Prostate Cancer Susceptibility Gene Research Articles

GATA2 co-opts TGFβ1/SMAD4 oncogenic signaling and inherited variants at 6q22 to modulate prostate cancer progression

BackgroundAberrant somatic genomic alteration including copy number amplification is a hallmark of cancer genomes. We previously profiled genomic landscapes of prostate cancer (PCa), yet the underlying causal genes with prognostic potential has not been defined. It remains unclear how a somatic genomic event cooperates with inherited germline variants contribute to cancer predisposition and progression.MethodsWe applied integrated genomic and clinical data, experimental models and bioinformatic analysis to identify GATA2 as a highly prevalent metastasis-associated genomic amplification in PCa. Biological roles of GATA2 in PCa metastasis was determined in vitro and in vivo. Global chromatin co-occupancy and co-regulation of GATA2 and SMAD4 was investigated by coimmunoprecipitation, ChIP-seq and RNA-seq assays. Tumor cellular assays, qRT-PCR, western blot, ChIP, luciferase assays and CRISPR-Cas9 editing methods were performed to mechanistically understand the cooperation of GATA2 with SMAD4 in promoting TGFβ1 and AR signaling and mediating inherited PCa risk and progression.ResultsIn this study, by integrated genomics and experimental analysis, we identified GATA2 as a prevalent metastasis-associated genomic amplification to transcriptionally augment its own expression in PCa. Functional experiments demonstrated that GATA2 physically interacted and cooperated with SMAD4 for genome-wide chromatin co-occupancy and co-regulation of PCa genes and metastasis pathways like TGFβ signaling. Mechanistically, GATA2 was cooperative with SMAD4 to enhance TGFβ and AR signaling pathways, and activated the expression of TGFβ1 via directly binding to a distal enhancer of TGFβ1. Strinkingly, GATA2 and SMAD4 globally mediated inherited PCa risk and formed a transcriptional complex with HOXB13 at the PCa risk-associated rs339331/6q22 enhancer, leading to increased expression of the PCa susceptibility gene RFX6.ConclusionsOur study prioritizes causal genomic amplification genes with prognostic values in PCa and reveals the pivotal roles of GATA2 in transcriptionally activating the expression of its own and TGFβ1, thereby co-opting to TGFβ1/SMAD4 signaling and RFX6 at 6q22 to modulate PCa predisposition and progression.

Abstract A011: Whole genome sequencing of the Alabama Hereditary Cancer Cohort to identify African American breast cancer genetic risk variants

Abstract Regardless of having higher rates of triple-negative breast cancer (TNBC) and breast cancer-related deaths, African Americans are drastically understudied in hereditary breast cancer research. Our group has established the Alabama Hereditary Cancer Cohort to carry out next-generation sequencing (NGS) to address this gap. These efforts aim to identify inherited breast cancer risk variants in African Americans. Interestingly, African American TNBC tumors have been investigated through NGS, identifying somatic mutations unique to African American breast cancer. Now, African American-specific variants associated with inherited risk need to be identified, including those in genes harboring somatic mutations in African American TNBC. This study carried out whole genome sequencing (WGS) to investigate inherited African American breast cancer risk. All coding and non-coding regions of the nuclear genome and the entirety of the mitochondrial genome were explored, all of which can play a role in hereditary breast cancer risk. Individuals provided a blood or saliva sample for DNA extraction upon study consent. Subsequently, paired-end Illumina sequencing was carried out. Fastq files were trimmed using Trimmomatic and further processed according to the Genome Analysis ToolKit Best Practices, resulting in variant call format (VCF) files. Coding, non-coding, and mitochondrial regions were individually extracted using VCFtools and UCSC Table Browser tracks. Coding and mitochondrial variants were annotated using Annovar and MSeqDR, respectively. Coding variants were further filtered for minor allele frequency (MAF) classes (i.e., rare and low-frequency) and mutation type (i.e., protein-truncating variants; PTVs) using R (v. 4.2). Preliminary WGS data of 60 African American hereditary breast cancer cases have identified statistically significant rare and low-frequency PTVs in genes reported to harbor somatic mutations exclusively in African American TNBC tumors. Furthermore, we have identified variants in prostate cancer susceptibility genes that are statistically associated with African American breast cancer risk. We have also identified multiple variants in the mitochondrial genome that are statistically linked to breast cancer risk, some African American-specific. Our data shows that WGS is an invaluable tool for identifying breast cancer susceptibility variants. Further sequencing and functional analyses will validate our preliminary findings. Citation Format: Troy LoBue, Isaac Mcneely, Nancy Merner. Whole genome sequencing of the Alabama Hereditary Cancer Cohort to identify African American breast cancer genetic risk variants [abstract]. In: Proceedings of the 15th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2022 Sep 16-19; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2022;31(1 Suppl):Abstract nr A011.

Putative germline findings in tumor-only and liquid biopsy sequencing in veterans with aggressive prostate cancer.

179 Background: Tumor-only and/or liquid-biopsy based Next Generation Sequencing (NGS)-based tests, which are routinely performed in metastatic prostate cancer patients, may identify putative germline mutations. The European Society of Medical Oncology (ESMO) made recommendations on findings which should be referred for germline genetic testing; however, it is unknown the burden of genetic testing referrals that may result from implementation of these recommendations. We therefore determined the frequency of putative germline findings in Veterans with metastatic prostate cancer who have undergone NGS-based sequencing of tumor and/or cell-free DNA (cfDNA) on the Foundation Medicine (FMI) platform. Methods: This is a retrospective analysis of Veterans with FMI NGS testing results reported from January 2019-February 2021 who had prostate cancer as the submitted diagnosis and metastatic diagnosis according to a VINCI natural language processing tool. Raw variant data were extracted from FMI reports and harmonized for variant annotation. Variants were annotated using ANNOVAR. Putative germline mutations were defined as 1) likely pathogenic or pathogenic (LP/P) by Clinvar annotation and VAF> 30%. Mutation rates are reported in genes recommended by ESMO to trigger referral for germline testing in all tumor types and all ages of diagnosis and proposed prostate cancer susceptibility genes ( ATM, BARD1, CHEK2). Results: 1,597 Veterans with metastatic prostate cancer underwent FMI NGS testing (63% White, 33% African American, 4% other). Median age was 66 years, with 78.6% of cases from men >60 years. Of 1,597 prostate cancer patients who underwent blood or tumor testing, n=85 (5.3%) had an LP/P mutation in an ESMO-guideline gene. When mutations in ATM, BARD1 and CHEK2 were added, n=133 (8.3%) of patients had an LP/P mutation. The most commonly identified putative germline findings were in BRCA2 (n=49 patients, 3.1%). 18 patients (1.1%) had mutations in other prostate cancer risk genes on the ESMO list ( BRCA1, MLH1, MSH2, MSH6, PMS2). 18 (1.1%) of patients had putative incidental germline findings, which included mutations in PALB2, BRIP1, RAD51C, RAD51D, SDHC. No putative incidental germline mutations were identified in RET, SDHA, SDHB, SDHD, TSC2, VHL. Comparing self-identified White versus self-identified Black patients, putative germline mutation rates were nearly the same in all ESMO-referral genes combined (8.2% vs 8.5%), BRCA2 (2.9% vs 3.0%), and ATM (2.4% vs 2.1%). Conclusions: While guidelines recommend that all veterans with metastatic prostate cancer undergo germline genetic testing, significant patient and system-level barriers continue to limit access to germline genetic testing for many Veterans. Tumor-only NGS testing, with a low rate of putative incidental findings, can help to prioritize which Veterans should be referred for germline genetic testing.

Initial Findings from a High Genetic Risk Prostate Cancer Clinic

To improve prostate cancer screening for high-risk men, we developed an early detection clinic for patients at high genetic risk of developing prostate cancer. Despite the rapidly growing understanding of germline variants in driving aggressive prostate cancer and the increased availability of genetic testing, there is little evidence surrounding how best to screen these men. We are reporting on the first 45 patients enrolled, men between the ages of 35-75, primarily with known pathogenic germline variants in prostate cancer susceptibility genes. Screening consists of an intake lifestyle survey, PSA, DRE, and SelectMDx urine assay. A biopsy was recommended for any of the following indications: 1) abnormal DRE, 2) PSA above threshold, or 3) SelectMDx above threshold. The primary outcomes were number needed to screen, and number needed to biopsy to diagnose a patient with prostate cancer. Patients enrolled in the clinic included those with BRCA1 (n=7), BRCA2 (n=16), Lynch Syndrome (n=6), and CHEK2 (n = 4) known pathogenic germline variants. The median age and PSA were 58 (range 35-71) and 1.4 ng/ml (range 0.1-11.4 ng/ml), respectively. 12 patients underwent a prostate needle biopsy and there were 4positive biopsies for prostate cancer. These early data support the feasibility of opening a dedicated clinic for men at high genetic risk of prostate cancer. This early report on the initial enrollment of our long-term study will help optimize early detection protocols and provide evidence for personalized prostate cancer screening in men with key pathogenic germline variants.

Abstract LB011: Meta-analysis in more than 80,000 men of African ancestry identified nine novel variants associated with prostate cancer

Abstract In search for common genetic variants contributing to the risk of prostate cancer in men of African ancestry, we conducted a meta-analysis of GWAS summary statistics from the African Ancestry Prostate Cancer Consortium (AAPC; 12,643 cases and 16,627 controls) and the VA Million Veteran Program (6,107 cases and 47,412 controls). A total of 29,896,808 common (minor allele frequency (MAF) > 0.01) genotyped and imputed variants (r2 > 0.3) were meta-analyzed in a total of 18,750 prostate cancer cases and 64,039 controls. Of the 269 established risk variants for prostate cancer, 265 were polymorphic and 168 were nominally (P<0.05) associated with prostate cancer risk with directionally consistent effect estimates, of which 44 reached the genome-wide significance (P<5x10-8). Of the 3,018 genome-wide significant variants, eight were considered novel susceptibility loci for prostate cancer in men of African ancestry. Of the eight variants, five were only found in populations of African ancestry (MAF 2% - 34%) but not in European or Asian populations, and two were substantially more common in African ancestry populations (MAF 40%) than in other populations (MAF < 8%). One of the novel variants, rs60985508 (odds ratio (OR) = 1.12 [1.08 - 1.15]; P = 2.93×10-13; MAF = 34%), introduces a stop codon in exon 24 in the prostate-specific gene anoctamin 7 (ANO7), a known prostate cancer susceptibility gene. A polygenic risk score including 273 variants (265 of 269 established risk variants and 8 novel variants from this analysis) conferred an increased prostate cancer risk for men in the 90 - 100th percentile (OR = 3.91 [3.50 - 4.36]) and those in the 99 - 100th percentile (OR = 7.05 [5.51 - 9.02]), compared to men in the 40-60th percentile. These estimates were higher than what was observed with the PRS of 265 variants (90 - 100th percentile: OR = 3.49 [3.13 - 3.90]; 99 - 100th percentile: OR = 6.40 [4.99 - 8.21]). Our finding of 8 novel susceptibility loci for prostate cancer may improve risk prediction for men of African Ancestry and provide further insight into the underlying biology of prostate cancer. Citation Format: Fei Chen, Ravi K. Madduri, Xin Sheng, Alex Rodriguez, Alisha Chou, Todd L. Edwards, Stephen K. Van Den Eeden, Rosalind A. Eeles, John S. Witte, Michael B. Cook, William J. Blot, David V. Conti, John M. Gaziano, Amy C. Justice, Christopher A. Haiman, VA Million Veteran Program and PRACTICAL/ELLIPSE Consortium. Meta-analysis in more than 80,000 men of African ancestry identified nine novel variants associated with prostate cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr LB011.

Novel prostate cancer susceptibility gene SP6 predisposes patients to aggressive disease

Prostate cancer (PrCa) is one of the most common cancers in men, but little is known about factors affecting its clinical outcomes. Genome-wide association studies have identified more than 170 germline susceptibility loci, but most of them are not associated with aggressive disease. We performed a genome-wide analysis of 185,478 SNPs in Finnish samples (2738 cases, 2400 controls) from the international Collaborative Oncological Gene-Environment Study (iCOGS) to find underlying PrCa risk variants. We identified a total of 21 common, low-penetrance susceptibility loci, including 10 novel variants independently associated with PrCa risk. Novel risk loci were located in the 8q24 (CASC8 rs16902147, OR 1.86, padj = 3.53 × 10−8 and rs58809953, OR 1.71, padj = 4.00 × 10−6; intergenic rs79012498, OR 1.81, padj = 4.26 × 10−8), 17q21 (SP6 rs2074187, OR 1.66, padj = 3.75 × 10−5), 11q13 (rs12795301, OR 1.42, padj = 2.89 × 10−5) and 8p21 (rs995432, OR 1.38, padj = 3.00 × 10−11) regions. Here, we describe SP6, a transcription factor gene, as a new, potentially high-risk gene for PrCa. The intronic variant rs2074187 in SP6 was associated not only with overall susceptibility to PrCa (OR 1.66) but also with a higher odds ratio for aggressive PrCa (OR 1.89) and lower odds for non-aggressive PrCa (OR 1.43). Furthermore, the new intergenic variant rs79012498 at 8q24 conferred risk for aggressive PrCa. Our findings highlighted the power of a population-stratified approach to identify novel, clinically actionable germline PrCa risk loci and strongly suggested SP6 as a new PrCa candidate gene that may be involved in the pathogenesis of PrCa.

Design Of Primer And Probe To Detect SNP Rs 1892901 In Fosl-1Gene In Different Types Of Cancer In Iraqi Population

It has been shown that the etiology of thyroid, breast and prostate cancer is associated with hereditary and some environmental factors that cause damage to DNA. Protein coding genes are responsible for the development of protein and thus have been reported to be good candidate susceptibility genes for thyroid, breast and prostate cancer. (FOSL1) proteins have important functions in the growth, including the regulation of cell proliferation, differentiation and transformation. There have been studies of elevated levels of FOSL1 in cancers. However, the available methods for measuring FOSL1 levels are direct and quantitative using Poly Chain Reaction (RT-PCR) in real time. In the present study, whole blood was isolated from 100 individuals distributed into four groups as follows: Group 1 included: 25 samples from thyroid cancer patients; Group 2: 25 samples from breast cancer patients; Group 3: 25 samples from prostate cancer and Group 4:25 samples from apparently healthy individuals. The messenger RNA (mRNA) expression levels of FOSL_1in the peripheral blood was analyzed using reverse transcription polymerase chain reaction (RT PCR). The expression of FOSL_1 mRNA in the fold of gene expression in prostatic cancer group was 4 time higher than that of healthy group. That for the breast cancer group was 3 times higher than the healthy group and the thyroid cancer group was 3 times higher than the healthy group., respectively, Using GAPDH as Housekeeping Gene. In conclusion, there is an important link between blood and tumor tissue expression of FOSL1 gene. in thyroid, breast and prostate cancer, could allow the introduction in clinical practice of a simple test that would measure mRNA levels of DNA protein coding genes in peripheral blood samples instead of tissue samples; thus justifying its use as a prognostic and predictive factors in thyroid, breast and prostate cancer patients.

Mutations in ATM, NBN and BRCA2 predispose to aggressive prostate cancer in Poland

In designing national strategies for genetic testing, it is important to define the full spectrum of pathogenic mutations in prostate cancer (PCa) susceptibility genes. To investigate the frequency of mutations in PCa susceptibility genes in Polish familial PCa cases and to estimate gene-related PCa risks and probability of aggressive disease, we analyzed the coding regions of 14 genes by exome sequencing in 390 men with familial prostate cancer and 308 cancer-free controls. We compared the mutation frequencies between PCa cases and controls. We also compared clinical characteristics of prostate cancers between mutation carriers and noncarriers. Of the 390 PCa cases, 76 men (19.5%) carried a mutation in BRCA1, BRCA2, NBN, ATM, CHEK2, HOXB13, MSH2 or MSH6 genes. No mutations were found in BRIP1, PTEN, TP53, MLH1, PMS2 and SPOP. Significant associations with familial PCa risk were observed for CHEK2, NBN, ATM, and HOXB13. High-grade (Gleason 8-10) tumors were seen in 56% of BRCA2, NBN or ATM carriers, compared to 21% of patients who tested negative for mutations in these genes (OR = 4.7, 95% CI 2.0-10.7, P = .0003). In summary, approximately 20% of familial prostate cancer cases in Poland can be attributed to mutations in eight susceptibility genes. Carriers of mutations in BRCA2, NBN and ATM develop aggressive disease and may benefit from intensified screening and/or chemotherapy.

Prevalence of the Ser217Leu Variant of the ELAC2 Gene and Its Association with Prostate Cancer in Population of the Littoral Region of Cameroon.

Background. HPC2/ELAC2 has been identified as a prostate cancer (PC) susceptibility gene. Ser- Leu changes at amino acid 217 have been one of the most studied variants of this gene. Several reports have shown association of this variant with PC in samples of men drawn from families with hereditary PC and even sporadic cases. Aim. This study aimed at assessing this association and the prevalence of the Ser217Leu variant of ELAC2 in populations of the Littoral Region of Cameroon. Method. 103 PC case subjects and 80 randomly selected controls identified from the study population participated in the study. 2 milliliters of blood samples was collected from each of the consented participants and used for human genomic DNA extraction and genotyping of the ELAC2 gene by the nonenzymatic salting out and PCR-RFLP methods, respectively. Results. The frequencies of the wild type (SS), heterozygous mutant (SL), and homozygous mutant (LL) genotypes were, respectively, 28.2%, 49.5%, and 22.3% in prostate cancer patients and 28.8%, 67.5%, and 3.7% in controls. Comparing the LL with SS and (SL+LL) with SS showed that the presence of two copies of the L allele confers a high risk of prostate cancer as compared to the presence of only one L allele which presents no risk of prostate cancer (OR = 6.080 and 1.030, respectively). Analysis of our results also suggested an association (P = 0.0012) of the Ser217Leu variant with increased risk of prostate cancer. Conclusion. Alterations in the ELAC2 gene contribute to prostate cancer susceptibility in men living in the Littoral Region of Cameroon.

MiR-183-5p Inhibits Occurrence and Progression of Acute Myeloid Leukemia via Targeting Erbin.

Erbin has been shown to have significant effects on the development of solid tumors. However, little is known about its function and regulatory mechanism in hematological malignancies. The biological function of Erbin on cell proliferation was measured in vitro and in vivo. The predicted target of Erbin was validated by dual-luciferase reporter assay and rescue experiment. We found that overexpression of Erbin could inhibit the cell proliferation and promote the cell differentiation of acute myeloid leukemia (AML) cells, whereas depletion of Erbin could enhance the cell proliferation and block the cell differentiation in AML cells in vitro and in vivo. Besides, miR-183-5p was identified as the upstream regulator that negatively regulated the Erbin expression. The results were confirmed by dual-luciferase reporter and RNA pull-down assay. Furthermore, we found that miR-183-5p negatively regulated Erbin, resulting in enhanced cell proliferation of AML cells via activation of RAS/RAF/MEK/ERK and PI3K/AKT/FoxO3a pathways. The activation of RAS/RAF/MEK/ERK and PI3K/AKT/FoxO3a pathways was mediated by Erbin interacting with Grb2. These results were also validated by rescue experiments in vitro and in vivo. All above-mentioned findings indicated that the miR-183-5p/Erbin signaling pathway might represent a novel prognostic biomarker or therapeutic target for treatment of AML.

Association of homeobox B13 (HOXB13) gene variants with prostate cancer risk in an Iranian population.

Background: Prostate cancer is a complex condition in which both genetic and environmental factors concomitantly contribute to the tumor initiation and progression. Recently, HOXB13 has been proposed as a susceptibility gene for prostate cancer. Objective: The present study was conducted to determine the existence of potential variations in HOXB13 gene in Iranian men with prostate cancer (PCa) compared to benign prostatic hyperplasia (BPH) cases. Methods: HOXB13 genetic status was screened in 51 samples, including 21 blood and tissue of PCa cases, and compared to 30 cases affected by BPH using PCR/sequencing. Then, the existence of potential association was investigated between genomic DNA alterations in blood and tissue PCa specimens. Results: Analysis of BPH tissues showed single nucleotide variations c.366C > T (rs) or c.513T > C (rs9900627) in exon 1, but not in exon 2. Evaluation of PCa tissues revealed 2 cases with both synonymous c.366C > T and c.513T > C variants and 2 cases with the synonymous c.366C > T variant in exon 1. The variants c.366C > T and c.513T > C, simultaneously or separately, were found in blood samples of PCa patients. The novel variant c.127A > G in exon 2 was detected in 1 PCa blood sample. Our analysis indicated a significant reciprocal correlation between HOXB13 mutation in the tissue and blood samples of PCa cases (p= 0.02). Conclusion: The variants in exon 2 of HOXB13 may influence the risk of prostate cancer. Also, evaluation of HOXB13 mutation may be considered as a novel marker for screening PCa. Further investigations are warranted to evaluate the clinical significance of HOXB13 in Iranian population.

Abstract B70: Thymoquinone regulates cytochrome P450 genes involved in prostate cancer disparity

Abstract African American (AA) men have a higher incidence and greater mortality from prostate cancer (PCa) than Caucasian American (CA) men. The factor influencing the racial disparity is not clearly understood and is probably genetic variation attributed to the disease. Androgen and androgen receptor (AR) pathways have long been associated with prostate growth. Racial differences have also been found among variants of the genes of the enzymes involved in androgen biosynthesis and metabolism, such as CYP3A4, CYP3A7, and CYP17A1. Although several inhibitors are approved for CYPs genes, the major drawback of these inhibitors is they contain the steroid scaffold, which contributes to the undesirable side effects (dyspnea, edema, contusion, etc.) observed in patients. In this regard, using nonsteroid scaffolds such as natural compound acts as a more potent inhibitor and interacts more selectively with the cytochrome P450 family. In this study, our data showed the effect of natural compound thymoquinone (TQ), a constituent of Nigella sativa (black seed), on CYP3A4, CYP3A7, and CYP17A1 genes in PCa cells, and found that TQ-treated cells significantly downregulated the expression of CYP3A4, CYP3A7, and CYP17A1 in MDA PCa 2b and E006AA-hT (African American) compared to LNCaP (Caucasian) cell lines. These findings were further confirmed by flow cytometry, Western blots, and immunofluorescence. These studies suggested that TQ could be the potent inhibitor of the active sites of the cytochrome P450 enzymes, which are an important target in the treatment of PCa. Additionally, knowledge of the PCa susceptibility genes (CYPs) could be used to identify individuals at risk of developing PCa with poor outcomes for heightened screening or prevention modalities and to identify optimal treatment strategies for men of African descent. Citation Format: Santosh K. Singh, James W. Lillard, Jr., Rajesh Singh. Thymoquinone regulates cytochrome P450 genes involved in prostate cancer disparity [abstract]. In: Proceedings of the Tenth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2017 Sep 25-28; Atlanta, GA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2018;27(7 Suppl):Abstract nr B70.

Prostate cancer susceptibility gene HIST1H1A is a modulator of androgen receptor signaling and epithelial to mesenchymal transition.

In 2018, approximately 165,000 new prostate cancer (PC) cases will be diagnosed, and over 29,000 men will succumb to PC in the U.S. alone. The means of assessing outcome in the clinic are inaccurate, and there is a pressing need to more precisely identify men at risk of aggressive PC. We previously identified HIST1H1A as a susceptibility gene for aggressive PC. HIST1H1A encodes H1.1, a member of the linker histone family that is involved in chromatin organization and compaction. To understand the molecular basis of aggressive PC, we have characterized how germline variation modulates susceptibility to neuroendocrine differentiation, which is a form of aggressive PC. Immunohistochemistry studies revealed that HIST1H1A is over-expressed in normal human prostate tissue compared to prostate adenocarcinoma. Functional characterization of HIST1H1A in prostate LNCaP cells indicated that HIST1HA over-expression increased cell growth, as well as the expression of neuroendocrine and epithelial-to-mesenchymal markers in vitro. Assay for Transposase-Accessible Chromatin (ATAC-seq), which is used to assess chromatin compaction and thus the transcriptional availability of individual genomic regions, demonstrated that H1.1 plays a prominent role in modulating Wnt signaling pathway genes, which are implicated in prostate tumorigenesis. These results demonstrate that HIST1H1A is a modulator of aggressive PC susceptibility.

LanCL1 protects prostate cancer cells from oxidative stress via suppression of JNK pathway

Prostate cancer (PCa) is the most commonly diagnosed malignancy in male. Numerous studies have focused on the molecular mechanisms of carcinogenesis and progression, aiming at developing new therapeutic strategies. Here we describe Lanthionine synthase C-like protein 1 (LanCL1), a member of the LanCL family, is a potential prostate cancer susceptibility gene. LanCL1 promotes prostate cancer cell proliferation and helps protect cells from damage caused by oxidative stress. Suppression of LanCL1 by siRNA results in increased cancer cell apoptosis. Clinical data also indicate that LanCL1 upregulation in human prostate cancers correlates with tumor progression. Finally, we demonstrate that LanCL1 plays such important role through inhibiting JNK pathway. Altogether, our results suggest that LanCL1 protects cells from oxidative stress, and promotes cell proliferation. LanCL1 reduces cell death via suppression of JNK signaling pathway.

Abstract 4956: Transcriptome-wide association study identifies new prostate cancer susceptibility genes in the OncoArray data

Abstract Genome-wide association studies (GWAS) have identified over 150 genomic regions harboring risk variants for prostate cancer which explain one third of all familial risk. However, with some notable exceptions, the causal variants and target susceptibility genes at these risk loci have yet to be identified. Recent work has shown a strong overlap between loci associated with gene expression levels (eQTLs) in prostate tissue and GWAS loci, which suggests that the causal mechanism at a significant proportion of risk loci includes causal alleles that regulate expression levels of nearby susceptibility genes. While overlapping eQTLs with GWAS is a powerful method to prioritize susceptibility genes, it is often the case that multiple eQTLs co-localize at the GWAS risk region (due to linkage disequilibrium (LD) and correlations across transcript levels). This prohibits the identification of the true susceptibility gene as opposed to spurious co-localization at the same locus. We recently leveraged gene expression imputation to perform transcriptome-wide association studies (TWAS) as a principled approach to measure the strength of association between gene expression and disease status. Here, we use imputed expression to identify new susceptibility genes for prostate cancer in the OncoArray GWAS data. We integrate gene expression data from more than 44 tissues across ~4,000 individuals with GWAS of prostate cancer from the OncoArray in ~140,000 individuals. Our approach identified 118 susceptibility genes for prostate cancer that reside in 90 independent loci across the genome. Of these, we report 7 genes located more than 0.5 Megabases away from any previously reported GWAS loci for prostate cancer, thus providing new risk loci. Second, we use TWAS to investigate genes previously reported as susceptibility genes for prostate cancer through overlaps of eQTL and GWAS. We find 36 (out of 86 previously reported genes) to be significant in TWAS. Overall, our findings highlight the power of integrating gene expression data with GWAS and provide testable hypotheses for future functional validation of prostate cancer risk. Citation Format: Nicholas Mancuso, Wei Zheng, Kathryn Penney, The PRACTICAL Consortium, Zsofia Kote-Jarai, Christopher Haiman, Simon Gayther, Matthew Freedman, Bogdan Pasaniuc. Transcriptome-wide association study identifies new prostate cancer susceptibility genes in the OncoArray data [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 4956. doi:10.1158/1538-7445.AM2017-4956

RNase L Suppresses Androgen Receptor Signaling, Cell Migration and Matrix Metalloproteinase Activity in Prostate Cancer Cells.

The interferon antiviral pathways and prostate cancer genetics converge on a regulated endoribonuclease, RNase L. Positional cloning and linkage studies mapped Hereditary Prostate Cancer 1 (HPC1) to RNASEL. To date, there is no correlation of viral infections with prostate cancer, suggesting that RNase L may play additional roles in tumor suppression. Here, we demonstrate a role of RNase L as a suppressor of androgen receptor (AR) signaling, cell migration and matrix metalloproteinase activity. Using RNase L mutants, we show that its nucleolytic activity is dispensable for both AR signaling and migration. The most prevalent HPC1-associated mutations in RNase L, R462Q and E265X, enhance AR signaling and cell migration. RNase L negatively regulates cell migration and attachment on various extracellular matrices. We demonstrate that RNase L knockdown cells promote increased cell surface expression of integrin β1 which activates Focal Adhesion Kinase-Sarcoma (FAK-Src) pathway and Ras-related C3 botulinum toxin substrate 1-guanosine triphosphatase (Rac1-GTPase) activity to increase cell migration. Activity of matrix metalloproteinase (MMP)-2 and -9 is significantly increased in cells where RNase L levels are ablated. We show that mutations in RNase L found in HPC patients may promote prostate cancer by increasing expression of AR-responsive genes and cell motility and identify novel roles of RNase L as a prostate cancer susceptibility gene.

Abstract B35: A breast cancer susceptibility gene screening panel for variant discovery and gene exclusion in an African American cohort from Alabama

Abstract African American (AA) women are diagnosed with breast cancer (BC) at a higher rate under the age of 40 compared to Caucasian women and are more often diagnosed with triple-negative (TN) BC, a less treatable and more aggressive BC sub-type. Since an early age of onset is a key characteristic of hereditary BC, genetic risk factors are likely contributing towards these BC disparities. Genes that harbor genetic risk variants are referred to as BC susceptibility genes. Prior to searching for novel BC susceptibility genes, previously identified BC susceptibility genes should initially be excluded. Since the introduction of next-generation sequencing, gene-screening panels have been implemented; this innovative approach involves designing probes for target-capture of genes of interest, amplification, and sequencing on a massively parallel array. AA BC genetics is understudied; however, recently, Churpek et al. published the first article to screen AA hereditary/early onset/TN BC cases for a panel of known BC susceptibility genes. This study identified 68 pathogenic germline mutations in 65 of 289 (22%) AA cases; 18% had a BRCA1 or BRCA2 mutation. The authors acknowledged the paucity of their study and that more gene panel screening studies are needed. Currently, it appears that the majority and spectrum of BC susceptibility genes/risk variants that contribute towards the disproportionate number of aggressive and young onset AA BCs remain to be identified. Our group has custom-designed an Agilent Technologies (AT) HaloPlex probe kit, named BRAP (BReast And Prostate) that targets 87 known and candidate BC and prostate cancer (PC) susceptibility genes using the AT SureDesign program. PC genes were included on the panel since AA males are frequently diagnosed with PC in BC families, more susceptible to PC compared to Caucasians, and normally diagnosed at a younger age with larger tumors. Furthermore, men carrying BRCA1/2 mutations have a higher risk of PC, so further genetic overlap will likely be detected through BRAP screening. Ultimately, the probes were designed to generate 100 base pair (bp) reads on an Illumina platform. All coding exons as well as the 5' and 3' untranslated regions of the 87 genes were targeted, totaling 499.5 kbp. The designed probes covered 98.9% of the targeted region. Forty-six seemingly unrelated individuals (24 AA and 22 Caucasians) from Alabama who were diagnosed with BC under the age of 45 and/or had a BC family history were selected for the initial BRAP capture; the HaloPlex HS Target Enrichment System For Illumina Sequencing Protocol (Version C0) was followed. Each individually prepared and indexed library was quantified using a Bioanalyzer 2100. The targeted DNA from 44 of the 46 individuals were successfully captured and amplified. The successful samples were pooled for sequencing; the sample was loaded onto one flow cell lane and run on an Illumina HiSeqTM 2500 at the HudsonAlpha Genomic Services Laboratory. The sequencing data was downloaded and is being processed using an in-house, bioinformatics pipeline. Two of the screened individuals served as positive controls since upon recruitment one reported a mutation in BRCA1 and the other a mutation in BRCA2. The pipeline has been optimized using the control with BRCA1 p.M1775R, which has been successfully identified. Variant calling files are being processed for the remaining screened individuals. This data provides great insight towards the array of mutations in known BC and PC susceptibility genes that contributes towards hereditary AA BC. Furthermore, non-mutation individuals/families identified through BRAP screening will be whole-genome sequenced in order to identify novel, BC susceptibility genes that may contribute towards disease disparity. Citation Format: Madison R. Chandler, Kasey J. Shepp, Stephanie M. Spina, Nancy D. Merner. A breast cancer susceptibility gene screening panel for variant discovery and gene exclusion in an African American cohort from Alabama. [abstract]. In: Proceedings of the Ninth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2016 Sep 25-28; Fort Lauderdale, FL. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2017;26(2 Suppl):Abstract nr B35.

Whole exome sequencing in 75 high-risk families with validation and replication in independent case-control studies identifies TANGO2, OR5H14, and CHAD as new prostate cancer susceptibility genes.

Prostate cancer (PCa) susceptibility is defined by a continuum from rare, high-penetrance to common, low-penetrance alleles. Research to date has concentrated on identification of variants at the ends of that continuum. Taking an alternate approach, we focused on the important but elusive class of low-frequency, moderately penetrant variants by performing disease model-based variant filtering of whole exome sequence data from 75 hereditary PCa families. Analysis of 341 candidate risk variants identified nine variants significantly associated with increased PCa risk in a population-based, case-control study of 2,495 men. In an independent nested case-control study of 7,121 men, there was risk association evidence for TANGO2 p.Ser17Ter and the established HOXB13 p.Gly84Glu variant. Meta-analysis combining the case-control studies identified two additional variants suggestively associated with risk, OR5H14 p.Met59Val and CHAD p.Ala342Asp. The TANGO2 and HOXB13 variants co-occurred in cases more often than expected by chance and never in controls. Finally, TANGO2 p.Ser17Ter was associated with aggressive disease in both case-control studies separately. Our analyses identified three new PCa susceptibility alleles in the TANGO2, OR5H14 and CHAD genes that not only segregate in multiple high-risk families but are also of importance in altering disease risk for men from the general population. This is the first successful study to utilize sequencing in high-risk families for the express purpose of identifying low-frequency, moderately penetrant PCa risk mutations.

Single Nucleotide Polymorphisms: A New Paradigm in Predicting the Risk of Prostate Cancer

Prostate cancer (PC) is a most important health care problem because of its high prevalence, health-related costs, and mortality. Even though most patients have clinically localized and indolent tumors at diagnosis, worldwide, this disease still holds second place in the leading causes of cancer deaths. Research on susceptibility genes is one of hot issues in risk factors of prostate cancer. Nevertheless, the confirmation of prostate cancer susceptibility genes has been challenging. Thus focusing on the increasing number of single nucleotide polymorphisms (SNPs) that have been suggested to be implicated in the development and progression of PC. While individual SNPs are only moderately associated with PC risk, in combination, they have a stronger association. Therefore, identification of numerous variations in genes and analysis of their effects may lead to a better understanding of their impact on gene function and health of an individual. This improved knowledge may provide a starting point for the development of new useful SNP markers for medical testing and a safer individualized medication to treat the most common devastating disorders. This will revolutionize the medical field in the future. To illustrate the effect of SNPs on gene function and phenotype, this review focuses on genetic susceptibility of prostate cancer and role of single nucleotide polymorphism and revealing the impact of SNPs on the development and progression of prostate cancer.

Loss of heterozygosity for chromosomal regions 15q14-21.1, 17q21.31, and 13q12.3-13.1 and its relevance for prostate cancer

Although prostate cancer is one of the most common cancers in men, the genetic defects underlying its pathogenesis remain poorly understood. DNA damage repair mechanisms have been implicated in human cancer. Accumulating evidence indicates that the fidelity of the response to DNA double-strand breaks is critical for maintaining genome integrity. RAD51 is a central player in double-strand break repair via homologous recombination, and its alterations may confer and increase the risk of cancer. RAD51 functioning depends on the indirect or direct interactions with BRCA1 and BRCA2. To evaluate the contribution of RAD51 to sporadic prostate cancer, loss of heterozygosity (LOH) for chromosomal region 15q14-21.1 (RAD51locus) was determined and compared to LOH in 17q21.31 (BRCA1 locus) and 13q12.3-13.1 (BRCA2 region). DNA was isolated from prostate biopsies and matched peripheral blood of 50 patients. The regions 15q14-21.1, 17q21.31, and 13q12.3-13.1 were examined using microsatellite markers on chromosome 15 (D15S118, D15S214, D15S1006), chromosome 17 (D17S855, D17S1323), and chromosome 13 (D13S260, D13S290), respectively. The LOH in tumors was analyzed by PCR with fluorescently labeled primers and an ABI PRISM 377 DNA Sequencer. Allele sizing was determined by GeneScan version 3.1.2 and Genotyper version 2.5 software (Applied Biosystems, USA). LOH was identified in 57.5, 23, and 40 % for chromosomal regions 15q14-21.1, 17q21.31, and 13q12.3-13.1, respectively. Twenty-six percent of studied cases manifested LOH for at least one marker in 15q14-21.1 exclusively. A significant correlation was found between LOH for studied region and PSAD (prostate-specific antigen density). The findings suggest that RAD51 may be considered as a prostate cancer susceptibility gene.