MicroRNA Expression Profiles in Prostate Cancer Cell Lines

MicroRNAs (miRNAs), a group of small non-coding RNAs, can regulate gene expression by triggering translation repressing and/or RNA degradation. Recent studies proved that they were deeply involved in tumorigenesis. Here we show that, compared with the two normal prostate cell lines, eighteen miRNAs in the array were over-expressed and 18 showed lower levels of expression in at least 2 of 3 cancer cell lines using miRNA microarray. MiR-99a, miR-335, miR-375 and miR-625 were the most significantly over-expressed miRNAs, whereas miR155, miR-205, miR-224, miR-422a, miR-422b, miR-452, and miR-452* (* refer to miR-452-3p) were among the most down-regulated miRNAs. Expressions of several of the most significantly differential expression miRNAs were confirmed by Northern blot analysis and real-time RT-PCR. In this study, the expression of miR-10a, miR-99a and miR-125b were also up-regulated in prostate cancer tissues compared with their own normal tissues. For miR-99a, its expression was up-modulated in prostate cancer in comparison with all three normal tissues. Whereas miR-27a and miR-205 have lower level expression in cancer tissues than that in normal tissues. Some miRNAs are aberrantly expressed in human prostate cancer suggesting their involvement in the development and progression of this malignancies. Further studies of these deregulation miRNAs will help clarify their role in tumorigenesis and detect their potential clinical usefulness for early diagnosis, prognosis and therapy of prostate cancer.