Adenoviral Gene Therapy Shows Promise in Cancer Treatment

Strategic Insights -

Recent studies from the United States and Japan have made significant progress in the field of adenoviral gene therapy, showing promise in the treatment of various types of cancers. Researchers have been working to improve the efficacy and safety of adenoviral vectors, which have shown limited clinical efficacy in cancer gene therapy thus far. By modifying the p53 transgene and introducing it into cancer cells, scientists have been able to improve p53 stability and cancer cell killing in vitro.

Key Takeaways:

  • A study from New York University School of Medicine found that modification of the p53 transgene of a replication-competent adenovirus prevents mdm2- and E1b-55kD-mediated degradation of p53, improving p53 stability and cancer cell killing in vitro (Sauthoff et al., 2006).
  • A Phase I/II study from Chiba University in Japan evaluated the safety, feasibility, and biological activity of adenoviral p53 gene therapy in patients with chemoradiation-resistant advanced esophageal squamous cell carcinoma, showing that intratumoral injection of Ad5CMV-p53 is safe and feasible, and results in local antitumor effects (Shimada et al., 2006).
  • Researchers from the University of Alabama used liver tissue slice analysis to assay hepatotoxicity linked to replicative and nonreplicative adenoviral agents, demonstrating that human and mouse liver tissue slices showed a marked increase in extracellular release of aminotransferase enzymes on infection with a conditionally replicative adenovirus, and that apoptosis induction was detected by caspase-3 immunohistochemical staining, TUNEL assay, and microarray analysis (Stoffkhalili et al., 2006).

Statistics:

  • 10 patients with chemoradiation-resistant advanced esophageal squamous cell carcinoma received intratumoral injections of Ad5CMV-p53 in the Phase I/II study, with no dose-limiting toxicity reported (Shimada et al., 2006).
  • 26 cycles of Ad5CMV-p53 treatment were administered in the Phase I/II study, with 9 cases of stable disease and 1 case of progressive disease reported (Shimada et al., 2006).
  • A conditionally replicative adenovirus (Ad Delta 24) showed increased liver toxicity compared to a replication-incompetent adenovirus (Adnull) in liver tissue slice analysis (Stoffkhalili et al., 2006).

Sources:

  • Sauthoff H, Wang Z, McDonald M, et al. (2006) Modification of the p53 transgene of a replication-competent adenovirus prevents mdm2- and E1b-55kD-mediated degradation of p53. Cancer Gene Ther, 13(7), 686-695.
  • Shimada H, Sakai H, Nishi T, et al. (2006) Phase I/II adenoviral p53 gene therapy for chemoradiation resistant advanced esophageal squamous cell carcinoma. Cancer Sci, 97(6), 554-561.
  • Stoffkhalili MA, Genter L, Wall AS, et al. (2006) Employment of liver tissue slice analysis to assay hepatotoxicity linked to replicative and nonreplicative adenoviral agents. Cancer Gene Ther, 13(6), 606-618.