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Targeted inhibition of glucuronidation markedly improves drug efficacy in mice - a model.

ABSTRACT: Finding UDP-glucuronosyltransferases (UGT) require protein kinase C-mediated phosphorylation is important information that allows manipulation of this critical system. UGTs glucuronidate numerous aromatic-like chemicals derived from metabolites, diet, environment and, inadvertently, therapeutics to reduce toxicities. As UGTs are inactivated by downregulating PKCs with reversibly-acting dietary curcumin, we determined the impact of gastro-intestinal glucuronidation on free-drug uptake and efficacy using immunosuppressant, mycophenolic acid (MPA), in mice. Expressed in COS-1 cells, mouse GI-distributed Ugt1a1 glucuronidates curcumin and MPA and undergoes irreversibly and reversibly dephosphorylation by PKC-specific inhibitor calphostin-C and general-kinase inhibitor curcumin, respectively, with parallel effects on activity. Moreover, oral curcumin-administration to mice reversibly inhibited glucuronidation in GI-tissues. Finally, successive oral administration of curcumin and MPA to antigen-treated mice increased serum free MPA and immunosuppression up to 9-fold. Results indicate targeted inhibition of GI glucuronidation in mice markedly improved free-chemical uptake and efficacy using MPA as a model.

SUBMITTER: Basu NK

PROVIDER: S-EPMC2034522 | biostudies-literature | 2007 Aug

REPOSITORIES: biostudies-literature

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Targeted inhibition of glucuronidation markedly improves drug efficacy in mice - a model.

Basu Nikhil K NK Kole Labanyamoy L Basu Mousumi M McDonagh Antony F AF Owens Ida S IS

Biochemical and biophysical research communications 20070614 1

Finding UDP-glucuronosyltransferases (UGT) require protein kinase C-mediated phosphorylation is important information that allows manipulation of this critical system. UGTs glucuronidate numerous aromatic-like chemicals derived from metabolites, diet, environment and, inadvertently, therapeutics to reduce toxicities. As UGTs are inactivated by downregulating PKCs with reversibly-acting dietary curcumin, we determined the impact of gastro-intestinal glucuronidation on free-drug uptake and efficac ...[more]

PMID: 17586469

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Project description:Targeted delivery of anticancer drugs to tumor cells using monoclonal antibodies against oncogenic cell surface receptors is an emerging therapeutic strategy. These strategies include drugs directly conjugated to monoclonal antibodies through chemical linkers (Antibody-Drug Conjugates, ADCs) or those encapsulated within nanoparticles that in turn are conjugated to targeting antibodies (Antibody-Nanoparticle Conjugates, ANPs). The recent FDA approval of the ADC Trastuzumab-TDM1 (Kadcyla; Genentech; San Francisco) for the treatment of ErbB2-overexpressing metastatic breast cancer patients has validated the strong potential of these strategies. Even though the activity of ANPs and ADCs is dependent on lysosomal traffic, the roles of the endocytic route traversed by the targeted receptor and of cancer cell-specific alterations in receptor dynamics on the efficiency of drug delivery have not been considered in these new targeted therapies. For example, constitutive association with the molecular chaperone HSP90 is thought to either retard ErbB2 endocytosis or to promote its recycling, traits undesirable for targeted therapy with ANPs and ADCs. HSP90 inhibitors are known to promote ErbB2 ubiquitination, targeting to lysosome and degradation. We therefore hypothesized that ErbB2-targeted drug delivery using Trastuzumab-conjugated nanoparticles could be significantly improved by HSP90 inhibitor-promoted lysosomal traffic of ErbB2. Studies reported here validate this hypothesis and demonstrate, both in vitro and in vivo, that HSP90 inhibition facilitates the intracellular delivery of Trastuzumab-conjugated ANPs carrying a model chemotherapeutic agent, Doxorubicin, specifically into ErbB2-overexpressing breast cancer cells, resulting in improved antitumor activity. These novel findings highlight the need to consider oncogene-specific alterations in receptor traffic in the design of targeted drug delivery strategies. We suggest that combination of agents that enhance receptor endocytosis and lysosomal routing can provide a novel strategy to significantly improve therapy with ANPs and ADCs.

Dataset Information

Targeted inhibition of glucuronidation markedly improves drug efficacy in mice - a model.

Publications

Targeted inhibition of glucuronidation markedly improves drug efficacy in mice - a model.

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