Published online Mar 28, 2015. doi: 10.3748/wjg.v21.i12.3519
Peer-review started: October 29, 2014
First decision: November 14, 2014
Revised: December 22, 2014
Accepted: January 16, 2015
Article in press: January 16, 2015
Published online: March 28, 2015
AIM: To explore the microRNA (miRNA) profiles and to determine the key miRNAs within the side population (SP) cells of the gastric cancer cell line MKN-45.
METHODS: We used fluorescence-activated cell sorting and Hoechst 33342 labeling to obtain SP cells from the human gastric carcinoma cell line MKN-45. The miRNA expression profiles of the SP and major population (MP) cells were examined using a miRNA gene chip, and key miRNAs were obtained according to aberrant expression and the miRNAs’ possible targets as predicted by bioinformatics.
RESULTS: Using a significance criterion of a 1.5-fold or greater difference in expression level, we observed an increase in the expression of 34 miRNAs and a decrease in the expression of 34 miRNAs when comparing SP to MP cells. Using quantitative real-time reverse transcription-polymerase chain reaction to test for differentially expressed miRNAs combined with bioinformatics results, we found that the downregulated miRNAs, such as hsa-miR-3175 and hsa-miR-203, and the upregulated miRNAs, including hsa-miR-130a, hsa-miR-324-5p, hsa-miR-34a, and hsa-miR-25-star, may be important in maintaining and regulating the characteristics of SP cells.
CONCLUSION: There are key miRNAs expressed within the SP cells of the gastric cancer cell line MKN-45, and include hsa-miR-3175, hsa-miR-203, hsa-miR-130a, hsa-miR-324-5p, hsa-miR-34a, and hsa-miR-25-star.
Core tip: MicroRNAs (miRNAs) act as one mechanism by which coding genes are regulated, and they are involved in many biological and pathological processes including carcinogenesis. However, identifying specific miRNAs is difficult, because many miRNAs possess more than one target and many target genes are regulated by more than one miRNA. We used fluorescence-activated cell sorting and Hoechst 33342 labeling to obtain side population (SP) cells from the human gastric carcinoma cell line MKN-45. The miRNA expression profiles of SP and major population cells were examined by miRNA gene chip analysis, and key miRNAs were identified according to aberrant expression and their possible targets as predicted by bioinformatics.