title: Leptin receptor is involved in STAT3 activation in human colorectal adenoma.
abstract: The possible role of leptin in colorectal tumors has been investigated in previous studies; however, to date, the conclusions remain under debate. Therefore, we investigated the serum leptin levels in colorectal adenoma patients. In addition, expression of the leptin receptor, and the leptin receptor-mediated signaling pathways were investigated in biopsy specimens collected from human patients with colorectal adenoma. No significant difference in the mean serum leptin level was observed between the colorectal adenoma patients and the control subjects; however, increased expression and activation of the leptin receptor, as indicated by findings such as the phosphorylation of Tyr 1141, was observed in the colorectal adenoma tissues. In addition, activation of the JAK/STAT signaling pathway mediated by the leptin receptor and increased transcriptional regulation of downstream target molecules were observed in colorectal adenomas compared with the non-adenoma tissues. These results indicate STAT3-mediated leptin receptor signaling pathways may be activated in human colorectal adenomas.
authors.affiliation: Gastroenterology Division, School of Medicine, Yokohama City University, Yokohama, Kanagawa, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Uchiyama
authors.forename: Hirokazu
authors.initials: H
authors.lastname: Takahashi
authors.forename: Michiko
authors.initials: M
authors.lastname: Sugiyama
authors.forename: Eiji
authors.initials: E
authors.lastname: Sakai
authors.forename: Hiroki
authors.initials: H
authors.lastname: Endo
authors.forename: Kunihiro
authors.initials: K
authors.lastname: Hosono
authors.forename: Kyoko
authors.initials: K
authors.lastname: Yoneda
authors.forename: Masato
authors.initials: M
authors.lastname: Yoneda
authors.forename: Masahiko
authors.initials: M
authors.lastname: Inamori
authors.forename: Yoji
authors.initials: Y
authors.lastname: Nagashima
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Inayama
authors.forename: Koichiro
authors.initials: K
authors.lastname: Wada
authors.forename: Atsushi
authors.initials: A
authors.lastname: Nakajima
mesh_terms: D000236:Adenoma / Q000378:metabolism*; D015153:Blotting, Western; D015179:Colorectal Neoplasms / Q000378:metabolism*; D004789:Enzyme Activation; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D020738:Leptin / Q000097:blood; D008297:Male; D008875:Middle Aged; D054411:Receptors, Leptin / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D050796:STAT3 Transcription Factor / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology*
chemical_list: D020738:Leptin; D054411:Receptors, Leptin; D050796:STAT3 Transcription Factor; C494086:STAT3 protein, human