Effects of NS-398 on the proliferation and apoptosis of HepG2 cells

AIM: To evaluate the effects of NS-398, a cyclooxygenase-2(COX-2) inhibitor, on the proliferation and apoptosis in HepG2 cells. METHODS: The effects of NS-398 on the proliferation of HepG2 cells was evaluated by MTT. DNA fragmentation gel analysis was used to analyze the apoptotic cells; DNA ploidy and apoptotic cell percentage were examined by flow cytometry. Furthermore, the expression of COX-2 and Bcl-2 mRNA was identified by competitive RT-PCR. RESULTS: NS-398 inhibited cell proliferation and induced apoptosis in HepG2 in a concentration-dependent manner. DNA ploidy analysis showed that S phase cells were significantly decreased with NS-398 concentration increasing. The quiescent G₀/G₁ phase was accumulated with decreasing of Bcl-2 mRNA. Whereas NS-398 had no effect on the expression of COX-2 mRNA, no correlations were found between COX-2 mRNA and the HepG2 cell proliferation and apoptosis induced by NS-398 (r=0.056 and r=0.119, respectively). CONCLUSION: NS-398 significantly inhibits the proliferation and induces apoptosis in HepG2. Mechanisms may be involved in accumulation of quiescent G₀/G₁ phase and decrease in Bcl-2 mRNA expression, but independent to COX-2 mRNA expression.     

Effect of inhibited ubiquitin-proteasome pathway on growth and activity of telomerase in esophageal carcinoma cells

AIM: To investigate the effect on growth and activity of telomerase in esophageal carcinoma cells by inhibiting ubiquitin-proteasome pathway(UPP). METHODS: The esophageal carcinoma cell strain Eca9706 was treated with MG-132 to inhibit its UPP specially. The effect of growth suppression on cells was evaluated with MTT assay, morphologic changes of cells were observed under microscope, cell cycle and apoptosis were detected by flow cytometry (FCM). DNA fragment analysis was used to confirm the presence of apoptosis. The activity of telomerase was detected. RESULTS: MG-132 had obvious inhibitory effect on the growth of Eca9706 cells in a dose and time-dependent manner. Obvious pathologic change of cells were observed under microscope, cells became round, small and exfoliating. The FCM analysis showed that the ratio of esophageal carcinoma cells of G₁ phase increased and a obviously apoptotic sub-G₁ peak was found. Agarose electrophoresis showed marked ladder. The activity of telomerase was obviously inhibited. CONCLUSIONS: MG-132 significantly inhibits the growth and the activity of telomerase of Eca 9706 cells. These findings indicate that inhibiting UPP is a new strategy for the treatment of esophageal carcinoma.     

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 HMBA on proliferation and expression of KLF6 and related proteins in human tongue carcinoma Tca8113 cells

AIM: To study the effect of hexamethylene bisacetamide(HMBA) on the proliferation and expression of KLF6 and related proteins in human tongue carcinoma Tca8113 cells. METHODS: After cultured with HMBA, the growth of the Tca8113 cells was assayed by MTT method, and the morphology of the cells was observed under microscope. The cell cycle was determined by flow cytometry. The mRNA expression of KLF6 was detected by RT-PCR. The protein levels of KLF6, p53, cyclin D1 and c-Jun were measured by the method of immunohistochemistry. RESULTS: The number of adherent cells obviously decreased along with the concentration of HMBA, and the growth inhibition of Tca8113 cells was in a concentration/time-effect relationship after treated with HMBA. Some reversal features of the Tca8113 cells developed to normal cells in morphology after induced by HMBA. The proportion of the cells in G₁ phase was (52.00?0.02)% before treating with HMBA. The proportion of the cells in S phase was (34.00?0.08)%, and (14.00?0.10)% of G₂ phase cells. After treated with HMBA, the cell number in G₁ phase significantly increased with the exposure time going on, while the cell number in S phase significantly reduced, so did the cell number in G₂ phase. The cell cycle was significantly arrested in G₁ phase (P<0.05). The apoptosis peak also appeared. The mRNA expression of KLF6 significantly increased after induced by HMBA (P<0.05), so did the protein levels of KLF6 and p53 (P<0.05), while the expression of cyclin D1 and c-Jun was significantly decreased (P<0.05). CONCLUSION: HMBA inhibits the proliferation of Tca8113 cells by arresting the cell cycle in G₀/G₁ phase and resuming Tca8113 cells to normal and apoptosis at last.     

Effects of simvastatin on PDGF-BB and serum-induced proliferation of vascular smooth muscle cells and on the expression of tumor suppressor gene PTEN

AIM:To observe the effect of simvastatin on the proliferation of vascular smooth muscle cells(VSMCs) induced by serum and growth factor PDGF-BB and the effect of simvastatin on the expression of PTEN,a important regulator of G₁/S cell cycle transition. METHODS:The DNA synthesis was determined by [³H]-TdR incorporation, cell cycle was examined with flow cytometry, the protein level of PTEN was measured by Western blot method. RESULTS: (1)Simvastatin inhibited [³H]-TdR incorporation in a dose dependent manner. (2) Flow cytometric DNA analysis revealed that simvastatin induced significantly enhancement of G₀/G₁ phase and decrease in S phase VSMCs.(3)Simvastatin increased protein level of PTEN and mevalonate, a metabolite of HMG-COA, reversed the effect of simvastatin on PTEN protein expression. CONCLUSION:Simvastatin may inhibit proliferation of VSMCs and retarded cell cycle in G₀/G₁ phase by increasing PTEN expression through inhibiting synthesis of mevalonate.     

Effects of human growth arrest-specific homeobox gene delivery on proliferation,migration and cell cycle distribution of vascular smooth muscle cells

AIM: To explore a new gene therapeutic strategy for vein graft restenosis by investigating the effects of adenovirus-mediated human growth arrest-specific homeobox (Ad5-hGax) gene delivery on the proliferation, migration and cell cycle distribution of serum-induced rabbit vascular smooth muscle cells (VSMCs). METHODS: The recombinant adenovirus vector containing hGax gene was constructed and transfected into rabbit VSMCs. The expression of hGax in VSMCs was detected by RT-PCR and immunofluorescent staining. Methyl thiazolyl tetrazolium (MTT) assay was used to assess the effect of hGax over-expression on serum-induced proliferation of VSMCs. Wound healing method was applied to examine the distance of serum-induce VSMCs migration. Flow cytometry was employed to analyze the cell cycle distribution. RESULTS: The recombinant adenovirus vector Ad5-hGax was successfully constructed. The results of RT-PCR and immunofluorescent staining revealed that the hGax -transfected cells contained a 174 bp specific fragment of hGax gene and target protein 48 h after transfection. The proliferation of serum-induced VSMCs was significantly inhibited by overexpression of hGax gene as compared with control group. The migration of serum-induced VSMCs was inhibited after hGax gene delivery. Flow cytometry showed that 72 h after serum induction, the cells in G₀/G₁ phase in Ad5-hGax group were significantly increased, whereas the cells in G₂/M+S phase were significantly decreased. CONCLUSION: Overexpression of hGax gene inhibits the proliferation and migration of serum-induced rabbit VSMCs, and arrests the cells in G₀/G₁ phase. It is likely that hGax gene is a potential target for the gene therapy of vein graft restenosis.     

Effect of SC58125 on cell proliferation and apoptosis in HepG-2 cells

AIM: To clarify the effect of SC58125 on cell proliferation and apoptosis in HepG-2 cells and explore the molecular mechanisms. METHODS: Cell culture, MTT, TUNEL, DNA ladder, flow cytometry and Western blot analysis were employed in the present study. RESULTS: SC58125 inhibited the growth of HepG-2 cells and induced the apoptosis. Furthermore, it arrested G₀/G₁ phase and inhibited S phase in HepG-2 cells. Depressed expression of P33^cdk2, P34^cdc2, cyclin B₁, cyclin E, Mpm-2, Rb, PCNA proteins were found in HepG-2 cells treated with SC58125. CONCLUSION: SC58125 inhibits cell proliferation and induces apoptosis, which may be related to the altered low protein levels of P33^cdk2, P34^cdc2, cyclin B₁, cyclin E, Mpm-2, Rb, PCNA.     

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.     

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.     

Inhibitory effect of decorin on human pterygium fibroblasts in vitro

AIM: To investigate the effect of decorin (DCN) on the proliferation and apoptosis of human pterygium fibroblasts (HPF) in vitro , and to compare the effect of mitomycin C (MMC) in order to search for a new method to prevent the recurrence after pterygium surgery. METHODS: Human pterygium fiborblasts were isolated from the caudomedial part of pterygium tissues in pterygium patients and then cultured in vitro using tissue inoculation method. The cells were treated with DCN and MMC at concentrations of 0.01, 0.1, 1, 5 and 10 mg/L. The morphological alterations of HPF were observed after 24 h, 48 h or 72 h of treatment. MTT method was used to assay the effects of the 2 drugs at different doses after 12 h, 24 h and 48 h on the proliferation of the cells. The expression of proliferating cell nuclear antigen (PCNA) in each group treated with different doses of DCN was detected by the method of immunohistochemistry after 48 h. The cell cycle distribution was determined by flow cytometry analysis. RESULTS: After administration of 10 mg/L DCN or 1 mg/L MMC for 12 h, the proliferation of HPF was significantly inhibited by both drugs in a dose- and time-dependent manner (P<0.05). After treated with 1~10 mg/L DCN for 48 h, the percentage of HPF in G₀/G₁ phase was increased, while the percentage of HPF in G₂/M phase and S phase (G₂/M%+S%) was decreased after treated with 5~10mg/L DCN for 48 h (P<0.05). The late-apoptotic cells were not found in DCN group and MMC group. DCN dose-dependently inhibited the expression of PCNA in HPF (P<0.05). CONCLUSION: Decorin significantly inhibits the proliferation of HPF, and blocks the cells in G₁ phase.     

Effect of Bmi-1 gene overexpression on proliferation of human gastric mucosal epithelial cell line GES-1

AIM: To investigate the effect of B lymphoma Moloney murine leukemia virus insertion region 1 ( Bmi-1 ) gene overexpression on the proliferation of a human normal gastric epithelial cell line GES-1. METHODS: The plasmid containing Bmi-1 gene or empty plasmid was transfected into GES-1 cells by retroviral mediation. The expression of Bmi-1 at mRNA and protein levels was detected by quantitative real-time PCR (qRT-PCR) analysis and Western blotting, respectively. The effect of Bmi-1 gene overexpression on the cell cycle of GES-1 cells was evaluated by flow cytometry. The proliferation of the stably transfected cells was measured by Cell Counting Kit-8. RESULTS: The results of qRT-PCR analysis and Western blotting demonstrated that stably transfected cell line was successfully established. The results of flow cytometry analysis showed that overexpression of Bmi-1 reduced the G₀/G₁ phase, arrested the cells in G₂/M phase and S phase. The growth curve showed that overexpression of Bmi-1 resulted in increased growth speed. CONCLUSION: Increase in Bmi-1 gene expression regulates the cell cycle and promotes the proliferation of GES-1 cells.     

Effects of tumor necrosis factor alpha on proliferation and apoptosis of HSCs

AIM:To explore the role of tumor necrosis factor alpha(TNF-α) in the pathogenesis of liver fibrosis.METHODS:The proliferation and apoptosis of hepatic stellate cells (HSCs) in vitro were detected with flow cytometry, electron microscopy and TUNEL.RESULTS:The flow cytometry analysis showed that the cell proliferation index (PI) in the TNF-α(0.5 μg/L, 2.0 μg/L, 8.0 μg/L) groups was evidently lower than that in the control group (P＜0.05). In the cell cycle distribution, the portion of G₀/G₁ phase in the TNF-α groups was significantly higher than that in the control group(P＜0.05), but the portion of S phase in the TNF-α groups was evidently lower than that in the control group(P＜0.05). These indicated that TNF-α interfered with HSCs entrance into S phase from G₀/G₁ phase whereupon the proliferation of HSCs was inhibited. The apoptotic rate in the TNF-α groups was evidently higher than that in the control group(P＜0.05). The gene expression of bcl-2 and bax was also detected with flow cytometry. The expression of bcl-2 in the TNF-α groups was evidently lower than that in the control group(P＜0.05), but the expression of bax in the TNF-α groups was significantly higher than that in the control group(P＜0.05). TUNEL analysis showed the apoptotic rate of HSCs in the TNF-α(2.0 μg/L) group was 18.7%±2.5% compared with 5.3%±1.2% in the control group(P＜0.05).CONCLUSIONS:TNF-α interfered with HSCs entrance into S phase from G₀/G₁ phase whereupon the proliferation of HSCs was inhibited. TNF-α down-regulated bcl-2 gene expression and up-regulated bax gene expression whereupon the apoptosis of HSCs was induced.     

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.     

Lovastatin-induced G1 phase synchronization in human endometrial cancer JEC cells

AIM: To investigate the method of inducing G₁ phase synchronization in human endometrial cancer JEC Cells by lovastatin and the cell cycle progress of JEC cells after desynchronization. METHODS: The doubling time of JEC cells was detected by Cell Counting Kit-8 (CCK-8) assay. To determine the best lovastatin concentrations for G₁ synchronization, JEC cells were treated with lovastatin at concentrations of 10, 20, 30 and 40 μmol/L for 1× doubling time, and the cell cycle was detected using flow cytometry (FCM). To determine the best period of lovastatin treatment to achieve G₁ synchronization, JEC cells were treated with lovastatin at the best concentration for 0.5× to 2× doubling time, and the cell cycle was detected every 4 h using FCM. Furthermore, the cell cycle progress of JEC cells after desynchronization was also observed. RESULTS: The doubling time of JEC cells was almost 24 h. Treatment with lovastatin at the concentration of 20 μmol/L for 24 h achieved maximum G₁ arrest in JEC cells. Minimum G₁ phase and maximum S phase were observed after desynchronization for 16 h. CONCLUSION: Maximum G₁ synchronization of JEC cells is induced by lovastatin at the concentration of 20 μmol/L for 24 h. The JEC cells show minimum G₁ phase and maximum S phase after desynchronization for 16 h.     

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.     

Photoactivation promotes curcumin to induce apoptosis of human gastric cancer MGC-803 cells

AIM: To investigate the effect of photoactivated curcumin on apoptosis of human gastric cancer MGC-803 cells. METHODS: The effect of photoactivated curcumin on the growth inhibitory rate of gastric cancer MGC-803 cells was detected by MTT assay. The changes of nuclear morphology were observed under optical microscope with Hoechst 33258 fluorescent staining. The apoptotic rate, mitochondrial membrane potential, intracellular reactive oxygen species and Ca²⁺ level was determined by flow cytometry. The activity of caspase-3, caspase-8 and caspase-9 was detected by colorimetry. The protein levels of cytochrome C, Bcl-2, Bax and heat-shock protein 70 (HSP70) were analyzed by Western blotting. RESULTS: The growth inhibitory rate of MGC-803 cells treated with curcumin at concentration of 5.0 μmol/L was (29.74±2.30)%.Some apoptotic cells were observed under optical microscope, and the apoptotic rate was (12.54±1.75)%. The growth inhibitory rate of MGC-803 cells treated with photoactivated curcumin was (44.93±3.61)%.Significant morphological changes in the nucleus, such as chromatin condensation and apoptotic body formation, were observed under light microscope, and the apoptotic rate was (26.58±2.67)%. The cell cycle was arrested at G₀/G₁ phase. Compared with curcumin group, significant reduction in mitochondrial membrane potential,significant increase in cytochrome C, intracellular reactive oxygen species, Ca²⁺ level and the activity of caspase-3, caspase-8 and caspase-9 were observed in photoactivated curcumin group (P<0.01). Photoactivated curcumin also significantly inhibited the protein expression of Bcl-2 and HSP70 in the cells. CONCLUSION: Photoactivated curcumin enhances the apoptosis of gastric cancer MGC-803 cells by inhibiting Bcl-2 expression and promoting the mitochondrial pathway.     

Inhibition of cell proliferation and arrest of cell cycle progression by blocking Cl- channels in nasopharyngeal carcinoma cells

AIM: The roles of Cl^-channels in regulatory volume decrease (RVD), cell proliferation and cell cycle progression in nasopharyngeal carcinoma cells (CNE-2Z) were investigated. METHODS: Image analysis of living cells was used to detect the volume changes following exposure to hypotonic solutions. Cell viability was determined by the trypan blue assay. MTT method was applied to detected cell proliferation. The effect of the blocker on the cell cycle distribution was monitored by the flow cytometry. RESULTS: 5-nitro-2-(3-phenylpropylamino) benzoic acid (NPPB) inhibited RVD and cell proliferation in a dose-dependent manner. NPPB at the concentration of 100 μmol/L arrested cells in G₁ phase (G₁ population increased from 54% to 71% at 48 h after treatments), but did not significantly alter cell viability. CONCLUSION: Block of chloride channels suppressed cell proliferation by arresting cells in G₁ phase. The results suggest that activation of Cl^-channels and RVD is necessary for facilitating cells to proceed to the S phase from G₁ phase and maintaining cell proliferation.     

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 ginsenoside Rh2 on cultured PC-3M cells in vitro

AIM:To explore the influence of ginsenoside Rh₂ on cultured PC-3M cell cycle in vitro. METHODS:DNA content was measured using [³H]-TdR incorporation assay. To analysis the cycle changes of PC-3M cells, flow cytometry was used in the experiment.RESULTS:The results indicated that the rate of [³H]-TdR incorporation was lower in Rh₂-treated cells than the control in a dose-dependent manner. Flow cytometry demonstrated that the pecent of G₁ phase treated with Rh₂ was higher than that of control. CONCLUSION:These results suggested that PC-3M cells cultured with Rh₂ for 24 h were blocked at G₁ phase, and Rh₂ inhibited the growth of PC-3M cells in vitro.     

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.