The fields of pharmacogenetics and pharmacogenomics have become increasingly promising regarding the clinical application of genetic data to aid in prevention of adverse reactions. Specific screening tests can predict which animals express modified proteins or genetic sequences responsible for adverse effects associated with a drug. Among the genetic variations that have been investigated in dogs, the multidrug resistance gene (MDR) is the best studied. However, other genes such as CYP1A2 and CYP2B11 control the protein syntheses involved in the metabolism of many drugs. In the present study, the MDR-1, CYP1A2 and CYP2B11 genes were examined to identify SNP polymorphisms associated with these genes in the following four canine breeds: Uruguayan Cimarron, Border Collie, Labrador Retriever and German Shepherd. The results revealed that several SNPs of the CYP1A2 and CYP2B11 genes are potential targets for drug sensitivity investigations.
Animals ; Aryl Hydrocarbon Hydroxylases/*genetics/metabolism ; Cytochrome P-450 CYP1A2/*genetics/metabolism ; Dogs/*genetics/metabolism ; P-Glycoprotein/*genetics/metabolism ; *Polymorphism, Single Nucleotide ; Steroid Hydroxylases/*genetics/metabolism

In pancreatic acinar cells Ca(2+)-dependent secretagogues promote the fusion of zymogen granules (ZG) with the apical plasma membrane (PM) and exocytosis of digestive enzymes. In addition to exocytotic fusion complexes between SNARE proteins in the ZG membrane (ZGM) and the apical PM, enzyme secretion elicited by Ca(2+)-dependent secretagogues requires cytosolic Cl and K+ and is inhibited by blockers of Cl- and K+-channels. We have identified a Cl-conductance activated by ATP, and a K+-conductance (with properties similar to ATP-sensitive K+-channels), regulated by the granule matrix protein Zg-16p in the ZGM. Both conductances are inversely regulated by a 65-kD mdr1 gene product. We have also identified a novel Ca(2+)-activated anion conductance in ZGM, the Ca(2+)-sensitivity of which increases 50-fold when Cl is replaced by 1. This conductance is blocked by micromolar H2-DIDS or DTT, reminiscent of a family of epithelial Ca(2+)-activated Cl -channels (CaCC). Expression of a CaCC in exocrine pancreas has been confirmed by RT-PCR analysis, and by immunoblotting and immunogold labeling of ZG membranes. These data suggest that ion channels in the ZGM are essential elements in pancreatic exocytosis.
Animal ; Chloride Channels/metabolism* ; Chloride Channels/genetics ; Exocytosis/physiology* ; Gene Expression/physiology ; P-Glycoprotein/metabolism ; P-Glycoprotein/genetics ; Pancreas/secretion* ; Pancreas/cytology ; Potassium Channels/metabolism* ; Potassium Channels/genetics ; Secretory Vesicles/secretion ; Secretory Vesicles/metabolism* ; Support, U.S. Gov't, P.H.S.

Resistance to anticancer chemotherapeutic drugs remains a major obstacle in cancer chemotherapy. A variety of mechanisms responsible for drug resistance has been posed. Mdr gene overexpression and detoxification by glutathione are believed to be involved in such mechanisms. Recently, we established two low-dose cisplatin-resistant human bladder cancer cell lines, T24RO.5 and T24R1, which showed resistance at O.5 hg/ml and 1 hg/ml of cisplatin, respectively. The resistance of T24RO.5 and T24R1 cells to cisplatin were 9.4 and 9.37 fold compared to that of the parental T24 cells In this study, we investigated the total glutathione content and p-glycoprotein expression, a mdr gene product, in parent and resistant cell lines to elucidate the drug resistance mechanism to cisplatin. Glutathione content was measured by biochemical method. P-glycoprotein expression was measured by flowcytometry using monoclonal antibody to p-glycoprotein. Glutathione content and p-glycoprotein expression were not different between parental and all resistant cell lines. These results suggest that mdr gene and glutathione do not play a role in cisplatin resistance mechanism in these low-dose cisplatin-resistant cell lines. Further work will be necessary to determine the mechanism of drug resistance in this model.
Cell Line* ; Cisplatin* ; Drug Resistance ; Drug Therapy ; Genes, MDR* ; Glutathione* ; Humans ; Metabolism* ; P-Glycoprotein ; Parents ; Urinary Bladder Neoplasms ; Urinary Bladder*

<p>OBJECTIVETo detect the redistribution of platelet surface glycoprotein (GP)Ib alpha and cytoskeleton reorganization in the course of thrombin receptor activation, and investigate the mechanism of GPIb alpha re-translocation and the role of thrombin receptors in platelet signal transduction.p><p>METHODSThe thrombin receptor activating peptide (PAR1-AP, TRAP) was used for stimulating platelet at different time points (0 - 60 min), then the platelet surface GPIb alpha and P-selectin were examined with flow cytometry, and the alterations of GPIb alpha, actin and myosin were analyzed in cytoskeleton by Western blot and GPIb alpha immunoprecipitation. Cytochalasin D and/or Apyrase VII were used for investigating their inhibitory effect on platelet activation.p><p>RESULTSAn increase of P-selectin and reversible internalization of GPIb alpha were observed within platelets upon TRAP activation, and transient changes of actin, myosin and GPIb alpha/myosin, GPIb alpha/actin association were also found in this course. These changes were apparently blocked by cytochalasin D, which inhibited the incorporation of GPIb alpha, actin and myosin into cytoskeleton. Apyrase VII had a weak effect on GPIb alpha internalization, although it accelerated the return of GPIb alpha to platelet surface. In addition, Apyrase VII also quickened the GPIb alpha disappearance in cytoskeleton and the dissociation of GPIb/myosin or GPIb/actin during activation.p><p>CONCLUSIONThrombin receptor activation takes part in platelet signal transduction, inducing a reversible redistribution of GPIb alpha. This process is related to cytoskeleton reorganisation and ADP.p>
Actins ; metabolism ; Blood Platelets ; cytology ; drug effects ; metabolism ; Blotting, Western ; Cells, Cultured ; Cytoskeleton ; metabolism ; Humans ; Myosins ; metabolism ; P-Selectin ; metabolism ; Peptide Fragments ; pharmacology ; Platelet Activation ; drug effects ; physiology ; Platelet Glycoprotein GPIb-IX Complex ; metabolism ; Receptors, Thrombin ; metabolism ; physiology

<p>OBJECTIVETo explore the effect of Danhong Injection (DHI) on platelet activation and inflammatory factors in patients of acute coronary syndrome (ACS) after intervention therapy.p><p>METHODSOne hundred ACS patients were randomly assigned to the DHI group and the control group equally. Both were treated with the conventional treatment, including aspirin, clopidogrel, beta-receptor blocker, angiotensin converting enzyme inhibitor, etc. for 2 weeks after percutaneous coronary intervention (PCI), and to the patients in the DHI group, intravenous dripping of DHI was given simultaneously. Fasting venous blood of patients were collected before PCI and on the next morning of PCI to determine the platelet activation indices, expression of CD62p and receptor complex of glucose protein (GP) II b/III a by flow cytometry; plasma fibrinogen C (FIB-C) by scattering turbidimetry, and serum high-sensitivity C-reactive protein (hs-CRP) with emulsoid immuno-enhancing turbidimetric test kit. The outcomes were compared with those determined in 40 healthy persons for control.p><p>RESULTSSerum levels of CD62p, GP II b/III a, FIB-C and hs-CRP in ACS patients were significantly higher than those in the healthy control (all P<0.01), and those were significantly higher after PCI than before PCI (P <0.05 or P<0.01). After being treated for 2 weeks, the 4 platelet activation indices were lowered to different extent in both groups, but the lowering in the DHI group was more significant than that in the control group (P<0.05).p><p>CONCLUSIONDHI can inhibit the platelet activation and inflammatory reaction in ACS patients after PCI.p>
Acute Coronary Syndrome ; metabolism ; therapy ; Aged ; Angioplasty, Balloon, Coronary ; Drugs, Chinese Herbal ; therapeutic use ; Female ; Fibrinogen ; metabolism ; Humans ; Inflammation ; drug therapy ; metabolism ; Male ; Middle Aged ; P-Selectin ; blood ; Platelet Activation ; Platelet Glycoprotein GPIIb-IIIa Complex ; metabolism

MDR1 promoter has been shown to contain heat shock elements (HSE), and it has been reported that FM3A/M and P388/M MDR cells show a constitutively activated heat shock factor (HSF), suggesting that HSF might be an important target for reversing the multidrug resistance. Therefore, it was examined whether quercetin, which has been shown to interfere with the formation of the complex between HSE and HSF, and to downregulate the level of HSF1, can sensitize MDR cells against anticancer drugs by inhibition of HSF DNA-binding activity. In this study, quercetin appeared to inhibit the constitutive HSF DNA-binding activity and the sodium arsenite-induced HSF DNA-binding activity in the MDR cells. The basal and sodium arsenite-induced MDRCAT activities were remarkably suppressed by the treatment of quercetin. These results were well consistent with the finding that the treatment of quercetin decreased the expression level of P-gp, MDR1 gene product, in dose-dependent manner, and markedly increased the sensitivity of MDR cells to vincristine or vinblastine. These results suggest that quercetin can decrease the expression of P-gp via inhibition of HSF DNA-binding activity, and might be useful as a chemosensitizer in MDR cells.
Animal ; Antineoplastic Agents/pharmacology ; Arsenites/pharmacology ; Carcinoma/drug therapy ; Drug Resistance, Multiple/physiology* ; Drug Resistance, Neoplasm/physiology ; Heat-Shock Proteins/metabolism ; Heat-Shock Proteins/drug effects* ; Heat-Shock Proteins/antagonists & inhibitors ; Leukemia, Experimental/drug therapy ; Mice ; P-Glycoprotein/genetics ; P-Glycoprotein/drug effects ; Quercetin/pharmacology* ; Sodium Compounds/pharmacology ; Tumor Cells, Cultured ; Vinblastine/pharmacology ; Vincristine/pharmacology

The mutation and reduction of mitochondrial DNA (mtDNA) have been suggested as factors in the carcinogenesis. However, whether the depletion of mtDNA induces multidrug resistance in cancer cells has not been fully investigated. To elucidate the association of cellular mtDNA content and drug resistance, we generated HCT-8 colon cancer cells which revealed a marked decrease in cellular mtDNA and ATP content, concomitant with a lack of mRNAs encoded by mtDNA. The mtDNA-depleted cells showed a decreased sensitivity and accumulation of anti-cancer drugs, suggesting that mtDNA depletion could develop multidrug resistance (MDR) phenotype in HCT-8 cells. We found that the expression level of MDR1 mRNA and its translated product P-glycoprotein was increased in the mtDNA- depleted cells, indicating that the decrease of sensitivity and accumulation of anti-cancer drug in the mtDNA-depleted cells might be due to a substantial increase in the expression of P-glycoprotein. Furthermore, increased expression of MDR1 mRNA and P-glycoprotein was due to an increase of mRNA stability rather than transcriptional activation. Taken together, these results indicate that mtDNA depletion can induce an increased P-glycoprotein expression via an increase of mRNA stability and suggest that the mtDNA depletion in cancer cells plays an important role in the induction of MDR phenotype.
Cell Line, Tumor ; DNA, Mitochondrial/*metabolism ; Doxorubicin/pharmacology ; Gene Expression Regulation, Neoplastic/drug effects ; Humans ; P-Glycoprotein/*genetics/metabolism ; Paclitaxel/pharmacology ; Promoter Regions, Genetic/genetics ; *RNA Stability/drug effects ; RNA, Messenger/genetics/metabolism ; Up-Regulation/drug effects/*genetics

This study was purposed to explore the influence of S-nitrosoglutathione (GSNO) on membrane glycoprotein of frozen platelet. The levels of membrane glycoprotein on fresh liquid platelets, frozen platelets and frozen platelets with GSNO were measured by flow cytometry. The results showed that the GSNO obviously decreased platelet aggregation, the PAC-1 change in the three groups was not significant. The changes of CD42b and CD62P in fresh liquid platelet group, frozen platelet group and frozen platelets with GSNO were significant different. The change of membrane glycoprotein in above-mentioned three group was not significant. It is concluded that the GSNO inhibits platelet aggregation, maintains the function of platelets and may be used as a cryoprotectant. When frozen platelets were added with GSNO, the molecular rearrangement, structure change and other mechanism may occur in platelets.
Blood Platelets ; drug effects ; Blood Preservation ; methods ; Freezing ; Humans ; P-Selectin ; metabolism ; Platelet Activation ; drug effects ; Platelet Glycoprotein GPIb-IX Complex ; metabolism ; Platelet Membrane Glycoproteins ; metabolism ; S-Nitrosoglutathione ; pharmacology

The expression of p-glycoprotein (p-gp) was evaluated in pre- and post-chemotherapy states after the administration of adriamycin-based chemotherapy in 24 gastric cancer patients. Among them, group A was composed of twelve patients who relapsed after surgery plus adjuvant chemotherapy and group B was composed of another twelve patients who received neoadjuvant chemotherapy plus surgery. Pre-chemotherapy p-gp was evaluated in 18 out of 24 patients (6 patients had no pre-chemotherapy paraffin blocks) and post-chemotherapy p-gp was evaluated from all 24 patients. Pre- and post-chemotherapy p-gp was expressed in 5 of 18 patients (27.8%), and 9 of 24 patients (37.5%), respectively, with immunohistochemical stain using monoclonal antibody JSB-1. No differences of disease-free survivals were observed in Group A based on post-chemotherapy p-gp expression from relapsed lesions. In Group B, there was a higher relapse rate (p = 0.04) and a lower one-year disease-free survival rate (p = 0.04) in post-chemotherapy p-gp positive patients when adjuvant treatment was done with the same regimen as neoadjuvant chemotherapy. In all patients studied, post-chemotherapy p-gp expression correlated with a higher systemic recurrence (p = 0.04). These data suggest that p-gp can be induced by an adriamycin-based chemotherapy in gastric cancer. Thus, we suggest that the prognosis of gastric cancer may be poor if a multidrug resistance (MDR)-related regimen is used in the presence of p-gp after neoadjuvant chemotherapy with an adriamycin-based regimen, even if the initial response is good.
Adult ; Aged ; Combined Modality Therapy ; Dose-Response Relationship, Drug ; Doxorubicin/administration & dosage/*therapeutic use ; Drug Resistance ; Female ; Human ; Immunohistochemistry ; Male ; Middle Age ; Neoplasm Recurrence, Local ; P-Glycoprotein/*metabolism ; Stomach Neoplasms/*drug therapy/*metabolism/surgery ; Survival Analysis

It is generally accepted that tissue factor plays an important role in coagulation and intravascular thrombus formation. Tissue factor is not only found primarily on the surface of certain cells that are located outside the vasculature, but also found in circulating cells. Monocyte express tissue factor induced by endotoxin. Recently, many researches indicate that P-selectin, CD40 ligand and GPIIb/IIIa receptor of platelet can also affect expression of tissue factor by monocyters. In addition, a lot of studies showed that tissue factor exist in the circulation including contained platelet. Tissue factor in the platelet releases under certain condition, and initiates coagulation. In this review the relation between platelet and tissue factor was elaborated.
Blood Platelets ; drug effects ; metabolism ; physiology ; CD40 Ligand ; physiology ; Humans ; Monocytes ; drug effects ; metabolism ; P-Selectin ; physiology ; Peptides ; pharmacology ; Platelet Glycoprotein GPIIb-IIIa Complex ; physiology ; Thromboplastin ; biosynthesis ; drug effects ; physiology