Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.27.4 (ribonuclease)
 6,621 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

P-glycoprotein (PGP), a transporter conferring multidrug resistance to cancer cells, is expressed in the kidney. C219 monoclonal antibody binding revealed PGP in proximal tubules and mesangium of mouse kidneys. A cell line (TKPTS) expressing PGP was developed from proximal tubules of the 8Tg(SV40E)Bri7 mouse. Northern blot analysis demonstrated a 5.0-kb message identified as mdr1 by ribonuclease protection assay. Cyclosporin A (CSA) at 0.15 and 10 microM increased cellular accumulation of verapamil (VRP) by 32 and 121%, respectively (P < 0.001). VRP at 5 microM increased steady-state cellular accumulation of CSA by 46% (P = 0.02). Basal-to-apical transport of the PGP substrate vinblastine was inhibited by VRP. Rhodamine-123 (R-123) influx was rapid and independent of PGP. R-123 efflux was inhibited by VRP and CSA. Inhibition of PGP transport by VRP, CSA, and PSC-833 decreased the 50% effective dose of adriamycin. The concomitant administration of VRP and CSA was not deleterious and coincided with preferential accumulation of VRP over CSA. Inhibition of PGP-mediated transport is demonstrated as a mechanism of renal cell toxicity.
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PMID:Expression and function of P-glycoprotein in a mouse kidney cell line. 765 14

Immunotoxins based on human and humanized ribonuclease may have potential for cancer therapy while exhibiting less toxic side effects and stimulating less of an immune response in humans than immunotoxins based on plant and bacterial toxins (1). Both recombinant RNase fusion proteins (2-4 see also Chapter 6 , this volume) and chemical RNase conjugates have been made and characterized. The cytotoxic potential of targeted ribonuclease was first demonstrated with bovine RNase conjugated to transferrin or an antibody directed against the human transferrin receptor (5). Antibody RNase conjugates have also been shown to have potent anti-tumor activity against human glioma cells in athymic mice (6) and to enhance the activity of vincristine in mdr1 multidrug-resistant colon cancer cells in vitro and in vivo (7). Recently, RNase chemically conjugated to an antibody against CD22 was found to specifically kill Daudi lymphoma cells in cell culture at picomolar concentrations (IC(50), 10-50 pM) and to exhibit potent antitumor activity in SCID mice with disseminated Daudi lymphoma (unpublished data). Methods for linking RNase to specific cell binding ligands are described.
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PMID:Construction of ribonuclease-antibody conjugates for selective cytotoxicity. 2131 38

Onconase, a ribonuclease isolated from Rana pipiens oocytes and early embryos, is a member of the RNase A superfamily. Onconase has anti-neoplastic properties both in vitro and in vivo, and is undergoing clinical evaluation. In the present study, Onconase was combined with or conjugated to MRK16, an anti-P-glycoprotein (Pgp) monoclonal antibody. The interaction of these combinations with vincristine (VCR) against parental and multidrug resistant (MDR), Pgp expressing, human colon carcinoma cells caused increased VCR cytotoxicity in vitro and enhanced survival of athymic nude mice given transplants of drug resistant HT-29(mdr1) cells in vivo. The results suggest that combination treatment with Onconase and other agents that modulate the chemosensitivity of Pgp-expressing human tumor cells has the potential to overcome MDR.
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PMID:Anti-tumor ribonuclease, combined with or conjugated to monoclonal antibody MRK16, overcomes multidrug resistance to vincristine in vitro and in vivo. 2154 69