A novel apoptotic mechanism of genetically engineered adenovirus-mediated tumour-specific p53 overexpression through E1A-dependent p21 and MDM2 suppression

Yasumoto Yamasaki, Hiroshi Tazawa, Yuuri Hashimoto, Toru Kojima, Shinji Kuroda, Shuya Yano, Ryosuke Yoshida, Futoshi Uno, Hiroyuki Mizuguchi, Akira Ohtsuru, Yasuo Urata, Shunsuke Kagawa, Toshiyoshi Fujiwara

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30 Citations (Scopus)


Oncolytic viruses engineered to replicate in tumour cells but not in normal cells could be used as tumour-specific vectors carrying the therapeutic genes. We previously developed a telomerase-specific oncolytic adenovirus, OBP-301, that causes cell death in human cancer cells with telomerase activities. Here, we further modified OBP-301 to express the wild-type p53 tumour suppressor gene (OBP-702), and investigated whether OBP-702 induces stronger antitumour activity than OBP-301. The antitumour effect of OBP-702 was compared to that of OBP-301 on OBP-301-sensitive (H358 and H460) and OBP-301-resistant (T.Tn and HSC4) human cancer cells. OBP-702 suppressed the viability of both OBP-301-sensitive and OBP-301-resistant cancer cells more efficiently than OBP-301. OBP-702 caused increased apoptosis compared to OBP-301 or a replication-deficient adenovirus expressing the p53 gene (Ad-p53) in H358 and T.Tn cells. Adenovirus E1A-mediated p21 and MDM2 downregulation was involved in the apoptosis caused by OBP-702. Moreover, OBP-702 significantly suppressed tumour growth in subcutaneous tumour xenograft models compared to monotherapy with OBP-301 or Ad-p53. Our data demonstrated that OBP-702 infection expressed adenovirus E1A and then inhibited p21 and MDM2 expression, which in turn efficiently induced apoptotic cell death. This novel apoptotic mechanism suggests that the p53-expressing OBP-702 is a promising antitumour reagent for human cancer and could improve the clinical outcome.

Original languageEnglish
Pages (from-to)2282-2291
Number of pages10
JournalEuropean Journal of Cancer
Issue number14
Publication statusPublished - Sep 1 2012



  • Apoptosis
  • Oncolytic adenovirus
  • P21
  • P53
  • Telomerase

ASJC Scopus subject areas

  • Oncology
  • Cancer Research

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