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 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.     

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.     

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.     

Preparation of m1AChR-G11 fusion protein and m4AChR-G16 fusion protein and effects of various ligands on them

AIM:To prepare m₁AChR-G₁₁ and m₄AChR-G₁₆ fusion protein in Baculovirus-Sf9 cell system and detect the effects of various muscarinic ligands on the interaction between m₁AChR and G₁₁ and m₄AChR and G₁₆, and screen different kinds of ligands specific for m₁ and m₄. METHODS:To prepare fused DNA of m₁AChR-G₁₁and m₄AChR-G₁₆ in two PCR, then expressed in Sf9 cells and detect the pharmacological function of m₁AChR-G₁₁ fusion protein and m₄AChR-G₁₆ fusion protein by QNB and GTPγS binding experiments; To expore the way of the activation of m₁AChR-G₁₁ and m₄AChR-G₁₆ fusion protein by various ligands includingcetylcholine (ACh), Pilocarpine (Pilo), 4-hydroxy-2-butynyl-1-trimethylammonium-m-chloro-carbanilatechloride (McN-A-343), tetrandrine, pirenzepine (PZ), alcuronium, atropine, R-(+)-hyoscyamine and gallamine by displacement by GDP on GTPγS binding experiments. RESULTS:The expression levels of m₁AChR-G₁₁ and m₄AChR-G₁₆ fusion protein were (45.39±2.62) nmol·g^-1 protein, (47.04±1.58) nmol·g^-1 protein. The affinity of GDP to G₁₁ and G₁₆ partner changed in the presence of different muscarinic ligands. CONCLUSION: The m₁AChR-G₁₁ and m₄AChR-G16 showed the pharmacological specificity to m₁ and m₄ receptor and the efficient signaling of the two partners. Ligands of m₁AChR and m₄AchR mediated different signal transduction by changing the affinity of G₁₁/G₁₆ and GDP. So m₁AChR-G₁₁ fusion protein and m₄AChR-G₁₆ fusion protein can be taken as a tool to screen ligands specific for m₁AChR and m₄AChR.     

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.     

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.     

类番茄茄与番茄属间有性杂交的研究

用类番茄茄与番茄属的 9个种进行有性杂交 ,通过人工离体胚培养获得栽培番茄‘粤农二号’×类番茄茄的F1植株。杂种近于不育。用栽培番茄、类番茄茄、野生番茄及(栽培番茄×野生番茄 )与之回交及杂交 ,获得与栽培番茄的回交子一代及与秘鲁番茄、多腺番茄、潘那利番茄、粤农二号×秘鲁番茄F1的杂种 ,但它们的能育性很低。用栽培番茄、野生番茄与它们再回交及杂交 ,未能得到与栽培番茄的二次回交子一代 ,只获得 (粤农二号×类番茄茄 )× (粤农二号×秘鲁番茄 )的F1与秘鲁番茄、多腺番茄的复合杂种。人工苗期接种黄瓜花叶病毒 (CMV)结果表明 ,类番茄茄及其与番茄属的远缘杂种对CMV有较强的抗性。     

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.     

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 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.     

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 calcitonin gene-related peptide on proliferation of vascular smooth muscle cells

AIM: To elucidate the effect of calcitonin gene-related peptide (CCRP) in the therapy of atherosclerosis.METHODS:Effect of CGRP on cell cycle kinetics of cultured vascular smooth muscle cells(HA-VSMC) was investigated by flow cytometry. The expression of cyclins D₁ and E required for initiation of S phase were also studied by immunochemistry method. RESULT: CGRP was shown to arrest VSMC in the G₀/G₁ phase of cell cycle and reduced expression of cyclins D₁ and E. CONCLUSION:CGRP inhibits proliferation of HA-VSMC by arresting cells in G₁ phase via limiting accumulation of cyclin D₁ and E. It might play a role in the therapy of atherosclerosis.     

Inhibition of proliferation and influence of proto-oncogenes expression by Tanshinone ⅡA in U251 cells

AIM: To investigate the inhibitory effect of Tanshinone ⅡA on U251 glioma cell line and its mechanism. METHODS: MTT was used to measure the levels of the proliferation in U251 cultured with Tanshinone ⅡA at different concentrations. The effects of Tanshinone ⅡA on cell cycle of U251 were observed by FCM. The expression of proto-oncogene c-myc was measured by RT-PCR. RESULTS: The proliferation of U251 was obviously inhibited by Tanshinone ⅡA in a dose dependent manner. The inhibitory rate came to the peak at (54.2±0.9)%, when cultured with Tanshinone ⅡA at 0.10 g/L. The outcome of FCM showed that the proportion of G₀/G₁ phase cells was increased and the proportion of S phase cells was reduced obviously, when cultured with Tanshinone ⅡA at 0.10 g/L for 3 days. The RT-PCR experiment showed that the expression of proto-oncogene c-myc was notably decreased, when the dose of Tanshinone ⅡA was increased. CONCLUSION: Tanshinone ⅡA inhibited the proliferation of U251 and the expression of proto-oncogene c-myc.     

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.     

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 role of epigallocatechin-3-gallate in proliferation of human nasopharyngeal carcinoma cells by targeting P53/miR-34a

AIM: To study the effect of epigallocatechin-3-gallate(EGCG) on the proliferation of human nasopharyngeal carcinoma(NPC) cells, and to explore its mechanism by targeting miR-34a.METHODS: Nasopharyngeal carcinoma CNE-2Z cells were treated with various concentrations of EGCG. The ability of cell proliferation was detected by CCK-8 assay, 5-ethynyl-2-deoxyuridine(EdU) incorporation assay and colony-forming assay. The cell cycle distributions were analyzed by flow cytometry. The protein levels of P53 and Notch1 were detected by Western blot. The expression of miR-34a and Notch1 mRNA was measured by real-time PCR.RESULTS: EGCG effectively inhibited the proliferation and colony formation of CNE-2Z cells in a dose-dependent manner, which was related to its induction of cell cycle arrest at G₀/G₁ phase. The expression of P53 and miR-34a in CNE-2Z cells was significantly increased after treated with EGCG, while the expression of Notch1 at mRNA and protein levels was markedly suppressed.CONCLUSION: EGCG induces cell cycle arrest and suppresses cell proliferation by regulating the P53/miR-34a/Notch1 pathway in NPC cells.     

Effects of Centella asiatica extracts on cell cycle and intracellular free calcium in spleen lymphocytes

AIM: To investigate the effects of Centella asiatica extracts on the cell cycle and intracellular free calcium ( _i) in spleen lymphocytes. METHODS: Centella asiatica was extracted with alcohol and different organic solvents. Sephadex-LH20 gel column chromatography was applied for further purification. To screen the active constituents, the scavenging ability of the fractions generated by elution of chromatography against radicals of OH·, DPPH· and their anti-proliferative effects on spleen lymphocytes were measured. To assess the cell cycle and _i in spleen lymphocytes, flow cytometry was performed. RESULTS: The D fraction eluted from the crude extract of Centella asiatica was obtained, which had strong suppressive effect on lymphocyte proliferation and decreased the _i of the cells in a dose-dependent manner. The cell cycle of the spleen lymphocytes arrested at S and G₂/M stages when treated with the D fraction. CONCLUSION: The effects of Centella asiatica for lowing _i and arresting cell cycle at S and G₂/M stages of spleen lymphocytes are responsible for its anti-proliferative activitiy.     

Tetrandrine enhances radiosensitivity of human nasophayrngeal carcinoma cell lines

AIM: To study whether tetrandrine (Tet) enhances the radiosensitivity of human nasopharyngeal carcinoma cell lines in vitro and its mechanism.METHODS: The inhibitory effect on proliferation was evaluated by MTT assay. The radiosensitivity of the cells was compared by colony formation assay. The cell cycle was analyzed by flow cytometry. RESULTS: The maximum non-cytotoxic doses of Tet for CNE1 and CNE2 cells were 1.5 and 1.8 μmol/L, respectively. Compared with radiation group, the cell proliferation in Tet plus radiation group was significantly inhibited on the 4th to 6th days (P<0.01). The mean lethal doses for CNE1 and CNE2 cells in radiation group were (1.26±0.02) Gy and (2.27±0.04) Gy, respectively,and the values changed to (0.73±0.05) Gy and (1.61±0.08) Gy in Tet plus radiation group, respectively, resulting in the sensitivity enhancement ratio of 1.73 and 1.40, respectively (P<0.05). The CNE1 and CNE2 cells in G₂ phase of the cell cycle in radiation group were (42.62±2.07)% and (34.82±2.74)%, respectively, while those in Tet plus radiation group were (17.02±1.87)% and (19.64±4.82)%, respectively. CONCLUSION: Tetrandrine enhances the radiosensitivity of human nasopharyngeal carcinoma cell lines and the mechanism may be related to the abrogation of radiation-induced G₂ phase arrest.     

Biological characteristics of side population cells sorted from hepatoma SMMC-7721 cell line

AIM: To study the biological characteristics of side population (SP) cells sorted from hepatoma SMMC-7721 cell line. METHODS: Fluorescence-activated cell sorter (FACS) was used to sort SP cells and non-SP (NSP) cells from SMMC-7721 cell line. The colony-formation ability and proliferation ability between SP cells and NSP cells were compared in terms of plate colony assay and growth curve. The migratory and invasive properties of SP cells and NSP cells were tested by Transwell method. The cell cycle and apoptosis were analyzed by flow cytometry. The oncogenicity of the cells was analyzed by nude mouse transplantation tumor experiment in vivo. RESULTS: The results of FACS analysis indicated that (9.2±0.2)% of the SMMC-7721 cells were SP cells. The proportion of G₀/G₁ phase of SP cells was higher, and the apoptotic rate was lower than those of NSP cells (P<0.05). The proliferation ability and colony-forming ability and migratory and invasive properties of SP cells were significantly higher than those of NSP cells (P<0.05). The nude mouse transplantation tumor experiment displayed that the oncogenicity of SP cells was higher than that of NSP cells. CONCLUSION: The SP cells sorted from SMMC-7721 cell line may enrich tumor stem cells.