DNA and All-Trans Retinoic Acid as Immunotherapy or Add-on Adjuvants to 5-Azacytidine In Myelodysplastic Syndromes

• Published in: Blood 2010-11, Vol.116 (21), p.2938-2938
• Main Authors: Le Pogam, Carole, Krief, Patricia, Beurlet, Stéphanie, Reboul, Murielle, West, Robert, Pla, Marika, Charron, Dominique, Fenaux, Pierre, Chomienne, Christine, Padua, Rose Ann
• Format: Article
• Language: English
• ISSN: 0006-4971; 1528-0020
• DOI: 10.1182/blood.V116.21.2938.2938

Abstract 2938 Myelodysplastic syndromes (MDS) are clonal stem cell hematological disorders characterized by ineffective hematopoiesis leading to cytopenia, which evolve to acute myeloid leukemia (AML). The ability of the DNA vaccination to induce effective immune responses has been demonstrated in different preclinical models of diseases. Having previously shown that DNA vaccination with a PMLRARaFrC plasmid in combination with all-trans retinoic acid (ATRA) induced long term remissions with appropriate immune responses in a mouse model of acute promyelocytic leukemia (APL), our aim was to use this strategy in a mouse model of MDS we have created using transgenic mice bearing a mutant NRAS and overexpression of human BCL-2. We used our MDS-like triple transgenic mice bearing NRASD12/MMTVLTRtTA/TetoBCL-2 (Omidvar et al Cancer Res 67:11657-67, 2007). We cloned part of the kanamycin resistance gene and adjacent pVax1 plasmid sequences flipped so the antisense sequences were inserted into the pVax1 vector (named Flipper). These sequences code for 5 polypeptides. We treated the MDS mice with either DNA alone, ATRA alone (10mg daily release for 21 days) or a combination of ATRA+DNA or as add-on therapy with 5-azacytidine (5-aza). 5-aza (5mg/kg) was administered 3 times a week and continued until death. Treatment with ATRA and/or DNA was initiated after 12 courses of 5-aza injections. Sequencing of the Flipper insert predicted 5 peptides, which were synthesized and shown not to affect growth in vitro of myeloid leukemic NB4, K562 and p39 cell lines. In vivo injections of healthy mice with these peptides had no effect on mortality. The inserted sequences did not appear to have detrimental effects. The studies on our MDS mouse model show that DNA vaccination, alone or in combination with ATRA induces a long-term survival of the treated mice compared to untreated controls (p