Objective To investigate the effect of the 8-bromum-cyclic adenosine monophosphate (8-Br-cAMP) on the telomerase activity and changes of cell cycle in retinoblastoma （RB） cells. Methods The cultured RB cells were divided into the experimental group (8-Br-cAMP) and control group. After cultured for 24, 48 and 72 hours in vitro, the telomerase activity of RB cells was detected by polymerase chain reaction enzyme-linked immunosorbent assay (PCR-ELISA) and the changes of cell cycle were detected by flow-cytometry. Results The difference of telomerase activity was significant between the experimental groups and control group (Plt;0.01). There was a negative correlation between the A value of absorbance and the time in the experimental groups (r=-0.778 9, F=33.936, Plt;0.01). The changes of the cell cycle were that the percentages increased in G1 phase and decreased in S phases. Conclusion 8-Br-cAMP may weaken telomerase activity, affect the cell cycle, and inhibit the proliferation of RB cells. (Chin J Ocul Fundus Dis，2004，20：358-360)
Objective To know the abnormal expression of the cell cycle-regulated proteins in pancreatic adenocarcinoma and their effect on tumor cell growth. Methods The expression of p16, p21, Rb and p53 protein in 47 cases were investigated by immunohistochemistry with wet autoclave pretreatment for antigen retriaval. Furthermore, tumor growth index were assessed by a novel anti-ki-67 antibody (ki-s5). Results All the expression of p53, p16, p21 and Rb protein were the nuclear stainning. The positive rates of p53, p16, p21 and Rb protein were 55%, 53%, 74% and 98% respectively. There was negative correlation between of p16, p21 or Rb protein expression and ki-67 growth index. No relation of p53 protein stainning and the expression of p21 protein was found. Conclusion In pancreatic adenocarcinoma, the negative expression of p16 protein and p21 protein may play an important role in tumor cell growth, but tumor proliferation caused by abnormality of Rb protein is rare. The expression of p21 protein was not associated with the expression of p53 protein.
Objective To study the expression and its significance of cyclin D1,cyclin E and p27 protein in gastric carcinoma. Methods The expression of cyclin D1,cyclin E and p27 protein in 60 cases of gastric carcinoma were detected by immunostaining method. Results The positive rates of cyclin D1,cyclin E and p27 protein expression in gastric carcinoma were 41.7%（25/60）,38.3%（23/60）and 36.7%（22/60）,respectively.The expression of cyclin D1 was significantly correlated with Lauren type of tumor,the expression of cyclin E was significantly correlated with tumor differentiation,infiltration and stage,while the expression of p27 protein was significantly correlated with tumor infiltration,lymph nodes metastasis and stage. Further more, the expression of cyclin E was inversely correlated with the expression of p27. Conclusion Detection of cyclin D1,cyclin E and p27 expression in gastric carcinoma may be helpful in determining tumor progression.
Objective To investigate cell cycle as a new tool to evaluate the biocompatibility of biomaterials.Methods The cell cycle and the expression of related genes were analyzed by the methods of immunocytochemistry, protein blotting, RT PCR and flow cytometry. Results The physical properteis, chemical properties and topological properities of biomaterials could not only influence cell cycle of the cells attached onto biomaterials but also affect the expression of related genes of target cells. Conclusion As an important extension of routine proliferation epxeriments, the study of cell cycle control will be great help for us to to study the cell group as an organic society. It revealed the balance between cell proliferation, cell differentiation and apotosis. It is suggested that the study of cell cycle control will play a key role in the research of tissue engineering.
Objective To investigate the effects of chitosan on the cell cycle of the human fibroblasts and on the Ki-67 antigen expression in vitro and to investigate the mechanism of chitosan preventing the postoperative tissue adhesion. Methods The cultured fibroblasts were treated for 48 hours with 0，0.01，0.1，1.0，10.0 mg/ml of chitosan, respectively;then, the cell cycle of the fibroblasts was measured by the flow cytometry. The cultured fibroblasts were treated for 24 hours with the chitiosan at the above concentrations; then, the Ki-67 antigen in the cell nucleus was detected with the immunohistochemical staining toobserve its expression. Results The growth of the fibroblastswas obviously suppressed by chitosan, especially in the cell morphology. When the concentrations of chitosan were 1.0 mg/ml and 10.0 mg/ml, the percentages of the fibroblasts in the proliferation stage were 32.3%±5.2% and 14.7%±2.9%, respectively,which were significantly smaller than the percentage of the fibroblasts when the concentration of chitosan was 0 mg/ml (the control group) (41.9%±5.8%， P＜0.05). When the concentrations were 0.01 mg/ml and 0.1 mg/ml, the percentages of the fibroblasts in the proliferation stage were 39.0%±6.0% and 35.5%±3.4%, respectively, which were smaller than that of the control, but not significantly different from that of the control (P＞0.05). When the concentrations of chitosan were 0.1 mg/ml,1.0 mg/ml and 10.0 mg/ml, the percentages of the fibroblasts that had the positiveKi-67 antigen were 37.3%±3.4%, 30.5%±6.2% and 17.8%±3.0%，respectively, which were significantly smaller than that of the control (57.6%±8.9%， P＜0.05). When the concentration was 0.01 mg/ml, the percentage of the fibroblasts that had the positive Ki-67 antigen was 54.1%±8.0%, which was smaller than that of the control, but not significantly different from that of the control (P＞0.05). ConclusionChitosan can inhibit the proliferation of the fibroblasts and increase the percentage of the fibroblasts in the quiescent stage, which can be considered as one of the mechanisms that chitosan can prevent the postoperative tissueadhesion.
ObjectiveTo analyze the expression and clinical significance of cyclin-dependent kinase 1 (CDK1) in lung adenocarcinoma by bioinformatics.MethodsBased on the gene expression data of lung adenocarcinoma patients in The Cancer Genome Atlas (TCGA), the differential expression of CDK1 in lung adenocarcinoma tissues and normal lung tissues was analyzed. The expression of CDK1 gene in lung adenocarcinoma was analyzed by UALCAN at different angles. Survival analysis of different levels of CDK1 gene expression in lung adenocarcinoma was performed using Kaplan-Meier Plotter. Correlation Cox analysis of CDK1 expression and overall survival was based on clinical data of lung adenocarcinoma in TCGA. Gene set enrichment analysis was performed on gene sequences related to CDK1 expression in clinical cases. The protein interaction network of CDK1 from Homo sapiens was obtained by STRING. CDK1-related gene proteins were obtained and analyzed by the web server Gene Expression Profiling Interactive Analysis (GEPIA).ResultsBased on the analysis of TCGA gene expression data, CDK1 expression in lung adenocarcinoma was higher than that in normal lung tissues. UALCAN analysis showed that high CDK1 expression may be associated with smoking. Survival analysis indicated that when CDK1 gene was highly expressed, patients with lung adenocarcinoma had a poor prognosis. Univariate and multivariate Cox regression analysis of CDK1 expression and overall survival showed that high CDK1 expression was an independent risk factor for survival of patients with lung adenocarcinoma. Gene set enrichment analysis revealed that high CDK1 expression was closely related to DNA replication, cell cycle, cancer pathway and p53 signaling pathway.ConclusionCDK1 may be a potential molecular marker for prognosis of lung adenocarcinoma. In addition, CDK1 regulation may play an important role in DNA replication, cell cycle, cancer pathway and p53 signaling pathway in lung adenocarcinoma.
ObjectiveTo construct DPC4 gene recombinant expression vector and to study the inhibitory effect of DPC4 on the growth of human pancreatic adenocarcinoma cell line (PC3) cells.MethodsDPC4 cDNA was amplified from K562 cell line using RTPCR, and was cloned into the pcDNA3.1 vector to construct a recombinant expression vector plasmid pcDNA3.1DPC4. The recombinant expression plasmid was transferred into PC3 cells by liposome method. After G418 selection, cell cycle and apoptosis were assessed by flow cytometry, then the cell growth rate was estimated by cell count. The cells being not transferred plasmid and transferred pcDNA3.1 plasmid were used as controls.ResultsThe DPC4 gene recombinant expression vector was constructed. Wildtype DPC4 gene attributed to the increase of G1 phase cells and the decrease of S phase cells in PC3 cells,and could inhibit the growth of PC3 cells, the cell growth rates was reduced to 34.3%-41.1% of that of the controls, but cell apoptosis was not observed on all groups. ConclusionWildtype DPC4 gene could inhibit the proliferation of human pancreatic adenocarcinoma cells and could become one of the target genes of pancreas adenocarcinoma gene therapy
Objective To investigate the effect on proliferation and apoptosis of vascular endothelial cells exposed to high glucose. Methods The cultured human umbilical vein endothelial cells (HUVEC) were treated with high glucose at concentrations of 10,20,30,40,50 mmol/L for 2,4,6,8,10,12,14 days,cpm value was studied by using tritium-labelled thymidine deoxyribose(3H-TdR)incorporation assay.Flow cytometry was used to detect apoptosis index,proliferation index and cell cycle. Results Treated with high glucose,the proliferation index and cpm were significantly reduced in a dose and time dependent manner than the control groups(Plt;0.05).The apoptosis index of HUVEC were higher compared with the control groups(Plt;0.05).The percent of the cultured cells in G1 phase in all high glucose groups were increased,the percent in S phase were largely decreased(Plt;0.05). Conclusion Exposed to high glucose,the apoptosis of HUVEC was accelerated and the suppressive effect of high glucose on the proliferation of HUVEC was observed.Endothelial cells were possibly arrested in G1/S checkpoint. (Chin J Ocul Fundus Dis,2000,16:177-180)
ObjectiveTo explore the influence of different radiation doses of 125Ⅰseed on human poorly differentiated gastric cancer cells (BGC823). MethodsSixty four male nude mice of BLAB nu/nu inoculated with human poorly differentiated gastric cancer cells (BGC823) were took as animal models. When tumors of nude mice grew to 0.7-1.2 cm, the nude mice were randomly divided into blank control group, low dose group, middle dose group, and high dose group (n=16). The tumors of nude mice in blank control group were implanted with blank seed, but tumors of nude mice in low dose group, middle dose group, and high dose group were implanted with 125Ⅰseed (the radiation doses of 3 groups were 1.48×10-7 Bq, 2.22×10-7 Bq, and 2.96×10-7 Bq respectively). Four nude mice of 4 groups were randomly collected to measure the tumor volume and weight before implantation, and on 7, 14, 21, and 28 days after implantation, but apoptosis rates and expression levels of cyclinE mRNA were measured on 14 days and 28 days after implantation, by using flow cytometer and semi quantitative RT-PCR method respectively. Results①Except for the blank control group, the tumor volume and weight decreased over time in low dose group, middle dose group, and high dose group. The tumor volume and weight in blank control group were higher than those of other 3 groups on 7, 14, 21, and 28 days after implantation (P < 0.05);in addition, on 28 days after implantation, tumor volume and weight in low dose group were lower than those of middle dose group and high dose group (P < 0.05).②On 14 days and 28 days after implantation, the apoptosis rates of blank control group were lower than those of other 3 groups (P < 0.05), but expression levels of cyclinE mRNA were all higher than those of other 3 groups (P < 0.05). In addition, on 28 days after implantation, apoptosis rate of low dose group was higher than both of middle dose group and high dose group (P < 0.05), but expression level of cyclinE mRNA was lower (P < 0.05). Compared with 14 days in the same group, except for the blank control group (P > 0.05), the apoptosis rates in other 3 groups on 28 days were higher (P < 0.05), with the lower expression levels of cyclinE mRNA (P < 0.05). Conclusions125Ⅰseed in organizational implantation can effectively inhibit the expression of cyclinE mRNA and the growth of human poorly differentiated gastric cancer tissue. Compared with doses of 2.22×10-7 Bq and 2.96×10-7 Bq of 125Ⅰ, low dose (1.48×10-7 Bq) contributes to the apoptosis of human poorly differentiated gastric cancer cells (BGC823).
Objective Metal wear products cause the aseptic loosening of joint prosthesis. To investigate the effect of metal ions Co2+ and Cr3+ on the osteoblast apoptosis, cell cycle distribution, and secretion of alkal ine phosphatase (ALP), and to search a method to prevent and treat aseptic loosening. Methods The mouse calvarial osteoblasts (MC3T3-E1) were cultured in vitro to 3-5 generations (5 × 105 cells/ mL) and divided into 2 groups: the experimental group and the controlgroup. The osteoblasts were cultured in α-MEM medium containing 10%FBS (the control group), and the mixed solution ofCoCl2 and CrCl3 was added after the osteoblasts cultured in α-MEM medium containing 10%FBS attached completely (the experimental group). At 12, 24, and 48 hours after culture, the osteoblast apoptosis and the cell cycle distribution were assessed by flow cytometry; and ELISA method was appl ied to detect ALP content in serum supernatant. Results At 12, 24, and 48 hours after culture, the apoptosis rates in the experimental group (13.90% ± 0.52%, 14.80% ± 0.41%, and 13.40% ± 0.26%) were significantly higher than those in the control group (8.56% ± 0.31%, 8.19% ± 0.24%, and 2.15% ± 0.11%), (P lt; 0.05); G2M (dividing phase) distribution ratio significantly decreased and G0G1 (dormancy stage) distribution ratio significantly increased when compared with those in the control group (P lt; 0.05); and the absorbency (A) values of ALP were 0.955 ± 0.052, 0.624 ± 0.041, and 0.498 ± 0.026 in the exprimental group, and were 1.664 ± 0.041, 1.986 ± 0.024, and 2.192 ± 0.041 in the control group, showing significant differences between 2 groups (P lt; 0.05). Conclusion Metal ions Co2+ and Cr3+ have a marked effect on osteoblasts cell cycle distribution, which can make most of the cells to be in dormancy stage (G0G1), up-regulate the apoptosis rate and inhibit the releasion of ALP from osteoblasts.