title: Modulation of microRNAs by ionizing radiation in human gastric cancer.
abstract: Gastric cancer is one of the most common cancers in China. Although surgery is the primary therapeutic method, radiotherapy has become an integral part, particularly in the early and intermediate stages of gastric cancer. microRNAs (miRNAs) are involved in the regulation of diverse cellular processes in response to intrinsic and extrinsic stress. A change in miRNA expression profile has been identified in various types of tumor cells in response to radiation; however, there is no relevant information concerning gastric cancer. In the present study, we investigated the miRNA profiles of two clinical gastric cancer samples exposed to X‑rays using miRNA microarray. We found that 16 miRNAs were downregulated and 2 miRNAs were upregulated significantly in both irradiated samples when compared with the unirradiated samples. Decreases in the levels of miR‑300 and miR‑642 expression were confirmed by qRT‑PCR in more clinical samples and in cultured cell lines. We predicted the targets of the two miRNAs with TargetScan and classified all the candidate targets with Gene Ontology, which indicated that both miR‑300 and miR‑642 potentially regulate cellular radiation response by modulating apoptosis, cell cycle regulation and DNA damage and repair pathway-related genes. Cell cycle assay and immunofluorescence assay demonstrated that miR‑300 regulates radiation‑induced G2 cell cycle arrest and DNA damage repair. In conclusion, our findings indicate that ionizing radiation modulates the miRNA expression profile, and the changes in several specific miRNAs such as miR‑300 have the potential to be used in the treatment, diagnosis and prognosis of gastric cancer.
authors.affiliation: Department of Space Radiobiology, Key Laboratory of Heavy Ion Radiation Biology and Medicine, Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 73000, P.R. China.
authors.forename: Jinpeng
authors.initials: J
authors.lastname: He
authors.affiliation: Department of Space Radiobiology, Key Laboratory of Heavy Ion Radiation Biology and Medicine, Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 73000, P.R. China.
authors.forename: Junrui
authors.initials: J
authors.lastname: Hua
authors.affiliation: Department of Space Radiobiology, Key Laboratory of Heavy Ion Radiation Biology and Medicine, Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 73000, P.R. China.
authors.forename: Nan
authors.initials: N
authors.lastname: Ding
authors.affiliation: Department of Space Radiobiology, Key Laboratory of Heavy Ion Radiation Biology and Medicine, Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 73000, P.R. China.
authors.forename: Shuai
authors.initials: S
authors.lastname: Xu
authors.affiliation: Department of Oncology, The First People's Hospital of Lanzhou, Lanzhou 730000, P.R. China.
authors.forename: Rui
authors.initials: R
authors.lastname: Sun
authors.affiliation: Department of Space Radiobiology, Key Laboratory of Heavy Ion Radiation Biology and Medicine, Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 73000, P.R. China.
authors.forename: Guangming
authors.initials: G
authors.lastname: Zhou
authors.affiliation: School of Basic Medical Sciences, Lanzhou University, Lanzhou 730000, P.R. China.
authors.forename: Xiaodong
authors.initials: X
authors.lastname: Xie
authors.affiliation: Department of Space Radiobiology, Key Laboratory of Heavy Ion Radiation Biology and Medicine, Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 73000, P.R. China.
authors.forename: Jufang
authors.initials: J
authors.lastname: Wang
mesh_terms: D017209:Apoptosis / Q000528:radiation effects; D002453:Cell Cycle / Q000528:radiation effects; D045744:Cell Line, Tumor; D004260:DNA Repair / Q000528:radiation effects; D015972:Gene Expression Regulation, Neoplastic / Q000528:radiation effects*; D006801:Humans; D035683:MicroRNAs / Q000235:genetics*; D013274:Stomach Neoplasms / Q000235:genetics / Q000532:radiotherapy*
chemical_list: D035683:MicroRNAs