PA-MSHA Inhibits EGFR Signaling Pathway Activation And Induces Apoptosis In Bladder Cancer Cells In Vitro And In Vivo

BACKGROUND AND OBJECTIVEPseudomonas aeruginosa-mannose sensitive hemagglutinin (PA-MSHA), a peritrichous P. aeruginosa strain with MSHA fimbriae, has been shown to be a valuable anti-cancer drug in many kinds of cancers. However, the effect of PA-MSHA on bladder cancer has not been elucidated. In this study, we focused on the anti-tumor activities and related mechanisms of PA-MSHA on bladder cancer in vitro and in vivo.MATERIALS AND METHODS1、SV-40-immortalized normal uroepithelial cells (SV-HUC-1) and human bladder cancer cell lines (T24,5637, and HT-1376) were treated with PA-MSHA or PA (Heat-killed P. aeruginosa). At first, the effect of PA-MSHA on cancer cell proliferation was measured using Cell Counting Assay Kit-8(CCK-8).2、The changes of cell morphology were observed by transmission electron microscopy. 3、The early apoptosis induced by PA-MSHA was evaluated by flow cytometry (FCM)4、The expression level of apoptosis-related molecules were detected using western blot assay. We then investigated the activation of the EGFR signaling pathway stimulated by PA-MSHA, the expression and phosphorylation of several key regulators involved in the EGFR signaling pathway were detected.5、At last, xenograft tumor in nude mice was used to further investigate the anti-tumor effect of PA-MSHA in vivo.6、The apoptosis of tumor cells was evaluated by TUNEL stain. The levels of EGFR signaling pathway proteins of the tumor were detected by western blot assay.RESULTS1、 PA-MSHA could efficiently inhibit proliferation in bladder cancer cell lines, but little effect in SV-HUC-1. The three bladder cancer cell lines treated with PA-MSHA exhibited a large number of autophagocytic vacuoles formed, and some cells began to occur detachment.2、PA-MSHA could induce apoptosis in human bladder cancer cell lines.3、Furthermore, cells stimulated with PA-MSHA exhibited an inactivation of EGFR signaling.4、In vivo, PA-MSHA treatment significantly suppressed tumor growth and induced apoptosis in xenografts tumor in nude mice.5、PA-MSHA also could inhibit the activation of EGFR signaling pathway.CONCLUSIONPA-MSHA could efficiently inhibit proliferation and induce apoptosis in human bladder cancer cells in vitro and in vivo, which is associated with the inactivation of EGFR signaling pathway, it might be used as a potential therapeutic agent for bladder cancer.