Objective To test the telomerase SiRNA on telomerase mRNA and on KB cell growth of oral squamous cell carcinoma.Methods We synthesized 21 nucleotide SiRNA duplexes with symmetric 2 nucleotide 3′ overhangs corresponding to the target sequence (2 657～2 675 nucleotide downstream of the start codon) of telomerase mRNA . Telomerase activity, cell proliferation, cell cycle and apoptosis were measured after transfection. Results Twenty one nucleotide small interfering RNA (SiRNA) duplexes specifically suppressed expression of endogenous telomerase mRNA in human oral squamous carcinoma KB cells. This inhibitory effect lasted only for about 48 h after transfection. Telomerase activity reduction corresponded to the mRNA suppression. Cell proliferation decreased by 30% at 48 h after transfection and lasted for 120 h after treatment. This inhibitory effect resulted from the block of G 1 to S transition. Apoptosis was not involved in this process. Conclusions SiRNA is a powerful tool for studying gene function and can be used as gene specific therapeutics.
The development of a vaccine containing both B and T cell epitopes provides effective protection of guinea pigs against type O Foot and Mouth disease virus (FMDV). The vaccine expressing plasmid was developed in which the tandem repeat genes coding for two copies of the sequences of 141 160 amino acid residues and 21 40 amino acid residues of VP1 protein of FMDV were fused to a carrier gene coding for β galactosidace. The vaccine can be expressed in E. coli. Animal experiment result showed that this vaccine elicited high levels of neutralizing antibody and specific T cell proliferation in guinea pig and protected guinea pigs against type O FMDV injection.
Objective To observe the effect of leptin on proliferation and apoptosis of breast cancer MCF-7 cell line,and to explore the effect of leptin on occurrence and development of breast cancer.Method The MCF-7 cell line was treated with different concentration of leptin in vitro.Cell proliferation was evaluated by MTT assay. Distribution of cell cycle was determined by flow cytomery, meanwhile the rates of apoptosis were estimated on the basis of Annexin V-FITC/PI apoptosis detection. Results When treated with different concentration of leptin for 24 h, 48 h and 72 h, they could significantly induce the proliferation of MCF-7 cells by MTT method.There was not interaction between concentration of leptin and time course (F=0.919,P=0.523).The main effect of concentration of leptin and time course was statistically significant (F=12.699,P=0.000;F=647.881, P=0.000). Compared 200 ng/ml and 400 ng/ml with the control group, we found the difference was statistically significant by multiple comparison (P=0.007,P=0.000,respectively).The difference was also statistically significant among time course by multiple comparison (P=0.000,respectively).By the flow cytometry analysis,it was found that the 100 ng/ml and 400 ng/ml leptin groups could change the distribution of cell cycle of MCF-7 cell line after 48 h. Compared with control group, the cell number decreased by 14.42 ％ in G0/G1 phase (F=10.464, P=0.044),but increased by 7.57 ％ and 22.19 ％ respectively in S phase (F=47.361,P=0.005).The difference was not statistically significant in G2/M phase (F=1.77, P=0.311).However, the effect of apoptosis inhibition was not obvious. Conclusions Leptin could stimulate the proliferation of MCF-7 cell line and change the distribution of cell cycle.But leptin could not inhibit apoptosis of MCF-7 cell line.It suggested that leptin may serve as a risk factor of breast cancer development.
Key words:
Breast neoplasms; Leptin; Cell proliferation; Apoptosis
Objective To explore the role and mechanism of ATP in promoting peripheral nerve regeneration.Methods The sciatic nerves of 10 four to five-day-old SD rats were removed.After separa- ting SCs with typsin and collagenase,purified cell with G-418.The purified SCs were divided into five groups:ATP 0.1,1,10,100 mmol and the control group.Following 10 days in vitro,the cells from five group were counted with phase contrast microscope every two days.Flow cytometries were carried out in each group after 24 h and 72 h respectively.Results The doubling time of the control group and 0.1mmol group was about 8.0 days,the 1.0、10 and 100retool ATP groups were 6.4、5.6 and 10.2 days.The flow cytomery of the five groups showed that SCs in S phase of the 1.0 mmol and 10 mmol groups were signifi- cantly higher than the control group,but the 100mmol group was lower.Conclusion ATP could promote SCs proliferation and thereby facilitate peripheral nerve regeneration,the effect would change with the con- centration of ATP.
Objective To analyze the distribution of CD3+CD4+ and CD4+CD25+ lymphocyte subsets in the pigs with dumbing immune response to classical swine fever(CSF)vaccine. Methods Fifteen CSF virus(CSFV)antibody-negative pigs were screened by ELISA and serum neutralizing antibody test from the female breeding pigs immunized with CSF vaccine, using 15 antibody-positive pigs as control. The anticoagulant blood of pigs was collected for isolation of peripheral blood lymphocytes(PBLs)in which the distribution of CD3+CD4+ and CD4+CD25+ lymphocyte subsets was determined by flow cytometry. Results The percentage of CD3+CD4+ lymphocyte subsets was significantly lower in PBLs of CSFV antibody-negative pigs(24. 09% ± 1. 29%)than in CSFV antibody-positive ones(37. 49% ± 1. 60%), while that of CD4+CD25+ lymphocyte subsets was significantly higher in the former(2. 34% ± 0. 20%) than in the latter (1. 64% ± 0. 13%). Conclusion The decrease of CD3+CD4+ and increase of CD4+CD25+ lymphocyte subsets in PBLs might be the important causes of dumbing immune response to CSF vaccine.
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