Effect of aspirin administration on reversal of tumor-induced suppression of myelopoiesis in T-cell lymphoma bearing host.

The present investigation studied the effect of aspirin administration in tumor-bearing hosts on bone marrow cellularity and myelopoiesis. Aspirin administration to mice bearing a transplantable T-cell lymphoma, designated as Dalton's lymphoma (DL), augmented proliferation of bone marrow cells (BMC). BMC of aspirin-administered tumor-bearing mice were found to be predominantly in the S phase of cell cycle releasing them from G0/G1 arrest. Aspirin-exposed BMC also showed an altered expression of survival and cell cycle regulatory proteins p53, bcl2, caspase-activated deoxyribonuclease (CAD), cyclin B1 and cyclin D. Moreover, the BMC of aspirin-administered tumor-bearing mice showed an augmented colony-forming ability and differentiation in the macrophage lineage with an activated phenotype of bone marrow-derived macrophages (BMDM) with respect to macrophage-mediated tumoricidal activity and production of nitric oxide, IL-1β, TNFα and VEGF. On the other hand aspirin administration to normal mice showed little effect on bone marrow cellularity and myeloid differentiation. In this model, aspirin had a myelopoetic action in tumor-bearing host.