG maturity onset diabetes of the young, Reactome regulation of beta cell development, Biocarta role of epidermal growth factor (EGF) receptor transactivation by G-protein-coupled receptors in cardiac hypertrophy pathway, Nikolsky breast cancer chr17q11-q21 amplicon gene set, and Pujana ATM Pearson correlation coefficient (PCC) network gene set. We identified and validated rs876493 and three correlated SNPs (PGAP3) and rs3124737 (CASP7) as eQTLs in two normal derived pancreas tissue datasets. Conclusion Our agnostic gene set and pathway analysis integrated with functional annotation and eQTL analysis provides novel insight into genes and pathways that may be biologically relevant for risk of PDA. Citation Format: Naomi Walsh, Han Zhang, Paula L. Hyland, Qi Yang, Evelina Mocci, Mingfeng Zhang, Erica J. Childs, Zhaoming Wang, Stephen Chanock, Patricia Hartge, Robert Hoover, Peter Kraft, Donghui Li, Eric J. Jacobs, Gloria M. Petersen, Brian M. Wolpin, Harvey A. Risch, Laufey T. Amundadottir, Kai Yu, Alison P. Klein, Rachael Z. Stolzenberg-Solomon. Large pathway and gene set analysis of GWAS data identifies novel associations for pancreatic cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 242.

Abstract Ovarian cancer (OC) is most lethal gynecologic malignancy. About 75% of OC patients relapse and/or develop chemo-resistant disease after initial response to standard-of-care treatment with platinum-based therapies. HER2 amplifications and overexpression in OC are reported to vary and responses to HER2 inhibitors have been feeble. Next generation sequencing technologies in conjunction with testing using patient-derived xenografts (PDX) allow validation of personalized treatments. Using whole-genome mate-pair next generation sequencing protocol we profiled a set of serous OC to identify copy number changes and gene fusions. Specific focus was on DNA alterations which were therapeutically targetable. The efficiency of anti-Her2 therapy was tested in three different PDX lines with alterations at genes of ERBB pathway and various levels of HER2 protein expression. Tumor in one line harbored a duplication of ERBB2 and high expression of HER2 protein. Second PDX model had a fusion at NRG1 gene, a ligand for HER4 and HER4 receptors, that was highly expressed on protein level. Third line harbored an amplification of NRG3 gene, a known ligand for HER4 receptor. Treatment responses to pertzumab/trastuzumab were compared in each PDX line to standard carboplatin and paclitaxel combination treatment. In all three PDX models HER2-targeted therapy resulted in significant inhibition of tumor growth compared to untreated control. However, the responses in each were inferior to chemotherapy, even in chemo-resistant case. There was an extra benefit when chemotherapy and HER-2 targeted therapy were administered together, as a significant regression of tumor was observed after 6 weeks of treatment using this regiment compared to chemotherapy alone. Post-treatment analysis of the tissues, nevertheless, revealed inhibition of ERBB2 pathway on the level of phosphorylation and expression of downstream targets. In conclusion, targeting of presumably activated ERBB2 pathway alone in OC results in a modest treatment benefit. A combination therapy including both chemo drugs and Her2 inhibitors provides far better response. Further studies are needed to address development of recurrence and sensitivity of recurrent disease to Her2 targeted therapy. Citation Format: Irina V. Kovtun, Zhang Piyan, Faye R. Harris, Xiaonan Hou, Saravut J. Weroha, George Vasmatzis. Targeting ERBB2 pathway in ovarian cancer [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2017 Oct 26-30; Philadelphia, PA. Philadelphia (PA): AACR; Mol Cancer Ther 2018;17(1 Suppl):Abstract nr LB-A19.

ABSTRACT Dimethylarginine dimethylaminohydrolases (DDAHs) are known to degrade asymmetric dimethylarginine, an endogenous inhibitor of NOS, and maintain vascular homeostasis; however, the regulatory pathways of DDAHs remain unclear. In this study, we aimed to define the role of transmembrane glycoprotein neuropilin‐1 (NRP1) in the expression of DDAHs and investigate the potential roles of NRP1 in regulation of blood pressure. Short hairpin RNA–mediated knockdown of NRP1 reduced the level and mRNA stability of DDAH1 but not DDAH2 in HUVECs, whereas overexpression of NRP1 increased the mRNA stability of DDAH1. Meanwhile, mesenteric arteries and lung vascular endothelial cells of tamoxifen‐inducible endothelial cell–specific NRP1 knockout mice exhibited decreased expression of DDAH1 and slightly increased expression of DDAH2. Mechanistically, the regulation of NRP1 on DDAH1 expression is mediated by a posttranscriptional mechanism involving miR‐219‐5p in HUVECs. Although the endothelial cell–specific NRP1 knockout mice did not exhibit any significant change in blood pressure at the basal level, they were more sensitive to low‐dose angiotensin II infusion–induced increases in blood pressure. Our results show that NRP1 is required for full expression of DDAH1 in endothelial cells and that NRP1 contributes to protection from low‐dose angiotensin II–induced increases in blood pressure.—Wang, Y., Wang, E., Zhang, Y., Madamsetty, V. S., Ji, B., Radisky, D. C., Grande, J. P., Misra, S., Mukhopadhyay, D. Neuropilin‐1 maintains dimethylarginine dimethylaminohydrolase 1 expression in endothelial cells, and contributes to protection from angiotensin II–induced hypertension. FASEB J. 33, 494–500 (2019). www.fasebj.org

Abstract Despite a good response rate to front-line treatment, most of the patients with epithelial ovarian cancer (EOC) will eventually develop an incurable state of platinum (Pt)-resistant disease. Pt resistance is a multifactorial event driven by different molecular mechanisms such as increased ability to tolerate or repair DNA lesions, tendency to plasticity with acquisition of mesenchymal phenotype, and ability to modify/reprogram cellular metabolism. We recently identified in EOC relevant alterations in all of these factors, largely contributing to EOC aggressiveness. Focusing our attention on microRNAs (miRNAs), the master regulator of gene expression, we identified a cluster of miRNAs located on ChrXq27.3 (miR-506 family) whose downregulation is associated with advanced-stage EOC early relapse, and we found it to be the main contributor of a 35-miRNA based predictor (MiROvaR) of EOC risk of progression/relapse. We also contributed in defining altered choline metabolism in EOC that, through overexpression of choline kinase alpha (ChoK/CHKA) enzyme whose activity sustains tumor addiction to antioxidants, fosters EOC aggressiveness also by increasing chemoresistance. By in vitro and ex vivo studies performed in human EOC cell lines, non-tumoral immortalized ovarian cells and ex vivo EOC patient-derived ascitic tumor cells (PDAT), here we analyzed the role of miR-506 in regulating molecular network associated with drug resistance and evaluated the druggability of the cholinic phenotype, exploring its possible crosstalk with the immune system. We confirmed miR-506 to directly regulate the predicted target RAD17, a gene with a key role in guiding BRCA1 to DNA damage sites and stabilizing active signaling. Since an inactivation of DNA repair genes (BRCA1/2) is associated with better prognosis due to sensitization to DNA-damaging drugs, we investigated whether miR-506 can regulate DNA repair machinery by phenocopying/supporting the effects of BRCA1/2 mutation on Pt and PARP inhibitor sensitivity. We observed that miR-506 forced expression or RAD17 knockdown sensitized EOC cells to Pt and PARP inhibitors and, interestingly, showed a synthetic lethal effect with inhibitors of cell-cycle checkpoint kinases CHK1 and WEE1. Association of miR-506 cluster expression (RT-qPCR) with the BRCAness-phenotype is currently ongoing on a retrospective FFPE case material. We also recently link EOC cells plasticity, miRNAs expression, and Pt-sensitivity. Indeed, E-cadherin can exert a new and unexpected functional role in EOC cells by contributing to Pt susceptibility. We determined that overexpression of PLEKHA7 (Pleckstrin homology domain-containing family A member 7), a component of the zonula adherens in polarized epithelia and expressed at low levels in EOC biopsies, inhibits cell tumorigenicity and sensitizes EOC cells to Pt treatment. We will evaluate PLEKHA7 ability to regulate miRNAs driving tumor progression, including some of the miR-506 family. Concerning chemoresistance associated with metabolic rewiring, we showed that CHKA silencing altered the cellular oxidative stress redox status, decreasing glutathione content and raising reactive oxygen species (ROS) levels. Interestingly, the increase in intracellular ROS species improved EOC cells’ sensitivity to Pt/taxane treatments, contributing to cell death triggering. Moreover, upon CHKA silencing both in vitro and in PDAT cells, we observed an enhanced sensitization of cancer cells to TRAIL-mediated citotoxicity due to an augmented expression of pro-apoptotic/reduced expression of anti-apoptotic TRAIL receptor members, thus further increasing tumor cells’ weakness. Exploiting tumor’s reliance on these altered molecular and metabolic pathways is expected to be an appropriate strategy to improve efficacy of current treatment, possibly circumventing drug resistance. Funded by CARIPLO Foundation, AIRC and 5x1000 Institutional Research Funding. Citation Format: Marina Bagnoli, Roberta Nicoletti, Andrea Rizzo, Francesca Roggiani, Alessandro Satta, Mariangela Figini, Wei Zhang, Panagiotis Z. Anastasiadis, Egidio Iorio, Silvana Canevari, Antonella Tomassetti, Francesco Raspagliesi, Delia Mezzanzanica. An integrated molecular and metabolic approach for harnessing early relapse and chemoresistance in ovarian cancer. [abstract]. In: Proceedings of the AACR Conference: Addressing Critical Questions in Ovarian Cancer Research and Treatment; Oct 1-4, 2017; Pittsburgh, PA. Philadelphia (PA): AACR; Clin Cancer Res 2018;24(15_Suppl):Abstract nr A39.

How cells ensure symmetric inheritance Parental histones with modifications are recycled to newly replicated DNA strands during genome replication, but do the two sister chromatids inherit modified histones equally? Yu et al. and Petryk et al. found in mouse and yeast, respectively, that modified histones are segregated to both DNA daughter strands in a largely symmetric manner (see the Perspective by Ahmad and Henikoff). However, the mechanisms ensuring this symmetric inheritance in yeast and mouse were different. Yeasts use subunits of DNA polymerase to prevent the lagging-strand bias of parental histones, whereas in mouse cells, the replicative helicase MCM2 counters the leading-strand bias. Science , this issue p. 1386 , p. 1389 ; see also p. 1311

AbstractConvergence of life sciences, engineering, and basic sciences has opened new horizons for biologically inspired innovations, and a considerable number of organ‐on‐a‐chip platforms have been developed for mimicking physiological systems of biological organs such as the brain, heart, lung, kidney, liver, and gut. Various biophysicochemical factors can also be introduced into such organ‐on‐a‐chip platforms to study metabolic and systemic effects spanning from drug toxicity to different pathologic manifestations. There is also a pressing need to develop better disease models for common pathologies using variations of these platforms. This can be achieved by recapitulating the unique microenvironment of a disease to investigate the cause and development of abnormal conditions as well as the structural and functional changes resulting from such a pathology. In this review, the organ‐on‐a‐chip platforms that have been developed to model different pathologies of neurodegenerative, cardiovascular, respiratory, hepatic, and digestive systems, along with cancer are summarized. Although the field is still in its infancy, it is anticipated that developing disease model‐on‐a‐chip platforms will likely be a valuable addition to the field of disease modeling, pathology studies, and improved drug discovery.

Abstract BACKGROUND The collateral circulation is important in maintenance of blood supply to the ischemic kidney distal to renal artery stenosis (RAS). Obesity metabolic syndrome (MetS) preserves renal blood flow (RBF) in the stenotic kidney, but whether this is related to an increase of collateral vessel growth is unknown. We hypothesized that MetS increased collateral circulation around the renal artery. METHODS Twenty-one domestic pigs were randomly divided into unilateral RAS fed an atherogenic (high-fat/high-fructose, MetS-RAS) or standard diet, or controls (n = 7 each). RBF, glomerular filtration rate (GFR), and the peristenotic collateral circulation were assessed after 10 weeks using multidetector computed tomography (CT) and the intrarenal microcirculation by micro-CT. Vascular endothelial growth factor (VEGF) expression was studied in the renal artery wall, kidney, and perirenal fat. Renal fibrosis and stiffness were examined by trichrome and magnetic resonance elastography. RESULTS Compared with controls, RBF and GFR were decreased in RAS, but not in MetS-RAS. MetS-RAS formed peristenotic collaterals to the same extent as RAS pigs but induced greater intrarenal microvascular loss, fibrosis, stiffness, and inflammation. MetS-RAS also attenuated VEGF expression in the renal tissue compared with RAS, despite increased expression in the perirenal fat. CONCLUSIONS MetS does not interfere with collateral vessel formation in the stenotic kidney, possibly because decreased renal arterial VEGF expression offsets its upregulation in perirenal fat, arguing against a major contribution of the collateral circulation to preserve renal function in MetS-RAS. Furthermore, preserved renal function does not protect the poststenotic kidney from parenchymal injury.