Overexpression of histone demethylase Fbxl10 leads to enhanced migration in mouse embryonic fibroblasts.

Cell migration is a central process in the development and maintenance of multicellular organisms. Tissue formation during embryonic development, wound healing, immune responses and invasive tumors all require the orchestrated movement of cells to specific locations. Histone demethylase proteins alter transcription by regulating the chromatin state at specific gene loci. FBXL10 is a conserved and ubiquitously expressed member of the JmjC domain-containing histone demethylase family and is implicated in the demethylation of H3K4me3 and H3K36me2 and thereby removing active chromatin marks. However, the physiological role of FBXL10 in vivo remains largely unknown. Therefore, we established an inducible gain of function model to analyze the role of Fbxl10 and compared wild-type with Fbxl10 overexpressing mouse embryonic fibroblasts (MEFs). Our study shows that overexpression of Fbxl10 in MEFs doesn't influence the proliferation capability but leads to an enhanced migration capacity in comparison to wild-type MEFs. Transcriptome and ChIP-seq experiments demonstrated that Fbxl10 binds to genes involved in migration like Areg, Mdk, Lmnb1, Thbs1, Mgp and Cxcl12. Taken together, our results strongly suggest that Fbxl10 plays a critical role in migration by binding to the promoter region of migration-associated genes and thereby might influences cell behaviour to a possibly more aggressive phenotype.

KDM5C is overexpressed in prostate cancer and is a prognostic marker for prostate-specific antigen-relapse following radical prostatectomy.

Currently, few prognostic factors are available to predict the emergence of castration-resistant prostate cancer and no curative options are available. Epigenetic gene regulation has been shown to trigger prostate cancer metastasis and androgen independence. Histone lysine demethylases (KDMs) are epigenetic enzymes that can remove both repressive and activating histone marks. KDM5 family members are capable of removing the histone H3 lysine 4 dimethylation-activating mark, rendering them potential players in the down-regulation of tumor suppressors and suggesting that their activity could repress oncogenes. Here, we systematically investigated KDM5C expression patterns in two independent radical prostatectomy cohorts (822 prostate tumors in total) by immunohistochemistry. Positive nuclear KDM5C staining was significantly associated with a reduced prostate-specific antigen relapse-free survival. Our study confirmed that nuclear KDM5C expression is an independent prognostic parameter. Most strikingly, the prognostic value of nuclear KDM5C expression for progression-free survival was exclusively pronounced for the Gleason group 7. In addition, KDM5C knockdown resulted in growth retardation of prostate cancer cells in vitro and induced regulation of several proliferation-associated genes. Our data indicate that KDM5C is functionally involved in proliferation control of prostate cancer cells and might represent a novel attractive therapy target. Moreover, overexpression of KDM5C is an independent new predictive marker for therapy failure as determined by biochemical recurrence in patients after prostatectomy.

Functional mutation analysis provides evidence for a role of REEP1 in lipid droplet biology.

Hereditary axonopathies are frequently caused by mutations in proteins that reside in the endoplasmic reticulum (ER). Which of the many ER functions are pathologically relevant, however, remains to be determined. REEP1 is an ER protein mutated in hereditary spastic paraplegia (HSP) and hereditary motor neuropathy (HMN). We found that HSP-associated missense variants at the N-terminus of REEP1 abolish ER targeting, whereas two more central variants are either rare benign SNPs or confer pathogenicity via a different mechanism. The mis-targeted variants accumulate at lipid droplets (LDs). N-terminal tagging, deletion of the N-terminus, and expression of a minor REEP1 isoform had the same effect. We also confirmed an increase in LD size upon cooverexpression of atlastins and REEP1. Neither wild-type REEP1, LD-targeted HSP variants, nor a non-LD-targeted HMN variant reproduced this effect when expressed alone. We conclude that the N-terminus of REEP1 is necessary for proper targeting to and/or retention in the ER. The protein's potential to also associate with LDs corroborates a synergistic effect with atlastins on LD size. Interestingly, LD size is also altered upon knockdown of seipin, mutations of which also cause HSP and HMN. Regulation of LDs may thus be an ER function critical for long-term axonal maintenance.