M011L-deficient oncolytic myxoma virus induces apoptosis in brain tumor-initiating cells and enhances survival in a novel immunocompetent mouse model of glioblastoma

Alexandra Pisklakova, Brienne McKenzie, Franz Zemp, Xueqing Lun, Rajappa S. Kenchappa, Arnold B. Etame, Masmudur M. Rahman, Karlyne Reilly, Shari Pilon-Thomas, Grant McFadden, Ebba Kurz, Peter A. Forsyth

Research output: Contribution to journalArticlepeer-review

39 Scopus citations


Background Myxoma virus (MYXV) is a promising oncolytic agent and is highly effective against immortalized glioma cells but less effective against brain tumor initiating cells (BTICs), which are believed to mediate glioma development/recurrence. MYXV encodes various proteins to attenuate host cell apoptosis, including an antiapoptotic Bcl-2 homologue known as M011L. Such proteins may limit the ability of MYXV to kill BTICs, which have heightened resistance to apoptosis. We hypothesized that infecting BTICs with an M011L-deficient MYXV construct would overcome BTIC resistance to MYXV. Methods We used patient-derived BTICs to evaluate the efficacy of M011L knockout virus (vMyx-M011L-KO) versus wild-type MYXV (vMyx-WT) and characterized the mechanism of virus-induced cell death in vitro. To extend our findings in a novel immunocompetent animal model, we derived, cultured, and characterized a C57Bl/6J murine BTIC (mBTIC0309) from a spontaneous murine glioma and evaluated vMyx-M011L-KO efficacy with and without temozolomide (TMZ) in mBTIC0309-bearing mice. Results We demonstrated that vMyx-M011L-KO induces apoptosis in BTICs, dramatically increasing sensitivity to the virus. vMyx-WT failed to induce apoptosis as M011L protein prevented Bax activation and cytochrome c release. In vivo, intracranial implantation of mBTIC0309 generated tumors that closely recapitulated the pathological and molecular profile of human gliomas. Treatment of tumor-bearing mice with vMyx-M011L-KO significantly prolonged survival in immunocompetent - but not immunodeficient - mouse models, an effect that is significantly enhanced in combination with TMZ. Conclusions Our data suggest that vMyx-M011L-KO is an effective, well-tolerated, proapoptotic oncolytic virus and a strong candidate for clinical translation.

Original languageEnglish (US)
Pages (from-to)1088-1098
Number of pages11
Issue number8
StatePublished - Aug 1 2016
Externally publishedYes


  • Apoptosis
  • Brain tumor-initiating cells
  • Glioma
  • Oncolytic virus

ASJC Scopus subject areas

  • Oncology
  • Clinical Neurology
  • Cancer Research


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