Adenoviral Vectors Targeted to Hepatocellular Carcinoma

  • Author / Creator
    Sharon, David
  • Hepatocellular carcinoma (HCC) is the fifth most common cancer and third leading cause of cancer-related deaths. Due to the low response to current HCC therapy, many studies have been done to identify novel HCC therapeutics. Non-replicating first generation adenovirus (Ad) vectors and conditionally replicating oncolytic Ads have been extensively studied as potential HCC therapies. Several mechanisms have been utilized to target these Ads to HCC cells in order to reduce the potentially high liver toxicity associated with this therapeutic approach. Since the liver-specific miR-122 is downregulated in many HCC cells, the use of RNA interference-mediated post-transcriptional targeting of therapeutic genes by insertion of miR-122 targeted sequences is a promising targeting modality for Ads. Although miR-122-mediated targeting of FGAd vectors encoding pro-apoptotic genes may have potential as therapies for HCC, amplification of these vectors is currently challenging due to the induction of premature apoptosis of the packaging cells. In this study, we have attempted to circumvent this difficulty through post-transcriptional silencing of the apoptotic gene in packaging cells expressing miR-122. We have also utilized miR-122-mediated targeting modality to increase the specificity of oncolytic Ads for HCC cells. Furthermore, we show that HCC selectivity was increased by deletion E1b and VA-RNA genes. While these deletions reduced the activity of the virus, we found that the oncolytic activity of the virus could be enhanced by treatment with 2-aminopurine. Since VA-RNA-deleted Ads are attenuated in HEK293 cells commonly used for packaging virus, we have identified the HCC cell line Hep3B as a potential alternative for the amplification of these Ads. In our studies presented here, we have examined systems to increase the concentrations of first-generation and oncolytic Ads that are challenging to amplify. Furthermore, we show that Ads lacking E1b and VA-RNA genes have high potential as a novel targeted HCC therapy.

  • Subjects / Keywords
  • Graduation date
  • Type of Item
  • Degree
    Doctor of Philosophy
  • DOI
  • License
    This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.
  • Language
  • Institution
    University of Alberta
  • Degree level
  • Department
    • Department of Oncology
  • Specialization
    • Experimental Oncology
  • Supervisor / co-supervisor and their department(s)
    • Hitt, Mary M (Oncology)
  • Examining committee members and their departments
    • Shaw, Andrew (Oncology)
    • Fu, YangXin (Oncology)
    • Smiley, James (Medical Microbiology and Immunology)
    • Mymryk, Joe (University of Western Ontario, Oncology)