178P Smo inhibitor LDE225 reverses epithelial-mesenchymal transition (EMT) in non-small cell lung cancer (NSCLC) cells

Abstract

Background: LDE225 is a potent and selective oral inhibitor of Smo, a key component of the hedgehog (Hh) signaling pathway. It has been reported that LDE225 can inhibit the invasion in many solid tumors, and thus attenuate tumor metastasis, but its mechanism of action has been unclear in non-small cell lung cancers(NSCLCs). The aim of the present study was to evaluate whether LDE225 can reverse the epithelial-mesenchymal transition(EMT) induced by co-cultured with macrophage (THP-1) cell lines in NSCLC cells, and its possible mechanisms. Methods: The NSCLC cells (H460 and H1299) were co-cultured with THP-1 cells for 72h to obsreve EMT formation, and then were treated with 5μm LDE225 for 24h. Wound healing assays and transwell assays were used to detect the migratory and invasive activity of lung cancer cells. The EMT-related factors (E-cadherin and vimentin) were detected by western bloting analysis. SHH and GLI1, as the Hh pathway-related factors, were also detected by western bloting analysis. ELISA assays used to detect the concentration of TGF-β1 in the conditioned medium (CM) obtained from THP-1 cells before and after co-culture with NSCLC cells. Results: Our data showed that the expressions of E-cadherin and vimentin could significantly modulate after NSCLC cells co-culture with THP-1 cells, which further enhanced the capacity of the NSCLC cells to migrate and invade the extracellular matrix. LDE225 was able to compromise these effects. Additionally, LDE225 remarkably inhibited the activation of Hh signaling pathway in NSCLC cells after co-cultured with THP-1 cells. Further analysis showed that the concentration of TGF-β1 in the CM from co-culture of NSCLC cells & THP-1 cells was significantly lower in the presence of LDE225. It can suppresse the EMT and mimick the effect of LDE225 on NSCLC cells when administration of anti-TGF-β1 neutralizing antibody during co-culture. Conclusions: Our study confirmd that LDE225 can reverse lung cancer cells EMT and migration via downregulating the concentration of TGF-β1 in co-culture with THP-1 cells. Legal entity responsible for the study: 3rd Affiliated Hospital of Harbin Medical University Funding: National Natural Scientific Foundation of China (No: 81572824, 81673007 and 81773133), postdoctoral scientific research developmental fund of Heilongjiang Province, Health Department of Heilongjiang Provincial of China (No 2011-124) and Harbin Medical University Cancer Hospital major project Foundation (No: JJZ-2010-01). Disclosure: All authors have declared no conflicts of interest.