LEUKEMIA TREATMENT IN SEVERE COMBINED IMMUNODEFICIENCY MICE BY ANTISENSE OLIGODEOXYNUCLEOTIDES TARGETING COOPERATING ONCOGENES

Transformation of hematopoietic cells by the p210(bcr/abl) tyrosine kinase appears to require the expression of a functional MYC protein, suggesting that simultaneous targeting of BCR-ABL and c-myc might be a rational strategy for attempting treatment of Philadelphia(1) leukemia. To test this hypothesis, severe combined immunodeficiency mice injected with Philadelphia(1) leukemic cells were treated systemically with equal doses of bcr-abl or c-myc antisense oligodeoxynucleotides (ODNs) or with both ODNs in combination. Compared with the mice treated with individual agents, the disease process was much slower in the group treated with both ODNs, as revealed by now cytometry, clonogenic assay, and reverse transcriptase-polymerase chain reaction analysis to detect leukemic cells in mouse tissue cell suspensions, and by enumeration of liver metastases. The retardation of the disease process was positively correlated with a markedly increased survival of leukemic mice treated with both ODNs. These data demonstrate the therapeutic potential of targeting multiple cooperating oncogenes.