Melatonin set out to ER stress signaling thwarts epithelial mesenchymal transition and peritoneal dissemination via calpain-mediated C/EBP and NFB cleavage
Melatonin set out to ER stress signaling thwarts epithelial mesenchymal transition and peritoneal dissemination via calpain-mediated C/EBP and NFB cleavage
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DOI：
10.1111/jpi.12295
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发表时间：
2016-03-01
影响因子：
10.3
通讯作者：
Sheu, Meei-Ling
中科院分区：
文献类型：
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作者：
Wu, Sheng-Mao;Lin, Wan-Yu;Sheu, Meei-Ling
腹膜播散性肿瘤具有较高的死亡率，与肿瘤细胞失去上皮特征、获得移动性间充质形态特征和侵袭性有关。褪黑素是所有植物体内产生的一种具有抗肿瘤活性的内源分子，但到目前为止，其潜在的机制和抗腹膜转移的效果还不是很清楚。本研究测定了褪黑素在体内的抗腹膜扩散潜能，并评价了其与内质网应激抑制上皮间充质转化(EMT)信号机制的关系，这可能是褪黑素抗癌的主要分子机制。结果表明，褪黑素抑制了体内腹膜转移，并激活了内质网应激，在Cignal erse Reporter分析中，在透射电子显微镜图像中，细胞器结构，钙蛋白酶活性，以及p-elF2等蛋白质生物标志物。此外，转录因子C/EBP在胃癌中的过表达与NFB相互作用，进一步调节COX-2的表达。免疫荧光成像、免疫沉淀、EMSA和芯片分析证实，褪黑素可使这些细胞解离并下调。褪黑素或C/EBP基因沉默通过Topflash活性降低了EMT蛋白标记物(E-钙粘蛋白、蜗牛和鼻涕)和Wnt/β-catenin的活性，增加了内质网应激标记物。在一项动物研究中，褪黑素治疗的结果与体外研究结果一致，并减弱了全身促血管生成因子的产生。综上所述，褪黑素对C/EBP和NFB的抑制可能通过诱导ER应激和抑制EMT来抑制胃肿瘤的生长和腹膜转移。
Peritoneal dissemination of tumor has high mortality and is associated with the loss of epithelial features, acquisition of motile mesenchymal morphology characteristics, and invasive properties by tumor cells. Melatonin is an endogenously produced molecule in all plant species that is known to exert antitumor activity, but to date, its underlying mechanisms and antiperitoneal metastasis efficacy is not well defined. This study determined the antiperitoneal dissemination potential of melatonin in vivo and assessed its association with the inhibition of epithelial-to-mesenchymal transition (EMT) signaling mechanism by endoplasmic reticulum (ER) stress, which may be a major molecular mechanism of melatonin against cancer. The results demonstrate that melatonin inhibited peritoneal metastasis in vivo and activated ER stress in Cignal ERSE Reporter Assay, organelle structure in transmission electron microscopy images, calpain activity, and protein biomarkers like p-elf2. Moreover, the overexpression of transcription factor C/EBP in gastric cancer interacted with NFB and further regulates COX-2 expression. These were dissociated and downregulated by melatonin, as proven by immunofluorescence imaging, immunoprecipitation, EMSA, and ChIP assay. Melatonin or gene silencing of C/EBP decreased the EMT protein markers (E-cadherin, Snail, and Slug) and Wnt/beta-catenin activity by Topflash activity, and increased ER stress markers. In an animal study, the results of melatonin therapy were consistent with those of in vitro findings and attenuated systemic proangiogenesis factor production. In conclusion, C/EBP and NFB inhibition by melatonin may impede both gastric tumor growth and peritoneal dissemination by inducing ER stress and inhibiting EMT.