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Biomedical subjects

Robert G Bristow

Publications and source records attributed to Robert G Bristow.

3 recordsLinked to original sources

Recurrent mechanisms of biallelic epigenetic inactivation reveal new putative tumour suppressor genes in prostate cancer.

The inactivation of tumour suppressor genes is a key step in cancer development, and is usually achieved by homozygous loss. In prostate cancer, however, large genomic regions are often hemizygously lost, which complicates the identification of putative tumour suppressors in these regions. Here, we develop Epi2Hit, an integrative computational method that leverages whole genome sequencing, epigenomic profiling and gene expression to identify biallelic inactivation of tumour suppressor genes involving DNA methylation of promoter and enhancer regions of one allele and genomic loss of the other allele. We apply Epi2Hit to a cohort of 2,021 prostate cancers to discover tumour suppressor genes. In particular, we identify epigenetic biallelic inactivation of ZFHX3 at a recurrence level similar to TP53. Biallelic inactivation of ZFHX3, a transcriptional repressor, leads to upregulation of oncogenes, including MYC and a shorter time to metastasis. Finally, we provide evidence that epigenetic silencing as 2nd hit is particularly enriched in regions with nearby essential genes, precluding homozygous loss.

Prostatic Neoplasms

Integrated signatures define mutational processes in prostate cancer.

Prostate cancer follows a long and heterogeneous disease course with incompletely understood aetiology1. Here we dissect the mutational processes shaping the genomes of 959 donors from the Pan Prostate Cancer Group and assess their clinical relevance. By integrating de novo extracted single-base substitution, insertion-deletion and copy-number signatures with six novel complex structural variant signatures, we identify eight integrated mutational footprints (IMFs) that collectively explain the mutational processes in 85% of primary prostate cancer genomes. IMFs were strongly influenced by regional biases in the genome, most prevalently androgen receptor-mediated mutagenesis and replication stress. Four IMFs, present in 37% of primary tumours, were significantly associated with shorter time to metastasis. These included reactive oxygen-species-driven mutagenesis and both canonical and non-canonical homologous recombination deficiency, the latter being enriched in patients of African ancestry. Extending to the metastatic setting, we found that IMFs predicted sensitivity to androgen receptor pathway inhibitors. Taken together, our study delineates the aetiologies and mutational processes that drive the genomic and clinical heterogeneity of prostate cancer, introduces IMFs as a unifying framework, and highlights their potential to improve both risk stratification and biomarker-guided treatment selection.

Journal Article

Patient-derived models of prostate cancer: Capturing tumour complexity from initiation to metastasis.

Prostate cancer is a growing global health challenge. To identify new ways to improve patient care, researchers need a variety of preclinical models that faithfully recapitulate human tumours across the disease continuum, from initiation to metastasis. These complementary models include primary cultures of prostate epithelial cells (PrECs), co-cultures, patient-derived explants (PDEs), patient-derived organoids (PDOs) and patient-derived xenografts (PDXs). Collectively, these models enable researchers to study tumour biology and therapeutic responses in clinically relevant contexts. Yet, there is still a need to improve the fidelity of preclinical models to human tumours by integrating diverse cell types from the tumour microenvironment and mimicking biomechanical features. By improving culture methods with matrix components that resemble the tumour microenvironment and new formulations of media that imitate human plasma, in vitro models will more accurately reflect human physiology, nutrient availability, and metabolism. In time this may reduce the reliance on animal testing through organ-on-chip and related techniques. These more complex models are suited to more detailed experimental readouts, including single-cell and spatial analyses. Intravital imaging also enables dynamic visualisation of cell-cell interactions and treatment responses in vivo. Collectively, these approaches are facilitating a shift towards sophisticated models that capture patients' tumour heterogeneity, different cellular niches, and provide opportunities to carefully study tumorigenesis, metastasis, lineage plasticity, and therapy resistance. In this review, we discuss the current progress and future directions for patient-derived models of prostate cancer, highlighting how they can be generated, refined, characterised and shared to accelerate the worldwide effort in translational research.

Humans