Project description:We observe preferential accumulation of gH2AX at chromosome ends upon irradiation comparison of quiescent vs senescent human fibroblasts
Project description:H2AX phosphorylation at Ser139 (gH2AX) is an early key event of the DNA damage response (DDR) following DNA double strand breaks (DSB) induction. Although gH2AX distribution has been extensively used as a damage marker, genome-wide investigation of the subsequent DNA repair has been poorly addressed. Here we present ChIP-Seq-based distributions of Histone H3, H2AX and gH2AX under physiological conditions in HeLa cells. Additionally the same histones were studied after a single exposure to 10 Gy X-ray at 0.5, 3 and 24 hours post irradiation
Project description:Keloid radiotherapy is clinically effective but has an incomplete underlying molecular mechanism and limited accessibility; we used X-ray exposure to identify effector pathways replicating its antifibrotic benefits without further radiation. After collecting patient keloid samples, primary human keloid fibroblasts and normal skin fibroblasts, non-targeted metabolomics and RNA-seq were performed, identifying phytosphingosine (PHS) and KIF20A as key mediators of fibrosis and cell death in keloid radiotherapy. X-ray irradiation increased PHS release in keloid fibroblasts; exogenous PHS and X-ray irradiation independently induced cell death and reduced fibrosis, their combination exerted radiosensitization by boosting G2/M arrest and apoptosis while lowering fibrosis progression, and both PHS and irradiation reduced KIF20A whose loss induced cell cycle arrest and apoptosis. Our findings reveal that X-ray irradiation enhances keloid fibroblast PHS secretion that downregulates KIF20A to exert keloid therapeutic effects, and topical PHS or KIF20A-targeting agents are immediately translatable alternatives for radiotherapy-ineligible patients.
Project description:The action of RB as a tumor suppressor has been difficult to define, in part, due to the redundancy of the related proteins p107 and p130. By coupling advanced RNAi technology to suppress RB, p107 or p130 with a genome wide analysis of gene expression in growing, quiescent or ras-senescent cells, we identified a unique and specific activity of RB in repressing DNA replication as cells exit the cell cycle into senescence, a tumor suppressive program. Experiment Overall Design: Expression profiles of IMR90 cells before and after RNAi-mediated supppression of RB, p107 or p130 in growing, quiescent or ras-induced senescent conditions. RNA was extracted from growing, low serum (0.1% FBS), confluent, or ras-senescent cells.
Project description:Quiescent (Q) and stress induced premature senescent (SIPS) fibroblasts were treated for the duration of 4 days with growth medium supplemented with a plant extract (1201) from Solidago vigaurea subspecies alpestris. Rna was isolated with Trizol and sent to GATC for next generation sequencing with Ilumina technology. The plant extract proofed to block the negative effects of senescence in human skin fibroblasts in various experiments by delaying the acquisition of a senescent phenotype/favouring a papillary-like phenotype and attenuating the senescence associated secretory phenotype. The RNAseq was performed to understand the underlying molecular mechanism of the observed effects. SIPS was induced by chronic oxidative stress treatment (9 days with 1 h 100 µM H2O2 per day).
