ABSTRACT
【Objective】 To investigate the expression level of B7-H6 in peripheral blood and bone marrow of patient with chronic myeloid leukemia (CML), and to analyze its association with clinicopathological characteristics and prognosis. 【Methods】 A total of 120 CML patients from January 2010 to May 2013 were selected as study subjects. The expression of B7-H6 mRNA in CML peripheral blood and bone marrow pre- and 3-, 6-, 12-month-posttreatment was detected by quantitative real time PCR, and its correlation between prognosis and clinicopathological factors was analyzed. 【Results】 The expression level of B7-H6 mRNA in the PB, BMMCs of CML patients was lower than that of the normal population (P0.1%(P<0.0001) or without CCR (P<0.001). The expression level of B7-H6 in BMMCs was negatively correlated with the BCR-ABL1/ABL level (r=–0.260, P<0.05). Signifiant difference in PFS was observed between patients with high expression level of B7-H6 (not reached, HR: 0.06, 95% CI =0.03-0.37) and low expression level (81 months, HR: 15.58, 95% CI =2.68-30.23) in BM (P<0.05). 【Conclusion】 The low expression of the B7-H6 gene in CML is correlated with BCR-ABL1 copy number and responsiveness to treatment, and monitoring of B7-H6 expression may be used to evaluate CML prognosis, progression and treatment efficacy.
ABSTRACT
Dasatinib is a highly effective second-generation tyrosine kinase inhibitor used to treat chronic myeloid leukemia (CML). In 2007, a pivotal phase-2 study of dasatinib as second-line treatment was initiated in 140 Chinese CML patients. This report from the 4-year follow-up revealed that 73% of 59 patients in chronic phase (CML-CP) and 32% of 25 patients in accelerated phase (CML-AP) remained under treatment. The initial dosage of dasatinib for CML-CP and CML-AP patients were 100 mg once daily and 70 mg twice daily (total = 140 mg/ day), respectively. The cumulative major cytogenetic response (MCyR) rate among patients with CML-CP was 66.1% (versus 50.8% at 18 months), and the median time to MCyR was 12.7 weeks. All CML-CP patients who achieved MCyR after a 4-year follow-up also achieved a complete cytogenetic response. The cumulative complete hematological response (CHR) rate among patients with CML-AP was 64% (16/25), with three CML-AP patients achieving CHR between 18 months and 4 years of follow-up; the median time to CHR was 16.4 weeks. The adverse event (AE) profile of dasatinib at 4 years was similar to that at 6 and 18 months. The most frequently reported AEs (any grade) included pleural effusion, headache, and myelosuppression. These long-term follow-up data continue to support dasatinib as a second-line treatment for Chinese patients with CML.
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@# Objective: To investigate the effect of down-regulation of miR-221 on cell proliferation and apoptosis of chronic myeloid leukemia (CML) K562 cells and its related regulatory mechanism. Methods: K562 cells were divided into control group, miRNAnegative control (miR-NC) group, miR-221 inhibitor group, miR-221 inhibitor+ negative control siRNA(NC siRNA) group and miR-221 inhibitor+SOCS3 siRNA group. The cells in the control group received no additional treatment. Cells in miR-NC group and miR-221 inhibitor group were transfected with miR-NC and miR-221 inhibitor, respectively. Cells in miR-221 inhibitor+NC siRNA group and miR-221 inhibitor+SOCS3 siRNA group were transfected with NC siRNA and SOCS3 siRNA, respectively, on the basis of successful transfection with miR-221 inhibitor. The transfection efficiency of miR-221 inhibitor was identified by qPCR. Cell viability in each group was measured by CCK-8 assay. Apoptosis in each group was detected by Annexin V-FITC/PI staining using a flow cytometry. The protein expressions of SOCS3, p-JAK1, p-JAK2, p-STAT3 and survivin in each group were detected by WB. Results: Compared with the control group, miR-221 expression was significantly down-regulated in miR-221 inhibitor group (P<0.01), cell viability was significantly reduced at 48 and 72 h after transfection (P<0.05 or P<0.01), the number of apoptotic cells was significantly increased (P< 0.01), the expression of SOCS3 was significantly increased (P<0.01) and the expression levels of p-JAK1, p-JAK2, p-STAT3 and survivin were significantly reduced (all P<0.01). Compared with miR-221 inhibitor group, cell viability was significantly increased at 24, 48 and 72 h after transfection (P<0.05 or P<0.01), the number of apoptotic cells was significantly decreased (P<0.01) and the expression levels of p-JAK1, p-JAK2, p-STAT3 and survivin were significantly increased in miR-221 inhibitor+SOCS3 siRNA group (all P< 0.01). Conclusion: Down-regulation of miR-221 inhibits proliferation and promotes apoptosis of K562 cells, the mechanism of which may be related with up-regulating SOCS3 expression to suppress JAK-STAT3 signaling pathway.
ABSTRACT
Alternative splicing (AS) is a process by which the transcriptome diversity, and thereby the proteome diversity, is augment-ed by splicing or joining together different parts of the pre-mRNA in eukaryotic cells . AS at different splice sites is regulated by multi-ple cis-acting elements and trans-acting factors. Chronic myeloid leukemia (CML) is a clonal myeloproliferative disease in which there is a translocation between the long arms of chromosome 9 and chromosome 22, represented as t(9;22) (q34;q11). This translocation results in the formation of a BCR-ABL fusion gene. Hence it is not surprising that resistance to tyrosine kinase inhibitors, which inhibit BCR-ABL activity, has become a critical problem in the clinical treatment of CML. Using second generation high-throughput sequencing technology, it has been found that AS abnormalities are closely related to the occurrence, progression, drug resistance, and immune escape of CML. This paper reviews the research related to AS and CML resistance and investigates the potential causes of CML resis-tance. Drug resistance mechanisms and potential therapeutic targets are also reviewed.
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Objective To observe the effect of aptamer-siRNA nucleic acid compound on the apoptosis of K562 cells in human chronic myelogenous leukemia (CML)and explore its acting mechanisms.Methods K562 cells were transfected with different concentrations of aptamer-siRNA solution.The effects of aptamer-siRNA on the proliferation and apoptosis of K562 cells were detected by MTT method and AnnexinV/PI double staining method,respectively.The effects of aptamer-siRNA on the expressions of bcl-2,Bax and casepase-3 at protein and mRNA levels in K562 cells were detected by Western blot and RT-PCR method,respectively.Results Compared with the control group,the proliferation of K562 cells was significantly inhibited,early apoptosis rate of K562 cells increased significantly,the expression levels of bcl-2 protein and mRNA were significantly decreased,while the expression levels of Bax and caspase-3 protein and mRNA were significantly increased after transfection with aptamer-siRNA (P <0.05).Aptamer-siRNA nucleic acid complex at the concentration of 50 -250 μmol/L)had a significant dose-effect relationship on bcl-2,Bax and caspase-3 mRNA.Conclusion Aptamer-siRNA nucleic acid compound can promote the decreased number of bcl-2 gene and the growth of Bax and caspase-3 genes,thus promoting the apoptosis of K562 cells.
ABSTRACT
Objective To observe the effect of aptamer-siRNA nucleic acid compound on the apoptosis of K562 cells in human chronic myelogenous leukemia (CML)and explore its acting mechanisms.Methods K562 cells were transfected with different concentrations of aptamer-siRNA solution.The effects of aptamer-siRNA on the proliferation and apoptosis of K562 cells were detected by MTT method and AnnexinV/PI double staining method,respectively.The effects of aptamer-siRNA on the expressions of bcl-2,Bax and casepase-3 at protein and mRNA levels in K562 cells were detected by Western blot and RT-PCR method,respectively.Results Compared with the control group,the proliferation of K562 cells was significantly inhibited,early apoptosis rate of K562 cells increased significantly,the expression levels of bcl-2 protein and mRNA were significantly decreased,while the expression levels of Bax and caspase-3 protein and mRNA were significantly increased after transfection with aptamer-siRNA (P <0.05).Aptamer-siRNA nucleic acid complex at the concentration of 50 -250 μmol/L)had a significant dose-effect relationship on bcl-2,Bax and caspase-3 mRNA.Conclusion Aptamer-siRNA nucleic acid compound can promote the decreased number of bcl-2 gene and the growth of Bax and caspase-3 genes,thus promoting the apoptosis of K562 cells.
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Background & objectives: Imatinib is the standard first-line treatment for chronic myeloid leukaemia (CML) patients. About 20 to 30 per cent patients develop resistance to imatinib and fail imatinib treatment. One of the mechanisms proposed is varying expression levels of the drug transporters. This study was aimed to determine the expression levels of imatinib transporter genes (OCT1, ABCB1, ABCG2) in CML patients and to correlate these levels with molecular response. Methods: Sixty three CML chronic phase patients who were on 400 mg/day imatinib for more than two years were considered for gene expression analysis study for OCT1, ABCB1 and ABCG2 genes. These were divided into responders and non-responders. The relative transcript expression levels of the three genes were compared between these two categories. The association between the expression values of these three genes was also determined. Results: No significant difference in the expression levels of OCT1, ABCB1 and ABCG2 was found between the two categories. The median transcript expression levels of OCT1, ABCB1 and ABCG2 genes in responders were 26.54, 10.78 and 0.64 versus 33.48, 7.09 and 0.53 in non-responders, respectively. A positive association was observed between the expression of the ABCB1 and ABCG2 transporter genes (r=0.407, P<0.05) while no association was observed between the expression of either of the ABC transporter genes with the OCT1 gene. Interpretation & conclusions: Our findings demonstrated that the mRNA expression levels of imatinib transporter genes were not correlated with molecular response in CML patients. further studies need to be done on a large sample of CML patients to confirm these findings.
ABSTRACT
Allogeneic Stem Cell Transplantation (ASCT) remains the unique curative therapy for CML in all clinical phases of the disease. However, the results of Imatinib Mesilate (IM) therapy are sufficiently impressive to have displaced ASCT to second- or third-line treatment depending on the availability of newly developed tyrosine kinase inhibitors. The decision for transplantation depends on a variety of clinical and biological situations. The Leukemia Net recommendations as well the NCCN guidelines help us to choose the best moment to perform ASCT. In 1998, Gratwohl and colleagues published a score in order to establish the risk of ASCT before the procedure. In 2005, the Brazilian group, studying more than 1000 patients in an independent population, validated the risk score previously proposed by the EBMT Group. In this paper we discuss the position of ASCT in a country such as Brazil that presents resource limitations. In 2006, the EBMT published an activity survey about ASCT in CML and discussed the changes in treatment indications over the past 15 years and presented differences in medical conduct in West versus East Europe concerning ASCT indication. Despite of risks, ASCT remains a valid curative treatment. To delay or to perform the ASCT in advanced phases (accelerated- or blastic-phase) increases procedure-related mortality rates and reduces the probability of cure.
O transplante alogênico de célula-tronco hematopoética permanece como a única terapêutica com potencial terapêutico para a LMC in todas as fases da doença. Entretanto, os resultados com a utilização do mesilato de imatinibe são suficientemente impressionantes para deslocar a utilização do transplante para segunda ou mesmo terceira linha de tratamento dependendo da disponibilidade dos novos inibidores de tirosino quinases. A decisão para a indicação do transplante depende da fase clínica e dos achados biológicos. As recomendações da Leukemia Net e as diretrizes da NCCN nos auxiliam a escolher o melhor momento para a elaboração do transplante. Em 1998, Gratwohl e colaboradores publicaram um escore no sentido de estabelecer o risco do transplante antes de sua realização. Em 2005, um grupo brasileiro estudando mais de 1.000 pacientes em uma população independente validou o escore de risco proposto pelo grupo europeu. Neste manuscrito o autor discutirá a posição do transplante em países com limitações de recursos como o Brasil. Em 2006, a mesma escola européia publicou um estudo de monitoramento do transplante e discutiu as mudanças desta modalidade de tratamento nos últimos 15 anos e apresentou as diferenças no comportamento médico na Europa do oeste (mais rica) versus do leste (mais pobre) na indicação e utilização do transplante. A despeito dos riscos, o transplante permanece como uma terapêutica curativa válida. Atrasar a indicação ou realizar o procedimento em fases avançadas, como a fase acelerada ou blástica, aumenta o risco de mortalidade relacionada ao procedimento e reduz a probabilidade de cura.