Cancer-associated missense mutations of caspase-8 activate nuclear factor-κB signaling

Mizuo Ando, Masahito Kawazu, Toshihide Ueno, Kazutaka Fukumura, Azusa Yamato, Manabu Soda, Yoshihiro Yamashita, Young L. Choi, Tatsuya Yamasoba, Hiroyuki Mano

Research output: Contribution to journalArticlepeer-review

29 Citations (Scopus)


Head and neck squamous cell carcinoma (HNSCC) is an aggressive cancer with a 5-year survival rate of ~50%. With the use of a custom cDNA-capture system coupled with massively parallel sequencing, we have now investigated transforming mechanisms for this malignancy. The cDNAs of cancer-related genes (n = 906) were purified from a human HNSCC cell line (T3M-1 Cl-10) and subjected to high-throughput resequencing, and the clinical relevance of non-synonymous mutations thus identified was evaluated with luciferase-based reporter assays. A CASP8 (procaspase-8) cDNA with a novel G-to-C point mutation that results in the substitution of alanine for glycine at codon 325 was identified, and the mutant protein, CASP8 (G325A), was found to activate nuclear factor-κB (NF-κB) signaling to an extent far greater than that achieved with the wild-type protein. Moreover, forced expression of wild-type CASP8 suppressed the growth of T3M-1 Cl-10 cells without notable effects on apoptosis. We further found that most CASP8 mutations previously detected in various epithelial tumors also increase the ability of the protein to activate NF-κB signaling. Such NF-κB activation was shown to be mediated through the COOH-terminal region of the second death effector domain of CASP8. Although CASP8 mutations associated with cancer have been thought to promote tumorigenesis as a result of attenuation of the proapoptotic function of the protein, our results now show that most such mutations, including the novel G325A identified here, separately confer a gain of function with regard to activation of NF-κB signaling, indicating another role of CASP8 in the transformation of human malignancies including HNSCC.

Original languageEnglish
Pages (from-to)1002-1008
Number of pages7
JournalCancer Science
Issue number8
Publication statusPublished - Aug 2013
Externally publishedYes

ASJC Scopus subject areas

  • Oncology
  • Cancer Research


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