Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0026986 (myelodysplastic syndrome)
 14,926 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Cytosine-arabinoside (ARA-C) in low doses induces complete remissions in myelodysplastic syndromes and acute leukemia. Evidence is accumulating that these remissions are not reached by differentiation induction but through cytotoxicity. In HL60 cells differentiation was measured by a comprehensive panel of quantitative and qualitative markers of maturation. After exposure to ARA-C (10(-7) M) for 4 days HL60 cells did not mature morphologically. Cell volume increased. The increase in esterase activity was small and did not reach the amount measured in normal monocytes. There was no significant difference in latex phagocytosis and NBT reduction between cultures with and without ARA-C. HL60 cells were arrested in S-phase and clonogenic capacity persisted. The observed changes after exposure to ARA-C seem to be caused by impeded cell division while synthesis of protein continues. We conclude that ARA-C in low dose exerts its effect by halting proliferation through cytotoxic effects and not by differentiation induction.
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PMID:Low dose cytosine-arabinoside has only minimal differentiation inducing capacity in HL60 cells. 259 48

Low dose Arabinosyl Cytosine (LD ARA-C) is widely used for treatment of acute non-lymphocytic leukemia (ANLL) and myelodysplastic syndrome (MDS) in the elderly, based on a favorable response rate and on the hypothesis that LD ARA-C can induce differentiation or maturation of leukemic cells. We investigated the effect of low concentration of ARA-C on the growth of marrow cells that were obtained from 6 cases of MDS and from 11 cases of ANLL by using the in vitro culture system for normal granulo-monocyte precursors (CFU-GM). At ARA-C concentrations equal to or higher than 1 ng/ml cell growth was inhibited in a dose-dependent manner. At ARA-C concentration of 0.1 ng/ml cell growth was slightly affected, but colony number and colony cell composition were identical to control cultures. This experiment did not support the hypothesis that ARA-C can induce leukemic cells to recover any normal growth patterns but confirmed that even very low ARA-C concentrations can inhibit or slow down leukemic cell proliferation.
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PMID:In vitro exposure of leukemic cells to low concentration Arabinosyl Cytosine: no evidence of differentiation inducing activity. 356 69