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Radiotherapy is frequently applied in the treatment of malignant gliomas, but it is unclear if radiotherapy exerts its effects via induction of apoptosis. The present study was designed to determine whether a single-fraction gamma-60Co radiation can induce apoptosis. In vitro cytological controlled study performed at a military medical university from October 2006 to June 2008. C6 cells were treated with a single fraction of gamma-60Co radiation at various doses [0, 4, 16, and 64 Gy]. The 3-[4,5]-dimethylthiazol-2]-2,5-diphenyl tetrazolium bromide [MTT] assay, apoptosis assays using Annexin V-fluorescein isothiocyanate /propidium iodide or Hoechst 33258 staining, and the cell cycle assay were performed, and the expression of p53 and p21 proteins was evaluated. The C6 cell numbers in the 16 Gy and 64 Gy groups were much lower than in the control group at 48, 96, and 144 hours after irradiation. The irradiated cells underwent apoptosis in a dose-dependent manner. Irradiation also impacted cell cycle progression, arresting cells in the G1 phase. The p53 protein expression was shown in both the nucleus and the cytoplasm of irradiated cells, whereas p53 was only expressed in the nucleus of control [untreated] cells. The p21 protein was expressed in irradiated cells but not in control cells. Single-fraction gamma-60Co radiation inhibited C6 cell growth by inducing apoptosis and G1 arrest, which correlated with the up-regulation of the p53-p21 pathway. The extent of apoptosis and G1 arrest was positively correlated with the dose of radiation. Better understanding of apoptosis induced by radiation therapy will help design optimal dosing schedules for radiation therapy, especially in combination with chemotherapy
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Animals, Laboratory , Apoptosis/radiation effects , Cells, Cultured/radiation effects , Rats , Tetrazolium Salts , Thiazoles , Cell Cycle , Tumor Suppressor Protein p53 , Cell Proliferation , ImmunohistochemistryABSTRACT
AIM: To explore the different effect and mechanism of arsenic sulfide on telemorase activity and hTERT-mRNA expression in CML cell lines-KS62 and APL cell lines-NB4. METHODS: Telomerase activity was determined by polymerase chain reaction enzyme-linked immunoassay (PCR-ELISA). The expression of hTERT-mRNA was analyzed by semi-quantitative RT-PCR. Flow cytometry was used to analyze the cell cycle and apoptosis. RESULTS: 0.15-0.6 mg/L arsenic sulfide (72 h)can induce apoptosis and inhibit telomerase activity and hTERT-mRNA expression in NB4 cell. The concentration of arsenic sulfide with the same effect on K562 cell was 0.3-3 mg/U 0.3 mg/L arsenic sulfide (72 h) can cause the proportion of the NB4 cell in G2/M phase increased, but for K562 cell, The concentration of arsenic sulfide was 1.5 mg/L. CONCLUSION: Telomerase system may be one.of the pathway for arsenic sulfide inducing apoptosis of NB4 and K562 cell; G2/M phrase arrest may have correlation with decrease of telomerase activity; The sensitivity of NB4 and K562 call for arsenic sulfide is different, the mechanism of it need to study more.
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AIM: To construct the replicative defecient adenovirus Ad-Runx3 expressing Runx3, and to express it in U251 malignant glioblastoma cells. METHODS: The runx3 gene with a flag tag was amplified by PCR using pCMV5-AML2 as a template, and was confirmed by DNA sequencing. The adenovirus shuttle vector pShuttle-CMVRunx3 was constructed by introducing runx3 DNA fragment into the sites of Kpn Ⅰ and Xho Ⅰ of pShuttle-CMV vector. This recombinant plasmid was linearized by Pmel and electronically transfected into BJ5183 cells to get the recombinant adenovirus vector Ad-Runx3. The recombinant adenovirus expressing Runx3 was infected into U251 malignant glioblastoma cells. The expression of exogenous Runx3 was observed by immonoblotting and its localization was detected by immunostaining using anti-Flag tag antibody. RESULTS: The recombinant adenovirus expressing Runx3 with a Flag tag was constructed and infected into U251 glioblastoma cells. The exogenous Runx3 protein was detected only in the nuclei. CONCLUSION: The recombinant adenovirus expressing Runx3 with a Flag tag is constructed successfully, and the Runx3 protein expressed in the nuclei of infected cells. The study laid a foundation for further research of the function of Runx3 in gliocarcinogenesis.
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0.05),but there are increases of that in 90dB/7d ( P 0.05). Conclusion The results showed that 8Hz, 90dB/130dB infrasound definitely induced increases of apoptosis ratio in the hippocampus cells after certain time of exposure, suggesting that there are damages occurred by infrasound field with 90dB or 130dB and some adaptation of the hippocampal cells ensued after a certain period of time.
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Objective To investigate the effects of gestrinone on growth and apoptosis, as well as the expression of phosphatase and tension homologue deleted on chromosome 10(PTEN) in isolated ectopic endometrium cells in vitro and the underlying mechanisms. Methods Ectopic endometrium cells were cultured and exposed to gestrinone of different doses of 0, 10 -6 and 10 -4 mol/L respectively. The inhibition of the cells during 48 hours was determined by methylthiazolyl tetrazolium (MTT) assay, and the cell growth curve was made. Gestrinone was administered to the cells and at 24 hours the morphological changes were observed by transmission electron microscopy and the apoptosis rate, cell cycle and PTEN expression were monitored by flow cytometry (FCM) at the same time. Results Gestrinone at different concentrations could inhibit the growth and proliferation of ectopic endometrium cells in a dose- and time-dependent manner. The inhibition rate of cell growth after exposed to gestrinone for 8,16,24,32,40 and 48 h was 99.6%,87.3%,79.8%,62.3%,51.7% and 44.2% in the 10 -6 mol/L group,and 99.2%,77.1%,69.6%,51.1%,33.7% and 23.6% in the 10 -4 mol/L group (P
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Aim To investigate radioprotective effects of platelet factor 4 (PF4) on hemopoiesis of mice after γ -ray irradiation and their mechanisms. Methods The mice were injected with PF4 twice at 6h intervals; and 20 h after the second injection they were given one irradiation of 7.5Gy 60Co γ -ray. 8d later the colony forming unit of granulocyte-macrophage (CFU-GM), colony forming of unit spleen (FU-S), number and DNA contents in bone marrow cells (BMCs) were examined by flow cytometry. Results 8d after irradiation, a significant difference was shown between DNA contents in BMCs and cell cycles of the PF4-injected mice and those of the irradiated mice (P∨ 0.01), whereas little difference was found between those of the irradiated mice and the controls (P∧ 0.05). Conclusion PF4 can obviously protect hemopoietic stem cells (HSCs) of mice from radiation injury and promote proliferation of HSCs after radiation.
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Objective:To investigate the expression and function of CD226 on NK s ubsets and its coexpression with other activation receptor and inhibition recept or on NK cells. Methods:The expression of CD226 on CD56 bright and CD56 dim NK subsets and coe xpress ion with CD16 and NKG2A in PBMC and MLC in the presence or absence of IL-2 or IL-15 were detected by double fluorescent staining and flow cytometry analysis. The level of IFN-? in the supernatants of PBMC culture and MLC treated with o r without IL-2 or IL-15 were evaluated by ELISA. 51Cr release assay w as employed to measure the specific lysis of NK cells killing target K562 cells. Results:CD226 was mainly expressed on CD56 dim NK subsets in PBMC. When s imulated by IL-2, CD226 expression was shifted to CD56 bright NK subsets, while IL-15 increased the subpopulation of NKG2A+CD226+double positive cell s. In MLC-generated NK cells, CD226 was mainly expressed on CD56 dim NK su bsets, and also shifted to CD56 bright NK subsets in the addition of IL-15 . Furt hermore, the percentage of CD16+CD226+和NKG2A+CD226+ subsets were increa sed when stimulated by IL-2 or IL-15. There was great increase in IFN-? lev el in the supernatants of PBMC culture in the presence of IL-2 or IL-15, but no difference in the supernatants of MLC treated with or without two cytokine s. Moreover, the cytotoxicity of NK cells in PBMC and MLC were greatly enhanced by IL-2 or IL-15. Conclusion:CD226 is mainly expressed on CD56 bright NK subsets in IL-2 or IL-1 5 activated NK cells, and is coexpressed with CD16 and NKG2A preferentiatly, whi ch maybe involve in the modulation of cytotoxicity of NK cells based on the balance of coexpressed activation and inhibition receptors. [
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Objective:To construct the prokaryotic expression vector of SEA mutant gene SEA(D227A).The gene was expressed in E.Coli, and the induced protein was purified and identified.Methods:The SEA gene was cloned by PCR from Staphylococcus aureus strain FRI 100.D227A was introduced by changing the Asp codon GAT into GCT(Ala)in the primer.The expression plasmid pRSET SEA(D227A)was constructed and transformed into E.Coli BL21(DE3)pLysS.The induced protein was identified by Western blot.Results:The nucleotide sequence of SEA(D227A)was found to be identical to the designed sequence. E.Coli BL21(DE3)pLysS contained pRSET SEA(D227A)can express a 32 kD protein which can specially bind with the anti SEA mAb.The induced protein was purified with Ni 2+ system.Conclusion:The SEA(D227A)gene was constructed and expressed successfully.The study gave a clue to the research of low toxic superantigen. [
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Objective To study the effects of activation and inhibition agents of protein kinase C on the function and expression of P glycoprotein in drug resistant gastric cancer cells. Methods Immunohistochemical staining and FACS were used to determine the expression of P glycoprotein on drug resistant gastric cancer cells SGC7901/VCR and its parent cells SGC7901, which were treated or not treated by activation or inhibition agents of protein kinase C(PMA or H 7). Double labeled immunoflurescent and laser scan confocal microscopy were used to detect the coexpression of protein kinase C ? and P glycoprotein on drug resistant gastric cancer cells. Rohdamin 123 was used as fluorescent probe to observe the effects of PMA and H 7 on the function of P glycoprotein and drug accumulation in SGC7901/VCR. Results P glycoprotein had positive staining on SGC7901 cells and much stronger staining on SGC7901/VCR cells. Protein kinase C ? and P glycoprotein exhibited coexpression on SGC7901 cells and much higher coexpression level on SGC7901/VCR cells. When treated by PMA, SGC7901/VCR cells showed time dependent decreasing of drug accumulation, enhancing function and decreasing expression of P glycoprotein. When treated by H 7, SGC7901/VCR cells showed time dependent increasing of drug accumulation, weakening function and increasing expression of P glycoprotein.Conclusion Protein kinase C may play a role in multidrug resistance of gastric cancer cells via modulating the expression and function of P glycoprotein.
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AIM To study if the activated T lymphocytes induced by hepatocellular carcinoma (HCC) rejection antigenic peptide SLIVHLNEV (mutant peptide of C met) pulsed dendritic cells (DCs) can provide protection against tumor challenge in nude mice HCC model and in vitro . METHODS SLIVHLNEV was eluted from HCC cell line HHCC by mild acid buffer and was identified by the mass spectrometry technique. SLIVHLNEV pulsed DCs isolated from HLA A2+ ruptured spleen were co cutured with isogeneic T lymphocytes. Cytotoxicity was tested using lactate dehydrogenase (LDH) release assay. The induced cytotoxic T lymphocytes (CTLs) were implanted into nude mice in order to protect them against transplanted HHCC tumor cells. The inhibition effect of CTLs on the growth of implanted tumor in nude mice was also observed. RESULTS The CTLs induced by SLIVHLNEV pulsed DCs had unique ability to kill HHCC tumor cells in vitro. They also protected the nude mice against the further challenge of HHCC tumor cells and inhibited the growth of implanted tumor. CONCLUSION DC based HCC rejection antigenic peptide SLIVHLNEV vaccine can induce powerful immune reaction both in nude mice HCC model and in vitro.
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AIM To gain insight into the biochemical mechanisms of Topotecan induced apoptosis in leukemia cells. METHODS The cytotoxic effect of Topotecan on HL 60 cells was measured by using MTT assay; Topotecan induced apoptosis in HL 60 cells was identified by morphological analysis, DNA agarose gel electropheresis and Annexin V FITC staining; correlation between Topotecan mediated apoptosis and caspase activation was investigated by caspase 8 or caspase 3 inhibitor. RESULTS After incubated with 0 1 ?mol?L -1 TPT for 8,12 and 16 h, survival rate in HL 60 cells significantly reduced to 62%?12%( P
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AIM: To study the role of hypoxia precondit io ning (HP) in hypoxia-reoxygenation (HR)-induced apoptosis in neonatal rat cardio myocytes and the possible mechanisms. METHODS: Cultured neonatal rat cardiomyocytes were divided into three groups: normal group, HP+H/R group and H/R group. Acridine orange (AO) sta ining was performed to detect morphological changes of apoptotic cells. Apoptosi s rates of cardiomyocytes were detected by flow cytometry. Colorimetric assay wa s used to detect caspase-3 activity. Expression of Bcl-2 protein was detected by immunohistochemistry combined with computer image analysis. RESULTS: Apoptotic cells were detected by AO staining after hypo xia of 6 h followed by 3 h-reoxygenation. The hypodiploid apoptotic peak was det ected by flow cytometry with the apoptotic rates of (29.7?5.4)%. A significan tly reduced apoptotic rates of (7.8?1.3)% was detected in HP group(P