Cox-2 expression-targeted gene therapy for the treatment of transitional cell carcinoma.

摘要

Targeted gene delivery for induced apoptosis of transitional cell carcinomas was carried out both in vitro and in vivo via utilization of the murine cyclooxygenase type 2 (Cox-2) promoter (Tis10). The non-viral cationic polymer, polyethylenimine (PEI), was used to deliver plasmids coding for various combinations of caspases to Cox-2-overexpressing cancer cell lines in vitro. It was found that the expression of delivered genes, controlled by the Cox-2 promoter, correlated with the expression of the endogenous Cox2 gene in each cell line in a relatively linear manner. Among the various caspase combination regimens, the combination of caspase 3 plus caspase 9 proved to be the most effective because of an apparent synergy between the two gene products, and produced phosphatidylserine flipping in addition to fragmentation of genomic DNA. Caspase 1 appeared to work independently of either caspases 3 or 9, as no synergistic effect was observed. Transfections with genes coding for granzyme B and caspase 8 yielded a lesser amount of cell death.The delivery of the combination of inducible forms of caspases 3 and 9, which remained inactive until a chemical inducer of dimerization was later injected intraperitoneally, were moved to in vivo bladder transitional cell carcinoma research. Significant improvements, in the form of reduced bladder mass, reduced tumor volume, anti-angiogenesis and inhibition of tumor growth were seen in untreated versus unactivated controls. In some instances, tumors were seen to go into complete remission.There were no apparent bystander effects associated with the treatments. Further comparative evaluation of this cox-2 expression-targeted gene therapy method with other treatment, such as celecoxib and Tice-BCG, demonstrated that this gene therapy method could inhibit tumor growth and development much more effectively.