Carino Adriana, Graziosi Luigina, D'Amore Claudio, Cipriani Sabrina, Marchianò Silvia, Marino Elisabetta, Zampella Angela, Rende Mario, Mosci Paolo, Distrutti Eleonora, Donini Annibale, Fiorucci Stefano
Dipartimento di Scienze Chirurgiche e Biomediche, Università degli Studi di Perugia, Perugia, Italy.
Azienda Ospedaliera di Perugia, Perugia, Italy.
Oncotarget. 2016 Sep 20;7(38):61021-61035. doi: 10.18632/oncotarget.10477.
GPBAR1 (also known as TGR5) is a bile acid activated receptor expressed in several adenocarcinomas and its activation by secondary bile acids increases intestinal cell proliferation. Here, we have examined the expression of GPBAR1 in human gastric adenocarcinomas and investigated whether its activation promotes the acquisition of a pro-metastatic phenotype. By immunohistochemistry and RT-PCR analysis we found that expression of GPBAR1 associates with advanced gastric cancers (Stage III-IV). GPBAR1 expression in tumors correlates with the expression of N-cadherin, a markers of epithelial-mesenchymal transition (EMT) (r=0.52; P<0.01). Expression of GPBAR1, mRNA and protein, was detected in cancer cell lines, with MKN 45 having the higher expression. Exposure of MKN45 cells to GPBAR1 ligands, TLCA, oleanolic acid or 6-ECDCA (a dual FXR and GPBAR1 ligand) increased the expression of genes associated with EMT including KDKN2A, HRAS, IGB3, MMP10 and MMP13 and downregulated the expression of CD44 and FAT1 (P<0.01 versus control cells). GPBAR1 activation in MKN45 cells associated with EGF-R and ERK1 phosphorylation. These effects were inhibited by DFN406, a GPBAR1 antagonist, and cetuximab. GPBAR1 ligands increase MKN45 migration, adhesion to peritoneum and wound healing. Pretreating MKN45 cells with TLCA increased propensity toward peritoneal dissemination in vivo. These effects were abrogated by cetuximab. In summary, we report that GPBAR1 is expressed in advanced gastric cancers and its expression correlates with markers of EMT. GPBAR1 activation in MKN45 cells promotes EMT. These data suggest that GPBAR1 antagonist might have utility in the treatment of gastric cancers.
G蛋白偶联胆汁酸受体1（也称为TGR5）是一种在多种腺癌中表达的胆汁酸激活受体，次级胆汁酸对其激活会增加肠道细胞增殖。在此，我们检测了G蛋白偶联胆汁酸受体1在人胃腺癌中的表达，并研究了其激活是否促进促转移表型的获得。通过免疫组织化学和逆转录-聚合酶链反应分析，我们发现G蛋白偶联胆汁酸受体1的表达与晚期胃癌（III-IV期）相关。肿瘤中G蛋白偶联胆汁酸受体1的表达与上皮-间质转化（EMT）标志物N-钙黏蛋白的表达相关（r = 0.52；P < 0.01）。在癌细胞系中检测到了G蛋白偶联胆汁酸受体1的mRNA和蛋白表达，其中MKN 45表达较高。将MKN45细胞暴露于G蛋白偶联胆汁酸受体1配体、石胆酸、齐墩果酸或6-乙基-鹅去氧胆酸（一种FXR和G蛋白偶联胆汁酸受体1双重配体）会增加与EMT相关基因的表达，包括KDKN2A、HRAS、IGB3、MMP10和MMP13，并下调CD44和FAT1的表达（与对照细胞相比，P < 0.01）。MKN45细胞中G蛋白偶联胆汁酸受体1的激活与表皮生长因子受体（EGF-R）和细胞外信号调节激酶1（ERK1）的磷酸化相关。这些效应被G蛋白偶联胆汁酸受体1拮抗剂DFN406和西妥昔单抗抑制。G蛋白偶联胆汁酸受体1配体增加MKN45细胞的迁移、对腹膜的黏附及伤口愈合能力。用石胆酸预处理MKN45细胞会增加其在体内向腹膜播散的倾向。这些效应被西妥昔单抗消除。总之，我们报道G蛋白偶联胆汁酸受体1在晚期胃癌中表达，其表达与EMT标志物相关。MKN45细胞中G蛋白偶联胆汁酸受体1的激活促进EMT。这些数据表明G蛋白偶联胆汁酸受体1拮抗剂可能对胃癌治疗有用。
