Pro-apoptotic effect of a tumor suppressor gene WWOX on ovarian cancer stem cells and its mechanism / 中国组织工程研究

ABSTRACT

BACKGROUND:WWOX,a tumor suppressor gene,can affect the growth of ovarian cancer stem cells;however,there is no report on whether its mechanism of action is related to Hedgehog signaling pathway.OBJECTIVE:To investigate the effect and mechanism of overexpression of WWOX on the apoptosis of ovarian cancer stem cells.METHODS:pcDNA3.1-WWOX (pcDNA3.1-WWOX group) and pcDNA4.0-WWOX (pcDNA4.0-WWOX group) were transferred into ovarian cancer stem cells,respectively;and meanwhile,pcDNA3.1 (pcDNA3.1 group) and pcDNA4.0 (pcDNA4.0 group) were transferred into the cells.A non-transfection group (only with Lipofectamine2000) was set up.After cultured 48 hours,the levels of WWOX in the pcDNA3.1-WWOX group and pcDNA4.0-WWOX group were detected using western blot assay,and the cell proliferation and apoptosis were detected using MTT assay and flow cytometry,respectively.Western blot assay was also used to detect the levels of Hedgehog signaling pathway associated proteins,SHH,PTCH1,Gli-1,SMO and apoptosis-related protein Cleaved Caspase-3 in the cells.Cyclopamine,Hedgehog signaling pathway inhibitor,was used in ovarian cancer stem cells without transfection (cyclopamine group) and after the transfection of WWOX overexpression vector (WWOX+cyclopamine group) followed by 48 hours of culture,and then MTT,flow cytometry and western blot detections were performed.RESULTS AND CONCLUSION:(1) The expression level of WWOX in the pcDNA4.0-WWOX group was significantly higher than that in the pcDNA3.1-WWOX group (t=27.84,P=0.00).The ovarian cancer stem cells which were transfected with pcDNA4.0-WWOX were used to overexpress WWOX in the late experiment.(2) Overexpression of WWOX could inhibit the proliferation of ovarian cancer stem cells and promote the apoptosis of ovarian cancer stem cells.(3) Overexpression of WWOX could inhibit the expression of Gii-1,PTCH1,SMO and SHH in ovarian cancer stem cells,and promote the expression of Cleaved Caspase-3.(4) Cyclopamine could inhibit the expression of SHH,PTCH 1,Gli-1,SMO,and promote the expression of Cleaved Caspase-3.Cyclopamine had obvious inhibitory effect on Hedgehog signaling pathway.(5) Cyclopamine could enhance the apoptosis induced by overexpression of WWOX in ovarian cancer stem cells,and enhance the inhibition of proliferation of ovarian cancer stem cells induced by overexpression of WWOX.To conclude,WWOX effects on proliferation and apoptosis of ovarian cancer stem cells may be related to the inhibition of Hedgehog signaling pathway.