Drug metabolism is an orchestrated process in which drugs are metabolized and disposed through a series of specialized enzymes and transporters.Alterations in the expression and/or activity of these enzymes and transp...Drug metabolism is an orchestrated process in which drugs are metabolized and disposed through a series of specialized enzymes and transporters.Alterations in the expression and/or activity of these enzymes and transporters can affect the bioavailability(pharmacokinetics,or PK)and therapeutic efficacy(pharmacodynamics,or PD)of drugs.Recent studies have suggested that the long non-coding RNAs(IncRNAs)are highly relevant to drug metabolism and drug resistance,including chemoresistance in cancers,through the regulation of drug metabolism and disposition related genes.This review summarizes the regulation of enzymes,transporters,or regulatory proteins involved in drug metabolism by IncRNAs,with a particular emphasis on drug metabolism and chemo-resistance in cancer patients.The perspective strategies to integrate multi-dimensional pharmacogenomics data for future in-depth analysis of drug metabolism related IncRNAs are also proposed.Understanding the role of IncRNAs in drug metabolism will not only facilitate the identification of novel regulatory mechanisms,but also enable the discovery of IncRNA-based biomarkers and drug targets to personalize and improve the therapeutic outcome of patients,including cancer patients.展开更多
Pregnane and Xenobiotic Receptor (PXR; or Steroid and Xenobiotic Receptor, SXR), a new member of the nuclear receptor superfamily, is thought to modulate a network of genes that are involved in xenobiotic metabolism a...Pregnane and Xenobiotic Receptor (PXR; or Steroid and Xenobiotic Receptor, SXR), a new member of the nuclear receptor superfamily, is thought to modulate a network of genes that are involved in xenobiotic metabolism and elimination. To further explore the role of PXR in body’s homeostatic mechanisms, we for the first time, report successful prokary- otic expression and purification of full-length PXR and preparation of polyclonal antibody against the whole protein. The full-length cDNA encoding a 434 amino acids protein was sub-cloned into prokaryotic expression vector, pET-30b and transformed into E. coli BL21(DE3) cells for efficient over expression. The inclusion body fraction, containing the expressed recombinant protein, was purified first by solubilizing in sarcosine extraction buffer and then by affinity column chromatography using Ni-NTA His-Bind matrix. The efficacy of anti-PXR antibody was confirmed by immunocytology, Western blot analysis, EMSA and immunohistochemistry. The antibody obtained was capable of detecting human and mouse PXR with high specificity and sensitivity. Immunofluorescence staining of COS-1 cells transfected with human or mouse PXR showed a clear nuclear localization. Results from immunohistochemistry showed that level of PXR in liver sections is immunologically detectable in the nuclei. Similar to exogenously transfected PXR, Western blot analysis of cell extract from HepG2 and COLO320DM cells revealed a major protein band for endogenous PXR having the expected molecular weight of 50 kDa. Relevance of other immunodetectable bands with reference to PXR isoforms and current testimony are evaluated. Advantages of antibody raised against full-length PXR protein for functional characterization of receptor is discussed and its application for clinical purposes is envisaged.展开更多
The nuclear receptors pregnane X receptor(PXR) and constitutive androstane receptor(CAR) were cloned and/or established as xenobiotic receptors in 1998.Due to their activities in the transcriptional regulation of phas...The nuclear receptors pregnane X receptor(PXR) and constitutive androstane receptor(CAR) were cloned and/or established as xenobiotic receptors in 1998.Due to their activities in the transcriptional regulation of phase I and phase II enzymes as well as drug transporters,PXR and CAR have been defined as the master regulators of xenobiotic responses.The discovery of PXR and CAR provides the essential molecular basis by which drugs and other xenobiotic compounds regulate the expression of xenobiotic enzymes and transporters.This article is intended to provide a historical overview on the discovery of PXR and CAR as xenobiotic receptors.展开更多
Vitamin K(VK), which was originally identified as a cofactor involved in the production of functional coagulation factors in the liver, has been shown to be involved in various aspects of physiological and pathologica...Vitamin K(VK), which was originally identified as a cofactor involved in the production of functional coagulation factors in the liver, has been shown to be involved in various aspects of physiological and pathological events, including bone metabolism, cardiovascular diseases and tumor biology. The mechanisms and roles of VK are gradually becoming clear. Several novel enzymes involved in the VK cycle were identified and have been shown to be linked to tumorigenesis. The VKs have been shown to suppress liver cancer cell growth through multiple signaling pathways via the transcription factors and protein kinases. A VK2 analog was applied to the chemoprevention of hepatocellular carcinoma(HCC) recurrence after curative therapy and was shown to have beneficial effects, both in the suppression of HCC recurrence and in patient survival. Although a large scale randomized control study failed to demonstrate the suppression of HCC recurrence, a meta-analysis suggested a beneficial effect on the long-term survival of HCC patients. However, the beneficial effects of VK administration alone were not sufficient to prevent or treat HCC in clinical settings. Thus its combination with other anti-cancer reagents and the development of more potent novel VK derivatives are the focus of ongoing research which seeks to achieve satisfactory therapeutic effects against HCC.展开更多
基金supported in part by NIH grant ES030429(to W.X.)and CA222274(to D.Y.)supported in part by the Joseph Koslow Endowed Professorship from the University of Pittsburgh School of Pharmacy.
文摘Drug metabolism is an orchestrated process in which drugs are metabolized and disposed through a series of specialized enzymes and transporters.Alterations in the expression and/or activity of these enzymes and transporters can affect the bioavailability(pharmacokinetics,or PK)and therapeutic efficacy(pharmacodynamics,or PD)of drugs.Recent studies have suggested that the long non-coding RNAs(IncRNAs)are highly relevant to drug metabolism and drug resistance,including chemoresistance in cancers,through the regulation of drug metabolism and disposition related genes.This review summarizes the regulation of enzymes,transporters,or regulatory proteins involved in drug metabolism by IncRNAs,with a particular emphasis on drug metabolism and chemo-resistance in cancer patients.The perspective strategies to integrate multi-dimensional pharmacogenomics data for future in-depth analysis of drug metabolism related IncRNAs are also proposed.Understanding the role of IncRNAs in drug metabolism will not only facilitate the identification of novel regulatory mechanisms,but also enable the discovery of IncRNA-based biomarkers and drug targets to personalize and improve the therapeutic outcome of patients,including cancer patients.
文摘Pregnane and Xenobiotic Receptor (PXR; or Steroid and Xenobiotic Receptor, SXR), a new member of the nuclear receptor superfamily, is thought to modulate a network of genes that are involved in xenobiotic metabolism and elimination. To further explore the role of PXR in body’s homeostatic mechanisms, we for the first time, report successful prokary- otic expression and purification of full-length PXR and preparation of polyclonal antibody against the whole protein. The full-length cDNA encoding a 434 amino acids protein was sub-cloned into prokaryotic expression vector, pET-30b and transformed into E. coli BL21(DE3) cells for efficient over expression. The inclusion body fraction, containing the expressed recombinant protein, was purified first by solubilizing in sarcosine extraction buffer and then by affinity column chromatography using Ni-NTA His-Bind matrix. The efficacy of anti-PXR antibody was confirmed by immunocytology, Western blot analysis, EMSA and immunohistochemistry. The antibody obtained was capable of detecting human and mouse PXR with high specificity and sensitivity. Immunofluorescence staining of COS-1 cells transfected with human or mouse PXR showed a clear nuclear localization. Results from immunohistochemistry showed that level of PXR in liver sections is immunologically detectable in the nuclei. Similar to exogenously transfected PXR, Western blot analysis of cell extract from HepG2 and COLO320DM cells revealed a major protein band for endogenous PXR having the expected molecular weight of 50 kDa. Relevance of other immunodetectable bands with reference to PXR isoforms and current testimony are evaluated. Advantages of antibody raised against full-length PXR protein for functional characterization of receptor is discussed and its application for clinical purposes is envisaged.
基金supported in part by the Joseph Koslow Endowed Professorship from the University of Pittsburgh School of Pharmacy
文摘The nuclear receptors pregnane X receptor(PXR) and constitutive androstane receptor(CAR) were cloned and/or established as xenobiotic receptors in 1998.Due to their activities in the transcriptional regulation of phase I and phase II enzymes as well as drug transporters,PXR and CAR have been defined as the master regulators of xenobiotic responses.The discovery of PXR and CAR provides the essential molecular basis by which drugs and other xenobiotic compounds regulate the expression of xenobiotic enzymes and transporters.This article is intended to provide a historical overview on the discovery of PXR and CAR as xenobiotic receptors.
文摘Vitamin K(VK), which was originally identified as a cofactor involved in the production of functional coagulation factors in the liver, has been shown to be involved in various aspects of physiological and pathological events, including bone metabolism, cardiovascular diseases and tumor biology. The mechanisms and roles of VK are gradually becoming clear. Several novel enzymes involved in the VK cycle were identified and have been shown to be linked to tumorigenesis. The VKs have been shown to suppress liver cancer cell growth through multiple signaling pathways via the transcription factors and protein kinases. A VK2 analog was applied to the chemoprevention of hepatocellular carcinoma(HCC) recurrence after curative therapy and was shown to have beneficial effects, both in the suppression of HCC recurrence and in patient survival. Although a large scale randomized control study failed to demonstrate the suppression of HCC recurrence, a meta-analysis suggested a beneficial effect on the long-term survival of HCC patients. However, the beneficial effects of VK administration alone were not sufficient to prevent or treat HCC in clinical settings. Thus its combination with other anti-cancer reagents and the development of more potent novel VK derivatives are the focus of ongoing research which seeks to achieve satisfactory therapeutic effects against HCC.
