title: Melatonin set out to ER stress signaling thwarts epithelial mesenchymal transition and peritoneal dissemination via calpain-mediated C/EBPβ and NFκB cleavage.
abstract: 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-elf2α. Moreover, the overexpression of transcription factor C/EBPβ in gastric cancer interacted with NFκB 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/EBPβ 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/EBPβ and NFκB inhibition by melatonin may impede both gastric tumor growth and peritoneal dissemination by inducing ER stress and inhibiting EMT.
authors.affiliation: Institute of Biomedical Sciences, National Chung Hsing University, Taichung, Taiwan.
authors.forename: Sheng-Mao
authors.initials: SM
authors.lastname: Wu
authors.affiliation: Department of Nuclear Medicine, Taichung Veterans General Hospital, Taichung, Taiwan.
authors.forename: Wan-Yu
authors.initials: WY
authors.lastname: Lin
authors.affiliation: Institute of Nuclear Energy Research, Atomic Energy Council, Taoyuan, Taiwan.
authors.forename: Chin-Chang
authors.initials: CC
authors.lastname: Shen
authors.affiliation: Faculty of Medicine, School of Medicine, National Yang-Ming University, Taipei, Taiwan.|Department of Neurosurgery, Taichung Veterans General Hospital, Taichung, Taiwan.
authors.forename: Hung-Chuan
authors.initials: HC
authors.lastname: Pan
authors.affiliation: Department of Nuclear Medicine, Kuang Tien General Hospital, Taichung, Taiwan.
authors.forename: Wang
authors.initials: W
authors.lastname: Keh-Bin
authors.affiliation: Department of Nuclear Medicine, Kuang Tien General Hospital, Taichung, Taiwan.
authors.forename: Yi-Ching
authors.initials: YC
authors.lastname: Chen
authors.affiliation: Department of Pathology and Laboratory Medicine, Taichung Veterans General Hospital, Taichung, Taiwan.
authors.forename: Yee-Jee
authors.initials: YJ
authors.lastname: Jan
authors.affiliation: Institute of Biomedical Sciences, National Chung Hsing University, Taichung, Taiwan.
authors.forename: De-Wei
authors.initials: DW
authors.lastname: Lai
authors.affiliation: Institute of Biomedical Sciences, National Chung Hsing University, Taichung, Taiwan.
authors.forename: Shu-Ching
authors.initials: SC
authors.lastname: Tang
authors.affiliation: Institute of Biomedical Sciences, National Chung Hsing University, Taichung, Taiwan.
authors.forename: Hsing-Ru
authors.initials: HR
authors.lastname: Tien
authors.affiliation: Institute of Biomedical Sciences, National Chung Hsing University, Taichung, Taiwan.
authors.forename: Chien-Shan
authors.initials: CS
authors.lastname: Chiu
authors.affiliation: Department of life Sciences, National Chung Hsing University, Taichung, Taiwan.
authors.forename: Tsung-Chih
authors.initials: TC
authors.lastname: Tsai
authors.affiliation: Division of Gastroenterology, Department of Internal Medicine, Armed Forces Taichung General Hospital, Taiping, Taichung, Taiwan.
authors.forename: Yi-Liang
authors.initials: YL
authors.lastname: Lai
authors.affiliation: Institute of Biomedical Sciences, National Chung Hsing University, Taichung, Taiwan.|Department of Medical Research, Taichung Veterans General Hospital, Taichung, Taiwan.|Rong Hsing Research Center for Translational Medicine, National Chung Hsing University, Taichung, Taiwan.
authors.forename: Meei-Ling
authors.initials: ML
authors.lastname: Sheu
mesh_terms: D000818:Animals; D022782:CCAAT-Enhancer-Binding Protein-beta / Q000235:genetics / Q000378:metabolism*; D002154:Calpain / Q000235:genetics / Q000378:metabolism*; D045744:Cell Line, Tumor; D059865:Endoplasmic Reticulum Stress / Q000187:drug effects*; D058750:Epithelial-Mesenchymal Transition / Q000187:drug effects*; D020868:Gene Silencing; D006801:Humans; D008550:Melatonin / Q000494:pharmacology*; D051379:Mice; D016328:NF-kappa B / Q000235:genetics / Q000378:metabolism*; D009363:Neoplasm Proteins / Q000235:genetics / Q000378:metabolism*; D010534:Peritoneal Neoplasms / Q000188:drug therapy* / Q000235:genetics / Q000378:metabolism / Q000473:pathology / Q000556:secondary; D059748:Proteolysis / Q000187:drug effects*; D015398:Signal Transduction / Q000187:drug effects*; D013274:Stomach Neoplasms / Q000188:drug therapy* / Q000235:genetics / Q000378:metabolism / Q000473:pathology
chemical_list: D022782:CCAAT-Enhancer-Binding Protein-beta; C545012:CEBPB protein, human; D016328:NF-kappa B; D009363:Neoplasm Proteins; D002154:Calpain; D008550:Melatonin
keywords: C/EBPβ; calpain; endoplasmic reticulum stress; epithelial-to-mesenchymal transition; melatonin; peritoneal dissemination