B2 SINE Copies Serve as a Transposable Boundary of DNA Methylation and Histone Modifications in the Mouse.

More than one million copies of short interspersed elements (SINEs), a class of retrotransposons, are present in the mammalian genomes, particularly within gene-rich genomic regions. Evidence has accumulated that ancient SINE sequences have acquired new binding sites for transcription factors (TFs) through multiple mutations following retrotransposition, and as a result have rewired the host regulatory network during the course of evolution. However, it remains unclear whether currently active SINEs contribute to the expansion of TF binding sites. To study the mobility, expression, and function of SINE copies, we first identified about 2,000 insertional polymorphisms of SINE B1 and B2 families within Mus musculus. Using a novel RNA sequencing method designated as melRNA-seq, we detected the expression of SINEs in male germ cells at both the subfamily and genomic copy levels: the vast majority of B1 RNAs originated from evolutionarily young subfamilies, whereas B2 RNAs originated from both young and old subfamilies. DNA methylation and chromatin immunoprecipitation-sequencing (ChIP-seq) analyses in liver revealed that polymorphic B2 insertions served as a boundary element inhibiting the expansion of DNA hypomethylated and histone hyperacetylated regions, and decreased the expression of neighboring genes. Moreover, genomic B2 copies were enriched at the boundary of various histone modifications, and chromatin insulator protein, CCCTC-binding factor, a well-known chromatin boundary protein, bound to >100 polymorphic and >10,000 non-polymorphic B2 insertions. These results suggest that the currently active B2 copies are mobile boundary elements that can modulate chromatin modifications and gene expression, and are likely involved in epigenomic and phenotypic diversification of the mouse species.

Characteristics of mild and severe apalutamide-related cutaneous adverse events in patients with prostate cancer: A review of the literature.

Apalutamide is an antiandrogen used to treat prostate cancer. Although it sometimes induces mild cutaneous adverse events and occasionally severe ones, clinical differences between severe and mild cases remain unclear. To assess the risks in patients experiencing apalutamide-related cutaneous adverse events (ARCAEs), we aimed to characterize severe and mild ARCAEs in terms of onset time and lymphocyte transformation test (LTT) for apalutamide. We reviewed 41 ARCAE cases: 24 from our institute and 17 from the literature, comprising (i) eight severe cases including six with toxic epidermal necrolysis, one with acute generalized exanthematous pustulosis, and one with drug reaction with eosinophilia and systemic symptoms, and (ii) 33 mild cases. Patients with evere cases developed ARCAEs significantly earlier than patients with mild cases (5.2 vs 9.6 weeks). No severe cases appeared ≥8 weeks after initiation of apalutamide. LTTs showed positive results in two of seven mild cases (28.6%) and four of four severe cases (100.0%). In conclusion, we found that severe ARCAEs are characterized by earlier onset and LTT positivity. Dermatologists and urologists should pay special attention to patients who develop ARCAEs <8 weeks after initiating apalutamide and/or show positive LTT results.