RESUMO
【Objective】 To investigate the relationship between hepatitis B virus X （HBx） protein and EGFR promoter， and the role of HBx protein in activating EGFR/PI3K/p-Akt signaling pathway and inhibiting apoptosis. 【Methods】 EGFR promoter plasmids were constructed and the relationship between HBx and EGFR promoters was characterized using a luciferase reporter assay. EGFR-overexpressing trophoblast cells were constructed， and EGFR expression in the overexpressing cells was knocked down using EGFR shRNA. The expression and localization of EGFR/PI3K/p-Akt were detected by Western blotting and confocal laser microscopy. Cell apoptosis was analyzed using flow cytometry. HBV plasmids carrying either full-length HBx or HBx with a deletion mutation （ΔHBx） and HBx plasmids were transfected into two types of trophoblast cells； HBx and PI3K/p-Akt protein expressions were detected by Western blotting. Cell apoptosis was analyzed using flow cytometry. 【Results】 Co-transfection of HBx and EGFR promoter plasmids in JEG-3 and HTR-8/Svneo cells significantly elevated the expression of EGFR promoter driven luciferase compared with the control group （P<0.01）. In EGFR-overexpressing cells， the expression of PI3K/p-Akt was significantly increased （P<0.01）， whereas the apoptosis rate was significantly decreased for JEG-3 cells and HTR-8/Svneo cells （both P<0.01）. These results were reversed in the EGFR-knock down group. When the intracellular HBx protein was expressed in JEG-3 and HTR-8 cells， PI3K/p-Akt protein expression was significantly increased （both P<0.05）， and the proportion of apoptosis was significantly decreased （both P<0.05）. 【Conclusion】 In placental trophoblast cells， HBx protein activates the expression of EGFR by acting on the EGFR promoter， and inhibits the apoptosis of trophoblast cells via the downstream EGFR/PI3K/p-Akt signaling pathway.
RESUMO
【Objective】 To investigate the effect and mechanism of inhibiting Yes-associated protein1 (YAP1) expression by verteporfin on proliferation, migration and invasion of human umbilical vein endothelial cells (HUVECs) exposed to hypoxia environment and the possible mechanisms that further affect placental angiogenesis in preeclampsia. 【Methods】 MTT method was used to detect the cell viability of HUVECs at different concentrations (0, 4, 8, 12 and 16 μg/mL) after 12 h and 24 h treatment with verteporfin under hypoxia and calculate the IC50 value to select the subsequent experimental drug concentration. Flow cytometry was made to analyze verteporfin’s effect on HUVEC apoptosis in hypoxic environment. The wound healing assay and Transwell invasion assay were used to determine the effect of verteporfin on HUVEC cell migration and invasion abilities under hypoxic environment. Angiogenesis test was used to detect the effect of verteporfin on the angiogenesis of HUVECs under hypoxic environment. The effects of verteporfin on the expression levels of YAP1 and TEAD1 in Hippo signaling pathway under normoxia and hypoxia were determined by Western blotting. 【Results】 Under hypoxic environment, verteporfin could inhibit the proliferation of HUVECs by calculating the IC50 value, the subsequent experimental group selected 16 μg/mL verteporfin to treat cells. Flow cytometry showed that verteporfin induced the apoptosis rate of HUVECs under hypoxia (P<0.01). The results of wound healing, Transwell invasion and the angiogenesis experiments confirmed that compared with the control group, verteporfin could inhibit the migration, invasion and angiogenesis of HUVECs in hypoxic environment (P<0.05). Western blotting assay indicated that under normoxia and hypoxia, the expressions of YAP1 and TEAD1 were reduced (P<0.01). 【Conclusion】 In hypoxic environment, verteporfin inhibits the proliferation of HUVECs by inhibiting the expressions of YAP1 and TEAD1, and reduces the migration, invasion and angiogenesis of HUVECs. It is confirmed that the Hippo-YAP1 signaling pathway may affect the placental angiogenesis of preeclampsia and participate in the occurrence of preeclampsia by regulating the proliferation and invasion of vascular endothelial cells.