Status and significance of BCR-ABL1 kinase domain mutations in imatinib-resistant chronic myelogenous leukemia and Philadelphia chromosome-positive acute lymphoblastic leukemia patients from Northeast China / 白血病·淋巴瘤

Objective:To explore the characteristics of BCR-ABL1 kinase domain mutations in imatinib-resistant chronic myelogenous leukemia (CML) and Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph + ALL) patients from Northeast China and their impact on prognosis. Methods:The clinical data of 252 CML patients and 49 Ph + ALL patients who were admitted to the First Hospital of Jilin University from January 2013 to October 2018 were retrospectively analyzed. The samples of bone marrow or peripheral blood were collected from patients when imatinib treatment was not effective. Nested polymerase chain reaction (PCR) was used to amplify the BCR-ABL1 kinase domain, and Sequencing Analysis v5.4 software was used to analyze the mutation of BCR-ABL1 kinase domain. Patients were followed up for 6-48 months, and the survival analysis was performed. Results:Among 252 CML patients, the mutations in ABL1 kinase domain were found in 57 patients (22.6%), including 25 patients in the chronic phase, 21 patients in the accelerated phase and 11 patients in the blast crisis; 50 patients had 20 types of single point mutation, and the most common mutation types were E255K (16.0%, 8/50), T315I (14.0%, 7/50), M244V (8.0%, 4/50) and G250E (8.0%, 4/50), which were all concentrated in the P-loop and C-helix domains; 7 patients had double mutations; patients with multiple mutations had the worst prognosis, with a median overall survival (OS) time of 3.2 months. Among 49 Ph + ALL patients, 17 cases (34.7%) were positive for mutations in the BCR-ABL1 kinase domain, 14 patients had 12 types of single point mutation, and 3 patients had multiple mutations; the median OS time of patients with multiple mutations, mutations located in the P-loop and C-helix domains and mutations located in the other domains was 2.0, 8.0 and 18.0 months, and the difference in OS among the three groups was statistically significant ( P < 0.01). Conclusions:Among the imatinib-resistant CML and Ph + ALL patients from Northeast China, point mutations in the P-loop and C-helix domains are most commonly found. Multiple mutations, mutations in the P-loop and C-helix domains are related to the poor prognosis of the patients.

Progress in molecular studies of Ph-positive and Ph-like acute lymphoblastic leukemia / 中国医师杂志

Acute lymphoblastic leukemia (ALL) is a highly heterogeneous disease. The prognosis of adolescents and adults with ALL is worse than that of children with ALL, mainly because of differences in biological characteristics. Molecular markers are of great value on risk stratification, prognosis evaluation, treatment guidance. The good news is with the deepening of studies on pathogenesis of ALL and the introduction of new technologies, novel molecular markers of prognostic relevance continue to be discovered. It was found that increased Sox4 expression was shown to correlate with accelerate leukemia progression. Unfortunately, resistance to medicine is associated with two cyclin-dependent kinase-inhibitor-2AB (CDKN2A/B) deletion.And the deletion of IKZF1 increase risk of relapse. Meanwhile, Ph-like acute lymphoblastic leukemia is characterized by a variety of genetic alterations that activate kinase or cytokine receptor signaling pathway. Identification of these molecular markers will provide important insights into the treatment strategies. This paper reviewed the advance in the Ph-positive ALL and Ph-like ALL.

Progress in molecular studies of Ph-positive and Ph-like acute lymphoblastic leukemia / 中国医师杂志

Acute lymphoblastic leukemia (ALL) is a highly heterogeneous disease.The prognosis of adolescents and adults with ALL is worse than that of children with ALL,mainly because of differences in biological characteristics.Molecular markers are of great value on risk stratification,prognosis evaluation,treatment guidance.The good news is with the deepening of studies on pathogenesis of ALL and the introduction of new technologies,novel molecular markers of prognostic relevance continue to be discovered.It was found that increased Sox4 expression was shown to correlate with accelerate leukemia progression.Unfortunately,resistance to medicine is associated with two cyclin-dependent kinase-inhibitor-2AB (CDKN2A/B) deletion.And the deletion of IKZF1 increase risk of relapse.Meanwhile,Ph-like acute lymphoblastic leukemia is characterized by a variety of genetic alterations that activate kinase or cytokine receptor signaling pathway.Identification of these molecular markers will provide important insights into the treatment strategies.This paper reviewed the advance in the Ph-positive ALL and Ph-like ALL.

Effects of RNAi targeting CDX2 gene expression on biological characters of human leukemia cells and its relevant mechanisms / 天津医药

Objective To detect the effects of siRNA targeting CDX2 gene expression on of BCR-ABL, caspase and Bax expressions, and the mechanisms thereof. Methods According to the earlier experiments, siRNA specifically targeting CDX2 gene (CDX2-siRNA) and the negative control sequence (CDX2-siRNA-NC) were selected, and then were transfected into K562 cells by Roche X-tremeGENE HP DNA Transfection Reagent. The flow cytometry analysis was used to detect the effects of siRNA on cell apoptosis. The expressions of BCR-ABL, caspase-9, Bax mRNA and protein were tested by RT-PCR and Western blot assay. Results MTT and flow cytometry analysis showed that after the silence of CDX2 gene expression, the proliferation of K562 cells was prohibited and the apoptotic rate of K562 cells was distinctly increased compared with that of normal cell group, but the negative control group had no significant change. According to the RT-PCR and Western blot assay, in comparison with the normal cell group and the negative control group, the expression levels of BCR-ABL mRNA and protein were obviously decreased, and the difference was statistic significance. On the other hand, the expressions of caspase-9 and Bax mRNA and protein were significantly higher than those of other two groups (P<0.05). Conclusion CDX2-siRNA can promote apoptosis of K562 cells obviously, and the mechanism is related with the down-regulation of BCR-ABL and the up-regulation of caspase-9 and Bax.

Clinical analysis of bcr-abl fusion gene positive children with acute lymphoblastic leukemia / 白血病·淋巴瘤

Objective To analyze the clinical features of pediatric patients with acute lymphoblastic leukemia(ALL) with bcr-abl fusion gene transcript,and discuss the treatment,prognosis factors of this kind of ALL.Methods Clinical features,treatment and prognosis were studied retrospectively in 7 bcr-abl fusion gene positive ALL patients.bcr-abl fusion gene was detected by reverse transcription polymerase chain reaction (RT-PCR).Results The average age of the 7 patients was 8 years and 1 month old.All of them were common B-immunology ALL.The rate of complete response was 50 ％ after 33 days' treatment.Conclusions The incidence rate of bcr-abl fusion gene positive ALL in pediatric is low.This type of ALL has poor remission,high relapse rate and poor prognosis.

Adherence to treatment with imatinib in chronic myeloid leukemia: a study of the first decade of responses obtained at a Brazilian hospital

Objetive: The aim of this study was to identify the reasons for failure in adherence to imatinib mesylate treatment in chronic myeloid leukemia. Methods: A retrospective review was performed of 100 non-electronic records of patients with Ph+ chronic myeloid leukemia treated with imatinib mesylate. The study period was from January 2001 to January2011. Data were analyzed by Chi-Square and Correspondence analysis using the Statistical Analysis System software package. Results: At the beginning of treatment 41% of patients were in advanced stages of the disease. The unavailability of the drug (44.8%) and myelotoxicity (25.7%) were the most frequent reasons for interruption. The adherence rate was < 90% in 47% of the cases. The low adherence influenced the cytogenetic response (p-value = 0.020) and molecular response (p-value = 0.001). Very high adherence (> 95%) induced complete cytogenetic response, major cytogenetic response and major molecular response. Conclusion: The population of this study obtained lower-than-expected therapeutic responses compared to other studies. .

Chronic myeloid leukemia BCR/ABL1 mutation clonal evolution and treatment strategies / 中华检验医学杂志

Application of imatinib has made a lot of chronic myeloid leukemia (CML) patients longterm survival,but the CML BCR/ABL1 kinase domain mutations (KDM) will result in drug resistance of imatinib.There are many KDM types.The different types appear randomly.The leukemic clone with different KDM characteristics has a certain evolution.In the period of imatinib treatment,a higher degree of drug resistance mutations in cells likely to develop as the dominant clone.It is suggested that the treatment of imatinib-resistant CML in addition to efforts to develop next-generation tyrosine kinase inhibitors outside,but also consider the use of traditional medicine to help cure.

Association of HLA antigens and BCR-ABL transcripts in leukemia patients with the Philadelphia chromosome

OBJECTIVE: This study aimed to verify the association between human leukocyte antigens and the bcr-abl fusion protein resulting from t(9;22)(q34;q11) in chronic leukemia myeloid and acute lymphoblastic leukemia patients. METHODS: Forty-seven bcr-abl positive individuals were evaluated. Typing was performed bymicrolymphocytotoxicity and molecular biological methods (human leukocyte antigens Class I and Class II). A control group was obtained from the data of potential bone marrow donors registered in the Brazilian Bone Marrow Donor Registry (REDOME). RESULTS: Positive associations with HLA-A25 and HLA-B18 were found for the b2a2 transcript, as well as a tendency towards a positive association with HLA-B40 and a negative association with HLA-A68. The b3a2 transcript showed positive associations with HLA-B40 and HLA-DRB1*3. CONCLUSION: The negative association between human leukocyte antigens and the BCR-ABL transcript suggests that binding and presentation of peptides derived from the chimeric protein are effective to increase a cytotoxic T lymphocyte response appropriate for the destruction of leukemic cells.

Effects of celecoxib on bcr-abl fusion protein in chronic myeloid leukemia primary cells / 白血病·淋巴瘤

Objective To explore the effects of celecoxib, a cyclooxygenase-2 (COX-2) specific inhibitor, on the mRNA expression protein expression and protein tyrosine kinase (PTK) activity of bcr-abl fusion gene in chronic myeloid leukemia (CML) primary cells. Methods The primary cells were incubated with various concentration of celecoxib (0, 10, 20, 40, 80, 160 μmol/L) for 36 hours, then the changes of mRNA expression, p210 expression and PTK activity of bcr-abl fusion gene in each group were examined respectively by real time quantitative reverse transcriptase polymerase chain reaction (RQ-RT-PCR), Western blotting and PTK activity analysis. Results The mRNA expression was downregulated with high concentration of celecoxib (80-160 μmol/L), and p210 expression was decreased gradually after increasing celecoxib. The PTK activity was inhibited in a concentration-independent way, and the statistic difference was observed only above 40μmol/L concentration of celecoxib. Conclusion Celecoxib can downregulate mRNA,and the protein expression of bcr-abl fusion gene; and inhibit the PTK activity by defferent extent.

Effects of celecoxib combined with arsenic trioxide on bcr-abl protein and signal transduction in CML primary cells / 白血病·淋巴瘤

Objective To explore the effects of celecoxib combined with arsenic trioxide (As2O3) on the mRNA expression,protein expression and protein tyrosine kinase (PTK) activity of bcr-abl fusion gene and its downstream signal transduction in chronic myeloid leukemia (CML) primary cells.Methods The cells were incubated with celecoxib (40 μmol/L) or As2O3 (2 μmol/L) alone and celecoxib (40 μmol/L) combined with As2O3 (2 μmol/L) for 36 hours.The changes of mRNA expression,p210 expression and PTK activity of bcr-abl fusion gene in each group were examined respectively by real time quantitative reverse transcriptase polymerase chain reaction (RQ-RT-PCR),Western blot and PTK activity analysis.The important proteins STAT1,STAT5 and their phosphorylatic proteins p-STAT1 and p-STAT5 and inhibitor of DNA binding 1 (ID1)a common downstream target of oncogenic tyrosine kinase were also analyzed by Western blot.Results The mRNA expressions in control group,celecoxib group,As203 group and celecoxib combined with As2O3 group were (5.97±0.53) ％,(5.74±0.46) ％,(5.94±0.57) ％ and (3.06±0.41) ％ respectively,and the statistical difference was found only between celecoxib combined with As2O3 group and control group (t =28.35,P =0.00).The similar statistic difference was only observed between the two groups from PTK activity tests (t =4.38,P =0.04).Western blot also showed that p210,STAT1,STAT5,p-STAT1,p-STAT5 and ID1 were more extraordinaryly downregulated by celecoxib combined with As2O3 than others treatments.Conclusion Celecoxib combined with As2O3 can downregulate mRNA,p210 expression,PTK activity of bcr-abl fusion gene and inhibit STAT and ID1 signal transduction pathways in a synergistic way.

Protein transduction domain-oligomerization domain-hemagglutinin fusion proteins inhibit tumorigenicity of chronic myeloid leukemia BaF3-P210 cells in mice / 肿瘤

Objective: To investigate the effect of protein transduction domain-oligomerization domain-hemagglutinin (PTD-OD-HA) fusion proteins on tumorigenic ability of chronic myeloid leukemia (CML) BaF3-P210 cells in mice. Methods: The untreated BaF3-P210 cells and BaF3-P210 cells treated with 40 μmol/L PTD-OD-HA for 48 h were injected into BALB/c mice through the tail vein, respectively. The general status and survival time of mice in each group were observed. The number of peripheral white blood cells (WBCs) was counted. The Wright-Giemsa-stained blood and bone marrow smears were examined. The pathological changes of liver, spleen and lung tissues were observed by HE staining. The expression level of bcr/abl protein in bone marrow cells from mice was determined by Western blotting. Results: The incidence rates of CML in mice in the untreated BaF3-P210 cell group and the PTD-ODHA-treated BaF3-P210 cell group were 90% (9/10) and 80% (8/10), respectively; WBCs counts in the two groups were (44.3±4.8)×109/L and (20.6±3.2) ×109/L (P<0.05), respectively; the expression levels of bcr/abl protein in bone marrow cells in the two groups were 5.13±0.46 and 1.32±0.29 (P<0.05), respectively. The average survivals in the untreated BaF3-P210 cell group and the PTD-OD-HA-treated BaF3-P210 cell group were (101.3±6.2) d and (185.4±8.7) d (P<0.05), respectively. Wright-Giemsa staining showed that the infiltration degree of leukemic cells in bone marrow, liver and spleen was lower in the PTD-OD-HA-treated BaF3-P210 cell group than that in the untreated BaF3-P210 cell group. Conclusion: PTD-OD-HA can inhibit the tumorigenic ability of CML with BaF3-P210 cells in BALB/c mice. Copyright© 2011 by TUMOR.

Growth inhibition of arsenic trioxide in bcr-abl mutant cells and the potential mechanism / 白血病·淋巴瘤

Objective To investigate the effect of arsenic trioxide (ATO) on the growth inhibition of bcr-abl mutant cell lines in vitro and to explore its potential mechanism. Methods The growth inhibition of ATO on bcr-abl wild type cell lines (K562, KBM5 and 32Dp210) and imatinib(IM)-resistant cell lines (K562R, KBM5R, 32Dp210T315I, 32Dp210Q252H, 32Dp210Y253H, 32Dp210M351T and 32Dp210E255K) were measured by trypan blue exclusion. Apoptosis was assayed by AnnexinV and PI staining. Glutathione (CSH) levels were detected by DTNB colorimetry of Glutathione Assay Kit. Results ATO inhibited cell growth in both bcr-abl wild type and IM-resistant mutant type cells in a dose dependent manner. ATO significantly inhibited growth of bcr-abl point mutant cells compared with the corresponding wild type cells, and the IC50 of ATO in mutant cells was lower than that in wild type, while the IC50 in no point mutant cells K562R was not different compared with that in wild type cells K562. The GSH levels in bcr-abl point mutant cells were lower than that in the corresponding wild type cells(P =0.00106-0.0358) , but that in K562 was quite similar with K562R cells(P = 0.315). After depletion of intracellular GSH by using BSO, the growth inhibition of ATO in both bcr-abl point mutant cells and wild type cells was significantly enhanced. Conclusion The growth inhibition of ATO on bcr-abl point mutant cells is remarkably more effective than that on wild type cells, which may be related with intracellular GSH. ATO would be a potential therapeutic select against CML with bcr-abl point mutation including the T315I mutation.

The influence of PTD-OD-HA fusion proteins on apoptosis of bcr/abl positive cell lines / 肿瘤

Objective:To study the influence of protein transduction domain (PTD)-oligomerization domain (OD)-HA fusion proteins on apoptosis of bcr/abl-positive cell lines. Methods:bcr/abl-positive cells were treated with PTD-OD-HA protein. The apoptoses of the cells were detected by flow cytometry (FCM), DNA ladder and transmission electron microscopy (TEM), and the levels of apoptosis-related genes bax and bcl-2 were detected by RT-PCR and Western blotting. Results:FCM examination demonstrated that PTD-OD-HA protein induced the apoptosis of bcr/abl-positive cells; DNA ladder showed that the classic DNA ladders appeared in BaF3-P210 and K562 cells after 48 h treatment with PTD-OD-HA proteins; the apoptoses of BaF3-P210 cells were observed by TEM; the levels of bax in mRNA and protein increased in BaF3-P210 and K562 cells, and bcl-2 decreased. Conclusion:PTD-OD-HA proteins specifically induced the apoptosis of bcr/abl positive cells.

Eosinofilia reacional, leucemia eosinofílica crônica e síndrome hipereosinofílica idiopática / Reactive eosinophilia, chronic eosinophilic leukemia and idiopathic hypereosinophilic syndrome

A eosinofilia é freqüente na prática clínica, principalmente quando os valores estão entre 500 e 1000 eosinófilos/uL e indica a presença de doença parasitária, alérgica ou reação a medicamentos. Afora essas situações, a eosinofilia pode ser devida a doenças do tecido conjuntivo, infecções e, mais raramente, a doença hematológica maligna ou a tumores sólidos. Os critérios estabelecidos na década de 70 para a definição para a definição da síndrome hipereosinofílica idiopática se tornaram insuficientes para caracterizar todas as entidades albergadas sob o termo eosinofilia e, hoje, melhor compreendidas graças aos avanços na biologia celular e molecular, que proporcionaram a caracterização de doenças distintas e que envolvem células das linhagens mieloide e linfoide. Nesse contexto, as eosinofilias sanguíneas são categorizadas como reacionais, clonais e idiopáticas (SHE). O advento de terapia antitirosinoquinase (a exemplo do mesilato de imatinibe), eficaz para os casos com o rearranjo gênico FIP1L1/PDGFR, também abriu novas perspectivas para o controle ideal da leucemia eosinofílica crônica. Daí a importância do diagnóstico preciso e rápido para a indicação terapêutica ideal, antes que se instalem as complicações orgânicas, em especial cardíacas, que são irreversíveis. O presente manuscrito objetiva rever as situações de eosinofilia sanguínea e oferecer uma atualização da investigação diagnóstica e terapêutica.

Mild eosinophilia with values of less than 1000 eosinophils/µL is commonly seen in the clinical practice and can be secondary to parasitic, inflammatory or allergic diseases or to drug reactions. Additionally, eosinophilia may be due to connective tissue disorders, infections and occasionally to hematopoietic malignancies or solid tumors. The criteria established in the 1970s, for the definition of idiopathic hypereosinophilic syndrome is today unsatisfactory to characterize all conditions described as eosinophilia. Now these conditions are better understood due to the evolution of cellular and molecular biology. This knowledge has helped to characterize distinct disorders involving myeloid and lymphoid lineages. Hence, eosinophilia is categorized as reactive, clonal or idiopathic. With the introduction of anti-tyrosine kinase (imatinib mesylate) therapy, which is effective for the FIP1L1/PDGFRa rearrangement, there is a possibility to control or cure chronic eosinophilic leukemia. For this reason, precise and fast diagnosis is necessary for ideal therapeutic decisions before organic lesions that are irreversible, such as heart injury, become established. The aim of this manuscript is to review eosinophilia and offer an update on diagnostic and therapeutic investigations.

The role of BCR/ABL isoforms in the presentations and outcome of Philadelphia-positive acute lymphoblastic leukemia in adult patients / 中华内科杂志

Objective To investigate the difference of clinical characteristics and outcomes between different isoforms of BCR/ABL in adults with Philadelphia-positive acute lymphoblastic leukemia (ALL).Methods The data of 106 adults with Ph+ALL diagnosed in our hospital from January 1, 1996 to December 31, 2007 were reviewed. The difference of clinical characteristics between different subgroups of BCR/ABL was compared and their relation with outcomes was studied. Results The median age of the 106 patients was 34 years and the median white blood cell count at baseline was 28. 5 × 109/L. Comparative analysis demonstrated that patients in p210 group had an older age, higher blood platelet count (BPC) and more frequent occurrence of splenomegaly. Referring to the outcomes, the complete remission (CR) rate of the two groups were 92. 2% and 93.9%, respectively. The median overall survival (OS) and relapse free survival (RFS) in p190 group were 13 months and 10 months, the 1,3-year estimated OS were (54. 7±6. 7)% and (5.5±5.2)%, and the 1,3-year estimated RFS were (40. 2±6. 8)% and (7. 8±6. 7)%,while in p210 group, the median OS and RFS were 15 months and 10 months, respectively, the 1,3-year estimated OS were (65.8±8. 9)% and (14. 5±7.4)%, and the 1,3-year estimated RFS were (48. 3±9. 4)% and (12. 9±7. 7)%. All of the above data had no statistic significance between the two groups.Conclusion Majority of the adults with Ph+ALL is p190 positive and patients with p210 have older age, higher BPC and more frequent occurrence of splenomegaly, while there is no significant difference between p190 group and p210 group in CR rate, RFS and OS.

Imatinib combined with hematopoietic stem cell transplantation or chemotherapy for bcr-abl positive acute lymphoblastic leukemia / 白血病·淋巴瘤

Objective To investigate the efficacy of imatinib combining with allogeneic hematopioetic stem cell transplantation or chemotherapy for bcr-abl positive acute lymphoblastic leukemia (ALL). Methods 12 cases were diagnosed on morphology, cytochemistry, immunophenotype and bcr-abl fusion gene. The induction is imatinib (400 mg/d) combining chemotherapy. 8 cases accepted allogeneic hematopoietic stem cell transplantation after complete remission (CR). If bcr-abl became positive, the patient was treated with imatinib (400～600 mg/d). 3 cases were tested with imatinib alternating chemotherapy after cr. Results 11 patients gained CR, CR rate 91.7 %; 5 patients (41.7 %) became bcr-abl negative through 2 courses induction. 3 cases relapsed after transplantation. 2 cases relapsed in imatinib combining chemotherapy group. The median remission interval is 16 months (imatinib combining transplantation group) and 10 months (imatinib combining chemotherapy group) (P <0.01) respectively. The median survival time is 18 months (imatinib combining transplantation group), and the other group (imatinib combining chemotherapy) is 12 months (P <0.01). Conclusion Imatinib combining chemotherapy achieved high CR rate for the bcr-abl positive ALL. Imatinib combining allogeneic hematopoietic stem cell transplantation is superior to imatinib combining chemotherapy for CR patients.

Evaluating and detection of JAK2V617F point mutation in bcr-abl-negative myeloproliferative disorders / 白血病·淋巴瘤

Objective To study the Janus Kinase 2 V617F (JAK2V617F) point mutation in bcr-abl-negative myeloproliferative disorders (MPD) and explore its clinical significances. Methods Genomic DNA was isolated from bone marrow or peripheral-blood granulocytes. Allelespecific-polymerase chain reactions (AS-PCR), restriction enzyme digestion in combination with PCR product sequencing were performed to detect the mutation in genomic DNA. 110 patients were detected, including 41 with bcr-ablnegative MPD, 25 with bcr-abl-positive chronic myelogenous leukemia (CML), and 44 with acute leukemia.Results JAK2V617F was presented in 11 cases(91.7 %) of 12 polycythemia vera (PV), 8 cases(53.3 %) of 15 essential thrombocythemia(ET), 4 cases (57.1%) of 7 idiopathic myelofibrosis (IMF), while in other patients including 7 hypereosinophilic syndrome (HES), 25 bcr-abl-positive CML, 24 acute myelocytic leukemia (AML), 18 acute lymphoblastic leukemia(ALL), and 2 acute mixed lineage leukemia, JAK2V617F can not be detected. All positive samples and 10 negative samples identified by AS-PCR and restriction enzyme digestion were confirmed further by DNA sequencing. Conclusion The frequency of JAK2V617F mutation was more than 90 % among patients with PV, more than 50 % among patients with ET and IMF. The detection of JAK2V617F mutation will be of great significanees in the diagnosis and differential diagnosis of MPD. This mutation can be a molecular marker of MPD and might be a treatment target in the future.

Primary study of the phenotype and biological characteristics of chronic myelogenous leukemia derived mesenchymal stem cells / 白血病·淋巴瘤

Objective To isolate and study the phenotype and biological characteristics of chronic myelogenous leukemia-derived mesenchymal stem cells. Methods Cultivate the mesenchymal stem cells from chronic myelogenous leukemia in vitro, identify the immunophenotype by fluorescence-activated cell sorter (FACS), and detect the bcr-abl fusion gene by RT-PCR and FISH. Results The mesenchymal stem cells from chronic myelogenous leukemia can express the bcr-abl fusion gene. Conclusion These findings provide the evidence that the rearrangement of bcr-abl gene might happen at least more primitive than CD+34 CD-38 cells.

Killing K562 cells by RNA interference compared with imatinib / 肿瘤研究与临床

Objective To compare RNA interference (RNAi) with imatinib in killing K562 cells. Methods Design effective shRNA sequences special for bcr-abl silencing and insert them into the eukaryotic expression vector for RNAi by gene engineering. The recombinant plasmi(ts were then transfected into K562 cells. 48 hours later, the efficiency of transfection was identified by fluorescent microscope, bcr-abl mRNA level was detected by RT-PCR. Another group of K562 cells were treated respectively by imatinib with different concentration. All groups of K562 cells were finally analyzed in apoptosis, cell proliferation and phosphotyrosine-containing proteins. Results Both RNAi and imatinib induced apoptosis, decreased proliferation and reduced phosphotyrosine-containing proteins. Conclusion BNAi can kill K562 cells successfully as imatinib, and it may be a promising way to treat CML patients in clinic, especially for those who fail in imatinib or other chemotherapy.

Detection of single nucleotide insertion of BCR/ABL region in imatinib-resistant human myelogenous leukemia SR-1 cells

Imatinib mesylate is a selective Bcr/Abl kinase inhibitor and an effective anticancer agent for Bcr/Abl-positive chronic myelogenous leukemia. Most patients in chronic phase maintain durable responses; however, many in blast crisis fail to respond, or relapse quickly. Mutations within the BCR/ABL kinase domain are the most commonly identified mechanism associated with relapse. To overcome the imatinib resistance in CML, many investigators have tried to clarify molecular mechanism for imatinib resistance in cells of patients who failed to respond to imatinib. Our aim was to invesitigate underlying mechanism for imatinib resistance in SR-1 cells, which were derived from a CML patient in blast crisis. We detected the new mutation of BCR/ABL, resulting in premature termination and loss of BCR/ABL fusion protein expression, which might be possible mechanism for the resistance to imatinib in SR-1 cells.