Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.4.2.30 (PARP)
 13,611 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Poly(ADP ribose) polymerase (EC 2.4.2.30) was studied using monoclonal antibodies for three different epitopes on the enzyme. The epitopes were mapped in relation to the functional domains of the protein and the inhibitory properties of the antibodies. The intranuclear and interspecies immunoreactivity of the enzyme was also investigated. The epitope of antibody 2 was mapped to the 17 kDa fragment generated by chymotryptic digestion of the C-terminal 54 kDa NAD-binding domain. Antibody 9 binds to the N-terminal 29 kDa fragment of the DNA binding domain and inhibits the enzyme activity by 80%. This antibody was used to purify poly(ADP ribose) polymerase by immunoaffinity chromatography. The third antibody binds to a central 36 kDa fragment that possesses part of the DNA-binding domain and the automodification domain. This antibody increases the enzymatic activity by 30%. An analysis of the species cross-reactivity of the antibodies was carried out by immunoblot analysis of nuclear proteins. Antibody 10 binding was detected in rat FR3T3 cells, Chinese hamster ovary cells (CHO) and epidermoid carcinoma lung human cells (CALU-1). The other two antibodies are specific for the human and bovine enzymes. Western blot analysis showed the association of poly(ADP ribose) polymerase with residual nuclear material obtained after nuclease treatment and high-salt extraction. Immunofluorescence studies with the three different monoclonals demonstrated that accessibility of the epitopes varies in the nucleus.
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PMID:Structural and functional analysis of poly(ADP ribose) polymerase: an immunological study. 245 68

The understanding of the molecular mechanisms which regulate cancer cell sensitivity to epidermal growth factor receptor (EGFR) inhibitors is necessary for the optimal use of these drugs in cancer treatment. We developed an in vitro model of acquired resistance to two EGFR tyrosine kinase inhibitors (TKI), erlotinib and gefitinib, by continuously treating the human non-small cell lung cancer (NSCLC) cell line CALU-3 with escalating doses of each drug. In these two EGFR inhibitor-resistant cancer cell lines a significant increase in the expression of activated, phosphorylated AKT and of survivin compared to parental cells was observed. Treatment with several agents known to target directly or indirectly the AKT signalling pathway did not affect significantly EGFR inhibitor-resistant cancer cell proliferation. In contrast, bortezomib, a proteasome inhibitor, induced a significant inhibition of cancer cell growth and an increase in apoptosis in EGFR inhibitor-resistant cancer cells as compared to treatment with LY294002, a PI3K inhibitor, suggesting that, in addition to interference with AKT signalling, other mechanisms are involved in the pro-apoptotic effects of bortezomib. Bortezomib treatment activated endoplasmic reticulum (ER) stress-mediated apoptosis, as demonstrated by the induction of GADD153, an ER stress-inducible transcription factor, and of the death receptor DR5, in EGFR inhibitor-resistant cells, but not in parental cells. This effect resulted in the activation of the extrinsic apoptotic pathway, as shown by caspase 8 dependent-PARP and bid cleavage. Bortezomib significantly inhibited the growth of EGFR inhibitor-resistant CALU-3 cells which were established as subcutaneous tumor xenografts in athymic nude mice. These results suggest that bortezomib treatment could be a useful approach to overcome resistance to anti-EGFR therapies.
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PMID:Antitumor activity of bortezomib in human cancer cells with acquired resistance to anti-epidermal growth factor receptor tyrosine kinase inhibitors. 2061 23