Xihuang Pill (西黄丸) induces mesenchymal-epithelial transition and inhibits loss of apical-basal polarity in colorectal cancer cell through regulating ZEB1-SCRIB Loop

Abstract

To investigate the antiproliferative and anti-metastasis effect of Xihuang Pill (, XP) on human colorectal cancer cell and to explore the molecular mechanism by which it produces the effects. Highly metastatic human colorectal cancer cell line LoVo was treated with low-, medium-, and highdose XP-containing serum (XP-L, XP-M, XP-H) groups for 48 h, cells intervened with no drug rat serum and PD98059 [extracellular signal-regulated kinase (ERK) inhibitor] as negative and positive controls (NC and PC) groups. Cell proliferation assay was made using cell counting kit-8 (CCK8). The 8 μm pore-size transwell chamber and 4', 6-diamidino-2-phenylindole (DAPI) staining were applied to examine the ability of invasion and migration of the cells. The protein expression of ERK1/2, zinc fifi nger E-box-binding homeobox 1 (ZEB1), Scrib and lethal giant larvae homolog 2 (Lgl2) was detected by Western blotting while the relative mRNA quantity of E-cadherin, N-cadherin, Occludin and junctional adhesion molecule-1 (JAM1) was measured by realtime fluorescent quantitative polymerase chain reaction (RT-qPCR). XP induced a dose-dependent suppression on the proliferation of LoVo cells (P <0.05 or P<0.01), with the inhibition rates varied from 27.30% to 31.08%. Transwell assay showed that when preprocessed with PD98059 and XP-containing serum, the number of cells that passed the filter decreased significantly compared with that of NC group (P <0.05 or P<0.01). Moreover, XP inhibited the protein expression of ERK1/2 and ZEB1 (P <0.05); and up-regulated the protein expression of Scrib and Lgl2 (P <0.05). The mRNA levels of E-cadherin, Occludin and JAM1 of the XP intervened groups and PC group markedly ascended (P <0.05) while that of N-cadherin showed a descending tendency (P>0.05). XP intervention suppressed the ability of proliferation, invasion and migration of the LoVo cells. Regulating ZEB1-SCRIB Loop so as to recover epithelial phenotype and apical junctional complex might be one of the mechanisms by which XP produces the anti-metastasis effect.