Rac1 mediates behaviors of leukemic cells in response to down-regulation of E-cadherin expression

AIM: To investigate the effect of E-cadherin down-regulation on the behaviors of leukemic cells and its molecular mechanism, and to further determine the role of abnormal interactions between hematopoietic progenitor and bone marrow microenvironment in leukogenesis. METHODS: E-cadherin was silenced via small RNA interference in Raji leukemic cells and 293T stroma cells. The ability of cell-cell adhesion was determined by cell adhesion assay after E-cadherin was knockdown. Adhesion associated proliferation was examined by MTT assay after plating Raji cells onto 293T cells. The expression of Rho GTPase Rac1 was determined by Western blotting. RESULTS: After E-cadherin was silenced in Raji and 293T cells, the ability of cell-cell homophilic adhesion was reduced significantly and the proliferation of Raji cells cultured on 293T cells was promoted significantly. Additionally, siRNA mediated silencing of E-cadherin in Raji cells resulted in up-regulation of Rac1 protein. CONCLUSION: Silencing the expression of E-cadherin in leukemic cells results in decreased adhesion and enhanced proliferation of leukemic cells. Inhibition of E-cadherin expression is responsible for the malignant behaviors of leukemia cells, which may be mediated by Rac1 GTPase.     

Vasculogenic mimicry and E-cadherin expression in epithelial ovarian cancer

AIM: To explore whether vasculogenic mimicry (VM) exists in human epithelial ovarian cancer (EOC), and to elucidate the relationship between E-cadherin (E-cad) expression and VM. METHODS: The E-cad expression and VM in 80 specimens of EOC and 20 specimens of benign ovarian epithelial tumor tissues were detected by the methods of immunohistochemical and histochemical staining. RESULTS: The positive rates of VM and E-cad protein in EOC were 57.4% and 48.7%, respectively.The positive rates of VM and E-cad protein in benign epithelial tumor tissues were 0% and 75.0%, respectively.There was a significant difference between the two groups (P<0.05 or P<0.01). The E-cad expression and VM in EOC was significantly related to differentiation, metastasis to abdominal organ and lymphnode, and PTNM stage (P<0.05). A negative relationship between the expression of E-cad and VM (r=-0.578,P<0.01) was also observed. PTNM stage, metastasis to abdominal organ and lymphnode, the expression of E-cad and VM were independent prognosis factors of EOC patients after total correction (P<0.05). The five-year survival rate between VM-positive group and VM-negative group was significantly different (4.3% vs 88.2%), while the five-year survival rate was significantly lower in E-cad-negative group than that in E-cad-positive group (9.8% vs 71.8%). CONCLUSION: EOC with VM has a poor differentiation and a bad clinical prognosis. The levels of VM and E-cad correlate with the progression and prognosis of EOC.     

Fibrinolytic activity and its mechanisms in various leukemic cell lines

AIM:To study the relation between expression of uPAR and annexinⅡ and fibrinolytic activity in various leukemic cell lines. METHODS:The plasma activity was measured under the reaction between cells of NB4, SHI-1, K562, Jurkat, Raji and plaminogen by chromogenic assay. The protein expressions of uPAR and annexinⅡin cells of NB4, SHI-1, K562, Jurkat, Raji were detected by flow cytometry method. The mRNA expressions of uPAR and annexinⅡin cells of NB4, SHI-1, K562, Jurkat, Raji were detected by RT-PCR. RESULTS:The plasma activity in SHI-1 cells and NB4 cells were higher obviously than that in Raji, K562 and Jurkat cells. The protein expression ratio of uPAR and annexinⅡ in NB4 cells were (13.15±1.61)% and (95.97±1.19)%， respectively, they were (99.00±0.26)%, (90.35±2.15)% respectively in SHI-1 cells, and they were lower in K562, Jurkat, Raji cells. The expression of annexinⅡ mRNA in NB4 cells was higher than that in SHI-1 cells, and they were undectectable in K562 and Jurkat cells. The expression of uPAR mRNA in NB4 and SHI-1 cells were higher than that in Jurkat and K562 cells. The expression of uPAR mRNA in Raji cells was undectectable. CONCLUSION:The primary hyperfibrinolysis in leucocythemia cells was observed, and relation was closely with the expression of annexinⅡ. It might be the main reason for bleeding and disseminated intravascular coagulation in patients with acute promyelocytic leukemia and acute monocytic leukemia.     

MicroRNA-3666 regulates expression of phosphatase and tensin homologue deleted on chromosome ten in leukemic cells

AIM: To explore the regulatory effect of microRNA-3666 (miR-3666) on the expression of its target gene phosphatase and tensin homologue deleted on chromosome ten (PTEN) in leukemic cells. METHODS: miR-3666 expression levels in normal peripheral blood mononuclear cells and leukemic cells were determined by quantitative real-time PCR. miR-3666 targeting PTEN 3-untranslated region (3UTR) was predicted by TargetScan software. 3UTR of PTEN was inserted in the dual luciferase reporter vector psiCHECK2. The reporter activity was evaluated by the Dual-Luciferase Reporter Assay System after the luciferase promoter vector and miRNA were co-transfected into HEK293T cell line. K562 cells were transfected with synthetic miR-3666 inhibitor (anti-miR-3666) or a synthetic control miRNA (anti-miR-C). The expression of PTEN protein in the above transfected K562 cells was determined by Western blotting. RESULTS: miR-3666 was up-regulated in the human leukemic cell lines and primary leukemic cells compared to normal peripheral blood mononuclear cells. The results of dual luciferase assays validated PTEN as a specific target gene of miR-3666. Inhibition of miR-3666 resulted in an up-regulation of PTEN protein expression in the K562 cells. CONCLUSION: miR-3666 is over-expressed in leukemic cells. The abnormal over-expression of miR-3666 may play a key role in leukemia due to the down-regulation of PTEN.     

FAK shRNA inhibits growth of leukemic cell line BCR/ABL-BaF3

AIM: To investigate the effect of focal adhesion kinase (FAK) shRNA on the growth of leukemic cells.METHODS: Lentiviral-FAK-shRNA was transfected into BCR/ABL-BaF3 cells, while empty vector was transfected into the same cells for control. The proteins of FAK and other molecules were detected by Western blotting. Cell growth was observed by culturing the leukemic cells in RPMI-1640 medium in vitro, and colony formation was observed by culturing the leukemic cells in methylcellulose medium. To establish a murine model of leukemia, BCR/ABL-BaF3 cells were injected into BALB/c mice through tail vein. Survival time of the leukemic mice was monitored, and the distribution of the leukemic cells in spleen of the mice was also detected. RESULTS: FAK shRNA inhibited the protein expression of FAK, reduced STAT5 phosphorylation and induced caspases-3 activation in BCR/ABL-BaF3 cells. FAK shRNA inhibited the cell growth in vitro. Colony formation experiment showed that the number of colony in vector control group and FAK shRNA group was 215.60±13.01 and 125.00±9.06, respectively, and the difference was statistically significant (P<0.01). The mice in vector control group died between day 21 and day 27, while the mice in FAK shRNA group died between day 52 and day 60, and the difference was statistically significant (P<0.05). Moreover, 25 days after injection of leukemic cells, the percentage of leukemic cells in spleen of the leukemic mice in vector control group and FAK shRNA group was (82.40±6.13)% and (14.50±3.70)%, respectively (P<0.01). CONCLUSION: FAK shRNA inhibits the growth of leukemic cells in vitro and in vivo, indicating that FAK gene silencing might be a new therapeutic strategy for leukemia.     

DNA ploidy analysis and the expression of TIMP-2 and E-cadherin in gastric carcinoma

AIM:To investigate DNA ploidy and the expression of TIMP-2 and E-cadherin in gastric carcinoma in order to understand its molecular basis and probable mechanism of invasion and metastasis. METHODS:Immunohistochemical methods were used to detect the expression for TIMP-2 and E-cadherin in 99 cases of gastric carcinoma, 16 cases of adjacent noncancerous mucosa, 16 cases of distant metastases and 25 cases of metastatic lymph nodes. Flow cytometry DNA ploidy and S-phase fraction (SPF) analysis was performed on 47 cases of gastric cancer, 6 cases of adjacent noncancerous mucosa and 4 cases of distant metastasis cancer with the use of formalin-fixed paraffin embedded specimens. RESULTS:The expression of TIMP-2 was significantly correlated with Borrmann’s classification, LN metastasis and the depth of invasion. The expression of E-cadherin was significantly correlated with tumor cell differentiation, Lauren’s classification, Borrmann’s classification, LN metastasis and the depth of invasion. There was a positive relationship between DNA aneuploid rate and differentiation and LN metastasis. There was a positive relationship between SPF that is higher than 15% and tumor size, differentiation and LN metastasis. And there was a significantly difference between carcinoma and noncarcinoma when the expression of E-cadherin, DNA aneuploid rate and SPF were analyzed. There was no correlation between TIMP-2 and E-cadherin. There was a positive relationship between DNA ploidy or SPF and the expression of E-cadherin. CONCLUSION:As the development of tumor progression and heterogeneity, the abnormal expression of TIMP-2 or E-cadherin or the rate of DNA aneupoid or higher SPF gradually correspondingly increases, suggesting that they play a crucial role in gastric carcinoma progression. Furthermore, each factor influences one another and further accelerates the process of tumor progression.     

Influence of human mutant p27 gene on the biological behaviors of colorectal cancer cells

AIM: To observe the influence of human mutant p27 gene (p27mt) on the growth and so as to investigate the function and mechanism of p27mt in gene therapy for colorectal cancer.METHODS: Colorectal cancer cell line SW480 was infected with recombinant replication defective adenovirus Ad-p27mt,and expression of p27mt protein was detected by Western blotting.The inhibitory effect of p27mt on SW480 and cell cycle were determined by flow cytometry,and DNA fragment was analyzed to identify the occurrence of apoptosis.RESULTS: After transfected with Ad-p27mt,p27 protein was highly expressed in SW480 cells.77.96% colorectal cancer cells were blocked in phase G₀/G₁,while in Ad-LacZ group and blank control group,27.57% and 25.29% cells were blocked in the same phase,respectively.Growth curve showed Ad-p27mt had an obviously inhibitory effect on the growth of SW480 cells.DNA fragment assay demonstrated that p27mt was able to induce the apoptosis of colorectal cancer cells.CONCLUSION: p27mt has an obvious blocking effect on colorectal cancer cell cycle,and most cells are blocked in phase G₀/G₁.This blockage is related with the growth inhibition and apoptosis induced by p27mt.     

Effect of abnormal expression of miR-141 on malignant biological behaviors of human hepatocarcinoma cells

AIM: To investigate the expression of microRNA-141 (miR-141) in human hepatocellular carcinoma (HCC) cell line SMMC-7721 and normal hepatocyte line HL-7702, and to analyze the effect of abnormal expression of miR-141 on the malignant biological behaviors of human hepatocarcinoma cells. METHODS: The RNA from SMMC-7721 cells and HL-7702 cells was extracted. SYBR Green real-time PCR was performed to detect the expression of miR-141. Synthetic miR-141 mimic and its negative control were transfected into the SMMC-7721 cells, and miR-141 inhibitor and its negative control were transfected into the HL-7702 cells by the method of Lipofectamine. After transfection, MTS assay and BrdU-ELISA were employed to evaluate the effect of miR-141 on the cell proliferation. Flow cytometry was used to detect cell cycle and apoptosis. The changes of migration ability were investigated by Transwell invasion assay. RESULTS: The expression of miR-141 in the SMMC-7721 cells was significantly lower than that in the HL-7702 cells (P < 0.05). Compared with blank group, Lipofectamine group and negative control group, the proliferation of the SMMC-7721 cells transfected with 25 nmol/L miR-141 mimic was significantly inhibited in a time-dependent manner (P < 0.05). The percentages of G₁ phase cells and early apoptotic rate were significantly increased when miR-141 was up-regulated, but the migration ability was inhibited (P < 0.05). Compared with blank group, Lipofectamine group and negative control group, the proliferation of HL-7702 cells transfected with 50 nmol/L miR-141 inhibitor was significantly increased in a time-dependent manner (P < 0.05). When miR-141 was down-regulated, the percentages of G₁ phase cells and early apoptotic rate were significantly decreased, but the migration ability was enhanced (P < 0.05). CONCLUSION: miR-141 is down-regulated in human hepatocarcinoma cell line. Up-regulation of miR-141 will not only inhibit cell proliferation and migration ability, but also affect the cell cycle and apoptosis of SMMC-7721 cells. miR-141 may function as a tumor suppressor gene during HCC development.     

Correlation between E-cadherin and FOXO3a expression in gastric can-cer tissues and cells

AIM: To investigate the expression of E-cadherin and forkhead box protein O3a (FOXO3a) in gastric cancer tissues and cells, and its correlation with cell viability. METHODS: The expression of E-cadherin and FOXO3a was detected by immunohistochemical staining in 53 specimens of gastric cancer tissues and their adjacent tissues, and the relationship between their expression and clinicopathological characteristics were analyzed. E-cadherin-over-expressing gastric cancer AGS cells were constructed by lentivirus-mediated cell transfection, and the protein expression of E-cadherin and FOXO3a was detected by immunocytochemistry method. The expression of E-cadherin, FOXO3a, Akt, Bcl-2 and Bax was determined by Western blot. The cell viability was detected by CCK-8 assay. RESULTS: The positive expression rates of E-cadherin and FOXO3a proteins in gastric cancer tissues were both significantly lower than those in their adjacent tissues (P<0.05). E-cadherin positive expression in gastric cancer tissues was significantly related to tumor grade and TNM stage (P<0.05), but not related to age, sex, location, T stage or lymph node metastasis. FOXO3a positive expression was significantly related to tumor grade (P<0.05), but not related to age, sex, location, TNM stage, T stage or lymph node metastasis. The expression of E-cadherin was positively correlated with FOXO3a expression in gastric cancer tissues (r=0.376, P=0.003). After over-expression of E-cadherin, the viability of gastric cancer AGS cells was significantly inhibited, the expression of FOXO3a, Bcl-2 and Bax was significantly increased, and the expression of Akt was significantly decreased. CONCLUSION: E-cadherin and FOXO3a are involved in the development of gastric cancer, and E-cadherin may affect the viability of gastric cancer cells by regulating Akt/FOXO3a signaling pathway.     

Effects of ZIP14 on biological behaviors of hepatocellular carcinoma cell line BEL-7404

AIM: To study the expression of zinc transporter ZRT/IRT-like protein 14 (ZIP14) in the hepatocellular carcinoma (HCC) tissues, and to investigate the effects of ZIP14 over-expression on the biological behaviors of HCC cells. METHODS: The expression of ZIP14 at mRNA and protein levels in the HCC tissues and adjacent non-tumor tissues were detected by real-time PCR and immunohistochemical staining, respectively. The lentivirus expression system containing GV365-ZIP14 was constructed, and was used to infect the HCC cell line BEL-7404, which had relatively poor expression of ZIP14. The expression of ZIP14 at mRNA and protein levels in the transfected cells were detected by real-time PCR and Western blot, respectively. Under the conditions of zinc sulfate stimulation at different concentrations, the cell viability, the cell cycle, and the cell migration and invasion abilities were detected by MTT assay, DNA ploid detection, and Transwell assay, respectively. RESULTS: The mRNA expression level and the strong-positive rate of protein expression of ZIP14 in the HCC tissues were significantly lower than those in the adjacent non-tumor liver tissues (P<0.01). The expression of ZIP14 at mRNA and protein levels in the BEL7404 cells was significantly enhanced by infection of GV365-ZIP14 expression lentivirus. Compared with negative control group (transfected with negative control lentivirus), the cell viability, migration and invasion in ZIP14 over-expression group (transfected with GV365-ZIP14 expression lentivirus) were significantly reduced, and the percentage of the cells in G₂/M phase was significantly increased, all of which were more obvious with the elevation of zinc concentration in the culture medium. CONCLUSION: ZIP14 is low expressed in the HCC tissues. The ZIP14 over-expression has inhibitory effects on the viability, migration and invasion of HCC cells, and blocks the cell cycle in G₂/M phase, which might be closely related to the elevation of zinc concentration in cytoplasma of HCC cells due to enchanced zinc transport by ZIP14.     

Reverse effects of saikoside on multidrug resistance of human leukemic cell line K562/ADM in vitro

AIM: To study the reverse effects of saikoside (SS) on the multidrug resistance (MDR) of human leukemic cell line K562/ADM and to investigate the related mechanism. METHODS: K562 cells and K562/ADM cells in the culture were treated with SS at the concentrations of 1~100 mg/L. The inhibitory rate of the cell proliferation was measured by MTT assay. Non-cytotoxic dose of SS was determined. K562/ADM cells were treated with SS at non-cytotoxic doses of 1.25, 2.5 and 5.0 mg/L with different concentrations of adriamycin (ADM,0.05~100 mg/L). The 50% inhibitory concentration (IC₅₀) and the reversal index in all groups were determined. The cell morphology was observed after treated with SS+ADM. The effects of SS on ADM accumulation in K562/ADM cells, the cell cycle profile and apoptosis were examined by flow cytometry. RESULTS: The inhibitory rates were significantly increased in a dose-dependent manner when the cells were treated with different doses of SS (1~100 mg/L). The available reversal concentration of SS was 5.0 mg/L and the reversal index was 21.5 folds for K562/ADM cells. After treated with SS+ADM, the number of tumor cells was decreased and apoptotic cells were increased in a dose-response relationship. ADM accumulation in K562/ADM cells treated with SS was significantly higher than that in control cells (P<0.05). SS may significantly enhanced the apoptosis of K562/ADM cells treated with ADM (P<0.05). K562/ADM cells treated with SS were blocked in the stage of G₀/G₁. CONCLUSION: SS has effect on proliferation inhibition and MDR reversal in K562/ADM cell line. The reversal mechanisms of SS may be due to increasing the accumulation of chemo therapeutics in the cell, inducing the cell apoptosis and arresting the cells in G₀/G₁ phase.     

Effects of dexmedetomidine on behaviors and expression of BDNF and mTOR in hippocampus of depressive rats

AIM: To investigate the effects of dexmedetomidine (DEX) on the behaviors and the expression of brain-derived neurotrophic factor (BDNF) and mammalian target of rapamycin (mTOR) in the hippocampus of depressive rats. METHODS: Sprague-Dawley (SD) rats were randomly divided into 5 groups: sham operation group, model group, and DEX (2.5, 5 and 10 μg/kg) groups. The rats were randomly selected in each group (n=12). The rat depression model was established by chronic unpredictable mild stress and ovariectomy. The rats in DEX groups received daily DEX treatment via intraperitoneal injection for 21 d. The forced swimming immobility time (FSIT) and open-field test were used to evaluate the antidepressant effect of DEX. Escape latency and times of crossing the flat were evaluated by Morris water maze. The histological changes of hippocampal neurons were determined by Nissl staining. The mRNA levels of interleukin-1β (IL-1β), IL-6 and tumor necrosis factor-α (TNF-α) were detected by RT-qPCR. The protein expression of IL-1β, IL-6, TNF-α and BDNF, and the phosphorylation levels of protein kinase A (PKA), cAMP response element-binding protein (CREB), tropomyosin-related kinase B (TrkB), phosphatidylinositol 3-kinase (PI3K), protein kinase B (Akt) and mTOR in hippocampus were evaluated by Western blot. RESULTS: Compared with model group, the FSIT was significantly reduced and the spontaneous activity was markedly increased in DEX groups. The damage of the hippocampal neurons was obviously attenuated, the escape latency was obviously decreased, and times of crossing the flat were markedly increased (P<0.05 or P<0.01). The levels of IL-1β, IL-6 and TNF-α were obviously decreased, and the protein levels of p-PKA, p-CREB, BDNF, p-TrkB and p-PI3K, p-Akt, p-mTOR in hippocampal tissues were obviously increased (P<0.05 or P<0.01). CONCLUSION: Dexmedetomidine improves the behaviors and the spatial learning and memory ability of depressive model rats, which may be related to its anti-inflammatory effects, as well as up-regulating the protein levels of BDNF and p-TrkB, and activating PI3K/Akt/mTOR signaling pathway in the hippocampus.     

Effects of Mage-H1 expression on PC12 cell differentiation and cell cycle

AIM: To explore the effects of melanoma-associated antigen H1 (Mage-H1) on cell proliferation and differentiation. METHODS: A phase contrast microscope was used to observe the morphological changes of PC12 cells treated with or without nerve growth factor (NGF). The expression of Mage-H1 in pre-and post-differentiated PC12 cells was detected by RT-PCR and Western blotting, and its potential effects on the cell cycle were analyzed by flow cytometry. RESULTS: After induced by NGF for 8 days, over 92% of PC12 cells were differentiated. The relative levels of Mage-H1 mRNA and protein in the differentiated PC12 cells were 4.6 times and 2.6 times higher than those in control cells,respectively. Moreover, the PC12 cells transiently expressed Mage-H1 were significantly arrested in G₀-G₁ phase as compared to the cells transfected with an empty vector.CONCLUSION: Mage-H1 inhibits the proliferation of PC12 cells and promotes the differentiation of the cells.     

Effect of Jieyuwan on depression-like behaviors and expression of BDNF in hippocampus and prefrontal cortex of WKY rats

AIM:To investigate the mechanism of depression and its development, and to study the expression of brain-derived neurotrophic factor (BDNF) in the hippocampus and prefrontal cortex of Wistar-Kyoto (WKY) rats treated with Jieyuwan. METHODS:Adult male WKY rats were used as an animal model of endogenous depression. Wistar rats of the same strain were selected as control group. WKY rats were randomly divided into model group, citalopram group and Jieyuwan group. After intragastric administration for 21 d, the changes of depression-like behaviors were observed by sucrose preference test and forced swimming test. Immunofluorescence and Western blot were used to detect the expression of BDNF in the hippocampus and prefrontal cortex. RESULTS:WKY rats showed significant depression-like behaviors, and the expression of BDNF was significantly decreased in the hippocampus and prefrontal cortex (P<0.01). The reduction of neuronal axons in hippocampus was also observed. After drug treatment, the depression-like behaviors of WKY rats were significantly attenuated, and the expression of BDNF and the number of axons were increased (P<0.01). CONCLUSION:Jieyuwan effectively attenuates the depression-like behaviors of WKY rats, and BDNF is a key factor in its antidepressant effect. Our findings further confirm the involvement of BDNF in the development of depression.     

Influence of complement bypass-activation on IL-8 expression in endothelial cells

AIM:To study the induction of IL-8 expression by bypass-activated complement in human umbilical vein endothelial cells (HUVECs) and regulatory effect of nuclear factor-kappa B on the expression of IL-8. METHODS:In vitro, zymosan-activated human serum(ZAHS) directly challenged the HUVECs monolayers. Following techniques were used in the experiment: ① RIA for measurement of IL-8,ISH for measurement of their mRNA.② EMSA for measurement of nuclear factor-kappa B(NF-κB). RESULTS:①After HUVECs monolayers were stimulated with ZAHS, the level of IL-8 increased significantly at 4 h. ②The NF-κB activity began upregulated within 30 min after ZAHS stimulation, maximal NF-κB activity was observed at 120 min. Pretreatment of endothelial monolayers with PDTC (20 μmol/L) significantly inhibited the secretion of IL-8 (P＜0.05). CONCLUSION:Bypass-activated complement directly challenged HUVECs to secret IL-8. Cytoplasma to nuclear translocation of NF-κB was necessary for this response.     

Effects of up-regulation of c-myc expression on U937 cell line

AIM:To establish a human monocytic　leukemia cell line U937 stably expressing c-myc gene and to investigate the biological characteristics of this cell line. METHODS:The recombinant plasmid MSCV-c-myc-IRES-GFP (MMIG) was constructed. MMIG and MSCV-IRES-GFP (MIG) were used to package the viruses for infecting U937 cells. Fluorescence-activated cell sorter (FACS) was used for sorting U937/GFP and U937/MYC cells. The GFP-positive cells were detected by fluorescence microscopy and FACS. The protein expression of c-Myc, survivin, X-linked inhibitor of apoptosis protein (XIAP) and Bcl-2 was detected by Western blotting. Cell proliferation was evaluated by MTT assay. Propidium iodide (PI) staining was used to determine the cell cycle distribution. Self-renewal ability was observed by colony- forming assay. RESULTS:The GFP expression in the cells infected with MIG or MMIG virus was observed under fluorescence microscope. The green fluorescent rate of the cells infected with MIG was 26.0%, while that of the cells infected with MMIG was 27.7%. The protein expression of c-Myc in MMIG-infected U937 cells was higher than that in MIG-infected cells. After sorting, the green fluorescent rates of U937/GFP and U937/MYC cells reached 98.7% and 93.7%, respectively. The protein expression of c-Myc in U937/MYC cells was higher than that in U937/GFP cells. In addition, survivin, a downstream protein of c-Myc, was up-regulated, while the protein expression of XIAP and Bcl-2 remained unchanged. Cell cycle analysis showed that the percentage of the cells in S phase increased in U937/MYC cells. Moreover, the proliferation and colony-forming ability of U937/MYC cells were also enhanced. CONCLUSION: U937/MYC cell line stably expressing c-myc gene was successfully established. c-Myc may increase cell viability via enhancing the expression of anti-apoptotic protein survivin, the cell cycle transition and the self-renewal ability.     

Restricted expansion of T cell receptor (TCR)Vβ genes in leukemic patients subjected to allogeneic hematopoeitic stem cell transplantation

AIM: To investigate restricted expansion of TCR Vβ gene repertoire in patients with leukemia following allogeneic hematopoietic stem cell transplantation. METHODS: TCR Vβ subfamily genes in peripheral blood mononuclear cells from 7 cases of leukemia was amplified using RT-PCR. RESULTS: Only two-eight fragments of Vβ genes were detected in samples from these patients, and the detected fragments are different in different patients. CONCLUSION: TCR complexes were abnormal in all patients, part of the genes were seletively expansed and part of them were suppressed after transplantation.     

The expression of β2 integrins and L-selectin on acute lymophocytic leukemic cells and its clinical implications

AIM and METHODS: To investigate the expression of adhesion molecule β₂ integrins (CD11a、CD11b) and L-selectin (CD62L )on acute lymophocyte leukemia (ALL) cells and its clinical implications. Adhesion molecules CD11a, CD11b and CD62L of 45 ALL patients and 25 health people were measured by flow-cytometric analysis. RESULTS: ①CD11a and CD11b expression were lower on ALL cells than the normal hematopoietic cells. The rate of low expression was 100% for CD11b, 50% for CD11a, respectively. CD62L expression were higher on ALL cells than the normal hematopoietic cells. ②The CD11a was lower expressed on B-ALL than T-ALL. CD62L was higher on T-ALL than B-ALL. ③The expression of CD11a in the invasion group was much higher than that in the non-invasive group (P<0.05). ④The levels of CD11a, CD11b were returned to normal levels at remission. CONCLUSION: These results suggest that there are abnormalities in the expression of cell adhesion molecules in ALL which may help identify ALL subtypes and the treatment effect.     

Influence of basic fibroblast growth factor on ECV304 cell migration

AIM: To observe the influence of basic fibroblast growth factor (bFGF) at different concentrations on migration of ECV304 cells after scratch wound. METHODS: Cell migration of ECV304 was monitored by computer assisted video microscopy with an image analysis system after treatment with bFGF at concentrations of 0, 5, 10 and 15 μg/L. The morphological changes induced by bFGF were observed under light microscope and scanning electron microscope. RESULTS: bFGF increased the cell migration at low concentration (5 μg/L), and inhibited at high concentration (15 μg/L). The surface of migration cells exhibited numerous filopodia. CONCLUSION: bFGF has double direction adjustment effects on migration of ECV304 cells. The surface of migration cells exhibits affluent pseudopods, which are mainly filopodia.