P16 Protein and gigaxonin are associated with the ubiquitination of NFκB in cisplatin-induced senescence of cancer cells

Mysore S. Veena, Reason Wilken, Jun Ying Zheng, Ankur Gholkar, Natarajan Venkatesan, Darshni Vira, Sameer Ahmed, Saroj K. Basak, Clifton L. Dalgard, Sandhiya Ravichandran, Raj K. Batra, Noriyuki Kasahara, David Elashoff, Michael C. Fishbein, Julian P. Whitelegge, Jorge Z. Torres, Marilene B. Wang, Eri S. Srivatsan

Research output: Contribution to journalArticlepeer-review

23 Scopus citations


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 hasshownthat 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.

Original languageEnglish (US)
Pages (from-to)34921-34937
Number of pages17
JournalJournal of Biological Chemistry
Issue number50
StatePublished - Dec 12 2014
Externally publishedYes

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology


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