Guanine arabinoside as a bone marrow-purging agent

Area of Science:

• Oncology
• Hematology
• Pharmacology

Background:

• Arabinosylguanine (araG) is a nucleoside analogue with selective toxicity to T lymphoid cells.
• Previous studies demonstrated araG's efficacy in chemoseparation of malignant T lymphoblasts from bone marrow.
• T cell acute lymphoblastic leukemia (ALL) poses challenges in treatment and bone marrow transplantation.

Purpose of the Study:

• To evaluate the efficacy of araG in purging T cells from contaminated bone marrow.
• To assess the safety of araG purging on normal hematopoietic progenitor cells.
• To investigate the potential of araG in reconstituting hematopoietic lineages post-transplantation in a murine model.

Main Methods:

• Treatment of human T leukemia and lymphoblastoid cells with 100 microM araG for 18 hours.
• Utilizing a murine model of T cell ALL with 6C3HED tumor cells.
• Ex vivo purging of contaminated bone marrow with 100 mM araG for 18 hours before transplantation into lethally irradiated mice.

Main Results:

• Up to 6 logs of clonogenic T cells were eliminated without significant toxicity to normal myeloid, erythroid, and megakaryocytoid progenitors.
• Mice receiving araG-purged bone marrow contaminated with T leukemia cells showed long-term survival (>400 days) without relapse.
• Successful reconstitution of lymphoid, myeloid, and erythroid lineages was documented in surviving mice.

Conclusions:

• AraG effectively purges bone marrow of malignant T cells with minimal toxicity to hematopoietic stem cells.
• AraG purging is a potential strategy for T cell malignancies undergoing autologous bone marrow transplantation.
• AraG may serve as a viable option for T cell depletion to prevent graft-versus-host disease.