Leukemia stem cells: the root of chronic myeloid leukemia

Chronic myeloid leukemia (CML) is a clonal myeloproliferative disorder characterized by a chromosome translocation that generates the Bcr-Abl oncogene encoding a constitutive kinase activity. Despite remarkable success in controlling CML at chronic phase by Bcr-Abl tyrosine kinase inhibitors (TKIs), a significant proportion of CML patients treated with TKIs develop drug resistance due to the inability of TKIs to kill leukemia stem cells (LSCs) that are responsible for initiation, drug resistance, and relapse of CML. Therefore, there is an urgent need for more potent and safer therapies against leukemia stem cells for curing CML. A number of LSC-associated targets and corresponding signaling pathways, including CaMKII-γ, a critical molecular switch for co-activating multiple LSC-associated signaling pathways, have been identified over the past decades and various small inhibitors targeting LSC are also under development. Increasing evidence shows that leukemia stem cells are the root of CML and targeting LSC may offer a curable treatment option for CML patients. This review summarizes the molecular biology of LSC and its-associated targets, and the potential clinical application in chronic myeloid leukemia.

Triptolide induces apoptosis of human acute T lymphocytic leukemia Jurkat cells via inhibiting transcription of human endogenous retrovirus HERV-K Np9 gene / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the molecular?mechanisms by which triptolide induces apoptosis of human acute T lymphocytic leukemia Jurkat cells.</p><p><b>METHODS</b>MTT assay was employed to detect the proliferation inhibition of Jurkat cells by triptolide, and the IC50 was calculated by OriginPro8. Flow cytometry was used to analyze apoptosis of Jurkat cells. Np9 mRNA levels were detected by RT-PCR and analyzed quantitatively by Kodak 1D 3.6 software. Correlation between the inhibition of Np9 transcription and the cell apoptosis was analyzed by SPSS 19.0.Western blotting was employed to determine Np9 downstream signaling molecules c-myc, β-catenin, ERK, AKT and Notch1 protein level in Jurkat cells after exposure to different concentrations of triptolide for 48 h.</p><p><b>RESULTS</b>Triptolide treatment resulted in dose-dependent inhibition of Jurkat cells proliferation and its IC50 was 12.7 nmol/L. Triptolide induced apoptosis of Jurkat cells in dose- dependent manner. Furthermore, triptolide inhibited Np9 mRNA transcription level in Jurakt cells in a dose-dependent manner. There was a correlation between the triptolide-mediated the apoptosis and the inhibition of Np9 transcription of Jurkat cells (R(2)=0.907). Western blotting results displayed that triptolide inhibited transcription levels of Np9 mRNA with a concomitant decrease of its downstream signaling molecules c-myc, β-catenin, ERK, AKT and Notch1 at protein levels.</p><p><b>CONCLUSION</b>Inhibition of HERV-K Np9 mRNA and its downstream signaling molecules c-myc, β-catenin, ERK, Akt and Notch1 protein might be one of important molecular?mechanisms by which triptolide induces apoptosis of human acute T lymphocytic leukemia Jurkat cells.</p>

CaMKIIγ promotes in vitro and in vivo growth of colorectal cancer cells by upregulating nuclear factor-κB signaling pathway / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the effects of the γ isoform of Ca(2+)/calmodulin-dependent protein kinase II (CaMKIIγ) on colorectal cancer (CRC) cell growth in vitro and in vivo and explore the mechanisms.</p><p><b>METHODS</b>The mRNA levels of CaMKIIγ in 5 CRC cell lines, tumor tissues and matched adjacent tissues from 20 CRC patients were examined by semi-quantitative RT-PCR. The lentiviral vector pLenti6.3-MCS-IRES2-eGFP was used to generate the lentivirus particle Lenti-CaMKIIγ for transfecting SW620 cells. The proliferation ability of the transfected SW620-CaMKIIγ cells was assessed by growth curve and colony formation assay. The expression of IKKα, IKKβ, IKKγ, p-IKKα/β, p-IκB andIκB of the transfected cells were determined by Western blotting, and the expression and localization of nuclear factor-κB (NF-κB) p65 were detected by immunofluorescence. In nude mouse models bearing the transfected SW620-CaMKIIγ cell xenograft, the tumor volume was measured twice a week.</p><p><b>RESULTS</b>CaMKIIγ mRNA showed high expressions in the 5 colorectal cancer cell lines. Eighteen of the 20 tumor tissues showed higher expressions of CaMKIIγ than the adjacent non-tumor tissues. The proliferation of transfected SW620-CaMKIIγ cells was enhanced significantly. CaMKIIγ activated NF-κB signaling pathway and led to NF-κB p65 nuclear translocation. In the tumor-bearing mouse model, the volume of the tumors generated by the transfected SW620-CaMKIIγ cells was 1.46- and 1.68-fold higher than that of the tumors with the control cells at the 8th and 12th day, respectively.</p><p><b>CONCLUSION</b>CaMKIIγ can effectively promote the growth of colorectal cancer cells in vitro and in vivo by activating NF-κB signaling pathway.</p>

The role of peripheral blood, bone marrow aspirate and especially bone marrow trephine biopsy in distinguishing atypical chronic myeloid leukemia from chronic granulocytic leukemia and chronic myelomonocytic leukemia.

OBJECTIVES: To better realize the features of peripheral blood (PB), bone marrow (BM) aspirate and especially BM trephine biopsy in atypical chronic myeloid leukemia (aCML). METHODS: We studied PB, BM smears in 35 cases of aCML and compared with 84 cases of chronic granulocytic leukemia chronic phase (CGL-CP), 39 cases of chronic myelomonocytic leukemia (CMML). In addition, we evaluated characteristics of BM trephine biopsies in 21 cases of aCML and compared with 68 cases of CGL-CP, 20 cases of CMML. RESULTS: All aCML patients presented with leukocytosis (median WBC 17.3 x 10(9)/L), 48% had moderate anemia, and 85% had thrombocytopenia. Values of monocytes, eosinophils, basophils, percentage of immature granulocytes and monocytes (0.63 +/- 0.41 x 10(9)/L, 0.18 +/- 0.16 x 10(9)/L, 0.09 +/-0.08 x 10(9)/L, 6.27 +/- 3.09%, and 2.46 +/- 1.75%, respectively) were useful in distinguishing aCML from CGL-CP and CMML groups. The BM smears showed that striking dysgranulopoieis (100%), dyserythropoiesis (48.6%), percentage of blasts, nucleated erythrocytes, monocytes, eosinophils, and basophils (2.45 +/- 2.06%, 7.76 +/- 2.89%, 1.30 +/- 1.21%, 1.47 +/- 1.60%, and 1.15 +/- 1.08%, respectively) were all important parameters for a diagnosis of aCML. On BM trephine sections, aCML was characterized as hypercellularity, a moderate degree of reticulin fibrosis (71.4%), lymphocytopenia (76.2%), plasmacytopenia (90.5%), abnormal localization of immature precursors (28.5%), and absence of eosinophilia, basophilia, monocytosis. Furthermore, BM imprints, immunohistochemical, and cytochemical staining findings provided important morphological reference to BM trephine sections and made the identification of nucleated cells more convenient. CONCLUSIONS: Besides the findings observed in PB and BM aspirate, features of BM trephine biopsy (including BM trephine section, BM imprint, immunohistochemical, and cytochemical staining) can also aid in the diagnosis of aCML.

Molecular characteristics of leukemia stem cells and up-dating therapeutic strategy / 基础医学与临床

Drug resistance and relapse are two major causes for treatment failure of leukemia, but their mechanisms remain elusive. Recently, increasing evidence shows that there is a subset of leukemia stem cells apart from immature leukemia cells in leukemia patients. These malignant stem cells do not response to routine chemotherapeutic agents, and may be the source of drug resistance and relapse of leukemia. Permanent cure of leukemia need elimination of these leukemia stem cells. We describe molecular characteristics of leukemia stem cells and possible target therapeutic strategies in this review.

Apoptosis induced by berbamine in K562 cells correlates with the expression levels of bcr/abl gene and P210 / 中国病理生理杂志

AIM: To explore the effect of berbamine(BER) on apoptosis in K562 cells and its possible molecular mechanisms. METHODS: The apoptosis rate was measured by flow cytometry while electron microscopy and DNA electrophoresis were used to evaluate the characteristic changes of apoptosis, RT-PCR and Western blot were used to examine the expression levels of apoptosis related gene bcr/abl and BCR/ABL protein. RESULTS: By FCM, the apoptosis rate of K562 cells treated with 8.0 mg/L BER for 24 h and 72 h increased from (29.20?3.82)% to (61.77?4.35)% (P

Activation of caspase-3 during bacterial redox protein azurin -induced apoptosis in U2OS cells / 中国病理生理杂志

AIM: To study whether caspase-3,8 is activated during azurin-induced apoptosis in U2OS cells. METHODS: AnnexinV /PI method was used to detect apoptosis. The changes of procaspase-3 were analyzed by Western blot, the changes of caspase-3 mRNA were detected by semi-quantitative RT-PCR, and caspase-3 relative activity was determined by colorimetric assay. RESULTS: After U2OS cells were treated with 0, 25, 50, 100, 200, 500 mg/L azurin for 24 h, respectively, the level of procaspase-3 protein decreased and the level of caspase-3 mRNA increased as azurin concentration increased. When the cells were treated with 100 mg/L azurin for 6, 12, 24, 48 h , respectively, the caspase-3 activity began to rise from 6 h,reached the peak at 24 h,and was still higher than the control group at 48 h ( P

Modulation of bacterial redox protein azurin induces human osteosarcoma cell apoptosis by Fas antigen and caspase-8 / 中国病理生理杂志

AIM: To determine the role of Fas antigen and caspase-8 in modulating apoptosis of osteosarcoma cells induced by bacterial redox protein azurin. METHODS: The human osteosarcoma cell line U2OS was treated with bacterial redox protein azurin (150 mg/L) for 6, 12, 24 and 48 h, respectively. Cell immunohistochemistry and quantitative image pattern analysis were applied for detecting the expression of Fas antigen. Caspase-8 activity was detected using caspase-8 fluorescent assay kit. The apoptotic rate was measured by FCM. RESULTS: Compared with the control group, the expression of Fas antigen and activity of caspase-8 significantly increased in U2OS cells treated with 150 mg/L azurin (P