E1A, E1B double-restricted adenovirus for oncolytic gene therapy of gallbladder cancer.

New treatments, such as gene therapy, are necessary for advanced gallbladder cancer (GBC), but little has been studied. Recent studies have introduced mutant adenoviruses (Ads) with either defective E1B-55kD or mutated E1A, focusing on tumor-specific replication, and the results have been promising. To enhance the safety of this approach, we constructed AxdAdB-3, a double-restricted Ad with a mutant E1A and E1B-55kD deletion. We studied the effects of this Ad in vitro and in vivo on GBC, as well as its safety for normal human cells. We compared the replication and cytopathic effects of AxdAdB-3 in several lines of GBC and primary normal cells with those of wild-type Ad or of AxE1AdB, an E1B-55kD-deleted Ad. The efficacy in vivo was examined in nude mice with s.c. implanted or i.p. disseminated GBC. AxdAdB-3 replicated in and caused oncolysis of GBC cell lines (TGBC-44TKB and Mz-ChA2) as efficiently as wild-type Ad or AxE1AdB in vitro. By contrast, AxdAdB-3 replicated much less effectively in primary normal cells (e.g., epithelial cells, endothelial cells, and hepatocytes) than in GBC cells and had only mild cytopathic effects, unlike wild-type Ad. Furthermore, cytotoxicity of AxdAdB-3 in normal cells was milder than that of AxE1AdB. AxdAdB-3 significantly (P < 0.01) suppressed the growth of GBC (TGBC-44TKB) xenografts. AxdAdB-3 was also effective in the treatment of mice with peritoneally disseminated GBC (TGBC-44TKB), demonstrating tumor-selective replication and oncolysis that resulted in significantly (P < 0.05) prolonged survival. The present study shows that the E1 double-restricted Ad effectively and selectively replicates in and causes oncolysis of GBC in vitro and in vivo with reduced negative effects on normal cells, suggesting that this approach could be a promising tool for gene therapy of GBC.