Different roles of negative and positive components of the circadian clock in oncogene-induced neoplastic transformation

Chiharu Katamune, Satoru Koyanagi, Shoya Shiromizu, Naoya Matsunaga, Shigeki Shimba, Shigenobu Shibata, Shigehiro Ohdo

    Research output: Contribution to journalArticle

    11 Citations (Scopus)

    Abstract

    In mammals, circadian rhythms in physiological function are generated by a molecular oscillator driven by transcriptional-translational feedback loop consisting of negative and positive regulators. Disruption of this circadian clock machinery is thought to increase the risk of cancer development, but the potential contributions of each component of circadian clock to oncogenesis have been little explored. Here we reported that negative and positive transcriptional regulators of circadian feedback loop had different roles in oncogene-induced neoplastic transformation. Mouse embryonic fibroblasts prepared from animals deficient in negative circadian clock regulators, Period2 (Per2) or Cryptochrome1/2 (Cry1/2), were prone to transformation induced by co-expression of H-rasV12 and SV40 large T antigen (SV40LT). In contrast, mouse embryonic fibroblasts prepared from mice deficient in positive circadian clock regulators, Bmal1 or Clock, showed resistance to oncogene-induced transformation. In Per2 mutant and Cry1/2-null cells, the introduction of oncogenes induced expression of ATF4, a potent repressor of cell senescence-associated proteins p16INK4a and p19ARF. Elevated levels of ATF4 were sufficient to suppress expression of these proteins and drive oncogenic transformation. Conversely, in Bmal1-null and Clock mutant cells, the expression of ATF4 was not induced by oncogene introduction, which allowed constitutive expression of p16INK4a and p19ARF triggering cellular senescence. Although genetic ablation of either negative or positive transcriptional regulators of the circadian clock leads to disrupted rhythms in physiological functions, our findings define their different contributions to neoplastic cellular transformation.

    Original languageEnglish
    Pages (from-to)10541-10550
    Number of pages10
    JournalJournal of Biological Chemistry
    Volume291
    Issue number20
    DOIs
    Publication statusPublished - 2016 May 13

    ASJC Scopus subject areas

    • Biochemistry
    • Cell Biology
    • Molecular Biology

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