The Effect And Mechanism Of YAP/TAZ On The Progression Of Progestin Resistance In Endometrial Adenocarcinoma

Background and objectiveEndometrial carcinoma(EC)is one of the three major malignant tumors of the female reproductive system,whose incidence and mortality are on the rise every year.Especially the onset age of endometrial adenocarcinoma(EAC)is getting younger and younger.For the patients of childbearing age,who are suffering from early-stage,low-risk endometrial adenocarcinoma,conservative treatment with progestin to preserve fertility is the best option.Yet more than 30%of patients with EC will develop progestin resistance during conservative treatment,so addressing progestin resistance in EC is of great clinical value.At present,the mechanism of progestin resistance in EAC is not clear.YAP(Yes kinase-associated protein)and TAZ(Transcriptional coactivator with PDZbinding motif,also named WWTR1)are key transcription factors of the Hippo signaling pathway and are mainly regulated by a canonical kinase cascade of Hippo pathway.Studies have shown that YAP/TAZ as transcription coactivators play a role in a variety of tumors such as endometrial carcinoma,breast cancer as well as liver cancer and are also involved in the development of malignant tumor chemoresistance.This project aims to investigate the role and mechanism of YAP/TAZ in the process of progestin resistance in endometrial adenocarcinoma,and to explore the potential value of Verteporfin,a YAP/TAZ inhibitor,in the progestin treatment,which may provide ideas for the clinically targeted treatment of progestin resistance in EAC.Contents and methods1.We firstly analyzed the differential genes between progestin sensitive and progestin resistant cells in EAC,screened out the drug resistance related molecules YAP and TAZ.Moreover,the expression of YAP and TAZ was verified in progestin resistant tissues and cells,and thus the correlation between YAP/TAZ and progestin resistance was preliminarily confirmed.2.By comparing the roles of YAP,TAZ and YAP/TAZ(YAP and TAZ)in progestin resistant process through proliferation experiments,we concluded that YAP/TAZ as a whole complex played an important role in progestin resistance.Next,YAP/TAZ were knocked out in progestin resistant cells IshikawaPR and overexpressed in progestin sensitive cells Ishikawa.The changes of malignant phenotypes such as cell proliferation,apoptosis,migration and invasion under progestin treatment were detected by MTT,EDU,flow cytometry,Transwell and wound healing assays.3.The role of Verteporfin,a YAP/TAZ inhibitor,in progestin resistance was verified by in vivo proliferation and apoptosis assays and in vitro tumor formation assays in nude mice.4.Based on the results reveled by the next-generation sequencing,we performed Western Blot and rescue experiments to explore the specific mechanism of YAP/TAZ inducing progestin resistance of EAC.Results1.The expression of YAP and TAZ was increased in progestin resistant cells and progestin resistant tissues of endometrial adenocarcinoma.YAP/TAZ were activated in progestin resistant cells.The expression of YAP and TAZ in progestin resistant IshikawaPR cells gradually increased with increasing MPA concentration or extension of MPA action time.In endometrial adenocarcinoma,YAP and TAZ were negatively correlated with PGR expression.From the above it was concluded that YAP and TAZ are correlated with progestin resistance.2.As a key complex,YAP/TAZ played a more important role in progestin resistance to endometrial adenocarcinoma than single molecule YAP and TAZ.Knocking YAP/TAZ down decreased cell viability,inhibited cell migration and invasion and increased the sensitivity of IshikawaPR cell to progestin.Overexpression of YAP/TAZ conversely increased cell proliferation,metastasis and promoted progestin resistance.This leaded to the conclusion that YAP/TAZ promote the development of progestin resistance in EAC.3.Verteporfin could inhibit the growth and promote the apoptosis of progestin resistant cells in EAC by inhibiting the expression of YAP/TAZ both in vivo and in vitro,so as to reverse the resistance of progestin resistant cells to progestin.Verteporfin combined with progestin could increase the sensitivity of endometrial adenocarcinoma cells to progestin.4.The activation of PI3K-Akt signaling pathway was inhibited after knocking YAP/TAZ down.Knockdown of Akt reversed progestin resistance that was induced by the overexpression of YAP/TAZ.While overexpression of Akt increased the sensitivity of Verteporfin-treated progestin-resistant cells to progestin.Thus we concluded that YAP/TAZ induces progestin resistance in EAC through activation of PI3K-Akt signaling pathway.Conclusion1.YAP/TAZ can promote progestin resistance in endometrial adenocarcinoma.2.YAP/TAZ inhibitor Verteporfin can reverse progestin resistance and its combination with MPA can increase the sensitivity to progestin of endometrial adenocarcinoma cells.3.YAP/TAZ induce progestin resistance in endometrial adenocarcinoma through activating PI3K-Akt signaling pathway.