title: LIN28B confers radio-resistance through the posttranscriptional control of KRAS.
abstract: To screen the differentially expressed microRNAs related to radio-resistance, we compared the microRNA profiles of lung cancer cells with different responses to ionizing radiation (IR). Of 328 microRNAs in microarray, 27 microRNAs were differentially expressed in NCI-H460 (H460) and NCI-H1299 (H1299) cells. Among them, let-7g was down-regulated in radio-resistant H1299 cells, and the level of let-7g was higher in radio-sensitive cells like Caski, H460, and ME180 in qRT-PCR analysis than in radio-resistant cells like A549, H1299, DLD1, and HeLa. Over-expression of let-7g in H1299 cells could suppress the translation of KRAS, and increase the sensitivity to IR. When we knockdown the expression of LIN28B, an upstream regulator of let-7g, the level of mature let-7g was increased in H1299 cells and the sensitivity to IR was also enhanced in LIN28B knockdown cells. From these data, we suggest that LIN28B plays an important role in radiation responses of lung cancer cells through inhibiting let-7g processing and increasing translation of KRAS.
authors.affiliation: Department of Biomedical Sciences, Biochemistry and Molecular Biology, Seoul National University College of Medicine, Seoul 110-799, Korea.
authors.forename: Sun-Hye
authors.initials: SH
authors.lastname: Jeong
authors.forename: Hong-Gyun
authors.initials: HG
authors.lastname: Wu
authors.forename: Woong-Yang
authors.initials: WY
authors.lastname: Park
mesh_terms: D045744:Cell Line, Tumor; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D020869:Gene Expression Profiling; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D008175:Lung Neoplasms / Q000235:genetics*; D035683:MicroRNAs / Q000235:genetics*; D011518:Proto-Oncogene Proteins / Q000235:genetics* / Q000378:metabolism; D016283:Proto-Oncogene Proteins p21(ras); D016601:RNA-Binding Proteins; D011836:Radiation Tolerance; D018631:ras Proteins / Q000235:genetics* / Q000378:metabolism
chemical_list: D004268:DNA-Binding Proteins; C117307:KRAS protein, human; C516326:LIN28B protein, human; D035683:MicroRNAs; D011518:Proto-Oncogene Proteins; D016601:RNA-Binding Proteins; C487931:mirnlet7 microRNA, human; D016283:Proto-Oncogene Proteins p21(ras); D018631:ras Proteins