Objective To observe the expression of p53, bcl-2 genes, vascular endothelial cell growth factor（VEGF）, basic fibroblast growth factor（bFGF）, insulin-like growth factor-I （IGF-I）, and the receptors of these factors of retinal vascular endothelial cells (VECs) of 1- to 20-week diabetic rats, and the relationship between the expressions and cell cycle arrest.Methods Retinal sections of diabetic rats induced by alloxan were immunohistochemically stained and observed by light microscopy (LM) and electron microscopy (EM). Dot blotting and Western blotting were used to determine the expression of mRNA, proteins of p53 and bcl-2. Results Under LM, immunohistochemical positive expression of p53 and bcl-2 were found on the vessels of ganglion cell layer and inner nuclear layer of retinae of 8- to 20-week diabetic rats; under EM, these substances were observed depositing in VECs. The retinal VECs also expressed VEGF, bFGF, IGF-I and their receptors. There was no positive expression of other cell types in these retinae, all cell types of retinae in control group, or all cells of retinae of diabetic rats with the course of disease of 1 to 6 weeks. The result of dot blotting revealed that retinal tissue of 20-week diabetic rat expressed p53 and bcl-2 mRNA, and the result of Western blotting revealed that they also expressed p53 and bcl-2 proteins. But retinal tissues of control group did not. Positive expression of bax was not found in the retinae in control group or 1- to 20-week diabetic rats. Conclusion p53, bcl-2 may introduce cell cycle arrest of VECs of retinae in 8- to 20-week diabetic rats. High glucose might stimulate the expression of VEGF, bFGF, IGF-I and their receptors, and the growth factors may keep VECs surviving by self-secretion. (Chin J Ocul Fundus Dis，2003，19：29-33)
【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.
ObjectiveTo observe the expression and mechanism of hypoxia-inducible factor-1α (HIF-1α) and p53 protein at the altitude of 5000 meter plateau hypoxia environment in rats, as well as the effect of Astragalus injection. MethodsSixty Sprague Dawley rats were randomly divided into the Astragalus injection intervention group and normal saline control group, 30 rats in each group. Astragalus injection group rats were intraperitoneal injected of Astragalus injection (15 ml/kg) before 30 minutes into the plateau environment simulation cabin, normal saline group rats were intraperitoneal injected with the same volume of saline. 30 minutes after injection, rats in each group were reared in the plateau experiment cabin which simulated altitude of 5000 m (oxygen partial pressure 11.3 kPa) for 2, 6, 8, 12, 24 hours, each time period of 6 rats. When get out, the rats were executed immediately and eyes were harvested. Retinal sections were studied by hematoxylin eosin stain, and immunohistochemical method for HIF-1α and p53 expression. ResultsFor control rats, after 2 hours in the cabin, there was edema in retinal layers. HIF-1α and p53 were expressed mainly in the cytoplasm of retinal layers. When the periods in cabin extended, there was atrophy of retinal nerve fiber layer, swelling and degeneration of ganglion cells. The expression of HIF-1α and p53 was increased. Compared with the control group, the intervention group rat had similar but less severe retinal changes, and the expression of HIF-1α and p53 was significantly decreased (P<0.05). ConclusionAstragalus injection can reduce pathological retinal damage in rats at high altitude environment, and its mechanism may be associated with reduced HIF-1α, p53 expression.
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 explore whether mutations of p53 gene and hMLH1 gene may be an early event of carcinogenesis in rectal cancer. Methods The expressions of p53 and hMLH1 protein in 32 patients with early rectal cancer, 32 patients with rectal adenoma， and 30 patients with normal rectal mucosa were detected by PV-9000 immunohistochemical method between February 2003 and July 2009 in this hospital. Results ① The positive expression rates of p53 protein were 0 (0/30), 59.38% (19/32), and 68.75% (22/32) in the normal rectal mucosa, rectal adenoma, and early rectal cancer, respectively. There was no difference between the rectal adenoma and early rectal cancer (Pgt;0.05), but which were higer than that of the normal rectal mucosa (Plt;0.01). The negative expression rates of hMLH1 protein were 0 (0/30), 12.50% (4/32), and 50.00% (16/32) in the normal rectal mucosa, rectal adenoma, and early rectal cancer, respectively. The negative expression rate of hMLH1 protein in the early rectal cancer was significantly higher than that in the rectal adenoma or the normal rectal mucosa (Plt;0.01). ② The positive expression of p53 concomitant negative expression of hMLH1 in the rectal adenoma and early rectal cancer were 9.38% (3/32) and 37.50% (12/32), respectively, the difference was statistically significant (P=0.008). ③ In the early rectal cancer, the positive expression of p53 and the negative expression of hMLH1 were closely related to the degree of differentiation (Plt;0.05), but which weren’t related to the patient’s gender, age, tumor maximum diameter, depth of invasion or fecal occult blood (Pgt;0.05). ④ The positive expression of p53 was closely related to higher adenoma hyperplasia (P=0.009), while not of negative expression of hMLH1 (Pgt;0.05). Conclusion Simultaneous mutations of p53 gene and hMLH1 gene may be an early event of carcinogenesis in rectal cancer.
【Abstract】Objective To investigate the significance of cyclin D1 and p53 protein expression in synchronous breast carcinoma and fibrosarcoma in rats. Methods Immunohistochemical SP methods was used to study the expression of cyclin D1 and p53 in synchronous breast carcinoma and fibrosarcoma induced by DMBA in rats.Results There was no expression of cyclin D1 and p53 in normal breast tissue. In atypical hyperplasia of mammary, there was overexpression of cyclin D1(7/14) and no expression of p53. The overexpression of cyclin D1 and p53 were detected in breast carcinoma (8/18,7/18 respectively) and fibrosarcoma (9/14,5/14 respectively). There was no expression of cyclin D1 and p53 in adjacent sarcoma.The expression of cyclin D1 and p53 protein was associated with histological grading, and showed inverse relation between them. Conclusion There are cyclin D1 and p53 protein overexpression in the synchronous breast carcinoma and fibrosarcoma induced by DMBA in rats. Cyclin D1 may paticipate in the course of the carcinogenesis of breast carcinoma and fibrosarcoma in rats, and p53 protein overexpression may relate to the degree of malignancy of the tumors.
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.
Objective To investigate the possible interaction between the ras and p53 genes overexpression in thyroid carcinoma, and whether there is correlation between the ras and p53 overexpression and clinico-pathological criteria. Methods Thyroid lesions from eighty patients were examined for expression of ras and p53 genes by the LSAB immunohistochemistic method. Of these patients, 54 were diagnosed as malignant lesions and 26 benign nodular thyroid disorders. Results The positive immunostain rate for ras and p53 genes was 90.7%, 23.0% and 55.5%, 30.7% in carcinoma and benign lesions respectively with statistically significance between thyroid carcinomas and benign disorders (Ｐ＜0.05). Both ras and p53 overexpressions coexisted in 30 thyroid carcinomas and follow-up showed that 3 of them died and 5 of them had recurrence within 4 years.Conclusion Activation of ras gene and inactivation of p53 gene are cooperatively associated in thyroid tumorigenesis. The concurrent overexpression of ras and p53 could result in a poor prognosis.
Objective To study the expression of p53 and vascular endothelial growth factor (VEGF) and its correlation with hematogenous metastasis in colorectal cancer. MethodsAvidinbiotin complex method was used to study the expression of p53 and VEGF in 79 cases of colorectal cancer.ResultsThe positive rates of p53 and VEGF were 48.1% and 58.2% respectively in 79 cases of colorectal cancer. p53 and VEGF expression were identical in 49 (62.0%) cases. There was significant association between p53 or VEGF expression and venous invasion or hematogenous metastasis (P＜0.05). The incidence of hematogenous metastasis in the p53（＋）/VEGF（＋） subgroup was 66.7% and was significantly higher than that in the p53（－）/VEGF（－） or p53（＋）/VEGF（－） subgroup （P＜0.01）. Neither synchronous nor metachronous hematogenous metastasis were found in the p53（－）/VEGF（－） subgroup.Conclusion The combination of p53 and VEGF expression is an important predictor for hematogenous metastasis in patients with colorectal cancer.
Objective To evaluate the relationship between leptin level in serum and clinicopathologic features of colorectal cancer. Methods ABC-ELLSA was used to detect the leptin level in 30 cases of colorectal cancer without dystrophy (cancer group) and 24 normal controls (control group). The expressions of K-ras， p53， adenomatous polyposis coli （APC） gene and delete in colorectal carcinoma gene (DCC) mRNA of the tumor were examined by RT-PCR, the levels of serum CEA and CA19-9, and other clinicopathologic features were also recorded. Results The leptin level in cancer group 〔（3.53±1.72） μg/L〕 was higher than that in control group 〔（2.27±1.01） μg/L〕, P＜0.05, and the difference was independent on gender. There were no significant differences of leptin level in different tumor stages and different tumor location （Pgt;0.05）. Leptin level of poorly differentiated tumor was obviously lower than that of well differentiated and moderately differentiated tumor （P＜0.05）. There were no associations between leptin level and the levels of CEA and CA19-9, likewise there were no associations between leptin level and the expressions of K-ras, p53, APC and DCC in tumor （Pgt;0.05）. Conclusion The leptin level of colorectal cancer patient is higher than that of normal person, which is affected by the differentiation of tumor. But there are no significant correlations between the level of leptin in serum and TNM stage, tumor location, tumor markers of serum, K-ras, p53, APC or DCC in tumor.