The novel Aryl hydrocarbon receptor inhibitor biseugenol inhibits gastric tumor growth and peritoneal dissemination

Abstract

Biseugenol (Eug) is known to antiproliferative of cancer cells; however, to date, the antiperitoneal dissemination effects have not been studied in any mouse cancer model. In this study, Aryl hydrocarbon receptor (AhR) expression was associated with lymph node and distant metastasis in patients with gastric cancer and was correlated with clinicolpathological pattern. We evaluated the antiperitoneal dissemination potential of knockdown AhR and Biseugenol in cancer mouse model and assessed mesenchymal characteristics. Our results demonstrate that tumor growth, peritoneal dissemination and peritoneum or organ metastasis implanted MKN45 cells were significantly decreased in shAhR and Biseugenol-treated mice and that endoplasmic reticulum (ER) stress was caused. Biseugenol-exposure tumors showed acquired epithelial features such as phosphorylation of E-cadherin, cytokeratin-18 and loss mesenchymal signature Snail, but not vimentin regulation. Snail expression, through AhR activation, is an epithelial-to-mesenchymal transition (EMT) determinant. Moreover, Biseugenol enhanced Calpain-10 (Calp-10) and AhR interaction resulted in Snail downregulation. The effect of shCalpain-10 in cancer cells was associated with inactivation of AhR/Snail promoter binding activity. Inhibition of Calpain-10 in gastric cancer cells by short hairpin RNA or pharmacological inhibitor was found to effectively reduced growth ability and vessel density in vivo. Importantly, knockdown of AhR completed abrogated peritoneal dissemination. Herein, Biseugenol targeting ER stress provokes Calpain-10 activity, sequentially induces reversal of EMT and apoptosis via AhR may involve the paralleling processes. Taken together, these data suggest that Calpain-10 activation and AhR inhibition by Biseugenol impedes both gastric tumor growth and peritoneal dissemination by inducing ER stress and inhibiting EMT.

Role of the aryl hydrocarbon receptor in carcinogenesis and potential as an anti-cancer drug target

“…Thus, the in vivo mouse model clearly demonstrates tumor suppressor-like activity for the AhR in colon/cecum cancer and specific AhR ligands can inhibit tumorigenesis. In MNK5 gastric cancer cells ± AhR, in vitro and in vivo (xenograft-AhR) studies indicate that the AhR promotes growth, migration and apoptosis (Lai et al 2014; Yin et al 2013). TCDD induced proliferation and invasion of AGS cells (Peng et al 2009), whereas DIM decreased SGC-7901 cell growth (Yin et al 2012); however, it is not clear if the growth inhibitory effects of DIM are AhR-dependent.…”

Melatonin set out to ER stress signaling thwarts epithelial mesenchymal transition and peritoneal dissemination via calpain‐mediated C/EBPβ and NFκB cleavage

“…Human gastric cancer cell lines, AGS (moderately differentiated gastric adenocarcinoma) and MKN 45 (poorly differentiated gastric adenocarcinoma) cells, were cultured as previously described . Melatonin was obtained from Sigma (M5250, Sigma‐Aldrich, St. Louis, MO, USA).…”

“…Majority (80–90%) has poor prognosis due to its tendency for rapid peritoneal dissemination, which is resistant to therapy . Previous reports have shown a close relation among epithelial‐to‐mesenchymal transition (EMT), gastric cancer progression, and peritoneal dissemination . The EMT allows cancer cells to lose their epithelial characteristics and acquire a mesenchymal phenotype, initiating invasion and metastasis .…”

“…Previous reports show that increased E‐cadherin expression results from endoplasmic reticulum (ER) stress, a key factor in regulating cancer metastasis, from the calpain system activity. This also causes a reduction in Snail or AhR signaling as well as the expression of some candidate transcription factors that promote EMT . But some developmental transcriptional factors and signaling pathways that control peritoneal dissemination and invasion are unknown, so discovering the precise mechanisms that command EMT progression is urgently needed.…”

The aryl hydrocarbon receptor repressor – More than a simple feedback inhibitor of AhR signaling: Clues for its role in inflammation and cancer

“…Frank Cuttitta and his team observed a very low AhRR expression rate in several human cancer biopsies, which was due to hypermethylation of the AhRR promoter (73). These cancers include colon, lung, esophagus and stomach tumors (73), and, interestingly, AhR is abundantly expressed in these cancer types (74–78). A low AhRR expression level that correlated with poor prognosis was also found in gastric adenocarcinomas (79).…”