Disease relevance of RB1

• Interestingly, when compared to an antiserum produced against bovine 106-121 peptidic sequence (RB1), we found strikingly different ratios of the PrP res glycoforms, in both cattle with BSE and sheep with natural scrapie, but not in scrapie infected mice [1].
• 3':5'-Cyclic-AMP phosphodiesterase (EC 3.1.4.17) and the activating factor of cyclic nucleotide phosphodiesterase were detected in cultured human cell lines from patients with lymphoblastic leukemia and retinoblastoma and in the Brown-Pearce (rabbit) carcinoma [2].
• Fifty-five retinoblastoma specimens were studied by a sensitive immunoperoxidase method to determine the intermediate filament types present in human retina and retinoblastoma [3].
• Examination of the retinoblastoma protein expressions in these adenocarcinoma cell lines revealed a phosphorylated pattern that correlated inversely with the mucin synthesis status of these cell lines.(ABSTRACT TRUNCATED AT 250 WORDS)[4]
• The results indicate that certain neoplastic cells of medulloblastoma are capable of expression of photoreceptor-specific proteins and, thus, may be closely related to tumor cells of retinoblastoma and pineocytomas previously shown to bind antisera against retinal S-antigen and opsin [5].

High impact information on RB1

• The retinoblastoma gene (Rb) product is a negative regulator of cellular proliferation, an effect that could be mediated in part at the transcriptional level through its ability to complex with the sequence-specific transcription factor DRTF1 [6].
• Complex formation of human papillomavirus E7 proteins with the retinoblastoma tumor suppressor gene product [7].
• To investigate the consequence of the shear-induced p53 response, we found that prolonged laminar shear stress caused increases of the growth arrest proteins GADD45 (growth arrest and DNA damage inducible protein 45) and p21(cip1), as well as a decrease in phosphorylation of the retinoblastoma gene product [8].
• The resulting inhibition of cyclin-dependent kinase and hypophosphorylation of retinoblastoma protein lead to endothelial cell cycle arrest [8].
• Similarly, our results indicate that activation of the Rb pathway can prevent apoptosis induced by repression of the HPV18 E6 gene in HeLa cells [9].

Biological context of RB1

• Role of the retinoblastoma pathway in senescence triggered by repression of the human papillomavirus E7 protein in cervical carcinoma cells [9].
• To address the possibility that FGF-2 functions as a modulator of fiber cell survival, alphaAIgFGF-2 transgenic mice were crossed to transgenic mice exhibiting extensive apoptosis in the lens due to the functional inactivation of the retinoblastoma protein (alphaAE7 transgenic mice) [10].
• However, how RB phosphorylation might be regulated in apoptotic or postmitotic cells, such as neurons, remains unclear [11].
• Phosphorylation of RB results in a consequent loss of its ability to inhibit cell cycle progression [11].
• D-type CDKs, CDK4, and CDK6, phosphorylate retinoblastoma protein and are believed to regulate through the G1 phase of the cell cycle [12].

Anatomical context of RB1

• Importantly, there was an absolute correlation between the ability of mutant E7 proteins to inactivate the Rb pathway and to inhibit senescence in HeLa cells [9].
• Phorbol ester inhibits the phosphorylation of the retinoblastoma protein without suppressing cyclin D-associated kinase in vascular smooth muscle cells [13].
• Given the high frequency of progression to highly malignant phenotypes, the retinoblastoma susceptibility and related genes are good candidates as targets for mutations or deletions in early steps of human thyroid carcinogenesis [14].
• In summary, both fibroblast and pigment epithelium functioned as an effective carrier cell layer for retinoblastoma cells [15].
• The capacity to convert appreciable amounts of 18:3 to 22:6 appears to be a unique property of the retinoblastoma cells as compared with other continuously cultured cell lines [16].

Associations of RB1 with chemical compounds

• Retinoid-binding proteins in retinoblastoma tumors [17].
• More 18:3 than linoleic acid (18:2 n-6) was incorporated into phospholipids by the retinoblastoma cultures, and 18:3 was channeled to a larger extent into the ethanolamine glycerophospholipid fraction [16].
• Our results show that apigenin inhibits endothelial-cell proliferation by blocking the cells in the G(2)/M phase as a result of the accumulation of the hyperphosphorylated form of the retinoblastoma protein [18].
• Notably, doxazosin inhibited phosphorylation of Rb and expression of cyclin A, both of which are necessary for cell cycle progression [19].
• The difference in exposure rate between coralline hydroxyapatite (4.9%) and porous polyethylene (8.1%) implants is primarily related to a higher reported complication rate of uncovered porous polyethylene implants, particularly in retinoblastoma patients [20].

Analytical, diagnostic and therapeutic context of RB1

• A combination of Western blot, Northern blot, and radiolabeled ligand-binding techniques was used to investigate retinoid-binding proteins in retinoblastoma (RB) cells from fresh tumors and from 19 RB tumor lines cultured in vitro [17].
• Finally, we show that immunoprecipitation of RB from embryonic mouse brain homogenate results in the coprecipitation of Cdk5 and that Cdk5 kinase activity is maximal during late embryonic development, a period when programmed cell death of developing neurons is greatest [11].
• One retinoblastoma eye was also studied by indirect immunofluorescence microscopy of frozen sections with identical results [3].
• In both the iris and retinal pigment epithelium co-cultures with retinoblastoma cells, there were increased numbers of mitochondria in the tumor cells in areas adjacent to pigment epithelium but no pinocytotic vesicles were seen [15].
• Comparative gene mapping of lactoperoxidase, retinoblastoma, and alpha-lactalbumin genes in cattle, sheep, and goats [21].

References