Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.6.3.44 (P-glycoprotein)
 13,344 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

P-glycoprotein (Pgp) and pi-class glutathione S-transferase (GSTP1-1) are thought to be correlated with multiple drug resistance. In immunohistochemical staining, non-seminomatous germ cell tumours, which are more refractory than seminomas to anti-cancer chemotherapy, frequently expressed Pgp and GSTP1-1. Western blot analysis demonstrated lower amount of GSTP1-1 in seminoma than in teratoma. These results suggest that Pgp and GSTP1-1 might contribute to drug resistance in testis cancers.
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PMID:Immunohistochemical detection of P-glycoprotein and GSTP1-1 in testis cancer. 810 Apr 42

Previous studies in our laboratory have shown that the phase III efflux transporter multidrug-resistance protein (MRP)1 can act synergistically with the phase II conjugating glutathione S-transferases (GST) to confer resistance to the toxicities of some electrophilic drugs and carcinogens. To determine whether the distinct efflux transporter MRP2 could also potentiate GST-mediated protection from electrophilic toxins, we examined the effect of regulatable GSTP1-1 expression in MRP2-rich HepG2 cells on 4-nitroquinoline 1-oxide (4NQO)-induced cytotoxicity and genotoxicity (nucleic-acid adduct formation). Expression of GSTP1-1 was associated with a fourfold to tenfold protection from 4NQO-induced cytotoxicity. Inhibition of MRP2-mediated efflux activity by sulfinpyrazone or cyclosporin A completely reversed GSTP1-1-associated resistance-a result indicating that GSTP1-1-mediated cytoprotection is absolutely dependent on MRP2 efflux activity. Moreover, MRP2 efflux activity also augmented GSTP1-1-mediated protection from 4NQO-induced nucleic-acid adduct formation. We conclude that MRP2-mediated efflux of the glutathione conjugate of 4NQO and/or another toxic derivative of 4NQO is required to support GSTP1-1-associated protection from 4NQO toxicities in HepG2 cells.
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PMID:Role of multidrug-resistance protein 2 in glutathione S-transferase P1-1-mediated resistance to 4-nitroquinoline 1-oxide toxicities in HepG2 cells. 1110 62