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J Biol Chem. 2014 Dec 12;289(50):34921-37. doi: 10.1074/jbc.M114.568543. Epub 2014 Oct 20.

p16 Protein and gigaxonin are associated with the ubiquitination of NFκB in cisplatin-induced senescence of cancer cells.

Author information

1
From the Department of Surgery, Veterans Affairs Greater Los Angeles Healthcare System/David Geffen School of Medicine at UCLA, Los Angeles, California 90073.
2
Department of Chemistry and Biochemistry, UCLA, Los Angeles, California 90095.
3
From the Department of Surgery, Veterans Affairs Greater Los Angeles Healthcare System/David Geffen School of Medicine at UCLA, Los Angeles, California 90073, Department of Head and Neck Surgery, David Geffen School of Medicine at University of California Los Angeles, Los Angeles, California 90095.
4
Department of Head and Neck Surgery, David Geffen School of Medicine at University of California Los Angeles, Los Angeles, California 90095.
5
Departments of Anatomy, Physiology, and Genetics, Uniformed Services University, Bethesda, Maryland 20814.
6
Division of Pulmonary and Critical Care Medicine, Department of Medicine, Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, California 90073, Department of Medicine and Jonsson Comprehensive Cancer Center, UCLA, Los Angeles, California 90095.
7
Department of Medicine and.
8
Pathology and Laboratory Medicine, David Geffen School of Medicine at University of California Los Angeles, Los Angeles, California.
9
Department of Psychiatry and Biobehavioral Sciences, UCLA, Los Angeles, California 90095, and.
10
Department of Chemistry and Biochemistry, UCLA, Los Angeles, California 90095, Jonsson Comprehensive Cancer Center, UCLA, Los Angeles, California 90095.
11
From the Department of Surgery, Veterans Affairs Greater Los Angeles Healthcare System/David Geffen School of Medicine at UCLA, Los Angeles, California 90073, Department of Head and Neck Surgery, David Geffen School of Medicine at University of California Los Angeles, Los Angeles, California 90095, Jonsson Comprehensive Cancer Center, UCLA, Los Angeles, California 90095.
12
From the Department of Surgery, Veterans Affairs Greater Los Angeles Healthcare System/David Geffen School of Medicine at UCLA, Los Angeles, California 90073, Jonsson Comprehensive Cancer Center, UCLA, Los Angeles, California 90095 esrivats@ucla.edu.

Abstract

The molecular mechanism of p16-mediated senescence in cisplatin-treated cancer cells is not fully understood. Here we show that cisplatin treatment of head and neck cancer cells results in nuclear transport of p16 leading to a molecular modification of NFκB. Chromatin immunoprecipitation assays show that this modification is associated with the inhibition of NFκB interacting with its DNA binding sequences, leading to decreased expression of NFκB-transcribed proteins. LCMS proteomic analysis of LAP-TAP-purified proteins from HeLa cells containing a tetracycline-inducible GFP-S peptide-NFκB expression system identified gigaxonin, an ubiquitin E3 ligase adaptor, as an NFκB-interacting protein. Immunoblotting and siRNA studies confirmed the NFκB-gigaxonin interaction and the dependence of this binding on p16-NFκB binding. Using gel shift assays, we have confirmed p16-NFκB and gigaxonin-NFκB interactions. Furthermore, we have observed increased NFκB ubiquitination with cisplatin treatment that is abolished in the absence of p16 and gigaxonin expression. Analysis of 103 primary tumors has shown that increased nuclear p16 expression correlates with enhanced survival of head and neck cancer patients (p < 0.0000542), indicating the importance of nuclear p16 expression in prognosis. Finally, p16 expression is associated with reduced cytokine expression and the presence of human papilloma virus in chemoradiation-sensitive basaloid tumors. However, the absence of p16 expression is associated with enhanced cytokine expression and the absence of human papilloma virus in aggressive tumors. These results clearly demonstrate that nuclear p16 and gigaxonin play an important role in chemosensitivity of head and neck cancers through ubiquitination of NFκB.

KEYWORDS:

Cancer Stem Cells; Cellular Senescence; Chemoresistance; Cisplatin; Gigaxonin; Head and Neck Cancer; NFκB; Ubiquitination; p16 Suppressor Gene

PMID:
25331947
PMCID:
PMC4263890
DOI:
10.1074/jbc.M114.568543
[Indexed for MEDLINE]
Free PMC Article

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