pyrimidinones and edelfosine

Topics: Adolescent; Adult; Animals; Bleomycin; Bone Marrow; Bone Marrow Transplantation; Cell Separation; Child; Child, Preschool; Clinical Trials as Topic; Cyclophosphamide; Drug Evaluation; Etoposide; Graft vs Host Disease; Hematopoietic Stem Cells; Humans; Leukemia; Leukemia, Lymphoid; Lymphoma; Lysophosphatidylcholines; Methylprednisolone; Neoplasms, Experimental; Phospholipid Ethers; Pyrimidinones; Transplantation, Autologous; Transplantation, Isogeneic

Topics: Adolescent; Adult; Animals; Bleomycin; Bone Marrow; Bone Marrow Transplantation; Cell Separation; Child; Child, Preschool; Clinical Trials as Topic; Cyclophosphamide; Drug Evaluation; Etoposide; Graft vs Host Disease; Hematopoietic Stem Cells; Humans; Leukemia; Leukemia, Lymphoid; Lymphoma; Lysophosphatidylcholines; Methylprednisolone; Neoplasms, Experimental; Phospholipid Ethers; Pyrimidinones; Transplantation, Autologous; Transplantation, Isogeneic

Paediatric solid tumours exhibit steep dose-response curves to alkylating agents and are therefore considered candidates for high-dose chemotherapy and autologous stem cell support. There is growing evidence that autologous stem cell grafts from patients with solid tumours are frequently contaminated with live tumour cells. The objective of this study was to perform, in a preclinical purging model, an initial assessment of the safety and efficacy of a two-step purging procedure that combined Merocyanine 540-mediated photodynamic therapy (MC540-PDT) with a brief exposure to the alkyl-lysophospholipid, Edelfosine. Human and murine bone marrow cells and Neuro-2a murine neuroblastoma, SK-N-SH human neuroblastoma, SK-ES-1 and U-2 OS human osteosarcoma, G-401 and SK-NEP-1 human Wilms' tumour, and A-204 human rhabdomyosarcoma cells were exposed to a fixed dose of MC540-PDT followed by a brief incubation with graded concentrations of Edelfosine. Survival was subsequently assessed by in vitro clonal assay or, in the case of CD34-positive haematopoietic stem cells, by an immunohistochemical method. Combination purging with MC540-PDT and Edelfosine depleted all tumour cells by >4 log while preserving at least 15% of murine granulocyte/macrophage progenitors (CFU-GM), 34% of human CFU-GM, and 31% of human CD34-positive cells. The data suggest that combination purging with MC540-PDT and Edelfosine may be useful for the ex vivo purging of autologous stem cell grafts from patients with paediatric solid tumours.

Topics: Animals; Antineoplastic Combined Chemotherapy Protocols; Cell Survival; Dose-Response Relationship, Drug; Hematopoietic Stem Cell Transplantation; Humans; Mice; Neuroblastoma; Osteosarcoma; Phospholipid Ethers; Photochemotherapy; Photosensitizing Agents; Pyrimidinones; Rhabdomyosarcoma; Tumor Cells, Cultured; Wilms Tumor

High-dose chemotherapy combined with autologous stem cell support has improved response rates in high-risk and metastatic breast cancer, but has failed to improve long-term survival. Breast cancer has a tendency to metastasize to the bone marrow, and live tumor cells are known to circulate in the peripheral blood of breast cancer patients. Sensitive immunohistochemical, culture-based, and reverse transcriptase polymerase chain reaction (RT-PCR)-based methods have shown that about 50% of histologically normal stem cell grafts from breast cancer patients are contaminated with occult tumor cells, which may cause or contribute to tumor recurrences. Merocyanine 540 (MC540)-mediated photodynamic therapy (PDT) inactivates a wide range of leukemia and lymphoma cells and is well tolerated by normal hematopoietic stem and progenitor cells. Unfortunately, most solid tumor cells (including breast cancer cells) are only moderately sensitive or refractory to MC540-PDT. We report here that if MC540-PDT is followed by a 1-h incubation with the alkyl-lysophospholipid, Edelfosine (ET-18-OCH(3)), the depletion of murine and human breast cancer cells is greatly enhanced whereas the recovery of normal hematopoietic stem and progenitor cells is only minimally degraded. When used under conditions that reduce CD34-positive human bone marrow cells only 5.1-fold, and murine and human granulocyte/macrophage progenitors 6.8- and 3-fold, respectively, combination purging with MC540-PDT and Edelfosine depletes murine (Mm5MT) and human (MDA-MB-435S) breast cancer cells >17,000- and >125,000-fold, respectively. These data suggest that combination purging with MC540-PDT and Edelfosine may offer a simple, safe and effective method for the ex vivo purging of autologous stem cell grafts from breast cancer patients.

Topics: Animals; Antigens, CD; Antigens, CD34; Antineoplastic Agents; Antineoplastic Combined Chemotherapy Protocols; Breast Neoplasms; Cryopreservation; Female; Hematopoietic Stem Cells; Humans; Mice; Phospholipid Ethers; Photochemotherapy; Pyrimidinones; Radiation-Sensitizing Agents; Tumor Cells, Cultured; Tumor Stem Cell Assay

Short-term exposure to the alkyl-lysophospholipid, rac-2-methyl-1-octadecyl-glycero-(3)-phosphocholine (ET-18-OCH3) or the photosensitizing dye, Merocyanine 540 (MC540) and light kills a wide range of leukemia and some solid tumor cells but is relatively well tolerated by normal pluripotent hematopoietic stem cells as well as certain classes of committed progenitor cells. Both ET-18-OCH3 and MC540-mediated photodynamic therapy (PDT) have been used as purging agents in preclinical models of autologous hematopoietic stem cell transplantation and are currently undergoing phase I/II clinical testing for the same purpose. We report here that ET-18-OCH3 synergistically enhances the MC540-mediated photoinactivation of leukemia cells but only minimally reduces the survival of normal granulocyte-macrophage progenitors. Therapeutic indices are most favorable when MC540-mediated PDT precedes incubation with ET-18-OCH3 and when purging is followed by cryopreservation. Taken together, these data suggest that combination purging with alkyl-lysophospholipid and MC540-mediated PDT may provide a simple, versatile, and effective means of eliminating large numbers of leukemia cells from autologous bone marrow grafts without causing excessive damage to normal hematopoietic stem cells.

Topics: Animals; Antineoplastic Agents; Blood Component Removal; Cell Death; Combined Modality Therapy; Drug Synergism; Hematopoietic Stem Cell Transplantation; Humans; Leukemia; Mice; Phospholipid Ethers; Photosensitizing Agents; Pyrimidinones; Tumor Cells, Cultured