title: MiR-155 inhibits the sensitivity of lung cancer cells to cisplatin via negative regulation of Apaf-1 expression.
abstract: MicroRNA-155 (miR-155) overexpression is often found in malignancies including lung cancer. The objective of this study is to verify the hypothesis, based on the results of bioinformatics analysis, that miR-155 modulates cellular apoptosis and DNA damage through the regulation of Apaf-1 and is thus involved in the development and progression of lung cancer. First, we measured the expression of miR-155 and the Apaf-1 protein in lung cancer tissues. The results showed that expression of miR-155 was significantly higher in lung cancer tissues than in paracancerous and normal tissues; whereas Apaf-1 expression was lower in the lung cancerous tissues. We then established miR-155-silenced and Apaf-1-overexpressed A549 cell lines by transfection with pMAGic2.0-BIC-siRNA and pcDNA3.1-Apaf-1, respectively. These cell lines were then treated with cisplatin, and apoptosis and DNA damage were assessed, with non-transfected A549 cells used as negative controls. The results showed that, relative to controls, the silencing of miR-155 resulted in elevated expression of the Apaf-1 protein, whereas Apaf-1 mRNA levels remained unchanged. Both the silencing of miR-155 and the overexpression Apaf-1 greatly increased the sensitivity of A549 cells to cisplatin treatment, as evidenced by elevated rates of apoptosis and DNA damage. Furthermore, dual-transfection of A549 cells with miR-155 siRNA and Apaf-1 siRNA resulted in the attenuation of apoptosis and DNA damage. In conclusion, the inhibition of miR-155 can enhance the sensitivity of A549 cells to cisplatin treatment by modulation of cellular apoptosis and DNA damage through an Apaf-1-mediated pathway.
authors.affiliation: Department of Respiratory Medicine, Changzheng Hospital, Second Military Medical University/Center for Diagnosis and Treatment of Lung Cancer of the Chinese People's Liberation Army, Shanghai, China.
authors.forename: Y-S
authors.initials: YS
authors.lastname: Zang
authors.forename: Y-F
authors.initials: YF
authors.lastname: Zhong
authors.forename: Z
authors.initials: Z
authors.lastname: Fang
authors.forename: B
authors.initials: B
authors.lastname: Li
authors.forename: J
authors.initials: J
authors.lastname: An
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis; D053477:Apoptotic Protease-Activating Factor 1 / Q000235:genetics / Q000378:metabolism*; D053453:Caspase 9 / Q000235:genetics / Q000378:metabolism; D045744:Cell Line, Tumor; D002945:Cisplatin / Q000494:pharmacology*; D020552:Comet Assay; D004249:DNA Damage; D019008:Drug Resistance, Neoplasm / Q000187:drug effects*; D015972:Gene Expression Regulation, Neoplastic; D020868:Gene Silencing; D006801:Humans; D008175:Lung Neoplasms / Q000378:metabolism / Q000473:pathology; D035683:MicroRNAs / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D034741:RNA, Small Interfering / Q000235:genetics / Q000378:metabolism; D014162:Transfection
chemical_list: C506592:APAF1 protein, human; D000970:Antineoplastic Agents; D053477:Apoptotic Protease-Activating Factor 1; C524942:MIRN155 microRNA, human; D035683:MicroRNAs; D012333:RNA, Messenger; D034741:RNA, Small Interfering; C506433:CASP9 protein, human; D053453:Caspase 9; D002945:Cisplatin