PPARα activator irbesartan suppresses the proliferation of endometrial carcinoma cells via SREBP1 and ARID1A

Endometrial carcinoma(EMC)is associated with obesity;however,the underlying mechanisms have not yet been elucidated.Peroxisome proliferator-activated receptor alpha(PPARα)is a nuclear receptor that is involved in lipid,glucose,and energy metabolism.PPARαreportedly functions as a tumor suppressor through its effects on lipid metabolism;however,the involvement of PPARαin the development of EMC remains unclear.The present study demonstrated that the immunohistochemical expression of nuclear PPARαwas lower in EMC than in normal endometrial tissues,suggesting the tumor suppressive nature of PPARα.A treatment with the PPARαactivator,irbesartan,inhibited the EMC cell lines,Ishikawa and HEC1A,by down-regulating sterol regulatory element-binding protein 1(SREBP1)and fatty acid synthase(FAS)and up-regulating the tumor suppressor genes p21 and p27,antioxidant enzymes,and AT-rich interaction domain 1A(ARID1A).These results indicate the potential of the activation of PPARαas a novel therapeutic approach against EMC.

Mice-lacking LMP2, immuno-proteasome subunit, as an animal model of spontaneous uterine leiomyosarcoma

Uterine tumors are the most common type of gynecologic neoplasm.Uterine leiomyosarcoma(LMS)is rare,accounting for 2%to 5%of tumors of the uterine body.Uterine LMS develops more often in the muscle tissue layer of the uterine body than in the uterine cervix.The development of gynecologic tumors is often correlated with female hormone secretion;however,the development of uterine LMS is not substantially correlated with hormonal conditions,and the risk factors are not yet known.Radiographic evaluation combined with PET/CT can be useless in the diagnosis and surveillance of uterine LMS.Importantly,a diagnostic biomarker,which distinguishes malignant LMS and benign tumor leiomyoma(LMA)is yet to be established.Accordingly,it is necessary to analyze risk factors associated with uterine LMS in order to establish a method of treatment.LMP2-deficient mice spontaneously develop uterine LMS,with a disease prevalence of~40%by 14 months of age.It is therefore of interest whether human uterine LMS shows a loss of LMP2 expression.We found LMP2 expression is absent in human LMS,but present in human LMA.Therefore,defective LMP2 expression may be one of the risk factors for LMS.LMP2 is potentially a diagnostic biomarker for uterine LMS,and gene therapy with LMP2-encording DNA may be a new therapeutic approach.