title: mda-7/IL-24, a novel cancer selective apoptosis inducing cytokine gene: from the laboratory into the clinic.
abstract: An obstacle to effective gene-based cancer therapies is the limited number of cancer-specific growth suppressing and apoptosis-inducing genes. Using a differentiation induction subtraction hybridization (DISH) approach with human melanoma cells, melanoma differentiation associated (mda) genes were isolated that display elevated expression as a function of irreversible growth arrest, cancer reversion and terminal differentiation. This screening paradigm resulted in the cloning of mda-7 in the context of terminal differentiation of human melanoma cells. Based on its structure, chromosomal location, sequence homology and cytokine-like properties, mda-7 has now been renamed IL-24 and classified as a member of the expanding IL-10 cytokine gene family. Expression of mda-7/IL-24 inversely correlates with melanoma progression and administration of mda-7/IL-24 by means of a replication incompetent adenovirus, Ad.mda-7, results in growth suppression and apoptosis in melanoma cells as well as in a broad-spectrum of additional cancer cell types. In contrast, Ad.mda-7 does not elicit deleterious effects in normal cells, including those of epithelial, fibroblast, astrocyte, melanocyte or endothelial origin. Based on these distinctive properties and anti-tumor and anti-angiogenic activities in human tumor xenograft animal models, mda-7/IL-24 has now entered the clinical arena. A Phase I/II clinical trial in patients with advanced carcinomas involving intratumoral administration of mda-7/IL-24 [using a replication incompetent adenovirus; ING241 (Ad.mda-7)] has documented that this gene is safe and well tolerated by patients and a single virus injection elicits apoptosis in a majority of the tumor. Current data suggests that mda-7/IL-24 may function as a dual-acting cytokine in which its normal physiological functions may be related to specific aspects of the immune system and over-expression culminates in cancer-specific apoptosis. This review will provide a prospectus of our current understanding of mda-7/IL-24.
mesh_terms: D000256:Adenoviridae / Q000235:genetics; D000818:Animals; D017209:Apoptosis; D002454:Cell Differentiation; D045744:Cell Line, Tumor; D002986:Clinical Trials as Topic; D016207:Cytokines / Q000378:metabolism; D018450:Disease Progression; D016147:Genes, Tumor Suppressor; D015316:Genetic Therapy; D006801:Humans; D007378:Interleukins / Q000502:physiology*; D008545:Melanoma / Q000378:metabolism / Q000473:pathology; D008954:Models, Biological; D009368:Neoplasm Transplantation; D009369:Neoplasms / Q000188:drug therapy* / Q000473:pathology*; D009389:Neovascularization, Pathologic; D009693:Nucleic Acid Hybridization; D000099180:Interleukin-24
chemical_list: D016207:Cytokines; D007378:Interleukins; D000099180:Interleukin-24