ARHI gene inhibits cell growth,induces G2/M phase arrest and apoptosis of acute myeloid leukemia cell line U937

AIM: To investigate the expression of aplasia rashomolog member I (ARHI) gene in acute myeloid leukemia cells (AML) and to study the effects of ARHI on the growth of AML cell line U937.METHODS: The mRNA expression of ARHI in AML cells, 293FT cells, AML primary cells and healthy volunteer blood cells were detected by RT-PCR. After transfection with the MSCV-IRES-GFP-ARHI plasmid to the U937 cells, the growth curve was analyzed by MTT assay. U937 cells were re-suspended by fresh medium and cultured for 24 h, then the cell cycle distribution and apoptotic rate were determined. RESULTS: The mRNA of ARHI was positively detectable in 293FT cells and healthy volunteer blood cells instead of AML cell line and AML primary cells. The growth curve showed that cell viability in U937 cells with high expression of ARHI (U937-ARHI) was lower than that in the control cells (U937-GFP) on 6th~8th day. The ratio of G₂/M phase and apoptotic rate in the U937-ARHI cells were increased compare with control group(P<0.05). CONCLUSION: The mRNA level of ARHI is low in AML cells. High expression of ARHI gene in U937 cells inhibits cell growth, arrests the cells at G₂/M phase and induces apoptosis.     

Antitumor mechanism of danusertib in human AML HL-60 cells

AIM: To investigate the effects of danusertib, a pan-inhibitor of Aurora kinases, on the viability, cell cycle, apoptosis and autophagy of human acute myelocytic leukemia (AML) HL-60 cells.METHODS: The effect of danusertib on the viability of HL-60 cells was examined by MTT assay. The effect of danusertib on apoptosis of HL-60 cells was quantitated by the flow cytometry using an Annexin V/7-AAD apoptosis detection kit. The effect of danusertib on autophagy in the HL-60 cells was assessed by flow cytometry and confocal microscopic analysis. The levels of various proteins related to the cell cycle, apoptosis and autophagy were determined by Western blot.RESULTS: Danusertib decreased the viability of human AML HL-60 cells and induced the cell cycle arrest in G₂/M phase. Danusertib also induced mitochon-drium-dependent apoptosis by activation of caspase-3 and autophagy in the HL-60 cells via inhibition of PI3K/Akt/mTOR signaling pathway.CONCLUSION: Danusertib shows effective antitumor ability for promising AML treatment.     

Berberine enhances mitomycin C-induced cell cycle arrest and apoptosis of T24 bladder cancer cells

AIM: To observe the effects of the combination of berberin (Ber) and mitomycin C (MMC) on the cell cycle arrest and apoptosis of T24 bladder cancer cells and the underlying mechanisms. METHODS: The T24 cells were exposed to MMC in the presence or absence of difference concentrations of Ber. The viability of the T24 cells was determined by CCK-8 assay. The cell cycle distribution was detected by flow cytometry. The apoptosis was analyzed by flow cytometry with Annexin V-FITC/PI staining, and the protein expression levels of cyclin D1, survivin, CDK2, CDK4, p21 and p27 were determined by Western blot. RESULTS: CCK-8 experiments showed that Ber enhanced the inhibitory effect of MMC on the viability of T24 cells. The results of flow cytometry showed that Ber also enhanced the blockade effect of MMC on T24 cells in G₀/G₁ phase (P<0.05). Compared with the MMC group, Ber increased the expression of p21 and p27 up-regulated by MMC, and decreased the expression of cynlin D1, CDK2 and CDK4 (P<0.05). Meanwhile, Ber promoted MMC to inhibit the expression of survivin (P<0.05). Ber increased the apoptosis of T24 cells induced by MMC (P<0.05). CONCLUSION: Ber significantly enhances the inhibitory effect of MMC on the viability of T24 cells. The mechanism may be related to up-regulation of p21 and p27, thereby inhibiting the expression of cyclin D1, CDK-2 and CDK-4. At the same time, Ber inhibits the protein expression of survivin, which eventually leads to cell arrest in G₀/G₁ phase and promotes apoptosis.     

Effect of down-regulation of X-box binding protein 1 gene expression on viability and apoptosis of glioma cells

AIM: To investigate the effect of down-regulation of X-box binding protein 1 (XBP1) expression on the viability and apoptosis of glioma cells. METHODS: The mRNA expression of XBP1 in the glioma tissues was detected by qPCR. Small interfering RNA (siRNA) interfering with XBP1 expression (XBP1-siRNA) was transfected into human brain glioma U251 cells. At the same time, control group (the cells without special treatment) and negative control (NC-siRNA) group (transfected with siRNA without any interference) were set up. The mRNA expression of XBP1 in the 3 groups 48 h after transfection was detected by qPCR. The protein levels of XBP1, proliferating cell nuclear antigen (PCNA), B-cell lymphoma/leukemia-2 (Bcl-2), Bcl-2-associated X protein (Bax), cyclin D1 (cyclin D1), phosphatidylinositol 3-kinase (PI3K) and phosphorylated Akt (p-Akt) were determined by Western blot. The cell viability was measured by CCK-8 assay. The cell cycle distribution and apoptosis were analyzed by flow cytometry. RESULTS: The expression level of XBP1 in the glioma tissues was significantly higher than that in the tumor adjacent tissues (P<0.05). The XBP1 expression at mRNA and protein levels was significantly decreased in the cells transfected with XBP1-siRNA (P<0.05). No statistically significant difference of the cell viability, cell cycle, apoptotic rate and the protein levels of PCNA, Bcl-2, Bax, cyclin D1, PI3K and p-Akt between NC-siRNA group and control group was observed. Compared with control group, the cell viability, S-phase cells and the protein levels of PCNA, Bcl-2, cyclin D1, PI3K, and p-Akt in XBP1-siRNA group were decreased significantly, and the apoptotic rate, G₀/G₁-phase cells and Bax protein expression were significantly increased (P<0.05). CONCLUSION: Down-regulation of XBP1 gene expression in brain glioma cells reduces the viability of cancer cells, blocks the cells in G₁ phase and promote apoptosis. The mechanism is related to the inhibition of PI3K/Akt signaling pathway.     

Effect of fucoxanthin on growth and apoptosis of HSC-T6 cells

AIM: To explore the effect of fucoxanthin (Fu) on the growth and apoptosis of HSC-T6 cells. METHODS: HSC-T6 cells were divided into blank control group, negative control group and drug groups (treated with different concentrations of Fu). The cell viability was detected by CCK-8 assay at 24 h, 48 h and 72 h after Fu treatment. The cell cycle distribution and apoptotic rate were analyzed by flow cytometry. The protein expression of Bcl-2 and Bax were detected by Western blot. RESULTS: Compared with blank control group, the viability of HSC-T6 cells was inhibited by Fu at concentrations of 15~75 μmol/L in a dose- and time-dependent manner (P < 0.01). The cell ratio of G₁ phase was significantly decreased (P < 0.01) and the cell ratio of S phase and G₂ phase was significantly increased (P < 0.01) in 60 μmol/L Fu group after 24 h. The cell ratio of G₁ phase was significantly decreased (P < 0.05) and the cell ratio of S phase and G₂ phase was significantly increased (P < 0.05) in 15 μmol/L and 30 μmol/L Fu groups in a dose-dependent manner after 48 h. The early cell apoptotic rates and total cell apoptotic rates were significantly increased in the Fu treatment groups in a dose-dependent manner (P < 0.05). The protein expression of Bax was significantly increased in the Fu treatment groups and the protein expression of Bcl-2 was significantly decreased in 30 μmol/L and 60 μmol/L Fu groups (P < 0.05).CONCLUSION: Fu inhibits the growth of HSC-T6 cells possiblely via arresting the cell cycle at S phase and G₂ phase. The apoptosis of HSC-T6 cells induced by Fu might be via down-regulating the protein expression of Bcl-2 and up-regulating the protein expression of Bax.     

Effect of Sonic Hedgehog signaling blockade on growth of hepatocarcinoma cells

AIM: To investigate the effect of Sonic Hedgehog (Shh) signaling blockade on the growth of hematocarcinoma cells and underlying mechanisms. METHODS: The expression of Shh signaling molecules in hematocarcinoma cell lines BEL-7402, Huh7 and HepG2 was detected by RT-PCR. The cell viability was detected by MTT assay. The cell cycle and apoptosis were analyzed by flow cytometry. The expression of apoptosis-related proteins was determined by Western blot. RESULTS: Shh signaling molecules were all expressed in BEL-7402, Huh7 and HepG2 cells. The mRNA expression of Patched (Ptch), Gli1 and Gli2 was down-regulated by anti-Shh antibody. Blockade of Shh signaling pathway inhibited the proliferation of hepatocarcinoma cells with increasing cells in G₀/G₁ phase and induced the apoptosis of hepatocarcinoma cells. Treatment with anti-Shh antibody down-regulated the protein expression of pro-caspase-3, pro-caspase-8 and pro-caspase-9, while up-regulated the protein levels of cleaved caspase-3, cleaved caspase-8 and cleaved caspase-9 in BEL-7402 cells. CONCLUSION: Blockade of Shh signaling pathway inhibits the growth of hepatocarcinoma at different levels by cell cycle arrest and inducing apoptosis of hematocarcinoma cells.     

Effects of Smo gene silencing on cell activity and apoptosis of human cervical carcinoma HeLa cells

AIM: To investigate the effect of Hedgehog (Hh) signaling pathway on the viability and apoptosis of cervical carcinoma cells by shRNA technique to knock down Smoothened (Smo) gene. METHODS: Smo shRNA was used to transfect the cervical carcinoma HeLa cells. The expression of Smo and Gli1 at mRNA and protein levels in the HeLa cells was determined by RT-PCR and Western blot, respectively. The effect of Smo gene silencing on the growth of the cells was measured by MTT assay. The apoptosis and cell cycle were determined by flow cytometry. RESULTS: Compared with control group, the mRNA and protein expression of Smo and Gli1 were evenly reduced obviously after transfected with Smo shRNA for 72 h (P<0.05). The viability of HeLa cells transfected with Smo shRNA was significantly inhibited. The percentages of the cells in G₀/G₁ phase and early apoptosis rate were obviously higher in Smo shRNA transfection group than those in control group. CONCLUSION: Smo gene silencing effectively inhibits the cell growth and induces the apoptosis of human cervical carcinoma cells.     

Effect of 7-hydroxyisoflavone on HCT116 cells proliferation by Id1

AIM:To investigated the effect of 7-hydroxyisoflavone (7-HIF) on the proliferation, apoptosis and stem-like cell feature of colorectal cancer cells. METHODS:The effect of 7-HIF on the proliferation of HCT116 cells was detected by WST-1 assay and colony formation assay. The effects of 7-HIF on the cell cycle distribution and apoptosis in the HCT116 cells were analyzed by flow cytometry. The expression of cell-cycle related proteins and the stemness related proteins was determined by Western blot. RESULTS:After treated with 7-HIF (200 μmol/L), the viability of HCT116 cells was inhibited, and the size and number of the colony were decreased as compared with control group (P<0.05). The G₀/G₁ phase of the cell cycle was increased. The proportion of S phase was decreased and the cells were mainly arrested in G₀/G₁ phase. The apoptotic rate of HCT116 cells was 21.4%, which was significantly higher than that in the control group (1.1%). The results of Western blot revealed that the expression of inhibitor of differentiation 1(Id1) was significantly decreased (P<0.05). The expression of cell cycle markers cyclin D1 and cyclin E, the proliferative markers survivin and PCNA, and stem cell markers CD133, ALCAM and EpCAM were all down-regulated by 7-HIF treatment (P<0.05). CONCLUSION:7-HIF inhibits the proliferation and induces the apoptosis of colorectal cancer cells, and inhibits the stem-like cell feature, which may be related to Id1 inhibition.     

Effect of Radix Tetrastigma hemsleyani flavone on apoptosis and MAPK signaling pathway in myeloid leukemia NB-4 cells

AIM:To study the effects of Radix Tetrastigma hemsleyani flavone (RTHF) on the viability, apoptosis and MAPK signaling pathway in human acute promyelocytic leukemia NB-4 cells. METHODS:The inhibitory effects of RTHF on the viability and proliferation of NB-4 cells were measured by CCK-8 assay and BrdU test. Flow cytometry was used to analyze the apoptosis of NB-4 cells induced by RTHF, and the cell cycle distribution after RTHF treatment. The levels of apoptosis- and MAPK pathway-related proteins in the NB4 cells were determined by Western blot. RESULTS:RTHF inhibited the viability and proliferation of NB-4 cells in a time- and dose-dependent manner, and the IC₅₀ at 48 h was 2.26 g/L. RTHF blocked NB-4 cells into the cell proliferation cycle, with stagnation in the G₂ phase. Meanwhile, RTHF induced apoptosis of the cells, down-regulated the expression of anti-apoptotic protein Bcl-2, and up-regulated the expression of pro-apoptotic proteins Bax, caspase-3 and Cyt-C, in a dose-dependent manner (P<0.05). The expression of ERK5 was decreased, and p38 was increased induced after RTHF treatment. However, no obvious change of ERK1/2 and JNK after RTHF treatment was observed. CONCLUSION:RTHF effectively inhibits the viability and proliferation, and induces apoptosis of leukemic NB-4 cells in vitro. Its mechanism may be related to signaling pathways of p38 MAPK and apoptosis proteins.     

Effects of propofol on biological characteristics of colorectal cancer cells

AIM: To investigate the effect of propofol on the viability, invasion ability and apoptosis of colorectal cancer cells.METHODS: Propofol at 10, 25, 50 and 100 μmol/L was used to treat LoVo cells for 72 h, and propofol at 100 μmol/L was used to treat the LoVo cells for 12, 24, 48 and 72 h. The cell viability was measured by CCK-8 assay. The invasion ability of the LoVo cells treated with propofol at 100 μmol/L for 72 h was detected by Transwell assay. The cell cycle distribution and cell apoptotic rate were analyzed by flow cytometry. The protein levels of matrix metalloproteinase (MMP)-2, MMP-9, cleaved caspase-3, Notch1 and hairy and enhancer of split 1 (Hes1) were determined by Western blot.RESULTS: Propofol inhibited LoVo cell viability. The cell invasion ability, S stage cells, and the protein levels of MMP-2, MMP-9, Notch1 and Hes1 in propofol group were significantly lower than those in control group, and the apoptotic rate, G₀/G₁ cells and the protein level of cleaved caspase-3 were significantly higher than those in control group (P<0.01).CONCLUSION: Propofol inhibits the viability and invasion ability of colorectal cancer LoVo cells, blocks cell cycle and induces apoptosis. The mechanism is related to down-regulation of Notch1 signaling pathway.     

Repressive effect of miRNA-363 via SOX4 on human osteosarcoma cell growth and apoptosis

AIM: To detect the expression of miRNA-363 and SOX4 in osteosarcoma tissues and to investigate the effect of miRNA-363 on the viability and apoptosis of human osteosarcoma cell line MG-63.METHODS: Real-time PCR was used to detect the expression level and the relationship of miRNA-363 and SOX4 mRNA in the osteosarcoma tissues and the corresponding paratumorous tissues collected from 63 patients. The expression levels of miRNA-363 and SOX4 in osteosarcoma cell line MG-63 after transfected with miRNA-363 mimics were measured. The cell viability was measured by CCK-8 assay. Flow cytometry was used to monitor the changes of cell cycle and apoptosis. The changes of SOX4 and miRNA-363 expression levels in the MG-63 cells after transfection with SOX4 siRNA or pcDNA/SOX4 was detect by real-time PCR.RESULTS: The expressed level of miRNA-363 was lower, and the expression level of SOX4 was higher in the osteosarcoma tissues than those in the adjacent normal tissues. A significantly negative correlation between the expression levels of miRNA-363 and SOX4 was observed. The expression of miRNA-363 in the MG-63 cells after transfection with miRNA-363 mimics was significantly up-regulated, while the expression of SOX4 in the MG-63 cells was significantly down-regulated, with significant difference as compared with the cells transfected with miRNA-NC and control cells. The viability of MG-63 cells was inhibited, the cell cycle was arrested in G₀/G₁ phase, and the cell apoptosis was increased by transfection with miRNA-363 mimics. The relative protein expression levels of SOX4 in SOX4 siRNA group and pcNDA/SOX4 group were significantly different from those in negative control group, but the relative expression levels of miRNA-363 had no significant difference. Over-expression of SOX4 restored the viability of the MG-63 cells reduced by miR-363.CONCLUSION: The expression level of miRNA-363 is low in human osteosarcoma tissue. miRNA-363 may inhibits the viability of osteosarcoma cell line MG-63 and promotes cell apoptosis in vitro via inhibiting the SOX4 expression.     

mTOR kinase inhibitor CC-223 suppresses human breast cancer cell viability

AIM: To investigate the inhibitory effect of CC-223, an inhibitor of mammalian target of rapamycin (mTOR) kinase, on the viability of human breast cancer cells and its mechanism. METHODS: The inhibitory effect of CC-223 on the viability of MCF-7 cells and MDA-MB-231 cells was measured by CCK-8 assay. The cell cycle distribution of breast cancer cells was examined by flow cytometry. The expression of cell cycle-related proteins and oncoproteins c-Myc and survivin was analyzed by Western blot. RESULTS: CC-223 significantly inhibited the viability of both MCF-7 and MDA-MB-231 cells (P<0.05). CC-223 induced cell cycle arrest in both G₁ phase and G₂/M phase in the MCF-7 cells (P<0.05). However, low concentration of CC-223 treatment resulted in the accumulation of MDA-MB-231 cell cycle in the G₂/M phase, and the cell number in G₁ phase was unaffected. Treatment with CC-223 for 24 h clearly inhibited the protein levels of cyclin B1, cyclin D1 and phosphorylated cell division cycle protein 2 in the breast cancer cells (P<0.05). CC-223 suppressed the expression of c-Myc and survivin in both MCF-7 cells and MDA-MB-231 cells (P<0.05). CONCLUSION: CC-223 inhibits cell viability by blocking cell cycle progression and down-regulating expression of c-Myc and survivin in both MCF-7 and MDA-MB-231 cells.     

Effect of sodium selenite on proliferation of endometrial cancer cells

AIM: To investigate the effect and mechanism of sodium selenite (Na₂SeO₃) on the proliferation of endometrial cancer cells. METHODS: Endometrial cancer Ishikawa cells and HEC-1A cells were treated with Na₂SeO₃. The effect of Na₂SeO₃ on cell proliferation was determined by MTT assay. The effects of Na₂SeO₃ on cell cycle distribution and apoptosis were tested by flow cytometric analysis. The expression of cyclin A was detected by Western blotting. RESULTS: Na₂SeO₃ inhibited the proliferation of Ishikawa cells and HEC-1A cells. For Ishikawa cells, IC₅₀ was 3.26 μmol/L, and for HEC-1A cells, IC₅₀ was 4.77 μmol/L. After treated with Na₂SeO₃, the cells in G₀/G₁ phase were reduced and the cells in S phase and G₂/M phase were increased. Na₂SeO₃ also increased the percentage of apoptosis cells. The result of Western blotting showed that the expression of cyclin A was increased. CONCLUSION: Na₂SeO₃ inhibits the proliferation of endometrial cancer Ishikawa cells and HEC-1A cells via up-regulating the expression of cyclin A, arresting cell cycle and inducing apoptosis.     

Critical role of cystic fibrosis transmembrane conductance regulator in hypoxia-induced apoptosis of H9c2 cardiomyocytes

AIM:To explore the roles of cystic fibrosis transmembrane conductance regulator (CFTR) in hypoxia-induced apoptosis of H9c2 cardiomyocytes and the underlying mechanisms. METHODS:The rat H9c2 cardiomyocytes were exposed to a 1% hypoxic environment in a hypoxic chamber. After CFTR overexpression, H9c2 cardiomyocytes were cultured in a hypoxic environment. The mRNA and protein levels of CFTR were examined by RT-qPCR and Western blot, respectively. The cell viability was measured by MTT assay. The apoptotic rate was determined by Hoechst 33342 and Annexin V-FITC/PI staining, and the production of reactive oxygen species (ROS) was examined by dichloro-dihydro-fluorescein diacetate (DCF-DA) staining. RESULTS:Hypoxic exposure caused the apoptosis of H9c2 cardiomyocytes, which was accompanied by the down-regulation of CFTR at mRNA and protein levels and over-production of ROS (P<0.05). After CFTR overexpression, the apoptotic rate of the H9c2 cardiomyocytes induced by hypoxia was significantly reduced, with a prominent inhibition of ROS production (P<0.05). However, pretreatment with CFTRinh-172, a specific inhibitor of CFTR, reversed the protective effect of CFTR overexpression in H9c2 cardiomyocytes. CONCLUSION:CFTR has a critical role in protecting against hypoxia-induced apoptosis of H9c2 cells, which may be through inhibiting the generation of ROS.     

Effects of zinc on biological behavior of hepatocellular carcinoma cell line BEL-7404

AIM: To observe the effects of exogenous zinc on the biological behavior of hepatocellular carcinoma (HCC) cell line BEL-7404. METHODS: BEL-7404 cells were cultured with zinc sulfate at various concentrations. The intracellular concentration of zinc, cell viability, cell cycle, cell apoptosis and migration and invasion abilities were measured by TSQ fluorescent probe, MTT assay, DNA ploid analysis, acridine orange/ethidium bromide fluorescence staining and Transwell assay, respectively. The mRNA and protein expression levels of albumin in the BEL-7404 cells were determined by real-time PCR and Western blot, respectively. RESULTS: With the elevated concentration of zinc in culture condition, the concentration of zinc in the BEL-7404 cells was increased (P<0.05). The cell viability and migration and invasion abilities were decreased, while the apoptotic rate was increased (P<0.05). The cells in G₀/G₁ phase were decreased, while the cells in G₂/M phase were increased. Additionally, the mRNA and protein expression of albumin also increased (P<0.05). CONCLUSION: The zinc ion inhibits the cell viability as well as migration and invasion abilities, blocks the cells in G₂/M phase, and may reduce cell malignant phenotype.     

Effects of human xeroderma pigmentosum group D gene on proliferation of human vascular smooth muscle cells induced by interleukin-6

AIM: To investigate the effects of human xeroderma pigmentosum group D (XPD) gene on the proliferation of human vascular smooth muscle cells (VSMCs) induced by interleukin-6 (IL-6). METHODS: Recombinant plasmid pEGFP-N2/XPD and vacant plasmid pEGFP-N2 were transfected into VSMCs by liposome, and then these cells were incubated with IL-6 at 1×10⁵ U/L for 48 h. The cells were divided into 6 groups: blank control group; pEGFP-N2 group; pEGFP-N2/XPD group; IL-6 group; IL-6 + pEGFP-N2 group; IL-6 + pEGFP-N2/XPD group. The expression of green fluorescent protein was observed under fluorescence microscope. The cell growth was detected by MTT method. The cell cycle and apoptosis rate were examined by flow cytometre. The expression levels of XPD, Bcl-2, Bax and wild type P53 (wt-P53) were detected by RT-PCR and Western blotting.RESULTS: Green fluorescence was observed in the cells transfected with pEGFP-N2/XPD or pEGFP-N2, indicating successful transfection MTT results showed that the transfection of pEGFP-N2/XPD inhibited the cell growth, and reduced the positive effects of IL-6 on VSMCs growth. Flow cytometry results showed that the transfection of pEGFP-N2/XPD increased the apoptosis rate of VSMCs and the cell numbers in G₀/G₁ phase, decreased the cell numbers in S phase, and reduced the effects that IL-6 decreased the apoptosis rate of VSMCs and the cell numbers in G₀/G₁ phase, and increased the cell numbers in S phase. The results of RT-PCR and Western blotting showed that the transfection of pEGFP-N2/XPD increased the expression of XPD, Bax and wt-P53, decreased the expression of Bcl-2, and reduced the effects that IL-6 decreased the expression of Bax and wt-P53, and increased the expression of Bcl-2. CONCLUSION: XPD gene inhibits VSMCs proliferation, promotes VSMCs apoptosis, and reduces the effects that IL-6 promotes VSMCs proliferation and inhibits VSMCs apoptosis. Therefore, XPD gene is likely to be potential molecular target for treatment of atherosclerosis.     

Mechanism of elemene enhancing radiosensitivity of human glioma U251 cells

AIM To investigate the effect of elemene on the radiosensitivity of human glioma U251 cells and its mechanism. METHODS The U251 cells were used as a glioma model in vitro, and were exposed to different concentrations of elemene and different doses of radiation. The cell viability was measured by MTT assay, the apoptosis and cell cycle distribution were analyzed by flow cytometry, and the related protein levels were determined by Western blot. RESULTS Elemene inhibited the viability of U251 cells in vitro and enhanced the radiosensitivity of the cells. The cells in radiotherapy combined with elemene group had higher rates of early apoptosis, secondary necrosis and total cell death than those in radiation group. Elemene induced G₂/M phase arrest in the U251 cells. Elemene reduced the protein expression of cell division cycle protein 2 （Cdc2）, which resulted in the decrease in cyclin B1 expression induced by radiotherapy, thereby inhibiting the formation of cyclin B-Cdc2 complex. Elemene reduced Cdc2 activity by inhibiting the phosphorylation of Cdc2 protein at threonine 161, thereby inducing G₂/M phase arrest in the cells. It also mediated apoptosis by down-regulating survivin expression. CONCLUSION Elemene may increase the sensitivity of U251 cells to radiotherapy by down-regulating Cdc2 protein, decreasing cyclin B1 expression, inhibiting the formation of cylcin B-Cdc2 complex and down-regulating the expression of survivin.     

Expression of miRNA-93 in acute lymphocytic leukemia

AIM: To investigate the expression of microRNA (miRNA)-93 in acute lymphocytic leukemia (ALL) and its effect on the proliferation of acute T-cell leukemia Jurkat cells.METHODS: The expression of miRNA-93 in the bone marrow samples of patients with ALL was measured by real-time PCR. After down-regulation of miRNA-93 by transfection with miRNA-93 inhibitor in the Jurkat cells, the cell viability, cell proliferation and cell cycle distribution were detected by CCK-8 assay, EdU assay and flow cytometry, respectively. Furthermore, the protein levels of cell cycle-related molecules such as cyclin D1, cyclin-dependent kinase 4 (CDK4), phosphorylation retinoblastoma (Rb) and P27 were measured by Western blot.RESULTS: miRNA-93 was highly expressed in the patients with ALL, and the expression level was highest in the high risk patients. Down-regulation of miRNA-93 inhibited Jurkat cell viability, arrested cell cycle in G₁/S transition. In addition, the protein levels of cyclin D1, CDK4 and p-Rb were significantly decreased, the protein expression of P27 was increased in Jurkat cells trasfected with miRNA-93 inhibitor.CONCLUSION: miRNA-93 expression is increased in ALL patients. Down-regulation of miRNA-93 restrains cell proliferation in the acute T cell leukemia cell line Jurkat via regulating cell cycle-related molecules.