Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.2.1.23 (beta-galactosidase)
 14,648 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Complex formation between the human papilloma virus type-16 E7 protein (HPV-16 E7) and the retinoblastoma suppressor protein (pRB) is believed to be important in the process of cellular transformation that leads to cervical carcinoma. Utilizing an in vitro solution assay as well as a plate binding assay that measures the association between HPV-16 E7 and pRB proteins, we have examined a series of synthetic HPV-16 E7 peptides. HPV-16 E7 peptides which lie between amino acid residues 14 and 32 were found to be potent inhibitors of E7/pRB binding. The minimal peptide structure that possessed full antagonist activity was N-acetyl-E7-(21-29)-peptide amide. This peptide inhibited 100% of E7/pRB binding and exhibited an IC50 of 40 nM in the plate binding assay. A purified beta-galactosidase-E7 fusion protein exhibited an IC50 of 2 nM in the same assay. These results suggest that other regions of the E7 molecule in addition to amino acids 21-29 may contributed to E7/pRB interaction. Analysis of E7-(20-29)-peptides containing single amino acid substitutions suggests that Cys24, Tyr23, Tyr25, Asp21, and Glu26 are important residues for maintaining maximal antagonist activity. This series of peptides should prove useful in analyzing the biological consequences of E7/pRB binding in HPV-infected cells.
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PMID:Identification of HPV-16 E7 peptides that are potent antagonists of E7 binding to the retinoblastoma suppressor protein. 219 78

Mice were immunized i.p. with soluble or heat-denatured protein antigens [ovalbumin, beta-galactosidase, or recombinant E7 protein of human papilloma virus type 16 (HBV)]. Heat-denatured (100 degrees C) preparations of these proteins were able to induce cytotoxic T lymphocytes (CTL) that recognize cells expressing the respective genes, whereas native protein was either inefficient or required up to 30-fold higher doses. If the heat-treated proteins were separated into aggregated and soluble fractions by ultracentrifugation, only the aggregated fractions were able to induce specific CTL; this is probably because of the easier access to one of the major histocompatibility complex class I loading pathways for exogenous antigen. Addition of the adjuvant aluminium hydroxide (alum) to aggregated proteins abolished their ability to induce CTL; thus, a condition leading to a strong antibody response appeared to inhibit CTL induction. Interestingly, immunization with heat-denatured ovalbumin plus alum increased the IgM/IgG1 ratio compared to immunization with native ovalbumin and alum. Immunization of B6 mice transgenic for an HLA-A2/H-2K(b) hybrid gene with heat-denatured, recombinant HPV 16-E7 protein induced D(b)-restricted CTL specific for the peptide 49-57 of E7, indicating that this epitope is immunodominant over any A2-restricted E7 epitope in these mice. A whole influenza virus preparation heated to 100 degrees C or even autoclaved was still able to induce virus-specific CTL and BALB/c spleen cells heated to 100 degrees C could still cross-prime minor H-specific CTL in B6 mice, although with lower efficiency than fresh spleen cells. Thus, aggregated proteins can be considered as components for future vaccines.
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PMID:Priming of cytotoxic T lymphocytes by five heat-aggregated antigens in vivo: conditions, efficiency, and relation to antibody responses. 934 85

The retinoblastoma protein (pRb), the gene product of the first reported tumour suppressor gene, is functionally inactivated by the E7 protein of high-risk human papillomavirus (HPV) found in most human cervical cancers. We have, in this study, constructed an adenoviral vector expressing wild-type pRb (Ad5-Rb) and used the constructed Ad5-Rb to transfect the osteosarcoma cell line Saos-2, and three cervical cancer cell lines HeLa, SiHa and C-33A. Our results showed that pRb caused G1 arrest in Saos-2 cells after transfection with Ad5-Rb. The number of colonies formed by the Ad5-Rb-transfected Saos-2 cells in soft agar was also found to be significantly lower (P<0.05) than those transfected with the adenoviral control expressing Escherichia coli beta-galactosidase (Ad5-LacZ). The transfection of Ad5-Rb caused an increase in the population of SiHa and C-33A cells in the G1 phase from 53.0 and 52.9% to 72.4 and 64.3%, respectively, but not in the HeLa cells. However, Ad5-Rb did not show any inhibitory effect on the growth of SiHa, HeLa and C-33A cells, and inhibition of colony formation in soft agar was not observed either. In contrast, flow cytometric analysis showed that Ad5-p53, a p53-expressing adenovirus, induced apoptosis, i.e. the appearance of sub-G1 peak, in all three tested cervical cancer cell lines. Nevertheless, the Ad5-p53-induced apoptosis was partially inhibited when Ad5-Rb was added simultaneously. These findings suggested that pRb may not be a good candidate for cervical cancer gene therapy. Our data also showed that the use of full-length pRb in combination with TP53 might not be a suitable strategy for cancer gene therapy.
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PMID:pRb-expressing adenovirus Ad5-Rb attenuates the p53-induced apoptosis in cervical cancer cell lines. 1172 Aug 46

Human papillomavirus (HPV) 18 is related not only to squamous cell carcinoma of the cervix, but also to adenocarcinoma and small cell carcinoma of the cervix, in which prognosis is known to be poor. Small interfering RNA (siRNA) that targets HPV18 E6 and E7 was tested in HPV18-positive cell lines to investigate its effect and investigate its mechanism of action. Nude mice were also tested in a combination of siRNA and atelocollagen to determine whether it might be useful as a new molecule-targeting therapy for cervical cancer. siRNAs targeting HPV18 E6 and E7 were transfected into cervical cancer cells in vitro and they were investigated for cell growth inhibition, expression of E6 and E7 mRNA, expression of retinoblastoma protein, and senescence-associated beta-galactosidase staining. Sequence-specific siRNA inhibited cell growth. Decreased expression of E6 and E7 mRNA followed with E7 protein was observed in the transfected cells, but the expression of retinoblastoma protein and the beta-galactosidase staining increased, suggesting cell growth inhibitory effect through senescence. Treatment of xenografts established from SKG-II cells with siRNA specific for E6 and E7 obviously suppressed tumor growth in vivo. These results indicate that atelocollagen-mediated delivery of siRNA HPV18 E6 and E7 can be used as a novel therapeutic approach for cervical cancer.
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PMID:Intratumor injection of small interfering RNA-targeting human papillomavirus 18 E6 and E7 successfully inhibits the growth of cervical cancer. 1686 69