Successful mafosfamide purging of bone marrow from chronic myelogenous leukemia (CML) cells.
The in vitro sensitivity of human chronic myeloid leukemia-blast crisis and chronic phase (CML-BC and CML-CP, respectively) cells as well as adherent cell-depleted, T lymphocyte-depleted normal bone marrow cells (A-T-NBMC) to various concentrations of mafosfamide (ASTA Z7654), was examined by colony formation assay in the presence of IL-3 and GM-CSF, to test the possibility of purging of BMC from CML cells. Colony formation by CML cells was inhibited more efficiently than by NBMC. After the incubation with 50 micrograms/ml or 100 micrograms/ml of mafosfamide, the growth of leukemic CFU-GM was totally abrogated in 2/11 or 9/11 cases of CML-BC and in 1/7 or 6/7 cases of CML-CP, respectively. At the same time the CFU-GM arising from normal BMC were not inhibited totally with 50 or 100 micrograms/ml of the drug in any of five experiments. CML cells were still unable to form secondary colonies, while normal BMC were capable of regrowth. The CD34+ cells isolated form CML-BC and CML-CP patients were also more susceptible to mafosfamide cytotoxicity in comparison to CD34+ cells derived from NBMC. To confirm the possibility of purging, CML-BC cells were mixed with NBMC (1:1) and incubated with mafosfamide. Finally, the growing colonies were examined for the presence of bcr/abl hybrid gene by reverse transcriptase-Taq polymerase chain reaction (RT-PCR) and specific hybridization. The bcr/abl gene was not detected in the colonies growing after 100 micrograms/ml, and the signal was diminished after incubation with 50 micrograms/ml of mafosfamide, as compared to control. These results strongly suggest that high concentrations of mafosfamide may be useful for the purging of autologous BMC from CML cells.
Nieborowska-Skórska
M
M
Jefferson Cancer Institute, Thomas Jefferson University Hospital, Philadelphia, PA 19107.
Skórski
T
T
Ratajczak
M Z
MZ
Szczylik
C
C
Malaguarnera
L
L
Calabretta
B
B
D000970:Antineoplastic Agents / Q000627:therapeutic use*; D001752:Blast Crisis / Q000473:pathology / Q000628:therapy*; D001853:Bone Marrow / Q000187:drug effects* / Q000473:pathology; D016465:Bone Marrow Purging; D003114:Colony-Forming Units Assay; D003520:Cyclophosphamide / Q000031:analogs & derivatives* / Q000494:pharmacology / Q000627:therapeutic use; D004354:Drug Screening Assays, Antitumor; D006801:Humans; D015466:Leukemia, Myeloid, Chronic-Phase / Q000473:pathology / Q000628:therapy*; D015345:Oligonucleotide Probes; D016133:Polymerase Chain Reaction; D014407:Tumor Cells, Cultured
D000970:Antineoplastic Agents; D015345:Oligonucleotide Probes; C048341:mafosfamide; D003520:Cyclophosphamide; C011272:perfosfamide