title: N-myc downstream regulated gene1/Cap43 overexpression suppresses tumor growth by hepatic cancer cells through cell cycle arrest at the G0/G1 phase.
abstract: N-myc downstream regulated gene-1 (NDRG1)/Cap43 regulates tumor growth and metastasis in various carcinomas. In this study we examined whether and how NDRG1/Cap43 modulates tumor growth by human hepatocellular carcinoma (HCC) cells. NDRG1/Cap43 cDNA was used to transfect HCC cell lines (KIM-1), and stable transfectants overexpressing NDRG1/Cap43 (KIM-1/Cap43) were obtained. Cell cycle analysis showed that KIM-1/Cap43 cells were arrested in the G0/G1 phase. Western blot analysis demonstrated an increase in p21 in KIM-1/Cap43 cells in culture under full confluency as compared with KIM-1/Mock. When KIM-1 cells, which are very low in NDRG1/Cap43 expression, were treated with mimosine, a G0/G1 cell cycle blocker, expression of NDRG1/Cap43 was induced in a dose dependent manner, together with p21 induction and CDK4 reduction. In vivo, KIM-1/Cap43 cells showed markedly decreased tumor growth rates compared with those of KIM-1/Mock. Immunohistochemical staining demonstrated markedly higher p21 labeling index in the KIM-1/Cap43 tumor than KIM-1/Mock tumor, and lower CDK4 and Ki-67 labeling index in the KIM-1/Cap43 than KIM-1/Mock. In order to confirm suppressive effects of NDRG1/Cap43, we further established a stable transfectant expressing NDRG1/Cap43 (HAK-1B/Cap43) using another HCC cell line, HAK-1B. Western blot analysis demonstrated an increase in p21 and a decrease in CDK4 in HAK-1B/Cap43 cells in culture under full confluency as compared with HAK-1B/Mock. HAK-1B/Cap43 also showed decreased tumor growth rates as compared with its control counterpart in vivo. NDRG1/Cap43 overexpression thus induced cell cycle arrest at the G0/G1 phase accompanied by increased p21 and decreased CDK4 expression in HCC cells. NDRG1/Cap43 might play a key role in the cell cycle control of G0/G1 in HCC cells.
authors.affiliation: Department of Pathology, Kurume University School of Medicine, 67 Asahi-machi, Kurume 830-0011, Japan. akiba@med.kurume-u.ac.jp
authors.forename: Jun
authors.initials: J
authors.lastname: Akiba
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Murakami
authors.forename: Masaki
authors.initials: M
authors.lastname: Noda
authors.forename: Kosuke
authors.initials: K
authors.lastname: Watari
authors.forename: Sachiko
authors.initials: S
authors.lastname: Ogasawara
authors.forename: Takafumi
authors.initials: T
authors.lastname: Yoshida
authors.forename: Akihiko
authors.initials: A
authors.lastname: Kawahara
authors.forename: Sakiko
authors.initials: S
authors.lastname: Sanada
authors.forename: Makiko
authors.initials: M
authors.lastname: Yasumoto
authors.forename: Rin
authors.initials: R
authors.lastname: Yamaguchi
authors.forename: Masayoshi
authors.initials: M
authors.lastname: Kage
authors.forename: Michihiko
authors.initials: M
authors.lastname: Kuwano
authors.forename: Mayumi
authors.initials: M
authors.lastname: Ono
authors.forename: Hirohisa
authors.initials: H
authors.lastname: Yano
mesh_terms: D000818:Animals; D015153:Blotting, Western; D006528:Carcinoma, Hepatocellular / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D002453:Cell Cycle / Q000187:drug effects; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism*; D049109:Cell Proliferation; D051358:Cyclin-Dependent Kinase 4 / Q000378:metabolism; D050759:Cyclin-Dependent Kinase Inhibitor p21 / Q000378:metabolism; D005260:Female; D016193:G1 Phase / Q000187:drug effects; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism*; D008114:Liver Neoplasms, Experimental / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D008898:Mimosine / Q000494:pharmacology; D016192:Resting Phase, Cell Cycle / Q000187:drug effects; D014162:Transfection; D014183:Transplantation, Heterologous; D047368:Tumor Burden / Q000235:genetics; D000099259:N-myc Downstream-Regulated Gene 1 Protein
chemical_list: D018797:Cell Cycle Proteins; D051358:Cyclin-Dependent Kinase 4; D050759:Cyclin-Dependent Kinase Inhibitor p21; D047908:Intracellular Signaling Peptides and Proteins; D008898:Mimosine; D000099259:N-myc Downstream-Regulated Gene 1 Protein; C493956:CDKN1A protein, human; C495900:CDK4 protein, human