Journal of

Background and Aim: Acute promyelocytic leukemia (APL) is associated with the t(1517) ,fusing promyelocytic leukemia (PML) and retinoic acid receptor-a (RARa) genes. This disease is uniquely sensitive to treatment with all-trans retinoic acid (ATRA) and highly responsive to conventional chemotherapy. The t(1117)(q23q21) abnormality associated with a PLZF-RARa rearrangement is the commonest of the alternative translocations accounting for less than 1% APL. Blasts from PLZF-RARa cases have been found to be resistant to the differentiating effects of retinoids. In this study we aimed to determine the PLZF-RARa and fusion genes in patients with APL morphology who referred to Hematology-Oncology and BMT research center, Tehran Shariaty Hospital in 2006.

Materials & Methods: Peripheral blood and/or bone marrow samples were taken from 200 patients with APL morphology and 200 patients with other subtypes of AML. The mono-nuclear cells were enriched by centrifugation over a ficoll-isopaque gradient. RNA extracted by Trizol or TriReagent and then reverse transcribed to cDNA using random primers. PCR performed using specific primers for each fusion. PCR products electerophoresed on a 2% agarose gel containing 0.05% ethidiume bromide.

Results: In 2 (1%) patients with APL-morphology the RT-PCR analysis showed PLZF-RARa fusion transcripts.

Conclusion: It can be concluded that RT-PCR is a rapid and sensitive method for detection of abnormal fusion genes in leukemia and allows the definition of a correct strategy for treatment and subsequent minimal residual disease monitoring

Background and Aim: APL is a Prevalent leukemia that Approximately included 5-10% of patients with acute myeloblastic leukemia. ATRA and recently arsenic is used for treatment. ATRA leadsto resistance to treatment and arsenic is toxic in high doses.AZT induce cell death in different ways. The purpose of this study was Assessment of effect of AZT, a telomerase inhibitor, on NB4 cell line (APL cell line) to reduce toxic effect of high dose arsenic.

Materials and Methods: In this study, viability and metabolic activityof NB4 cells, treated by different concentrations of AZT(50,100,200 µM), was assessed by trypan blue dye method and MTT assay respectively.

Results: Treated cells with AZT=50,100,200µM showed decreased viability, both in dose-dependent and time-dependent through trypan blue dye method and decreased cell metabolic activity by MTT assay.

Discussion and Conclusion: Considering that AZT is able to induce apoptosis and decrease cell activity, it seems AZT is a suitable drug for inhibiting the growth of tumor cells.

Background and Aim: Acute promyelocytic leukemia (APL) is a distinct subtype of acute myeloid leukemia. APL is characterized by a balanced reciprocal translocation between chromosomes 15 and 17, t(517)). Important therapeutic strategies for this disease are ATRA and Arsenic trioxide. To eliminate tumor cells with arsenic, high dose of arsenic is needed. But high dose is toxic for normal tissue. The purpose of this study is Assessment of effect of low dose of arsenic trioxide in combination with AZT on NB4 cell line (APL cell line) to reduce toxic effect of high dose arsenic.

Materials and Methods: In this study after NB4 cell line culture and proliferation, the cells treated with low dose of arsenic trioxide(0.5µM) in combination with different doses of AZT(50, 100, 200 µM) and then viability and metabolic activity was assessed by try pan blue and MTT assay respectively.

Results: Low dose of arsenic (0.5µm) alone and in combination with dose of 50µm of AZT has little effect on viability and metabolic activity but in combination with higher dose of AZT has significant effect on viability and metabolic activity and both viability and metabolic activity significantly reduced.

Conclusion: Different apoptosis- induced mechanisms cause apoptosis by arsenic and AZT. Since some of these mechanisms between AZT and arsenic are similar, so maybe these similar mechanisms cause synergic effect and significant reduction of viability and metabolic activity in combination of these two drugs.

 Background and Aim: A goal of modern cancer research is to reach targeted therapies with drugs having fewer side effects. AZD1152 is a highly specific inhibitor of Aurora Kinase B, which leads to the programmed cell death by different mechanisms. The aim of this study was to evaluate the effects of AZD1152 on viability and metabolic activity of NB4 cells (APL derived cell line).

 Materials and Methods: The cells were treated with various concentrations of AZD1152. After 24, 48 and 72h treatments, the metabolic activity and viability of inhibitor-treated NB4 cells were assessed using MTT and trypan blue dye exclusion assays, respectively. Data were analyzed by applying student’s t-test (Microsoft Excel).

 Results: A t 25, 50 and 100 nM, AZD1152 reduced the metabolic activity by 9.2, 15.5 and 56.2% (after 24h), 10.3, 19.5 and 59.9% (after 48h), and 17.1, 28.4 and 64.8% (after 72h), respectively. Meanwhile, the percentage of viability was decreased to about 51, 45 and 40% (after 24h), 39, 36 and 30% (after 48h), and 34, 32 and 28% (after 72h), respectively.

 Conclusion : According to the results, AZD1152 has substantial efficacy on APL cell line and may be applied in some cases, e. g., for patients who have relapse or who become refractory to the conventional chemotherapy. Further studies are needed to show the molecular mechanisms regulating effects of this anti-cancer agent.

Background and Aim: Acute promyelocytic leukemia (APL) is a distinct type of leukemia which is caused due to a blockage in myeloid cells normal maturation. The most important therapeutic strategies include the use of ATRA and Arsenic trioxide. Although ATRA is generally well tolerated, some patients develop Retinoic acid syndrome. Some of the symptoms of this syndrome are directly or indirectly related to elevated WBC counts. This study aims to determine the effect of ATRA and BIBR1532 combination on WBC count as a factor leading to the formation of ATRA syndrome.

Materials and Methods: To investigate the effect of BIBR1532 and ATRA combination, NB4 cells were cultured in the presence of 30μ M and 1 μM densities of the drugs. To study the effect of drugs on living cells count, proliferation activity, and metabolic activity of the cells, Trypan blue, Brdu and MTT tests were used, respectively.

Results: The results of Trypan blue, MTT and Brdu suggest that the combination of ATRA and BIBR1532 is more effective than ATRA alone on the reduction of viable cell count, metabolic activity and proliferation of leukemic cells in the first five days of treatment.

Conclusion: The results suggest that the combination of ATRA and BIBR1532 is probably more effective in the treatment of APL patients. It seems that such improvement in results is more obvious especially among the patients who are at a higher risk of ATRA syndrome.