title: ECRG2, a novel candidate of tumor suppressor gene in the esophageal carcinoma, interacts directly with metallothionein 2A and links to apoptosis.
abstract: Esophageal cancer related gene 2 (ECRG2) is a novel candidate of the tumor suppressor gene identified from human esophagus. To study the biological role of the ECRG2 gene, we performed a GAL4-based yeast two-hybrid screening of a human fetal liver cDNA library. Using the ECRG2 cDNA as bait, we identified nine putative clones as associated proteins. The interaction of ECRG2 and metallothionein 2A (MT2A) was confirmed by glutathione S-transferase pull-down assays in vitro and co-immunoprecipitation experiments in vivo. ECRG2 co-localized with MT2A mostly to nuclei and slightly to cytoplasm, as shown by confocal microscopy. Transfection of ECRG2 gene inhibited cell proliferation and induced apoptosis in esophageal cancer cells. In the co-transfection of ECRG2 and MT2A assays, cell proliferation was inhibited and apoptosis was slightly induced compared with control groups. When we used antisense MT2A to interdict the effect of MT2A, the inhibition of cell proliferation and induction of apoptosis were significantly enhanced. When we used antisense ECRG2 to interdict the effect of ECRG2 in the group of Bel7402 cells co-transfected with ECRG2 and MT2A, the inhibition of cell proliferation and induction of apoptosis disappeared. The results provide evidence for ECRG2 in esophageal cancer cells acting as a bifunctional protein associated with the regulation of cell proliferation and induction of apoptosis. ECRG2 might reduce the function of MT2A on the regulation of cell proliferation and induction of apoptosis. The physical interaction of ECRG2 and MT2A may play an important role in the carcinogenesis of esophageal cancer.
authors.affiliation: Department of Etiology and Carcinogenesis, Cancer Institute, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing 100021, PR China.
authors.forename: Yongping
authors.initials: Y
authors.lastname: Cui
authors.forename: Jianbo
authors.initials: J
authors.lastname: Wang
authors.forename: Xinyu
authors.initials: X
authors.lastname: Zhang
authors.forename: Ronggang
authors.initials: R
authors.lastname: Lang
authors.forename: Meixia
authors.initials: M
authors.lastname: Bi
authors.forename: Liping
authors.initials: L
authors.lastname: Guo
authors.forename: Shih-Hsin
authors.initials: SH
authors.lastname: Lu
mesh_terms: D017209:Apoptosis / Q000502:physiology*; D002453:Cell Cycle / Q000502:physiology; D002460:Cell Line; D004938:Esophageal Neoplasms / Q000378:metabolism* / Q000473:pathology; D005434:Flow Cytometry; D017930:Genes, Reporter; D016147:Genes, Tumor Suppressor; D015894:Genome, Human; D006801:Humans; D008668:Metallothionein / Q000235:genetics / Q000378:metabolism*; D018613:Microscopy, Confocal; D008969:Molecular Sequence Data; D011485:Protein Binding; D053491:Proteinase Inhibitory Proteins, Secretory; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D000074162:Serine Peptidase Inhibitors, Kazal Type; D025521:Tumor Suppressor Proteins / Q000235:genetics / Q000378:metabolism*; D020798:Two-Hybrid System Techniques
chemical_list: D053491:Proteinase Inhibitory Proteins, Secretory; D011993:Recombinant Fusion Proteins; C473799:SPINK7 protein, human; D000074162:Serine Peptidase Inhibitors, Kazal Type; D025521:Tumor Suppressor Proteins; D008668:Metallothionein