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Background: Current diagnostic tools are unable to distinguish low‐grade indolent prostate cancer (PrCa) from that with a propensity to become metastatic and/or lethal. Recent evidence suggests that reprogramming of the transcriptome may drive the metastatic phenotype, and that this reprogramming is controlled, at least in part, by epigenetic changes to the DNA of cancer cells, including methylation. These changes, referred to as 'epigenetic drivers,' have previously been associated with cancer cell survival. Methods: Here, using Illumina Methylation EPIC array data of paired primary PrCa and metastatic bone samples, we identified WNT5A as a putative epi‐driver of PrCa metastasis to the bone, which was further validated in vitro. Results: Significantly higher WNT5A methylation was observed in primary PrCa samples and 22Rv1 cells compared to metastatic bone samples and PC‐3 cells. This higher methylation was associated with significantly lower WNT5A gene expression. Conclusion: Given the limited effective therapies available for metastatic cancer sufferers, particularly those whose disease has metastasised to the bone, WNT5A presents as a potential putative target for therapy. [ABSTRACT FROM AUTHOR]

Simple Summary: An urgent demand exists to identify inherited genetic risk variants for prostate cancer (PrCa), particularly in DNA damage repair genes targetable with precision medicine-based strategies. Though the most heritable common cancer, discovery of rare germline PrCa risk variants is hampered by their low frequency, even in sizeable population datasets. Through utilising two large, independent, familial PrCa resources and their likely enrichment of rare causative variants, we provide robust evidence for several novel risk variants in DNA damage repair genes. Rare, inherited variants in DNA damage repair (DDR) genes have a recognised role in prostate cancer (PrCa) susceptibility. In addition, these genes are therapeutically targetable. While rare variants are informing clinical management in other common cancers, defining the rare disease-associated variants in PrCa has been challenging. Here, whole-genome and -exome sequencing data from two independent, high-risk Australian and North American familial PrCa datasets were interrogated for novel DDR risk variants. Rare DDR gene variants (predicted to be damaging and present in two or more family members) were identified and subsequently genotyped in 1963 individuals (700 familial and 459 sporadic PrCa cases, 482 unaffected relatives, and 322 screened controls), and association analyses accounting for relatedness (MQLS) undertaken. In the combined datasets, rare ERCC3 (rs145201970, p = 2.57 × 10−4) and BRIP1 (rs4988345, p = 0.025) variants were significantly associated with PrCa risk. A PARP2 (rs200603922, p = 0.028) variant in the Australian dataset and a MUTYH (rs36053993, p = 0.031) variant in the North American dataset were also associated with risk. Evaluation of clinicopathological characteristics provided no evidence for a younger age or higher-grade disease at diagnosis in variant carriers, which should be taken into consideration when determining genetic screening eligibility criteria for targeted, gene-based treatments in the future. This study adds valuable knowledge to our understanding of PrCa-associated DDR genes, which will underpin effective clinical screening and treatment strategies. [ABSTRACT FROM AUTHOR]

Men living in regional and remote areas experience disparities in prostate cancer (PrCa) diagnosis, clinical characteristics and treatment modalities. We sought to determine whether such disparities exist in PrCa patients from Tasmania; a regional state of Australia with the second-highest rate of diagnosis and where over a third of residents live in outer regional and remote areas. Our study included clinicopathological data from 1526 patients enrolled in the Prostate Cancer Outcomes Registry-Tasmania. Regression analyses were undertaken to determine whether demographic, clinical and treatment variables differed between inner regional and outer regional/remote patients. Men from outer regional/remote areas were significantly more likely to reside in lower socio-economic areas, be diagnosed at a later age and with more clinically aggressive features. However, in contrast to previous studies, there were no overall differences in diagnostic or treatment method, although men from outer regional/remote areas took longer to commence active treatment and travelled further to do so. This study is the first to investigate PrCa disparities in a wholly regional Australian state and highlights the need to develop systematic interventions at the patient and healthcare level to improve outcomes in outer regional and remote populations in Australia and across the globe. [ABSTRACT FROM AUTHOR]

Prostate cancer (PrCa) is highly heritable, and although rare variants contribute significantly to PrCa risk, few have been identified to date. Herein, whole‐genome sequencing was performed in a large PrCa family featuring multiple affected relatives spanning several generations. A rare, predicted splice site EZH2 variant, rs78589034 (G > A), was identified as segregating with disease in all but two individuals in the family, one of whom was affected with lymphoma and bowel cancer and a female relative. This variant was significantly associated with disease risk in combined familial and sporadic PrCa datasets (n = 1551; odds ratio [OR] = 3.55, P = 1.20 × 10−5). Transcriptome analysis was performed on prostate tumour needle biopsies available for two rare variant carriers and two wild‐type cases. Although no allele‐dependent differences were detected in EZH2 transcripts, a distinct differential gene expression signature was observed when comparing prostate tissue from the rare variant carriers with the wild‐type samples. The gene expression signature comprised known downstream targets of EZH2 and included the top‐ranked genes, DUSP1, FOS, JUNB and EGR1, which were subsequently validated by qPCR. These data provide evidence that rs78589034 is associated with increased PrCa risk in Tasmanian men and further, that this variant may be associated with perturbed EZH2 function in prostate tissue. Disrupted EZH2 function is a driver of tumourigenesis in several cancers, including prostate, and is of significant interest as a therapeutic target. What's new? Prostate cancer has high heritability, yet few risk variants have been identified. Here, the authors went looking for rare variants using whole genome sequencing (WGS). They tested three members of a large, multigenerational Tasmanian family with a high proportion of prostate cancer cases. WGS turned up a rare variant in EZH2, a gene that has previously been associated with prostate tumorigenesis. The researchers found the variant was associated with PrCa both in familial and sporadic cases. Tumor analysis suggests that the mutation disrupts EZH2 function and alters the expression of downstream targets. [ABSTRACT FROM AUTHOR]

Background: Radiotherapy is a chosen treatment option for prostate cancer patients and while some tumours respond well, up to 50% of patients may experience tumour recurrence. Identification of functionally relevant predictive biomarkers for radioresponse in prostate cancer would enable radioresistant patients to be directed to more appropriate treatment options, avoiding the side-effects of radiotherapy. Methods: Using an in vitro model to screen for novel biomarkers of radioresistance, transcriptome analysis of a radioresistant (PC-3) and radiosensitive (LNCaP) prostate cancer cell line was performed. Following pathway analysis candidate genes were validated using qRT-PCR. The DNA repair pathway in radioresistant PC-3 cells was then targeted for radiation sensitization using the PARP inhibitor, niacinimide. Results: Opposing regulation of a DNA repair and replication pathway was observed between PC-3 and LNCaP cells from RNA-seq analysis. Candidate genes BRCA1, RAD51, FANCG, MCM7, CDC6 and ORC1 were identified as being significantly differentially regulated post-irradiation. qRT-PCR validation confirmed BRCA1, RAD51 and FANCG as being significantly differentially regulated at 24 hours post radiotherapy (p-value =0.003, 0.045 and 0.003 respectively). While the radiosensitive LNCaP cells down-regulated BRCA1, FANCG and RAD51, the radioresistant PC-3 cell line up-regulated these candidates to promote cell survival post-radiotherapy and a similar trend was observed for MCM7, CDC6 and ORC1. Inhibition of DNA repair using niacinamide sensitised the radioresistant cells to irradiation, reducing cell survival at 2 Gy from 66% to 44.3% (p-value =0.02). Conclusions: These findings suggest that the DNA repair candidates identified via RNA-seq hold potential as both targets for radiation sensitization and predictive biomarkers in prostate cancer. [ABSTRACT FROM AUTHOR]

The genetic architecture underpinning prostate cancer is complex, polygenic and despite recent significant advances many questions remain. Advances in genetic technologies have greatly improved our ability to identify genetic variants associated with complex disease including prostate cancer. Genome-wide association studies (GWASs) and microarray gene expression studies have identified genetic associations with prostate cancer susceptibility and tumour development. The integrins feature prominently in both studies examining the underlying genetic susceptibility and mechanisms driving prostate tumour development. Integrins are cell adhesion molecules involved in extracellular and intracellular signalling and are imperative for tumour development, migration, and angiogenesis. Although several integrins have been implicated in tumour development, the roles of integrin a2 and integrin a6 are the focus of this paper as evidence is now emerging that these integrins are implicit in prostate cancer susceptibility, cancer stem cell biology, angiogenesis, cell migration, and metastases to bone and represent potential biomarkers and therapeutic targets. There currently exists an urgent need to develop tools that differentiate indolent from aggressive prostate cancers and predict how patients will respond to treatment. This paper outlines the evidence supporting the use of a2 and a6 integrins in clinical applications for tailored patient treatment. [ABSTRACT FROM AUTHOR]

Genetic heterogeneity is a difficulty frequently encountered in the search for genes conferring susceptibility to prostate cancer. To circumvent this issue, we selected a large prostate cancer pedigree for genome-wide linkage analysis from a population that is genetically homogeneous. Selected cases and first-degree relatives were genotyped with Affymetrix 10K SNP arrays, identifying a 14 Mb haplotype on chromosome 5 (5p13–q12) inherited identical-by-descent (IBD) by multiple cases. Microsatellite genotyping of additional deceased case samples confirmed that a total of eight cases inherited the common haplotype (P=0.0017). Re-sequencing of eight prioritised candidate genes in the region in six selected individuals identified 15 SNPs segregating with the IBD haplotype, located within the ITGA2 gene. Three of these polymorphisms were selected for genotyping in an independent Tasmanian data set comprising 127 cases with familial prostate cancer, 412 sporadic cases and 319 unaffected controls. Two were associated with prostate cancer risk: rs3212649 (OR=1.67 (1.07–2.6), P=0.0009) and rs1126643 (OR=1.52 (1.01–2.28), P=0.0088). Significant association was observed in both familial and sporadic prostate cancer. Although the functional SNP remains to be identified, considerable circumstantial evidence, provided by in vivo and in vitro studies, supports a role for ITGA2 in tumour development.European Journal of Human Genetics (2009) 17, 368–377; doi:10.1038/ejhg.2008.171; published online 1 October 2008 [ABSTRACT FROM AUTHOR]

Examination of epigenetic changes at the ITGB4 gene promoter reveals altered methylation at different stages of prostate tumour progression and these changes may, in part, explain the complex patterns of gene expression of this integrin observed. Transcriptional re-programming perturbs expression of cell adhesion molecules and underpins metastatic tumour cell behaviour. Decreasing expression of the cell adhesion molecule ITGB4, which encodes the beta subunit of the integrin, alpha6 beta4 (α6β4), has been correlated with increased tumour aggressiveness and metastasis in multiple tumour types including prostate cancer. Paradoxically, in vitro studies in tumour cell models demonstrate that ITGB4 mediates cell mobility and invasion. Herein we examined whether transcriptional re-programming by methylation influenced ITGB4 gene expression at different stages of prostate cancer progression. Bisulphite sequencing of a large CpG island in the ITGB4 gene promoter identified differentially methylated regions in prostate cancer cell lines representing a localised tumour (22Rv1), lymph node metastasis (LNCaP), and a bone metastasis (PC-3). The highest levels of methylation were observed in the CpG island surrounding the ITGB4 transcription start site in PC-3 cells, and this observation also correlated with higher gene expression of ITGB4 in these cells. Furthermore, PC-3 cells expressed two distinct transcripts, using an alternate transcription start site, which was not detected in other cell lines. In prostate tumour biopsy samples, patterns of methylation across the ITGB4 promoter were similar overall in matched primary and metastatic samples (n = 4 pairs), with a trend toward loss of methylation at specific sites in metastatic lesions. [ABSTRACT FROM AUTHOR]