merocyanine-dye and Precursor-Cell-Lymphoblastic-Leukemia-Lymphoma

In order to evaluate the combined effect of Amifostine and Merocyanine 540 during photoirradiation in neoplastic cells, bone marrow cells from children with acute leukemia (AL), age-matched controls as well as HL-60 cell line were studied. Cell suspensions were incubated with Amifostine, then with MC 540 and they were subsequently exposed to different irradiation doses by Argon Laser 514 nm. Cell survival was estimated by trypan blue supravital stain following a 24-h incubation. The leukemic cell line was studied in continuous liquid cell cultures for 4 weeks. The survival of normal bone marrow progenitors has been estimated by colony formation assay in methylcellulose cultures. Our results showed that Amifostine enhances the photokilling effect of MC 540 on leukemic cells and significantly protects bone marrow nucleated and committed progenitors (BFU-E and CFU-GM) from children with AL under chemotherapy. In conclusion, Amifostine seems to be a promising cytoprotective agent in the clinical use of purging with MC 540 mediated phototherapy.

Topics: Amifostine; Bone Marrow; Bone Marrow Purging; Cell Survival; Drug Therapy, Combination; HL-60 Cells; Humans; Photochemotherapy; Photosensitizing Agents; Precursor Cell Lymphoblastic Leukemia-Lymphoma; Pyrimidinones; Radiation-Protective Agents

The effect of merocyanine 540 (Mc 540) mediated photoirradiation on both neoplastic and normal hemopoietic progenitor cells was studied. Bone marrow (BM) cells from children with acute lymphoblastic leukemia (ALL), acute myeloid leukemia (AML) at initial diagnosis, ALL in remission, neuroblastoma and normal children as well as cells of Reh-6 and HL-60 cell lines were incubated with Mc 540 in the presence of human albumin (HA) and exposed to different argon laser 514 nm doses. Cell survival was estimated using Trypan Blue supravital stain following a 24-h incubation and leukemic cell lines were studied in continuous cell cultures of 4 weeks duration. Our results showed that HA protects normal BM cells from Mc 540 mediated phototoxicity. A 99.9999% inhibition of Reh-6 and HL-60 was noted at irradiation doses where the corresponding mean survival of normal BM cells was 77.4 +/- 12 and 70.3 +/- 10%, respectively. BM leukemic cells from children with ALL and AML were also very sensitive to Mc 540 photoirradiation in contrast to neuroblastoma cells where only a three-fold reduction was observed. Finally, the survival of normal BM progenitors was 38% for colony forming unit erythroid CFU-E, 37% for burst forming unit erythroid BFU-E, 55% for CFU-GM and 29% for CFU-GEMM. In conclusion it seems that Mc 540 mediated photoirradiation in neoplastic cells exerts selective cytotoxicity and can be used in ex vivo purging of malignant cells in BM.

Topics: Bone Marrow; Bone Marrow Cells; Bone Marrow Purging; Cell Line; Cell Survival; Child; Dose-Response Relationship, Radiation; Hematopoietic Stem Cells; HL-60 Cells; Humans; Lasers; Leukemia, Myeloid, Acute; Neuroblastoma; Photolysis; Precursor Cell Lymphoblastic Leukemia-Lymphoma; Pyrimidinones; Radiation-Sensitizing Agents