A Suicide Gene Therapy Combining the Improvement of Cyclophosphamide Tumor Cytotoxicity and the Development of an Anti-Tumor Immune Response.
Touati W, Tran T, Seguin J, Diry M, Jean-Pierre F, Baillou C, Lescaille G, Andre F, Tartour E, Lemoine FM, Beaune P, de Waziers I. Curr Gene Ther. 2014 Apr
Gene-directed enzyme prodrug therapy (GDEPT) consists in targeted delivery to tumor cells of a suicide gene responsible for in situ conversion of a prodrug into cytotoxic metabolites. One of the major limitations of this strategy in clinical application was the poor prodrug activation capacity of suicide gene. We built a highly efficient suicide gene capable of bioactivating the prodrug cyclophosphamide (CPA) by fusing a CYP2B6 triple mutant with NADPH cytochrome P450 reductase (CYP2B6TM-RED). Expression of this fusion gene via a recombinant lentivirus (LV) vector converted resistant human (A549) and murine (TC1) pulmonary cell lines into CPA-susceptible cell lines. We tested the efficiency of our GDEPT strategy in C57Bl/6 immunocompetent mice, using TC1 cells expressing the HPV-16 E6/E7 oncoproteins. In mice bearing tumors composed only of TC1-CYP2B6TM-RED cells, four CPA injections (140 mg/Kg once a week) completely eradicated the tumors for more than two months. Tumors having only 25% of TC1-CYP2B6TM-RED cells were also completely eradicated by five CPA injections, demonstrating a major in vivo bystander effect. Moreover, surviving mice were rechallenged with parental TC1 cells. The tumors regressed spontaneously 7 days after cell inoculation or grew more slowly than in control naive mice due to a strong immune response mediated by anti-E7CD8+T cells. These data suggest that combining the CYPB6TM-RED gene with CPA may hold promise as a highly effective treatment for solid tumors in humans.
Une nouvelle piste de thérapie génique pour lutter contre le cancer
Le groupe de recherche d’Isabelle de Waziers (Inserm 1147, équipe 1 du CARPEM) vient de publier des travaux prometteurs dans Current Gene Therapy.
L’équipe du Dr de Waziers a mis à profit son expertise dans le domaine du métabolisme des xénobiotiques pour développer une méthode originale de thérapie consistant à sensibiliser les tumeurs à un anticancéreux par transfert d’un gène « suicide ». Cette approche vise à introduire, dans les cellules tumorales, un gène dont le produit permet la transformation in situ d’un médicament inactif (pro-drogue) en métabolites cytotoxiques (Gene-Directed Enzyme Prodrug Therapy : GDEPT). Ils ont produit un lentivirus recombinant exprimant un gène « suicide » (LV-2B6TM-RED) capable de métaboliser très efficacement un anticancéreux, le cyclophosphamide (CPA) en métabolites cytotoxiques. Ils ont montré ex vivo et in vivo que l’expression de ce transgène dans les cellules tumorales (poumon, ORL) les sensibilisait au CPA entraînant une mort des cellules tumorales et une disparition des tumeurs. Enfin, il semble que l’effet cytotoxique du CPA déclenche une réponse immunitaire dirigée contre les cellules tumorales optimisant ainsi la stratégie.“Grâce à ce gène suicide optimisé, le cyclophosphamide est très efficacement transformé en composés toxiques, et ce dans la tumeur elle-même. Les composés toxiques formés peuvent en outre diffuser passivement à travers les membranes des cellules malignes, de sorte qu’un petit nombre de cellules tumorales contenant le transgène est suffisant pour éliminer la tumeur entière “, explique le Dr Isabelle de Waziers
Retrouver l’article de vulgarisation consacré à ces travaux sur le site de l’Inserm
A Suicide Gene Therapy Combining the Improvement of Cyclophosphamide Tumor Cytotoxicity and the Development of an Anti-Tumor Immune Response.
Touati W, Tran T, Seguin J, Diry M, Jean-Pierre F, Baillou C, Lescaille G, Andre F, Tartour E, Lemoine FM, Beaune P, de Waziers I. Curr Gene Ther. 2014 Apr
Gene-directed enzyme prodrug therapy (GDEPT) consists in targeted delivery to tumor cells of a suicide gene responsible for in situ conversion of a prodrug into cytotoxic metabolites. One of the major limitations of this strategy in clinical application was the poor prodrug activation capacity of suicide gene. We built a highly efficient suicide gene capable of bioactivating the prodrug cyclophosphamide (CPA) by fusing a CYP2B6 triple mutant with NADPH cytochrome P450 reductase (CYP2B6TM-RED). Expression of this fusion gene via a recombinant lentivirus (LV) vector converted resistant human (A549) and murine (TC1) pulmonary cell lines into CPA-susceptible cell lines. We tested the efficiency of our GDEPT strategy in C57Bl/6 immunocompetent mice, using TC1 cells expressing the HPV-16 E6/E7 oncoproteins. In mice bearing tumors composed only of TC1-CYP2B6TM-RED cells, four CPA injections (140 mg/Kg once a week) completely eradicated the tumors for more than two months. Tumors having only 25% of TC1-CYP2B6TM-RED cells were also completely eradicated by five CPA injections, demonstrating a major in vivo bystander effect. Moreover, surviving mice were rechallenged with parental TC1 cells. The tumors regressed spontaneously 7 days after cell inoculation or grew more slowly than in control naive mice due to a strong immune response mediated by anti-E7CD8+T cells. These data suggest that combining the CYPB6TM-RED gene with CPA may hold promise as a highly effective treatment for solid tumors in humans.