MicroRNA-152 inhibits tumor cell growth while inducing apoptosis via the transcriptional repression of cathepsin L in gastrointestinal stromal tumor.

OBJECTIVE

MicroRNAs are widely thought to play a regulatory role in gene expression. Although the more unique microRNA expression profiles have been reported in several tumors, there remains a scarcity of knowledge in relation to microRNA expression profiles in GISTs. During this study, through the alteration in the expression of microRNA-152 (miR-152) in gastrointestinal stromal tumor (GIST) cells, we subsequently evaluated its ability to influence the processes associated with cancer, including proliferation, migration, invasion, and apoptosis, as well as the associated mechanisms.

METHODS

The expression of miR-152 and cathepsin L (CTSL) in GIST cell lines (GIST882, GIST430, GIST48 and GIST-T1) and normal gastric mucosal cell line RGM-1 were determined. A series of miR-152 mimics, miR-152 inhibitors, and siRNA against CTSL were introduced to treat GIST-T1 cells with the lowest miR-152 and the highest CTSL were assessed. Cell viability, cell cycle entry, apoptosis, and cell migration/invasion were all evaluated by means of CCK-8 assay, flow cytometry analyses of Annexin V-FITC/PI staining, and transwell assays.

RESULTS

The target prediction program and luciferase reporter gene assay verified CTSL is the target of miR-152. Regarding the biological significance of miR-152, siRNA knockdown and ectopic expression studies revealed that miR-152 mimic or siRNA against CTSL exposure reduced cell viability and migration/invasion, which resulted in more cells arrested at the S stage, and induced apoptosis. MiR-152 inhibitor exposure was observed to have induced effects on CTSL cells as opposed to those induced by that of the miR-152 mimics. In contrast, miR-152 downregulation abrogated the effects induced by siRNA against CTSL treatment.

CONCLUSION

The key findings of this study provided evidence suggesting that miR-152 functions by means of binding to CTSL to induce GIST cell apoptosis and inhibit proliferation, migration, and invasion. The anti-tumor role of miR-152 makes it an attractive therapeutic target for GIST.