Abnormalities in the expression of the P15 tumor suppressor gene and in cytokine production during the development of secondary hematologic disorders

Abstract

Studies were conducted of p15 methylation and expression and of cytokine levels in bone marrow cells during the development of AML. Surprisingly, the p15 gene was frequently methylated in the marrows of patients who had been cured of lymphoma and in whom hemopoiesis was believed to be normal. The level of methylation increased while the level of expression fell during evolution to MDS and then AML. As we have previously reported the % of bone marrows which contained transcripts for IL1ra fell with the appearance of MDS and fell further with evolution to AML. SCF transcripts in marrow cells fell in parallel while IL1β transcript levels were unchanged during disease evolution. Of interest is the observation that the marrow stromal cells of AML patients contained SCF transcripts while marrow aspirate cells did not. Cytokine protein levels were measured in the PB serum and BM serum of AML patients. SCF levels in both PB and BM serum of AML patients were 50% greater than that present in normal serum while serum ILlra levels were 50% less in AML than in normal. Serum TNFα levels in AML patients also exceeded that present in normal individuals. Both IL1β and IL1ra proteins were measured in normal and AML marrow cells. IL1β protein levels were 3.5 times greater in AML cells than in normal marrow cells while IL1ra levels were 25% less. Considered together, the ratio of IL1β:IL1ra protein levels was 6 times greater in AML and in normal marrow. The administration of IL4, amifostine, the combination of the two, or IL10 consistently increased IL1ra levels in AML serum. SCF serum levels were consistently increased by the administration of IL4, amifostine, IL4+amifostine while the administration of IL10 consistently lowered serum SCF levels. These studies demonstrate significant cytokine abnormalities in AML and that some of these abnormalities can be reversed by the administration of an biological agent. Data will be presented regarding the biologic and therapeutic consequences of the abnormalities described above and of the administration of biologic agents.