Baicalein modulates the radiosensitivity of cervical cancer cells in vitro via miR-183 and the JAK2/STAT3 signaling pathway.

ABSTRACT

BACKGROUND: Increasing radiosensitivity of cancer cells can enhance the efficacy of cervical cancer treatment. OBJECTIVES: This study evaluated the potential roles and mechanism of baicalein in regulating the radiosensitivity of cervical cancer cells in vitro. MATERIAL AND METHODS: Real-time quantitative polymerase chain reaction (RT-qPCR) was used to assess miR-183 expression in End1/E6E7 cells, Hela cells and Hela cells irradiated with X-ray (0 Gy, 1 Gy, 3 Gy, 5 Gy, and 10 Gy). Cell Counting Kit-8 (CCK-8) method measured cell viability of Hela cells after miR-183 regulation, baicalein or RO8191 treatment. Apoptosis rates were detected using flow cytometry. Thereafter, expression of Bcl-2, Bax and caspase-3 RNA was also detected through RT-qPCR. Protein concentrations of E-cadherin, N-cadherin, Vimentin in epithelial-mesenchymal transition (EMT), phospho-JAK2/STAT3, and total Janus kinase 2/signal transducer and activator of transcription 3 STAT3 (JAK2/STAT3) were examined using enzyme-linked immunosorbent assay (ELISA) methods. RO8191, a JAK2/STAT3 activator, was used to activate the JAK2/STAT3 signaling pathway. RESULTS: The miR-183 expression was significantly lower in Hela cells compared to End1/E6E7 cells. Following upregulation of miR-183 in Hela cells, cell viability was inhibited while apoptosis was promoted. Moreover, EMT was inhibited after miR-183 over-expression. X-ray treatment markedly reduced the cell survival rate and increased miR-183 RNA expression. Baicalein treatment severely reduced the cell viability of 10-Gy X-ray-irradiated Hela cells, partially reversing the effect of miR-183, and also increased apoptosis and prevented EMT in irradiated cells. Y1007/8 in JAK2 and tyrosine (Tyr) residue 705 of STAT3 were phosphorylated, resulting in high expression of JAK2/STAT3, which was decreased by irradiation and baicalein treatment. RO8191 activated JAK2/STAT3 signaling, promoted cell viability and EMT, and inhibited cell apoptosis, while baicalein partly reversed the functions of RO8191. CONCLUSIONS: Baicalein inhibited cell viability and EMT, and induced cell apoptosis of Hela cells, through upregulating miR-183 via inactivation of the JAK2/STAT3 signaling pathway.