Hwang, J. H. | Search bioRxiv

bioRxiv2021

Metaplasia of respiratory and digestive tissues in the Eastern oyster Crassostrea virginica associated with the Deepwater Horizon oil spill

Metaplasia is a well documented and deleterious effect of crude oil components on bivalved molluscs, including oysters. This reversible transformation of one cell type to another, is a common response to petroleum-product exposure in molluscs. It has been shown experimentally in previous work that eastern oysters (Crassostrea virginica) exposed to petroleum products will exhibit metaplasia of digestive tissues. Here we document for the first time that wild adult oysters inhabiting coastal waters in the northern Gulf of Mexico during and in the aftermath of the Deepwater Horizon oil spill (2010) exhibited metaplasia in both ctenidia and digestive epithelia at significantly higher levels than geographic controls of C. virginica from Chesapeake Bay. Both ctenidial (respiratory and suspension feeding) and digestive tract tissues exhibited significantly higher frequencies of metaplasia in specimens from the Gulf of Mexico compared to those from Chesapeake Bay. Metaplasia included the loss of epithelial cilia, transformations of columnar epithelia, hyperplasia and reduction of ctenidial branches, and vacuolization of digestive tissues. Evidence for a reduction of metaplasia following the oil spill (2010-2013) is suggestive but equivocal.

zoology↗

bioRxiv2020

Genome-scale genetic screening identifies PRMT1 as a critical vulnerability in castration-resistant prostate cancer

Androgen receptor (AR) signaling is the central driver of prostate cancer across disease states. While androgen deprivation therapy (ADT) is effective in the initial treatment of prostate cancer, resistance to ADT or to next-generation androgen pathway inhibitors invariably arises, most commonly through re-activation of the AR axis. Thus, orthogonal approaches to inhibit AR signaling in advanced prostate cancer are essential. Here, via genome-scale CRISPR/Cas9 screening, we identify protein arginine methyltransferase 1 (PRMT1) as a critical mediator of AR expression and signaling. PRMT1 regulates recruitment of AR to genomic target sites and inhibition of PRMT1 impairs AR binding at lineage-specific enhancers, leading to decreased expression of key oncogenes, including AR itself. Additionally, AR-driven prostate cancer cells are uniquely susceptible to combined AR and PRMT1 inhibition. Our findings implicate PRMT1 as a key regulator of AR output and provide a preclinical framework for co-targeting of AR and PRMT1 in advanced prostate cancer.

cancer biology↗