Deoxycytidine Kinase Expression In Patients With Leukemia, Fludarabine, And Cytarabine Resistance-related Research

ObjectiveFludarabine (Flud) is the firstline agent for chronic lymphocytic leukemia (CLL), and Flud-resistance is one of the predominant reasons for treatment failure. Deoxycytidine kinase (dCK) is the rate-limiting enzyme for Flud conversion to its active form. The study was purposed to explore the relationship between the dCK expression and Flud resistance in patients with CLL.MethodsTotal RNA was extracted from the peripheral blood or bone marrow of 30 CLL patients. Standard curves of dCK andβ-actin were made from the cDNA, which were quantified using real-time quantitative PCR with SYBR Green by Roche LightCycler.β-actin was used as the reference gene, and the relative expression levels of dCK were analyzed by 2 (-ΔCT) method.ResultsIn 18 Flud-sensitive, 12 Flud-resistant CLL patients and 10 normal controls, the median dCK expression level was 118.422 (20.101~928.690), 3.134 (0.098~536.601) and 75.323 (0.269~124.600), respectively. The results showed that dCK expression in the sensitive patients was much higher than that in the resistant one (p=0.001); dCK expression had no relationship with sex, age, Binet stage, IgVH mutations, CD38, ZAP-70 or p53 gene mutation and deletion (p>0.05).ConclusionIt is concluded that low expression or deficiency of dCK might contribute to Flud resistance, and the prognostic significance of dCK expression reserve further investigation. ObjectiveFLAG is one of the firstline regimen for refractory and relapsed acute leukemia (AL). Deoxycytidine kinase (dCK) is the rate-limiting enzyme for fludarabine (Flud) and cytarabine (Ara-C) conversion to their active forms, respectively. The study was to investigate dCK gene expression and its correlation with response to FLAG in refractory/relapsed AL patients.MethodsTotal RNA was extracted from the peripheral blood or bone marrow 20 refractory or relapsed AL. Standard curves of dCK andβ-actin were made from the cDNA, which were quantified using real-time quantitative PCR with SYBR Green by Roche LightCycler.β-actin was used as the reference gene, the relative expression levels of dCK in AL were analyzed by 2 (-ΔCT) method.ResultsIn 9 FLAG-sensitive, 11 FLAG-resistant AL patients and 10 normal controls, the median dCK expression level was 356.484 (126.756~589.220), 10.685(0.224~223.048) and 75.323 (0.269~124.600), respectively. The results showed that dCK expression in the sensitive patients was much higher than that in the resistant one (p=0.001). ConclusionIt is concluded that low expression or deficiency of dCK might contribute to FLAG resistance in refraxtory or relapsed AL patients, and the prognostic significance of dCK expression reserve further investigation.