DeRycke, Melissa S.

MicroRNAs (miRNAs) regulate up to one‐third of all protein‐coding genes including genes relevant to cancer. Variants within miRNAs have been reported to be associated with prognosis, survival, response to chemotherapy across cancer types, in vitro parameters of cell growth, and altered risks for development of cancer. Five miRNA variants have been reported to be associated with risk for development of colorectal cancer (CRC). In this study, we evaluated germline genetic variation in 1,123 miRNAs in 899 individuals with CRCs categorized by clinical subtypes and in 204 controls. The role of common miRNA variation in CRC was investigated using single variant and miRNA‐level association tests. Twenty‐nine miRNAs and 30 variants exhibited some marginal association with CRC in at least one subtype of CRC. Previously reported associations were not confirmed (n = 4) or could not be evaluated (n = 1). The variants noted for the CRCs with deficient mismatch repair showed little overlap with the variants noted for CRCs with proficient mismatch repair, consistent with our evolving understanding of the distinct biology underlying these two groups. © 2016 The Authors Genes, Chromosomes & Cancer Published by Wiley Periodicals, Inc.

Abstract African American Hereditary Prostate Cancer Study (AAHPC) was developed as a national collaboration to explore the role of genetics in the causation of hereditary prostate cancer (HPC) in African American (AA) men. AAHPC is in partnership with the International Consortium for Prostate Cancer Genetics (ICPCG), which conducts collaborative studies of HPC genetics in multiplex families. As part of an ICPCG sequencing study of 539 affected individuals from 366 HPC pedigrees, we performed whole exome sequencing in 21 ICPCG AA families, of which there were 14 AAHPC affected men from 11 pedigrees. The combined ICPCG AA cohort consisted of N=26 affected members. Post-variant calling quality control (QC) was implemented using Golden Helix SVS 8 software with filters set for removal of variants with Read Depth < 10, Quality Score < 20, Quality Score: Read Depth Ratio < 0.5, Call Rate < 0.75. Variants were additionally filtered by MAF based on the NHLBI ESP650051-V2 exomes variant frequencies for the AA population using a MAF threshold of 5%. Following QC, 176/299 SNVs and 20/39 INDELs remained for further analysis. In these analyses, we focused on 13 known cancer genes (MSR1, AR, BRCA1, BRCA2, BTNL2, EPHB2, CDH1, RNASEL, ELAC2, HOXB13, CHEK2, TP53 and NBN). Three sequenced families had > 1 affected members sequenced (2 or 3 per family) and the remaining 18 families had one member sequenced. Under the dominant model, our preliminary results show that no rare variants in the 13 candidate genes were found in 3/3 affecteds in two families. Rare SNVs in seven candidate genes (AR, CDH1, ELAC2, HOXB13, RNASEL, BRCA2 and EPHB2) were found in 2/3 affecteds for two families and 2/2 affecteds in one family. Several of the remaining 18 affected men (1 sequenced per pedigree) shared the same rare SNV in these candidate genes. For INDELs, rare variants in three candidate genes were found in pedigrees with ≥ 2 affecteds. Several of the remaining 18 affected men (one sequenced per pedigree) shared the same rare INDEL. Additional QC is underway to validate these variants and bioinformatic analyses are being used to predict effects of the variants in an effort to unravel the complex genetic heterogeneity of HPC in AA. Citation Format: Cheryl D. Cropp, Shannon K. McDonnell, Sumit Middha, Melissa DeRycke, Danielle M. Karyadi, Daniel Schaid, Stephen N. Thibodeau, William B. Isaacs, Elaine A. Ostrander, Janet Stanford, Kathleen A. Cooney, Joan E. Bailey-Wilson, John D. Carpten. Rare variant discovery in known cancer genes from whole-exome sequencingof African American hereditary prostate cancer families. [abstract]. In: Proceedings of the Eighth AACR Conference on The Science of Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; Nov 13-16, 2015; Atlanta, GA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2016;25(3 Suppl):Abstract nr B40.

Abstract The mechanisms by which ovarian cancer cells are released from the primary tumor, seed throughout the peritoneal cavity, attach to local organs, and then invade these organs, are not understood. In this study, the cell adhesion molecule, Nectin-4, was investigated as a potential mediator of several steps involved in ovarian cancer progression. In particular, due to the ability of Nectin-4 to promote cell-cell adhesions, we were interested in determining its role in mediating the formation of cell-cell aggregates (spheroids) which are commonly seen in the peritoneal fluid of ovarian cancer patients. Furthermore, since spheroids are known to have a decreased rate of cell proliferation and are chemoresistant, we were also interested in the role of Nectin-4 in ovarian cancer cell proliferation and invasion. In our previous studies, we performed gene microarray analysis and identified Nectin-4 overexpression in ovarian cancer tissues compared to normal ovaries and other normal tissues. By ELISA, we found soluble Nectin-4 in the sera of 50% of women with ovarian cancer. In this study, we performed a series of experiments in which two human ovarian cancer cells lines were transfected with Nectin-4 or shRNA targeting Nectin-4, and then the resultant cells were tested in functional assays. In the first case, MA148 cells, which do not express Nectin-4, were transfected with full-length Nectin-4. The resultant MA148 cells which expressed high levels of Nectin-4 showed an increased rate of proliferation compared to control cells which did not express Nectin-4. They also formed the initial cell-cell adhesions involved in spheroid formation faster than control cells. Furthermore, the spheroids which expressed Nectin-4 were slower to disaggregate and invade through monolayers of mesothelial cells. In the second case, NIH:OVCAR5 cells, which express moderate levels of Nectin-4, were transfected with shRNA targeting Nectin-4, resulting in the partial knockdown of Nectin-4 expression. We found that the NIH:OVCAR5 cells that express lower levels of Nectin-4 on their surface required a substantially longer time to form spheroids and migrated more slowly in a wound healing assay. In both cases, we verified the expression of Nectin-4 in the transfected cells by Western immunoblotting and flow cytometry. These results suggest that Nectin-4: (a) is important in the early events of cell-cell adhesion, (b) plays a role in multicellular aggregation within the ascites of ovarian cancer patients, and (c) causes tight spheroid formations that may impede disaggregation. Additional functional studies leading to a better understanding of the role of Nectin-4 overexpression and shedding in ovarian cancer are currently underway. Understanding the role of Nectin-4 in ovarian cancer progression is critical in order to facilitate its development as a novel therapeutic target for ovarian cancer. Citation Format: Kristin L. Boylan, Adam Meyer, Petra C. Buchanan, Melissa S. DeRycke, Amy P. Skubitz. Role of nectin-4 in the progression of ovarian cancer. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1984. doi:10.1158/1538-7445.AM2014-1984

Abstract Colorectal cancer (CRC) is estimated to be the third most common cancer in both men and women in the US in 2012, accounting for over 50,000 deaths. Familial CRC accounts for approximately 30% of all CRC, yet only 5% of familial CRCs can be attributed to mutations in known hereditary colon cancer (HCC) genes. Many families with a strong family history of CRC do not have mutations in known CRC genes. Finding the genes underpinning CRC in these families may improve screening for disease and allow the development of more targeted therapeutics. We completed targeted sequencing of over 2,000 genes and miRNAs in 1,500 cases of CRC from the Colon Cancer Family Registry (CCFR) in an effort to identify rare variants associated with CRC risk and to identify mutations in known CRC genes missed by conventional sequencing. Several categories of genes were included: 18 known HCC genes; 18 candidate HCC genes; 185 genes in previously reported CRC linkage peaks; 1,423 miRNAs; and 363 genes identified through whole exome sequencing of 40 affected cases in 16 families with hereditary CRC (n=2,007 total genes sequenced). Genomic DNA samples were indexed, then libraries were made using Agilent's SureSelect Targeted Enrichment kit. Samples were pooled (96 samples/pool), then each pool of samples was run on five lanes on an Illumina HiSeq2000 (average of 19.2 samples/lane). GenomeGPS, an in-house developed workflow, was used for read alignment, variant calling, and annotation. In early analyses of the first 161 cases, the mean number of mapped reads exceeded 20 million per sample and over 90% of the target region exceeded 40x coverage. A total of 26,484 SNPs were identified and passed quality filtering. Sequencing identified known mutations in MMR genes in positive control cases as well as mutations in HCC genes in previously untested cases. Analysis is currently on-going on the remaining samples and we will report results on the full set of 1500 cases at the meeting. Citation Format: Melissa S. DeRycke, Shanaka R. Gunawardena, Sumit Middha, Shannon K. McDonnell, Shaun M. Riska, Zachary C. Fogarty, Bruce W. Eckloff, Daniel J. Schaid, Ellen L. Goode, Stephen N. Thibodeau. Targeted sequencing to identify rare variants in colorectal cancer. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 2548. doi:10.1158/1538-7445.AM2013-2548

Abstract Background: Colorectal cancer (CRC) in densely affected families without Lynch Syndrome may be due to mutations in undiscovered genetic loci. Familial linkage analyses have yielded disparate results; the use of exome sequencing in coding regions may identify novel segregating variants. Methods: We completed exome sequencing on 40 affected cases from 16 multicase pedigrees to identify novel loci. Variants shared among all sequenced cases within each family were identified and filtered to exclude common variants and single-nucleotide variants (SNV) predicted to be benign. Results: We identified 32 nonsense or splice-site SNVs, 375 missense SNVs, 1,394 synonymous or noncoding SNVs, and 50 indels in the 16 families. Of particular interest are two validated and replicated missense variants in CENPE and KIF23, which are both located within previously reported CRC linkage regions, on chromosomes 1 and 15, respectively. Conclusions: Whole-exome sequencing identified DNA variants in multiple genes. Additional sequencing of these genes in additional samples will further elucidate the role of variants in these regions in CRC susceptibility. Impact: Exome sequencing of familial CRC cases can identify novel rare variants that may influence disease risk. Cancer Epidemiol Biomarkers Prev; 22(7); 1239–51. ©2013 AACR.

Abstract Several platforms for genome sequencing and methods for exon enrichment are now available and continue to evolve quickly. In this study, we compared the performance of whole exome sequencing using two instruments, Illumina's GAIIx and HiSeq 2000, comparing single versus duplicate runs. Eight runs of eight samples each were performed with genomic DNA derived from whole blood and sample libraries prepared with the Agilent SureSelect capture array. One run was conducted in duplicate on the GAIIx, and, for some analyses, the combined data were used. We used TREAT (Targeted RE-sequencing and Annotation Tool), developed in-house for data analysis, including sequence alignment (MAQ, BWA), local re-alignment (GATK), variant calling (utilizing MAQ), annotation (SIFT and Seattle Seq), and visualization. Overall, duplicate runs on the GAIIx platform (compared to a single run) increased the number of total reads by approximately two-fold: from ∼66 M to ∼130 M. For both single and duplicate runs, ∼90% of reads mapped to the reference sequence, and ∼55% of reads mapped on-target. Of importance, the percent coverage of the target region increased substantially with duplicate runs; ∼72% of the target region was covered at 40-fold or more when run in duplicate compared to only ∼52% when run once. At 30x, 20x, and 10x, there was a 1.3- (62% v. 78%), 1.2- (72% v. 84%), and 1.1-fold (84% v. 91%) increase respectively, in the percent coverage of the target region for samples run twice. A similar number of filtered, on-target SNPs per sample (∼24 K) was found for both single and duplicate run analyses. However, a 1.3-fold increase in the number of on-target indels was seen in the duplicate run (∼1,200) compared to the single run (∼900). When the combined data for samples run twice on a GAIIx were compared to the samples run using a HiSeq, the total number of reads were similar (∼130 M), although several of the samples had substantially more reads on the HiSeq platform. Samples run on a HiSeq had an increase in the percent coverage of the target region at 40x (72% v. 81%), 30x (78% v. 86%), 20x (84% v. 91%) and 10x (91% v. 95%) compared to the two-run approach on a GAIIx. A similar number of filtered on-target SNPs (∼24 K/sample) and indels (∼1200) was found with the HiSeq compared to two runs on a GAIIx. In summary, our results demonstrate increases in the total number of reads and in overall coverage with the HiSeq 2000 instrument. The total number of SNPs and indel that mapped on target for the version 1 Agilent SureSelect capture array is ∼25 K and 1,200 per sample, respectively. As capture is of variable efficiency for individual runs, higher average coverage of the target region is necessary for sufficient coverage of poorly captured regions. Additional analyses comparing Agilent SureSelect versions 1 and 2 arrays are underway. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 2742. doi:10.1158/1538-7445.AM2011-2742