Research on the efficacy of Celastrus Orbiculatus in suppressing TGF-β1-induced epithelial-mesenchymal transition by inhibiting HSP27 and TNF-α-induced NF-κB/Snail signaling pathway in human gastric adenocarcinoma

Abstract

BackgroundCelastrus orbiculatus has been used as a folk medicine in China for the treatment of many diseases. In the laboratory, the ethyl acetate extract of Celastrus orbiculatus (COE) displays a wide range of anticancer functions. However, the inhibition of the metastasis mechanism of COE in gastric cancer cells has not been investigated so far.MethodsThe present study was undertaken to determine if the anti-metastasis effect of COE was involved in inhibiting of epithelial–mesenchymal transition (EMT) of human gastric adenocarcinoma SGC-7901 cells. In vitro, a well-established experimental EMT model involving transforming growth factor β1 (TGF-β1) was applied. Viability, invasion and migration, protein and mRNA expression of tumor cells were analyzed by MTT assay, transwell assay, western blot and real-time PCR, respectively. The molecular targets of COE in SGC-7901 cells were investigated by two-dimensional gel electrophoresis (2-DE) and MALDI-TOF-TOF mass spectrometer. Overexpression of heat shock protein 27 (HSP27) was performed by transfected with the recombinant retroviral expression plasmid. In vivo, the anti-metastasis mechanisms of COE in the peritoneal gastric cancer xenograft model was explored and the effect was tested.ResultsThe non-cytostatic concentrations of COE effectively inhibited TGF-β1 induced EMT process in SGC-7901 cells, which is characterized by prevented morphological changes, increased E-cadherin expression and decreased Vimentin, N-cadherin expression. Moreover, COE inhibited invasion and migration induced by TGF-β1. Using a comparative proteomics approach, four proteins were identified as differently expressed, with HSP27 protein being one of the most significantly down-regulated proteins induced by COE. Moreover, the activation of nuclear factor κB (NF-κB)/Snail signaling pathway induced by tumor necrosis factor-α (TNF-α) was also attenuated under the pretreatment of COE. Interestingly, overexpression of HSP27 significantly decreases the inhibitory effect of COE on EMT and the NF-κB/Snail pathway. Furthermore, COE significantly reduced the number of peritoneal metastatic nodules in the peritoneal gastric cancer xenograft model.ConclusionsTaken together, these results suggest that COE inhibits the EMT by suppressing the expression of HSP27, correlating with inhibition of NF-κB/Snail signal pathways in SGC-7901 cells. Based on these results, COE may be considered a novel anti-cancer agent for the treatment of metastasis in gastric cancer.

Toosendanin suppresses oncogenic phenotypes of human gastric carcinoma SGC-7901 cells partly via miR-200a-mediated downregulation of β-catenin pathway

“…When gastric cancer cells receive signals from their microenvironment, such as TGF-β1, EMT occur and provide cells a distinct advantage in tumor progression and metastasis (48). The present study manifested that TGF-β1 could induce EMT in SGC-7901 cells by downregulating epithelial marker E-cadherin expression and upregulating mesenchymal marker N-cadherin and vimentin expression, consistent with previous reports (49)(50)(51). TSN treatment reversed the above effects of TGF-β1.…”

Molecular Chaperones in Cancer Stem Cells: Determinants of Stemness and Potential Targets for Antitumor Therapy

“…First indications about a link between HSP27 and cancer stemness appeared in 2010: The small chaperone was shown to be involved in TGF-β1-induced EMT in lung cancer cells (A549 cell line) and this involvement was independent of Smad [138]. Then, the contribution of HSP27 to EMT was found in several different cancer-related studies and models, including breast cancer [139], gastric cancer [140,141], prostate cancer [142,143], renal cell carcinoma [144], and salivary adenoid cystic carcinoma [145]. These HSP27-associated mechanisms of EMT were similar in some cases of cancer while different in others.…”

Knockdown of Radixin Suppresses Gastric Cancer Metastasis In Vitro by Up-Regulation of E-Cadherin via NF-κB/Snail Pathway

“…5C). As one of the upstream proteins of snail, NF-κB was examined because early studies indicated that activated NF-κB may accumulate in the nucleolus and serve as an enhancer of snail transcription [33][34][35]. Thus, we hypothesized that radixin knockdown may either reduce the total amount of NF-κB or induce its nuclear exclusion, in turn leading to the repression of snail and the consequent enhancement of E-cadherin transcription.…”