miR-4429 sensitized cervical cancer cells to irradiation by targeting RAD51

Cervical cancer (CC) is a prevalent malignancy in women, with the feature of metastasis and easy recurrence is responsible for a large proportion of global cancer deaths. Radiotherapy is one of the common treatment tools for CC patients with unresectable tumors. However, radio-resistance in patients could be a major reason for recurrence. Therefore, it is of significance to tunnel the molecular mechanism of radio-resistance in CC. MicroRNAs (miRNAs) are increasingly reported in the regulation of cancer progression and cellular response to radiotherapy and chemotherapy. miR-4429 is a newly discovered miRNA acting as a tumor-suppressor gene in multiple cancers, but its function in CC has never been explored yet. The current study tried to explore the role of miR-4429 in cell radio-sensitivity in CC. First, we validated the downregulation of miR-4429 in CC cells. Importantly, the association of miR-4429 with radio-resistance was validated by identifying the downregulation of miR-4429 in radio-resistant CC cells. Gain- and loss-of-function assays validated that miR-4429 sensitized CC cells to irradiation. Through bioinformatics tools, RAD51 recombinase (RAD51) was identified to be a target for miR-4429. RAD51 is known to be a crucial regulator for DNA damage repair and has been reported to influence cell radio-resistance in cancers, including in CC. Luciferase reporter assay confirmed the interaction between miR-4429 and RAD51. Finally, rescue assays indicated that miR-4429 promoted CC cell radio-sensitivity through RAD51. Consequently, our study showed that miR-4429 sensitized CC cells to irradiation by targeting RAD51, providing a potential therapeutic target for CC patients.