Limiting dilution analysis for detection of residual leukemic cells after bone marrow combined decontamination with mafosfamide followed by merocyanine-540-mediated photosensitization.
Human acute myelogenous or lymphoblastic leukemia cells of the K-562 and CCRF-SB lines were mixed with an excess of normal human bone marrow cells to simulate a leukemia remission marrow. The cell mixtures were then incubated in vitro with mafosfamide (AZ) followed by the photoreactive dye merocyanine-540 (MC). Treated cells (1 x 10(4] were seeded in microwell plates, and increasing numbers of the line used to contaminate the normal marrow were added. Treatment with AZ alone produced total elimination (i.e., 6 logs) of CCRF-SB cells, while addition of merocyanine-540 increased the cloning efficiency from 22% to 24.4%. After treatment of the K-562-contaminated cell mixtures with AZ, nearly 1.6 logs of K-562 acute myelogenous blasts were still present, whereas AZ purging followed by MC-mediated photosensitization resulted in 100% elimination of clonogenic cells. Moreover, the combined treatment caused an increase of the cloning efficiency from 37.3% to 62%, clearly indicating that cleansing by the two agents combined was more effective than treatment with one agent alone.
Porcellini
A
A
Servizio di Ematologia, Medicina II, Centro Trapianto Midollo Osseo, Cremona, Italy.
Rossi
M T
MT
Manna
A
A
Sparaventi
G
G
Pazzaglia
C
C
D000970:Antineoplastic Agents / Q000494:pharmacology*; D001853:Bone Marrow / Q000187:drug effects* / Q000473:pathology; D002460:Cell Line; D003114:Colony-Forming Units Assay; D003520:Cyclophosphamide / Q000031:analogs & derivatives* / Q000494:pharmacology; D004395:Dye Dilution Technique; D006801:Humans; D007938:Leukemia / Q000473:pathology*; D008027:Light; D011744:Pyrimidinones / Q000494:pharmacology*; D011838:Radiation-Sensitizing Agents / Q000494:pharmacology*; D014410:Tumor Stem Cell Assay
D000970:Antineoplastic Agents; D011744:Pyrimidinones; D011838:Radiation-Sensitizing Agents; C003954:merocyanine dye; C048341:mafosfamide; D003520:Cyclophosphamide