IDENTIFICATION AND FUNCTIONAL CHARACTERIZATION OF MICRORNAS REGULATING HTERT.

Background: Telomerase is a ribonucleoprotein (RNP) reverse transcriptase that replicates the ends of chromosomes, thereby maintaining genome integrity, and its inhibition may be envisioned to prevent carcinogenesis or treat cancer patients. Various approaches have been used to target hTERT, and one of the promising strategies is the use of hTERT-targeting microRNAs (miRNAs).

Aim: To investigate the interaction of miRNAs with hTERT, describing the strength, affinity, preferred binding orientation, and in vitro verification of miRNA on hTERT expression in cancer.

Materials and methods: The miRWalk, TargetScan, and miRDB databases were used for screening. Consistently, five top-hit miRNAs were found in all three databases that could interact with hTERT mRNA, namely, hsa-miR-4651, hsa-miR-608, hsa-miR-6796-5p, hsa-miR-6752-5p, and hsa-miR-6791-5p. We applied stringent in silico tools to firstly model the structures of lead miRNA and hTERT mRNA. Then docking was performed, and finally stability of miRNA-mRNA complexes was analyzed using MD simulations.

Results: The expression of the selected miRNAs was inhibited in the MCF-7 breast cancer cell line. The inhibition of hsa-miR-6796-5p was enhanced, while hsa-miR-4651 significantly reduced the expression of hTERT protein. Moreover, the inhibition of hsa-miR-4651 expression led to a reduction in melanoma and breast cancer cell proliferation.

Conclusion: The current study provided a detailed procedure for identifying and verifying miRNAs against mRNAs, as well as highlighting the differential regulation of hTERT by specific miRNAs. It demonstrated that miRNA inhibition can modulate hTERT expression and cell proliferation, with potential implications for targeted cancer therapies. The strategy used in this study could also be applied to other genes for screening potential miRNAs.