title: p16 Stimulates CDC42-dependent migration of hepatocellular carcinoma cells.
abstract: Hepatocellular carcinoma (HCC) is a leading cause of cancer-related deaths worldwide. Tumor dissemination to the extra-hepatic region of the portal vein, lymph nodes, lungs or bones contributes to the high mortality seen in HCC; yet, the molecular mechanisms responsible for HCC metastasis remain unclear. Prior studies have suggested a potential link between accumulated cytoplasm-localized p16 and tumor progression. Here we report that p16 enhances metastasis-associated phenotypes in HCC cells - ectopic p16 expression increased cell migration in vitro, and lung colonization after intravenous injection, whereas knockdown of endogenous p16 reduced cell migration. Interestingly, analysis of p16 mutants indicated that the Cdk4 interaction domain is required for stimulation of HCC cell migration; however, knockdown of Cdk4 and Cdk6 showed that these proteins are dispensable for this phenomenon. Intriguingly, we found that in p16-positive HCC samples, p16 protein is predominantly localized in the cytoplasm. In addition, we identified a potential role for nuclear-cytoplasmic shuttling in p16-stimulated migration, consistent with the predominantly cytoplasmic localization of p16 in IHC-positive HCC samples. Finally, we determined that p16-stimulated cell migration requires the Cdc42 GTPase. Our results demonstrate for the first time a pro-migratory role for p16, and suggest a potential mechanism for the observed association between cytoplasmic p16 and tumor progression in diverse tumor types.
authors.affiliation: National Institute of Cancer Research, National Health Research Institutes, Miaoli, Taiwan. ywc@nhri.org.tw
authors.forename: Ya-Wen
authors.initials: YW
authors.lastname: Chen
authors.forename: Hsiao-Chien
authors.initials: HC
authors.lastname: Chu
authors.lastname: Ze-Shiang Lin
authors.forename: Wei-Jyh
authors.initials: WJ
authors.lastname: Shiah
authors.forename: Chen-Pin
authors.initials: CP
authors.lastname: Chou
authors.forename: David S
authors.initials: DS
authors.lastname: Klimstra
authors.forename: Brian C
authors.initials: BC
authors.lastname: Lewis
mesh_terms: D015153:Blotting, Western; D006528:Carcinoma, Hepatocellular / Q000235:genetics / Q000378:metabolism*; D045744:Cell Line, Tumor; D002465:Cell Movement / Q000235:genetics / Q000502:physiology; D049109:Cell Proliferation; D019941:Cyclin-Dependent Kinase Inhibitor p16 / Q000235:genetics / Q000378:metabolism*; D005455:Fluorescent Antibody Technique; D015972:Gene Expression Regulation, Neoplastic; D056945:Hep G2 Cells; D006801:Humans; D008113:Liver Neoplasms / Q000235:genetics / Q000378:metabolism*; D020764:cdc42 GTP-Binding Protein / Q000235:genetics / Q000378:metabolism*
chemical_list: D019941:Cyclin-Dependent Kinase Inhibitor p16; D020764:cdc42 GTP-Binding Protein
references.citation: Cancer Res. 2008 Jan 15;68(2):476-82
references.pmid: 18199542
references.citation: Mutat Res. 2005 Aug 25;576(1-2):22-38
references.pmid: 15878778
references.citation: CA Cancer J Clin. 2011 Mar-Apr;61(2):69-90
references.pmid: 21296855
references.citation: Mod Pathol. 2010 Sep;23(9):1180-90
references.pmid: 20495535
references.citation: Cancer Res. 2007 Aug 15;67(16):7589-96
references.pmid: 17699762
references.citation: Cell. 2008 Jul 25;134(2):215-30
references.pmid: 18662538
references.citation: Oncogene. 1999 Jan 21;18(3):789-95
references.pmid: 9989830
references.citation: Annu Rev Med. 1994;45:297-323
references.pmid: 8198385
references.citation: J Biol Chem. 1999 May 7;274(19):13198-204
references.pmid: 10224076
references.citation: Mol Cell Biol. 2005 Feb;25(4):1228-37
references.pmid: 15684377
references.citation: Breast Cancer Res Treat. 2001 May;67(1):61-70
references.pmid: 11518467
references.citation: Neoplasia. 2004 Jan-Feb;6(1):1-6
references.pmid: 15068665
references.citation: Mol Cell Biol. 1997 Sep;17(9):4967-78
references.pmid: 9271375
references.citation: Cell. 1995 Dec 15;83(6):993-1000
references.pmid: 8521522
references.citation: Gastroenterology. 1999 Feb;116(2):394-400
references.pmid: 9922321
references.citation: Nat Med. 1998 Dec;4(12):1449-52
references.pmid: 9846587
references.citation: Methods Enzymol. 2002;345:349-59
references.pmid: 11665618
references.citation: Genes Dev. 2006 Jun 1;20(11):1511-24
references.pmid: 16705040
references.citation: Nature. 1993 Dec 16;366(6456):704-7
references.pmid: 8259215
references.citation: Br J Cancer. 1998 Dec;78(12):1661-8
references.pmid: 9862580
references.citation: Clin Cancer Res. 1999 May;5(5):977-83
references.pmid: 10353729
references.citation: Nat Genet. 1994 Sep;8(1):27-32
references.pmid: 7726912
references.citation: Cell. 1998 Mar 20;92(6):713-23
references.pmid: 9529248
references.citation: Mol Cell Biol. 2003 Jan;23(1):216-28
references.pmid: 12482975
references.citation: Semin Cancer Biol. 2000 Jun;10(3):185-200
references.pmid: 10936068
references.citation: Proteomics. 2007 Nov;7(22):4102-11
references.pmid: 17955473
references.citation: Nature. 2002 Dec 12;420(6916):629-35
references.pmid: 12478284
references.citation: Cancer Res. 2008 Aug 15;68(16):6779-88
references.pmid: 18701503
references.citation: Nat Rev Cancer. 2006 Sep;6(9):674-87
references.pmid: 16929323
references.citation: J Neurooncol. 2006 May;77(3):273-7
references.pmid: 16614947
references.citation: Lancet. 2003 Mar 15;361(9361):923-9
references.pmid: 12648972
references.citation: Genes Dev. 2004 Apr 15;18(8):862-76
references.pmid: 15078817
references.citation: Clin Cancer Res. 2001 Mar;7(3):544-50
references.pmid: 11297246
references.citation: Am J Pathol. 1998 Dec;153(6):1741-8
references.pmid: 9846965
references.citation: Cell Mol Life Sci. 2007 Nov;64(21):2746-62
references.pmid: 17687513
references.citation: EMBO J. 1999 Apr 15;18(8):2106-18
references.pmid: 10205165
references.citation: J Cancer. 2010 Sep 01;1:126-35
references.pmid: 20922054
references.citation: Clin Cancer Res. 2007 Feb 15;13(4):1133-9
references.pmid: 17317821
references.citation: Science. 1994 Apr 15;264(5157):436-40
references.pmid: 8153634
references.citation: Nat Rev Cancer. 2002 Jun;2(6):442-54
references.pmid: 12189386
references.citation: Hepatology. 1996 Sep;24(3):575-9
references.pmid: 8781327
references.citation: Oncogene. 1997 Oct 23;15(17):2049-57
references.pmid: 9366522
references.citation: Nat Rev Mol Cell Biol. 2001 Oct;2(10):731-7
references.pmid: 11584300
references.citation: PLoS One. 2012;7(8):e43593
references.pmid: 22937066