Antiangiogenic gene therapy in inhibition of metastasis.

This short review attempts to demonstrate the usefulness of antiangiogenic gene therapy in achieving inhibition of growth in experimentally-induced metastases. Certain normal tissues (for example skeletal muscle) may be used in vivo, after genetic modification, as a "bioreactor", able to produce and secrete into the bloodstream proteins known to exert antiangiogenic effects. By inhibiting neoangiogenesis these proteins would thus prevent the development of metastases. The review discusses also the perspectives of antimetastatic therapy based on certain types of allogenic cells (for example myoblasts and fibroblasts) that had been genetically modified and then microencapsulated. The strategy of encapsulation is aimed at protecting the modified cells secreting antiangiogenic factors from being eliminated by the immune system. Secretion of antiangiogenic proteins by these microencapsulated cells can be controlled with inducible promoters. Antiangiogenic genes remaining under the transcriptional control of such promoters may be switched on and off using antibiotics, such as tetracycline derivatives, or steroid hormones.