MiR-34b promotes oxidative stress and induces cellular senescence through TWIST1 in human cervical cancer.

Purpose: The aim of this research was to elucidate the role of miR-34b in cervical cancer progression and the underlying mechanism behind the miR-34b-mediated tumor suppression. The study revealed the role of miR-34b as a senescence inducer and serves as a potential therapeutic target in developing combination therapy with senotherapeutics.

Methods: MiR-34b was ectopically expressed in cervical cancer cell lines using a tetracycline inducible system and its effects on cell viability, apoptosis, senescence, DNA damage and oxidative stress were studied using MTT assay, acridine orange/ ethidium bromide staining, senescence associated β-galactosidase assay, gamma H2AX foci staining assay, western blotting and specific dyes for the detection of total and individual ROS species.

Results: Ectopic expression of miR-34b promoted cellular senescence but no significant induction of apoptosis was observed in cervical cancer cell lines. MiR-34b promoted increase in oxidative stress through increase in total and individual ROS species and contributed to increase in cellular senescence. Mechanistically, miR-34b mediates its action by targeting TWIST1 as evidenced by the similar actions of TWIST1 shRNA in cervical cancer cell lines. Furthermore, our study revealed TWIST1 is one of the most significant targets of miR-34b targetome and identified RITA as a novel senolytic agent for use in combination therapy with miR-34b.

Conclusion: MiR-34b promotes cellular senescence and oxidative stress by targeting TWIST1, a known oncogene and EMT regulator. This study delved into the mechanism of miR-34b-mediated tumor suppression and provided novel insights for development of miR-34b based therapeutics for cervical cancer.