Figure 8: ERα is required for Icaritin uptake and mediates the promotive effects of Icaritin on the expression of pluripotency transcription factors of mESC.
mESCs were transfected with control siRNA (Coni) or ERα siRNA (ERαi) followed by further analysis. The ERα protein (a) and transcript level (b) after transfection was verified by Western blot and real-time PCR respectively. Values were the mean ± SD (n = 3). **P < 0.01. (c) The effect of ERα knockdown on Icaritin cellular uptake was examined by flow cytometric analysis. Cells were collected at 24 h after Icaritin exposure. mRNA (d) and protein (e) levels of selected cell cycle regulators and pluripotency transcription factors in response to ERα knockdown with or without Icaritin treatment was detected by real-time PCR and Western blot analysis respectively. Western blot shown are cropped from the original blots. Values were the mean ± SD (n = 3). #P < 0.05, ##P < 0.01, compared with control siRNA under Icaritin treatment. *P < 0.05, **P < 0.01, compared with control siRNA without Icaritin treatment. (f) Proposed model of functional role of Icaritin in promoting mESCs self-renewal. Icaritin interacts and activates ERα, functions as a potent inhibitor for CDX2 and p130 to activate Cyclin E/CDK2 signaling and upregulate core-pluripotency transcription factors expression, subsequently promote G1/S phase transition and self-renewal of mESCs.
