Objective To study the effect of 5-fluorouracil (5-FU) induced apoptosis of the rectal carcinoma cell line HR8348 in vitro and the relationship between apoptosis induced by 5-FU and the expression of bcl-2，bcl-xl，bax and p53,and to investigate the possible mechanism of apoptosis of rectal carcinoma cell line HR8348 induced by 5-FU.Methods After treatment with 5-FU for 24 h,the apoptotic index was detected by methyl green and pyronine Y staining and by terminal deoxynucleotidyl transferase (TdT)mediated dUTP nick end labeling (TUNEL).The bcl-2,bcl-xl,bax and p53 gene expression of HR8348 cells were examined by immunohistochemical method.Results After treatment with 5-FU,the apoptotic index of experiment group was significantly increased,there was significant difference as compared with the control.Exposed to 5-FU for 12 h,24 h and 36 h,the expression of bcl-2 of HR8348 cell line remained unchanged,but the expression of bcl-xl slightly diminished,while the expression of bax was remarkly increased,the expression of p53 was not detected in both experiment and control groups.Conclusion This results indicate that 5-FU may induce apoptosis of rectal carcinoma cell line HR8348 and the possible mechanism of apoptosis induction is through upregulation of bax expression and the change of bax to bcl-xl ratio.
Objective To explore the progress of the relationship between the tumor suppressor gene p53 and oncogene c-erbB-2 and gastric cancer in recent years. Methods Relevant literatures about p53 and c-erbB-2 in gastric cancer were collected and analyzed. Results The mutation of p53 gene and the over-expression of c-erbB-2 gene were a common event in gastric cancer. The mutation of p53 gene was correlated with the location of gastric cancer and its aggressive biological behavior. The over-expression of c-erbB-2 gene could be used as an independent prognostic parameter in gastric cancer. The drugs targeted on p53 and c-erbB-2 gene were being developed. Conclusion Further research on the role of p53 and c-erbB-2 gene in the development of gastric cancer is helpful to understand the biological behavior and provide theoretical basis for gene therapy.
Objective To investigate the relationship of p53 codon 72 polymorphism and susceptibility to gastric cancer in high incidence area of Hexi area of Gansu province. Methods The Arg/Pro polymorphism of p53 gene was detected by real-time PCR in 140 patients with gastric cancer, 110 patients with gastric precancerous lesion and 125 healthy controls; Helicobacter pylori (Hp) infection was detected by Warthin-Starry silver method． Results The Pro allele frequencies of p53 gene in gastric cancer cases (0.543) were higher than those in gastric precancerous lesion (0.482) and controls (0.472). The Pro genotype had a more than 1.846 fold increased risk of gastric cancer 〔OR=1.846; 95% 〗CI (1.006-3.387); P =0.046〕． With statistical analysis， the genotype of p53 gene was correlated with location and Laurens histological type （ P ＜ 0.05）. A significantly higher risk of gastric cancer was also seen in cases with p53 Pro genotype, food, Hp infection, positive mind factor and positive family history． Conclusion There is a b correlation between the p53 gene codon 72 Arg/Pro polymophism and susceptibility to gastric cancer in Hexi area of Gansu province and the Pro/Pro genotype may be one of the major risk factors in patients with gastric cancer.
【Abstract】Objective To investigate the association between p53, c-erb B-2 oncogene protein and angiogenesis in breast carcinoma and breast with atypical hyperplasia. Methods Immunohistochemical reaction of p53, c-erb B-2 oncogene protein was evaluated in 103 benign and malignant lesion breast paraffin-embedded specimens. The microvessel endothelial area (MEA) was quantitated by computer image analysis system (CIAS), which was immunohistochemically stained by FⅧ-RA. The relationships between p53, c-erb B-2 and MEA were analyzed. Results The MEA of p53 oncogene protein positive expression in mild atypical hyperplasia breast lesion was significantly higher than that in p53 negative (t=2.302 4,P＜0.05). The MEA of p53 oncogene protein positive expression in severe atypical hyperplasia was higher than that in p53 negative (t=2.179 4,P＜0.05). Moreover, no significant association between c-erb B-2 oncogene protein and MEA was observed. Conclusion p53 oncogene mutant,protein expression is significantly related to angiogenesis.
Objective To investigate the growth inhibition and the apoptosis inducement effects of polysaccharide of trametes robiniophila murr (PS-T) on human rectal cancer cell line HR8348 and elucidate the possible mechanisms. Methods After treatment with PS-T, the growth inhibition rate of human rectal cancer cell strain HR8348 was studied by MTT method. The apoptotic index was detected by methyl green and pyronine Y staining and by terminal deoxynucleotidyl transferase(TdT) mediated dUTP nick end labeling (TUNEL). The bcl-2, bcl-xl, bax, bak and p53 gene expressions of HR8348 cells were examined by immunohistochemical method.Results PS-T induced a dosedependent inhibition of HR8348 cells in vitro. The maximum percentage of growth inhibition was 71.1% by 36 h after administration of PS-T at a concentration of 4.0 mg/ml. There was no significant difference in the inhibitory rate as compared to the positive control (5-FU 10 μg/ml, P gt;0.05). The typical apoptosis phenomenons were observed under the light microscope by both staining methods. The apoptotic index increased parallelling with the increase of concentration of PS-T. When the PS-T concentration was 4.0 mg/ml, the apoptotic index determined by methyl green and pyronine Y staining and by TUNEL method increased rapidly to 0.1620±0.0128 and 0.2612±0.0158, respectively, which was greater than that of the positive control (5-FU 10 μg/ml, Plt;0.05). The expression of bcl-2, bcl-xl, bak and p53 was increased in the PS-Ttreated HR8348 cells by 36 h, while the bax remained unchanged. Expression index of bak/bcl-2 and bak/bcl-xl was increased significantly as compared with the control (Plt;0.05). Conclusion PS-T can significantly inhibit growth and induce apoptosis of human rectal cancer cell strain HR8348 in vitro. The apoptosis induced by PS-T might be related to the increase of the ratio of bak to bcl-2 and to bcl-xl and upregulation of the expression of p53 gene.
Objective To investigate the relationship between p53 codon 72 polymorphism and susceptibility to keloid. Methods The p53 genotypes were detected by polymerase chain reactionreverse dot blot(PCRRDB) and DNA direct sequencing among 15 healthy controls and 15 patients with keloid. Results The frequency of the Proallele(P=0.035) and Pro/Pro genotype(P=0.030) in patients was significantly higher than that in the controlls. There was no significant difference in the frequency of Pro/Arg and Arg/Arg genotypes between patients and controls. Conclusion The p53 gene codon 72 polymorphism may play a role in susceptibility to keloid.
【Abstract】Objective To investigate whether SUMO-1 enhances the apoptosis induced by wild-type p53 plasmid transfection in HepG2 cells. Methods The HepG2 cells were transfected respectively or simultaneouly with the following expressional plasmids as pcDNA3-wtp53（pwtp53，including human wild-type p53 gene），pCMV-HDM1B（pMDM2，including HDM2 gene， homologous gene as murine double minute gene 2），pcDNA3-His6-SUMO-1（pSUMO-1 ，including small ubiquitin-like modifier1 gene）and plasmid pcDNA3.The proteins expressed in cells were detected by means of Western blotting and the apoptosis rates of cells were measured by flow cytometry. Results The protein bands of p53 and MDM2 could be seen in cells transfected with pwtp53 and pMDM2. Meanwhile，the relative larger molecular weight bands were also seen in cells transfected with pSUMO-1 which represented the p53 and MDM2 protein modification by SUMO-1. Merely the trace of p53 protein was detected in cells not transfected with any plasmid or only transfected with empty plasmid and pSUMO-1. In cells transfected with pwtp53 and pwtp53+pSUMO-1，the apoptosis rates were (16.79±1.62)%and (18.15±1.36)%. When transfected with pwtp53+pMDM2，the rate decreased to (5.17±1.23)%. The apoptosis rate would come up again to (14.06±1.84)% after transfected with pwtp53+pMDM2+pSUMO-1 and the difference of rates were significant compared to the cells transfected with pwtp53+pMDM2 (PH＜0.01）. The apoptosis rates in other cells were less than 2% and had no significant difference. Conclusion SUMO-1 could increase the apoptosis induced by wild-type p53 plasmid transfection in HepG2 cells through combining to p53 protein or its post-translational modification and inhibiting p53 degradation by MDM2.
Objective To explore the effect of exogenous estrogen receptor β1 (ERβ1) gene on the expression of p53 as well as the changes of apoptosis in MDA-MB-231 cell line and to investigate the biological role of ERβ1 in breast cancer. Methods Recombinant eukaryotic expressing vector containing ERβ1 cDNA was transfected into human breast cancer cell MDA-MB-231 by using cationic liposome LipofectamineTM 2000. The expression levels of p53 and ERβ1 in mRNA and protein were evaluated by real-time PCR and Western blot, respectively. Cell growth curve was used to detect the changes of cell proliferation ability. Cell apoptosis was detected by flow cytometry. Results After transfected with vector containing ERβ1 cDNA, proliferation ability of MDA-MB-231 cell decreased and the expression levels of both ERβ1 and p53 in both mRNA and protein increased (Plt;0.01). Rate of cell apoptosis increased in ERβ1 upregulation groups （Plt;0.01）. Conclusion ERβ1 can induce apoptosis and inhibit the growth of MDA-MB-231 cells by upregulating p53 expression.
【Abstract】ObjectiveTo study the expressions of P-gp, nm23 and p53 in primary breast cancer tissues and to evaluate the prediction significance in recurrence of the primary breast cancer. MethodsExpressions of P-gp, nm23 and p53 in 57 benign and malignant breast paraffin-embedded specimens, the difference of the rate and intensity of positive reaction of P-gp,nm23 and p53 were checked by immunohistochemical staining.ResultsThe positive rate of nm23 significantly increased in benign breast tissues compared with the tissues of recurrence of breast cancer. The positive intensity of nm23 was significantly decreased in the tissues of recurrence of breast cancer compared with the tissues of primary breast cancer. The positive rate of p53 was significantly increased in malignant breast tissues compared with benign breast tissues. The positive intensity of p53 was significantly increased in the tissues of recurrence of breast cancer compared with the tissues of primary breast cancer. There was no difference in the positive rate of P-gp in the tissue of recurrence and primary of breast cancer compared with benign breast tumor. But the positive intensity of P-gp was significantly decreased in the tissues of recurrence and primary of breast cancer compared with benign breast tumor. ConclusionThe expression of p53 may indicate the proliferating activity of carcinoma cell. The positive intensity of expression of p53 and nm23 is valuable in prediction of the recurrence of primary breast cancer.