title: MiR-101 induces senescence and prevents apoptosis in the background of DNA damage in MCF7 cells.
abstract: Moderately increased DNA damage due to the exogenous miR-101 (4 fold) over-expression in MCF7 cells was substantiated by an increase in the number of γ-H2AX foci, correlating with a simple-to-do Halo-assay. miR-101 induced mild/moderate DNA damage favoured senescence rather than apoptosis. An experimental support emanated from the induced mild/moderate DNA damage with 1 µM/5 µM etoposide in MCF7 cells, which resulted in an endogenous miR-101 over-expression (10/4 fold, respectively), followed by senescence. On the other hand, the severe DNA damage induced with 10 µM etoposide, resulted in a low (<1 fold) endogenous expression of miR-101 and an elevated percentage of apoptotic cells. Using bioinformatics tools along with in-vitro and in-vivo validations, miR-101 was found to target and downregulate the mRNA expression of UBE2N and SMARCA4, involved in DNA damage repair (DDR) pathways. Recovery of the expression of the two novel targets in anti-miR-101 transfection validated the results. We conclude that a threshold range of over-expressed miR-101, capable of inducing mild/moderate DNA damage, is sensed by cells to become senescent. The observation derives further support from in-silico protein-protein network analysis where the two novel targets showed their involvement in senescence pathway.
authors.affiliation: School of Biotechnology, Shri Mata Vaishno Devi University, Katra, Kakrayal, Jammu & Kashmir, India.
authors.forename: Siddharth
authors.initials: S
authors.lastname: Manvati
authors.affiliation: National Centre of Applied Human Genetics, School of Life Sciences, Jawaharlal Nehru University, New Delhi, India.
authors.forename: Kailash Chandra
authors.initials: KC
authors.lastname: Mangalhara
authors.affiliation: School of Biotechnology, Shri Mata Vaishno Devi University, Katra, Kakrayal, Jammu & Kashmir, India.
authors.forename: P
authors.initials: P
authors.lastname: Kalaiarasan
authors.affiliation: National Centre of Applied Human Genetics, School of Life Sciences, Jawaharlal Nehru University, New Delhi, India.
authors.forename: Niloo
authors.initials: N
authors.lastname: Srivastava
authors.affiliation: National Centre of Applied Human Genetics, School of Life Sciences, Jawaharlal Nehru University, New Delhi, India.
authors.forename: Bhupender
authors.initials: B
authors.lastname: Kumar
authors.affiliation: National Centre of Applied Human Genetics, School of Life Sciences, Jawaharlal Nehru University, New Delhi, India.
authors.forename: R N K
authors.initials: RN
authors.lastname: Bamezai
mesh_terms: D017209:Apoptosis; D016922:Cellular Senescence; D004249:DNA Damage; D004265:DNA Helicases / Q000235:genetics / Q000378:metabolism; D015972:Gene Expression Regulation, Neoplastic; D053263:Gene Regulatory Networks; D061986:MCF-7 Cells; D035683:MicroRNAs / Q000235:genetics* / Q000378:metabolism; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D044763:Ubiquitin-Conjugating Enzymes / Q000235:genetics / Q000378:metabolism
chemical_list: C534072:MIRN101 microRNA, human; D035683:MicroRNAs; D009687:Nuclear Proteins; D012333:RNA, Messenger; D014157:Transcription Factors; C471607:UBE2N protein, human; D044763:Ubiquitin-Conjugating Enzymes; C084108:SMARCA4 protein, human; D004265:DNA Helicases