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标题：let-7 MicroRNA Functions as a Potential Growth Suppressor in Human Colon Cancer Cells
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作者：Yukihiro Akao ; Yoshihito Nakagawa ; Tomoki Naoe 等
期刊名称：Biological and Pharmaceutical Bulletin
印刷版ISSN：0918-6158
电子版ISSN：1347-5215
出版年度：2006
卷号：29
期号：5
页码：903-906
DOI：10.1248/bpb.29.903
出版社：The Pharmaceutical Society of Japan
摘要：MicroRNAs (miRNAs) are endogenously expressed RNAs, 18—25 nucleotides in length, that repress protein translation through binding to target mRNAs. miRNAs have been implicated in many cellular processes including cell proliferation, differentiation, and death. Recently, let-7 miRNAs were found to regulate human RAS oncogene expression and to be often down-regulated in human lung tumors. In this study, we examined the expression of let-7 miRNAs in human colon cancer tumors and cell lines, with the result that 2 of 6 cases and 1 of 3 cell lines showed reduced expression of let-7 . When let-7 low-expressing DLD-1 human colon cancer cells were transfected with let-7a-1 precursor miRNA, which is located at chromosome 9q22.3, the cells underwent significant growth suppression. At that time, the levels of RAS and c-myc proteins were lowered after the transfection, whereas the levels of both of their mRNAs remained almost unchanged. These findings suggest the involvement of let-7 miRNA in the growth of colon cancer cells. Thus, miRNAs might provide a basis for novel RNA anti-cancer agents.
关键词：microRNA;let-7;colon cancer;RAS;growth inhibition