title: Recombinant human leptin induces growth inhibition and apoptosis in human gastric cancer MGC-803 cells.
abstract: The aim of this study is to investigate the effect of recombinant human leptin (rhLep) on the proliferation of human gastric cancer MGC-803 cells and its underlying mechanisms. RT-PCR was performed to identify the expression of leptin receptor (Ob-R). Cell proliferation was measured with MTT assay. DNA content and cell cycle were analyzed by flow cytometry. Apoptosis was assessed by DNA ladder assay and flow cytometry analysis using Annexin V-FITC/PI double staining. Underlying mechanisms of rhLep-induced apoptosis were evaluated by the activities of caspase-3, -8, -9, and cytochrome c release from mitochondria. Moreover, the phosphorylation of STAT3 in MGC-803 cells upon rhLep administration was detected by Western blot analysis. Our results demonstrated that two leptin receptors (Ob-Ra and Ob-Rb) were expressed in MGC-803 cells. rhLep diminished the proliferation rate of MGC-803 cells in a time- and concentration-dependent manner and induced MGC-803 cell apoptosis involving in the activation of caspase-8 and caspase-3 but not caspase-9. In addition, rhLep failed to induce cytochrome c release from mitochondria and had no effect on the activation of STAT3 in MGC-803 cells. Therefore, from these results, we concluded that rhLep significantly inhibited cell proliferation via G0/G1 phase cell cycle arrest and induced apoptosis through the extrinsic apoptotic pathway in human gastric cancer MGC-803 cells.
authors.affiliation: Cancer Research Center, Medical College of Xiamen University, No. 422 SiMing South Road, Xiamen, 361005, Fujian Province, People's Republic of China.
authors.forename: Na
authors.initials: N
authors.lastname: Wu
authors.forename: Yongjun
authors.initials: Y
authors.lastname: Wang
authors.forename: Shengyu
authors.initials: S
authors.lastname: Wang
authors.forename: Yuqiang
authors.initials: Y
authors.lastname: Chen
authors.forename: Jianghua
authors.initials: J
authors.lastname: Yan
mesh_terms: D017304:Annexin A5 / Q000032:analysis; D000970:Antineoplastic Agents / Q000378:metabolism*; D017209:Apoptosis; D001688:Biological Products / Q000378:metabolism*; D002453:Cell Cycle / Q000187:drug effects; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects*; D002470:Cell Survival / Q000187:drug effects; D053938:DNA Fragmentation; D005434:Flow Cytometry; D005562:Formazans / Q000032:analysis; D020869:Gene Expression Profiling; D006801:Humans; D020738:Leptin / Q000235:genetics / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013194:Staining and Labeling; D013778:Tetrazolium Salts / Q000032:analysis / Q000378:metabolism; D013844:Thiazoles / Q000378:metabolism
chemical_list: D017304:Annexin A5; D000970:Antineoplastic Agents; D001688:Biological Products; D005562:Formazans; D020738:Leptin; D013778:Tetrazolium Salts; D013844:Thiazoles; C079782:MTT formazan; C022616:thiazolyl blue