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Decreased expression of microRNA-143 and -145 in human gastric cancers.

Authors :: Takagi T
Iio A
Nakagawa Y
Naoe T
Tanigawa N
Akao Y
Source :: Oncology [Oncology] 2009; Vol. 77 (1), pp. 12-21. Date of Electronic Publication: 2009 May 12.
Publication Year :: 2009
Abstract: Objective: Downregulation of specific microRNAs (miRNAs) occurs in human tumors, which suggests a function for miRNAs in tumor suppression. We investigated the role of the miRNAs miR-143 and miR-145 in gastric cancers.<br />Methods: The expression levels of miR-143 and miR-145 in the samples from 43 patients with gastric cancer were determined by real-time PCR using TaqMan assay. The growth inhibitory effect was estimated by the transfection of human gastric cancer cells with the miRNA.<br />Results: The expression levels of miR-143 and -145 were decreased in most human gastric cancers examined, as previously reported to occur in colon tumors. The transfection of human gastric MKN-1 cells with miR-145 resulted in a greater growth inhibitory effect than that with miR-143, results which were contrary to those in colon cancers. In MKN-1 cells, an additive effect on growth inhibition was shown by the combined transfection with miR-143 and miR-145; further, higher sensitivity to 5-fluorouracil was also observed following the transfection with miR-143 or miR-145. The possible candidate target messenger RNAs of miR-145 were identified to be insulin receptor substrate-1 and beta-actin.<br />Conclusion: Taken together, these findings suggest that miR-143 and miR-145 act as anti-oncomirs common to gastrointestinal tumors.<br /> (Copyright 2009 S. Karger AG, Basel.)