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

Abstract

Increasing radiosensitivity of cancer cells can enhance the efficacy of cervical cancer treatment. This study evaluated the potential roles and mechanism of baicalein in regulating the radiosensitivity of cervical cancer cells in vitro. 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. 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. 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.