The effects of HSPC238 on the expression of RB in hepatoma carcinoma cells / 国际检验医学杂志

Objective To investigate the effect of up‐regulation and down‐regulation of HSPC238 on the RB gene mRNA and pRb protein .Methods PcDNA3 .1‐HSPC238 vector and PLL3 .7‐HSPC238 vector was transiently transfected into HepG2 cells re‐spectively .The level of RB mRNA was detected by real‐time PCR and pRb was detected by Western blotting .Results The level of RB mRNA and pRb in up‐regulation group both increased compared with control grops respectively .Conversely ,the level of RB mRNA and pRb in up‐regulation group both decreased compared with control grops respectively .Above results were all statistically significant(P<0 .05) .Conclusion HSPC238 could have a positive effect on the expression of the RB gene .

Resistencia a Phytophthora infestans linaje clonal EC-1 en Solanum tuberosum mediante la introducción del gen RB

Una de las opciones para el control de la enfermedad del tizón tardío de la papa es el desarrollo de variedades resistentes a Phytophthora infestans mediante la transferencia directa de genes de resistencia (R) por ingeniería genética. En el siguiente trabajo de investigación, se usó el gen RB de Solanum bulbocastanum, el cual otorga un amplio espectro de resistencia a razas de P. infestans. Para dicho fin, se transformó genéticamente vía Agrobacterium la variedad susceptible de papa Desiree (Solanum tuberosum) con el vector binario pCIP68 que contiene el gen RB. Como resultado, se obtuvieron 19 plantas transformadas con el gen RB, confirmadas por la prueba de resistencia a kanamicina y por la prueba de reacción en cadena de la polimerasa (PCR). Las 19 plantas transgénicas fueron sometidas a infección en invernadero bajo condiciones de bioseguridad con el aislamiento POX067 de P. infestans perteneciente al linaje clonal EC-1 que es dominante en el Perú. Tres de las 19 plantas ([RB]54, [RB]56 y [RB]70) presentaron un alto nivel de resistencia al aislamiento POX067 de P. infestans.

One of the most efficient options for the control of late blight disease in potato (Solanum tuberosum) is the development of resistant varieties to Phytophthora infestans mediated by the direct transfer of resistance (R) genes through genetic engineering. In the present work, we used Solanum bulbocastanum RB gene to confers broad spectrum resistance to P. infestans races. To that end, Agrobacterium - mediated genetic transformation was used to transform a susceptible potato variety, Desiree, with the binary vector pCIP68 harboring the RB gene. As a result, 19 transformed plants containing the RB gene were obtained. kanamycin resistance test and polymerase chain reaction (PCR) assays confirmed the integration of the T-DNA in the potato genome. The 19 transformed plants, also called transgenic events were subjected to infection under biosafety greenhouse conditions. Phytophthora infestans isolate POX067 of the EC-1 clonal lineage, commonly find in Peru, was used for the infection. Three of the 19 plants ([RB]54, [RB]56 and [RB]70) show high resistance levels to isolate POX067 of P. infestans.

Research advance in retinoblastoma / 中华实验眼科杂志

Retinoblastoma(RB) is the most common infant malignant tumor of eye.It seriously affects the life quality and life span.The rapid development of biological technology allows some new breakthroughs in the basic and clinical researches of RB.Current researches focus on its etiology and pathogenesis,and the ultimate aim is to guide clinical prevention,detection and management.Some literature revealed and summarized the histological source of RB,mutation detection of Rb gene,hereditary clue of RB susceptibility,and gene-therapy of RB.Gene therapy of RB is a new treating approach to RB in recent years,and its development brings a chance for achieving the goal of curing RB and improving patient prognosis.The research progress of RB is reviewed here.

Deficiency of pRb Decreases Hepatocyte Sensitivity to TGF-? / 中国生物工程杂志

Aim:to detect how Rb-deficiency will affect responses to TGF-? induced cell cycle arrest of hepatocyte.Methods:primary hepatocytes were isolated and cultured,and Rb-specific adenovirus siRNA was transformed into cells.Then TGF-? was added daily and cell growth and cell cycles variations.Western blot and FQ-RT-PCR were adopted to detect pRb,E2F,c-MYC and p16 expression changes.Results:Primary hepatocytes were isolated and infected with Rb-specific siRNA adenovirus.In control cells,treatment with TGF-? prevented cells to enter S phase via decreased cMYC activity,activation of P16INK4A activity.In Rb-null hepatocytes,E2F and cMYC activity decreased slightly but P16INK4A was not activated and the great majority of cells continued cycling.Rb is therefore central to TGF?-induced cell cycle arrest in hepatocytes.Conclusion:The present results show that otherwise genetically normal hepatocytes with disabled Rb genes respond less well to the antiproliferative effects of TGF-?.

Prognostic Significance of Immunohistochemical Expression of p53 and Retinoblastoma Gene Protein (pRB) in Curatively Resected Gastric Cancer

BACKGROUND: The aim of this study was to determine the prognostic significance of the expression of p53 and retinoblastoma (Rb) gene products in cases of curatively resected gastric adenocarcinoma, by immunohistochemical analysis. METHODS: Between January 1996 and December 2001, 736 curatively resected gastric cancer patients underwent immunohistochemical staining for p53 or Rb proteins (pRb), and we retrospectively analyzed the correlation of our results with the clinical outcomes of these cases. RESULTS: High levels of expression of p53 (> 25% p53-positive cells) and Rb (> 50% Rb-positive cells) proteins were detected in 40.1% and 43.7% of cases, respectively. Tubular type was found to frequently exhibit higher levels of p53 expression (high expression in 44.2%) than signet ring cell type (high expression in 26.0%) (p=0.042). The incidence of vascular invasion was lower in the high pRb expressors (43.2%) than in the pRb low expressors (56.8%), but this was not a statistically significant discrepancy (p=0.063). Preoperative CEA levels were found to be low in high pRb expressors: initial CEA level in the high pRb expressors was 2.31 +/- 3.30 ng/mL, and was 5.18 +/- 24.80 ng/mL in the low pRb expressors (p=0.033). Tumor depth and node metastasis were both independent of the levels of expression of p53 and Rb proteins. The seven-year overall survival rate and relapse-free survival rates of patients were 87.2% and 75.7%, respectively. Multivariate Cox regression analysis indicated that tumor stage, tumor size, patient age and pRb expression were the significant prognostic factors with regard to overall survival, and tumor stage and age were both significant factors with regard to relapse-free survival. CONCLUSION: Immunohistochemical staining of retinoblastoma gene products was an independent prognostic factor for the prediction of overall survival in curatively resected gastric cancer patients.

Expression of P16 and Rb Proteins in Gastric Carcinoma / 中国医师杂志

Objective It was designed to investigate the relationship between the productions of p16 and Rb genes expression and gastric carcinogenesis and evaluate the correlation between the expression of p16 and Rb genes in gastric carcinoma.Methods The expression of P16 and Rb proteins was examined in gastric carcinoma and precancerous lesion and normal gastric mucosa by streptavidin-peroxidase immunohistochemical method (S-P).Results The positive rates of P16 and Rb proteins expression showed as below: There were 96 25%(77/80) and 98 75%(79/80) in normal gastric mucosa, 92 00%(46/50) and 80 00%(40/50) in atypical hyperplasia gastric mucosa and 47 54%(58/122) and 59 84%(73/122) in gastric carcinoma respectively. The positive rates of P16 and Rb proteins expression in gastric carcinoma were significantly lower than that in normal gastric mucosa and atypical hyperplasia gastric mucosa (P

Analysis and Clinical Implication of Ha-ras, p53 and RB Gene Mutations and Infection of Bladder Cancer with Papillomavirus / 中国肿瘤生物治疗杂志

To clarify the clinical significance of alterations of Ha-ras, p53 and RB gene as well as infection with HPV16,18 in human bladder cancer, we examined the state of Ha-ras, p53 and RB genes, sequences of HPV16/18, and their association with clinicopathological parameters in 39 cases of bladder cancer and 7 cases of normal tissue, using nonisotopic PCR-SSCP and dot blot. The overall incidences of Ha-ras, p53 and RB gene mutation and HPV infection in tumor were 61.5% ,36% ,30.8% and 15.4% , respectively. The HPV positive rate was negatively correlated with clinical stage and pathological classification. Rather, the mutations of Ha-ras and p53 gene were positively correlated with the above clinical parameters. The incidence of Ha-ras gene mutation in recurring tumors was significantly higher than that in primary ones. A negative correlation between HPV infection and p53 mutation was also found. The results suggest that the above molecular events and their interaction play important roles in the development of bladder cancer, and that they wonld be of practical assistance in the prognosis and monitoring of bladder cancer.

Loss of heterozygosity on chromosome 10, 13q(Rb), 17p, and p53 gene mutations in human brain gliomas

Using the methods of restriction fragment length polymorphism (RFLP) and single strand conformation polymorphism (SSCP) analyses, we have examined 33 cases of human gliomas with various malignant grades to detect the deletions of putative tumor suppressor gene loci, chromosome 10, 13q(retinoblastoma gene, Rb), 17p, and p53 mutation. We observed loss of heterozygosity (LOH) at loci on chromosome 10 (36%), 13q(Rb) (54%), and 17p(50%) in malignant gliomas. There, however was no allelic loss on chromosome 10 and 17p in low-grade gliomas. Rb gene deletions were seen in low-grade gliomas, including oligodendroglioma and ependymoma. This finding suggests that Rb inactivation may be an early genetic event in the development and progression of gliomas. We correlated the results of LOH on chromosome 17p and p53 mutation. Among the 8 cases which showed LOH on chromosome 17p, only three cases (38%) revealed p53 mutations. Low incidence of p53 mutations in cases with chromosome 17p deletions suggests that some other tumor suppressor genes may be located on chromosome 17p.

Effect of blocking BRCAA1 gene with siRNA on proliferation of MCF-7 cells and expression of Rb gene / 中国肿瘤生物治疗杂志

Objective:To investigate the effect of blocking BRCAA1 gene expression with siRNA on the proliferation of tumor cell line MCF-7 and Rb gene expression.Methods:RNAi was employed to specifically knock down BRCAA1 expression.MCF-7 cells were transfected with complexes constructed with lipids and chemically synthesized Pre-designed anti-BRCAA1 siRNAs.The total RNA was isolated and reversely transcribed after 48 h.The expressions of BRCAA1 and Rb mRNA were determined by Real-Time PCR.Results:Compared with negative control,transfected MCF-7 cells had a 42.3% decrease in expression of BRCAA1 mRNA and an 11.1% increase in Rb mRNA expression.The inhibitory rate of MCF-7 cells proliferation was(81.6?6.1)%.Conclusion:There may be some antagonistic effect between BRCAA1 gene and Rb gene in proliferation of tumor cells,which provides a potential target for anti-tumor gene therapy.

Loss of Heterozygosity on Chromosome 10, 13, 17 and p53 Gene Mutations in Human Brain Gliomas

Gliomas, the most common primary tumors of the human central nervous system, are usually malignant and virtually incurable. They can be classified according to their cellular differentiation:astrocytoma, oligodendroglioma, and ependymoma. The majority of these brain tumors are astrocytomas, which typically progress through three histopathologically defined stages with the passage of time:one premalignant stage, low-grade astrocytoma, and two malignant stages, anaplastic astrocytoma and glioblastoma multiforme. Recent studies on the molecular mechanisms of carcinogensis have demonstrated a possible role for two classes of genes in neoplastic transformation:tumor suppressor genes and oncogenes. Tumor suppressor genes are wild-type alleles of genes that are believed to function normally in the cell to suppress cellular proliferation. Inactivation of both copies of suppressor gene may contribute to neoplastic transformation by removing a normal constraint to cell growth. The well characterised suppressor genes are RB gene and p53 gene. Gliomas, like most other cancers, are associated with several genetic changes, including oncogenes and suppressor genes. In an attempt to further our knowledge of tumor suppressor genes contributing glioma development and progression, restriction fragment length polymorphism(RFLP) analysis was done to determine loss of heterozygosity(LOH) on chromosome 10. 13q(RBI), 17p, and 22q containing putative tumor suppressor genes in 36 cases of human gliomas with various malignancy grades. And to detect p53 gene mutations at exon 5, 6, and 7 in 23 cases of malignant gliomas, polymerase chain reaction-single strand conformation polymorphisms(PCR-SSCP) analysis was performed. Loss of heterozygosity for loci on chromosome 10 were found in four of 5(60%) informative cases of glioblastoma multiforme and one of 2(50%) cases of anaplastic astrocytomas. Loss of heterozygosity on chromosome 17p was found in eight of 17(47%) informative cases of malignant gliomas, including 2 cases of anaplastic oligodendroglioma. There was no allelic loss of chromosome 10 and 17 in benign gliomas. Deletions on RBI locus were seen in six of 10(60%) informative cases of glioblastoma multiforme and two of 5(40%) informative cases of low-grade astrocytomas, suggesting that RBI gene may have a role associated with the early events in tumorigenesis. In PCR-SSCP analysis, six of 23(26%) cases of malignant gliomas, including one case of anaplastic oligodendroglioma, showed mobility shifts on exon 5 or 7 of p53 gene which suggest point mutations of this gene. There was no LOH at IGLC2 locus on chromosome 22. On the basis of the data presented here, it is possible to associate certain molecular abnormalities with gliomas of increasing grades of malignancy, deletion of RB gene, loss of heterozygosity on chromosome 17p, p53 gene mutation, and loss of allele on chromosome 10.

Loss of Heterozygosity on Chromosome 10, 13, 17 and p53 Gene Mutations in Human Brain Gliomas

Gliomas, the most common primary tumors of the human central nervous system, are usually malignant and virtually incurable. They can be classified according to their cellular differentiation:astrocytoma, oligodendroglioma, and ependymoma. The majority of these brain tumors are astrocytomas, which typically progress through three histopathologically defined stages with the passage of time:one premalignant stage, low-grade astrocytoma, and two malignant stages, anaplastic astrocytoma and glioblastoma multiforme. Recent studies on the molecular mechanisms of carcinogensis have demonstrated a possible role for two classes of genes in neoplastic transformation:tumor suppressor genes and oncogenes. Tumor suppressor genes are wild-type alleles of genes that are believed to function normally in the cell to suppress cellular proliferation. Inactivation of both copies of suppressor gene may contribute to neoplastic transformation by removing a normal constraint to cell growth. The well characterised suppressor genes are RB gene and p53 gene. Gliomas, like most other cancers, are associated with several genetic changes, including oncogenes and suppressor genes. In an attempt to further our knowledge of tumor suppressor genes contributing glioma development and progression, restriction fragment length polymorphism(RFLP) analysis was done to determine loss of heterozygosity(LOH) on chromosome 10. 13q(RBI), 17p, and 22q containing putative tumor suppressor genes in 36 cases of human gliomas with various malignancy grades. And to detect p53 gene mutations at exon 5, 6, and 7 in 23 cases of malignant gliomas, polymerase chain reaction-single strand conformation polymorphisms(PCR-SSCP) analysis was performed. Loss of heterozygosity for loci on chromosome 10 were found in four of 5(60%) informative cases of glioblastoma multiforme and one of 2(50%) cases of anaplastic astrocytomas. Loss of heterozygosity on chromosome 17p was found in eight of 17(47%) informative cases of malignant gliomas, including 2 cases of anaplastic oligodendroglioma. There was no allelic loss of chromosome 10 and 17 in benign gliomas. Deletions on RBI locus were seen in six of 10(60%) informative cases of glioblastoma multiforme and two of 5(40%) informative cases of low-grade astrocytomas, suggesting that RBI gene may have a role associated with the early events in tumorigenesis. In PCR-SSCP analysis, six of 23(26%) cases of malignant gliomas, including one case of anaplastic oligodendroglioma, showed mobility shifts on exon 5 or 7 of p53 gene which suggest point mutations of this gene. There was no LOH at IGLC2 locus on chromosome 22. On the basis of the data presented here, it is possible to associate certain molecular abnormalities with gliomas of increasing grades of malignancy, deletion of RB gene, loss of heterozygosity on chromosome 17p, p53 gene mutation, and loss of allele on chromosome 10.

EXPRESSION OF THE p16 AND Rb GENES mRNA AND PROTEIN LEVELS IN LUNG CANCER / 解放军医学杂志

The authors used immunohistochemistry and in situ hybridization to observe the expression of the p16 and Rb mRNA and protein levels in 89 cases of lung cancer. The results showed that the loss of p16 gene expression took place mainly in non small cell lung cancer, and loss of Rb gene expression mainly in small cell lung cancer. The expression of these genes on protein level fundamentally corresponded with mRNA level. It is suggested that the expression of these two genes are related to the histological type of lung cancer, and the p16 and Rb genes can be considered as one of molecular biological targets for gene classification diagnosis. There may exist a mechanism at gene translation level which leads to the inactivation of the p16 and Rb genes.