Time-dependent expressed markers and their characterization for premature senescence induced by ionizing radiation in MCF7

ABSTRACT: Recently, senescence has been suggested as a defense mechanism to block sporadic induction of cancer cells. Radiation treatment induces proliferating cancer cells to turn into non-proliferating senescent cells in vitro. To characterize transcriptional reprogramming after radiation treatment, we measured the gene expression profiles of MCF7 at different time points after treatment. In these experiments, we found that IR induced premature senescence in MCF7 cells, and IR treatment resulted in significant changes in the expression of 305 marker genes (less than 1% FDR), which were strongly correlated (|r|>0.9) with IR treatment in a time-dependent manner. Functional analysis of these markers indicated that the dynamics of cytoskeletal structure and lysosomal activity gradually increased. The expression of marker genes for modulator proteins, that were responsible for the dynamics of actin stress fibers and focal adhesion, displayed a particularly strong positive correlation with senescence-associated (SA) morphological changes through time. We also observed a strong induction of genes related to lysosomal metabolic activity, which was accompanied by an increase in the number of SA-beta-Gal positive cells. However, the expression of genes for the cell cycle progression, the post-transcription and the translation activities gradually decreased after radiation treatment. Especially, we observed clear cell cycle arrest specifically at the S and G2/M phases with consistent down-regulation of genes for microtubule assembly/disassembly or spindle biogenesis. Gene expression profiles were obtained from human MCF7 cells after ionizing radiation (6 Gy) at day 0 (no ionizing radiation), day 1 (after ionizing radiation), day 2, day 3, and day 4.

ORGANISM(S): Homo sapiens

SUBMITTER: Lee Cheol-Koo 

PROVIDER: S-ECPF-GEOD-21748 | biostudies-other |

REPOSITORIES: biostudies-other