microRNA expression alteration after arsenic trioxide treatment in HepG-2 cells.

Background And Aim: More and more microRNA (miRNA) are found to be involved in tumor genesis and progress. Arsenic trioxide has been an effective chemotherapeutic drug in cancer therapy for many years. In this study, we aimed to find the miRNA involved in the mechanisms of arsenic trioxide treatment in cancer therapy.

Methods: We detected the expression profile of miRNA by miRNA microarray and quantitative real-time polymerase chain reaction. Cell viability assay, flow cytometry analysis, prediction of miRNA targets, Western blot analysis and luciferase reporter assay were carried out to determine the role of one selected miRNA, namely mir-29a, in affecting the biological behaviors of HepG-2 cells.

Results: Among the 677 human miRNA in the microarray, five miRNA were upregulated and four were downregulated in HepG-2 cells treated with arsenic trioxide compared to their controls. If only changes above two folds were considered, four miRNA were identified, namely miR-24, miR-29a, miR-30a and miR-210, which were all upregulated. Among them, miR-29a showed a positive therapeutic effect in liver cancer cells by inhibiting cell growth and inducing cell apoptosis, and PPM1D was confirmed to be the target gene of miR-29a. Furthermore, a synergy effect was detected between miR-29a and arsenic trioxide.

Conclusions: Arsenic trioxide altered miRNA expression profile in HepG-2 cells. Among the altered miRNA, miR-29a seemed to take a role in the mechanism of arsenic trioxide in liver cancer therapy. The synergy effect between miR-29a and arsenic trioxide may offer this drug a new chance in cancer therapy by decreasing its dose and toxic side-effects.