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1.
Immunohematology ; 16(2): 61-7, 2000.
Article in English | MEDLINE | ID: mdl-15373620

ABSTRACT

The Duffy blood group antigens are encoded by the Duffy gene with its three major alleles: Fy*A (Fya+), Fy*B (Fyb+), and a nonexpressed Fy*Fy (Fya-b-), which is most commonly found among black people. Additionally, a fourth allele, Fyx, is found among white people and defined as weak Fyb not detectable by all anti-Fyb. Three polymerase chain reactions (PCRs) using sequence-specific priming (SSP) for detection of the major FY alleles were developed. Eighteen Fy(a-b-) samples of Tanzanian origin were correctly typed and of 300 random donors of Caucasian origin with known Fy phenotype, only four out of 59 Fy(a+b-) donors showed the discrepant DNA-type Fy(a+b+). Serologic reinvestigation by adsorption and elution techniques confirmed weakly expressed Fyb antigen in these cases and DNA sequencing of the entire Duffy gene revealed identical point mutations in all of them. Specific PCR reactions were used to reinvestigate the C265T (Arg89Cys) and G298A (Ala100Thr) substitution in the 300 samples. A298 was found to be present in both FY*X and FY*B alleles, pointing to an allelic variation among FY*B alleles. T265 was encountered exclusively in FY*X and is thought to be FY*X specific. Combining the T265 specific reaction with the three PCR-SSPs described above, we were able to correctly DNA-type all phenotypes investigated in our study.

2.
Biochem Pharmacol ; 56(7): 861-9, 1998 Oct 01.
Article in English | MEDLINE | ID: mdl-9774148

ABSTRACT

Bryostatin 1 is a new antitumor agent which modulates the enzyme activity of protein kinase C (PKC, phospholipid-Ca2+-dependent ATP:protein transferase, EC 2.7.1.37). Several reports have suggested that the pumping activity of the multidrug resistance gene 1 (MDR1)-encoded multidrug transporter P-glycoprotein (PGP) is enhanced by a PKC-mediated phosphorylation. It was shown here that bryostatin 1 was a potent modulator of multidrug resistance in two cell lines over-expressing a mutant MDR1-encoded PGP, namely KB-C1 cells and HeLa cells transfected with an MDR1-V185 construct (HeLa-MDR1-V185) in which glycine at position 185 (G185) was substituted for valine (V185). Bryostatin 1 is not able to reverse the resistance of cells over-expressing the wild-type form (G185) of PGP, namely CCRF-ADR5000 cells and HeLa cells transfected with a MDR1-G185 construct (HeLa-MDR1-G185). Treatment of HeLa-MDR1-V185 cells with bryostatin 1 was accompanied by an increase in the intracellular accumulation of rhodamine 123, whereas no such effect could be observed in HeLa-MDR1-G185 cells. HeLa-MDR1-V185 cells expressed the PKC isoforms alpha, delta and zeta. Down-modulation of PKC alpha and delta by 12-O-tetradecanoylphorbol-13-acetate (TPA) did not affect the drug accumulation by bryostatin 1. Bryostatin 1 depleted PKC alpha completely and PKC delta partially. In HeLa-MDR1-V185 cells, short-term exposure to bryostatin 1, which led to a PKC activation, was as efficient in modulating the pumping activity of PGP as long-term exposure leading to PKC depletion. Bryostatin 1 competed with azidopine for binding to PGP in cells expressing the MDR1-V185 and MDR1-G185 forms of PGP. It is concluded that bryostatin 1: i) interacts with both the mutated MDR1-V185 and the wild-type MDR1-G185; ii) reverses multidrug resistance and inhibits drug efflux only in PGP-V185 mutants; and iii) that this effect is not due to an interference of PKC with PGP. For gene therapy, it is important to reverse the specific resistance of a mutant in the presence of a wild-type transporter and vice versa. Our results show that it is possible to reverse a specific mutant PGP.


Subject(s)
ATP Binding Cassette Transporter, Subfamily B, Member 1/genetics , Amino Acid Substitution/genetics , Drug Resistance, Multiple , Lactones/pharmacology , Protein Kinase C/physiology , ATP Binding Cassette Transporter, Subfamily B, Member 1/biosynthesis , ATP Binding Cassette Transporter, Subfamily B, Member 1/metabolism , Binding, Competitive/drug effects , Bryostatins , Drug Resistance, Neoplasm , Female , HeLa Cells , Humans , KB Cells , Macrolides , Point Mutation
3.
Int J Cancer ; 77(1): 64-9, 1998 Jul 03.
Article in English | MEDLINE | ID: mdl-9639395

ABSTRACT

It has been shown previously that the staurosporine derivative CGP 41251, a specific inhibitor of protein kinase C (IC50 = 50 nM), exhibits antitumor activity and reverses mdr1 mediated multidrug resistance. At present, the compound is evaluated as an anticancer drug in clinical phase I trials. We compared the effects of CGP 41251 with CGP 42700, another staurosporine derivative, which exhibits low protein kinase C inhibiting activity (IC50 = > 100 microM). We found that in contrast to CGP 41251, CGP 42700 does not show antiproliferative activity in HeLa and KB cells in tissue culture (up to a concentration of 10 microM). We compared both compounds for their ability to reverse mdr1-mediated resistance in KB-C1 and in HeLa-MDR1 cells (transfected with the mdr1 gene). CGP 42700 is able to reverse mdr1-mediated resistance to a similar extent as CGP 41251. The intracellular accumulation of rhodamine 123 in KB-C1 cells following pretreatment with CGP 41251 for 30 min was higher than that following treatment with CGP 42700 if determined in medium without serum. However, quantitation of rhodamine efflux in an ex vivo assay using human CD8+ cells in serum showed that CGP 42700 is more effective in inhibiting the efflux of rhodamine 123 than CGP 41251. We conclude from our results that (1) CGP 42700 is more effective in reversal of multidrug resistance in serum than CGP 41251, indicating that the compound may be useful for treatment of patients, and (2) CGP 42700 does not inhibit protein kinase C and cell proliferation and, therefore, may be less toxic and elicit less side effects in humans than other chemosensitizers.


Subject(s)
Antineoplastic Agents/pharmacology , Drug Resistance, Multiple/genetics , Gene Expression Regulation/drug effects , Genes, MDR , Staurosporine/analogs & derivatives , HeLa Cells , Humans , Rhodamines , Staurosporine/pharmacology , Transfection
4.
Br J Cancer ; 76(7): 862-9, 1997.
Article in English | MEDLINE | ID: mdl-9328144

ABSTRACT

The thioether phospholipid ilmofosine (BM 41 440) is a new anti-cancer drug presently undergoing phase II clinical trials. Because resistance to anti-tumour drugs is a major problem in cancer treatment, we investigated the resistance of different cell lines to this compound. Here we report that the multidrug-resistant cell lines MCF7/ADR, CCRFNCR1000, CCRF/ADR500, CEM/VLB100 and HeLa cell lines transfected with a wild-type and mutated (gly/val185) multidrug resistance 1 gene (MDR1) are cross-resistant to ilmofosine compared with the sensitive parental cell lines. In CEMNM-1 cells, in which the resistance is associated with an altered topoisomerase II gene, no cross-resistance to ilmofosine was observed. Ilmofosine is not capable of modulating multidrug resistance and neither does it reduce the labelling of the P-glycoprotein (P-gp) by azidopine nor alter ATPase activity significantly. The resistance to ilmofosine in multidrug-resistant CCRF/VCR1000 cells cannot be reversed by the potent multidrug resistance modifier dexniguldipine-HCI (B8509-035). A tenfold excess of ilmofosine does not prevent the MDR-modulating effect of dexniguldipine-HCl. Treatment of cells with ilmofosine does not alter the levels of MDR1 mRNA. Long-term treatment of an ilmofosine-resistant Meth A subline with the drug does not induce multidrug resistance, indicating that ilmofosine does not increase the level of P-gp. Determination of the MDR2 mRNA levels in the cells revealed that the resistance pattern to ilmofosine is not correlated with the expression of this gene. It is concluded, therefore, that multidrug-resistant cells are cross-resistant to ilmofosine and that the compound is not a substrate of Pgp. No association between the expression of the MDR2-encoded P-gp and resistance to ilmofosine was observed. It is supposed that MDR1-associated alterations in membrane lipids cause resistance to ilmofosine.


Subject(s)
Antineoplastic Agents/pharmacology , Genes, MDR/genetics , Phospholipid Ethers/pharmacology , ATP Binding Cassette Transporter, Subfamily B, Member 1/metabolism , Antibiotics, Antineoplastic/pharmacology , Cell Division/drug effects , Cell Transformation, Neoplastic , Dihydropyridines/pharmacology , Dose-Response Relationship, Drug , Doxorubicin/pharmacology , Drug Resistance, Multiple , Drug Resistance, Neoplasm , HeLa Cells/drug effects , Humans , Time Factors , Tumor Cells, Cultured/drug effects
5.
Br J Cancer ; 74(6): 897-905, 1996 Sep.
Article in English | MEDLINE | ID: mdl-8826855

ABSTRACT

Inhibition of protein kinase C (PKC) is discussed as a new approach for overcoming multidrug resistance (MDR) in cancer chemotherapy. For evaluation of this concept we applied the bisindolylmaleimide GF 109203X, which shows a highly selective inhibition of PKC isozymes alpha, beta 1, beta 2, gamma, delta and epsilon in vitro. The efficacy of this compound in modulation of MDR was examined using several P-glycoprotein (P-gp)-overexpressing cell lines including a MDR1-transfected HeLa clone, and was compared with the activities of dexniguldipine-HCI (DNIG) and dexverapamil-HC1 (DVER), both of which essentially act via binding to P-gp. As PKC alpha has been suggested to play a major role in P-gp-mediated MDR, cell lines exhibiting different expression levels of this PKC isozyme were chosen. On crude PKC preparations or in a cellular assay using a cfos(-711)CAT-transfected NIH 3T3 clone, the inhibitory qualities of the bisindolylmaleimide at submicromolar concentrations were demonstrated. At up 1 microM final concentrations of the PKC inhibitor GF 109203X, a concentration at which many PKC isozymes should be blocked substantially, no cytotoxic or MDR-reversing effects whatsoever were seen, as monitored by 72 h tetrazolium-based colorimetric MTT assays or a 90 min rhodamine 123 accumulation assay. Moreover, depletion of PKC alpha by phorbol ester in HeLa-MDR1 transfectants had no influence on rhodamine 123 accumulation after 24 or 48 h. MDR reversal activity of GF 109203X was seen at higher final drug concentrations, however. Remarkably, [3H]vinblastine-sulphate binding competition experiments using P-gp-containing crude membrane preparations demonstrated similar dose dependencies as found for MDR reversion by the three modulators, i.e. decreasing efficacy in the series dexniguldipine-HCl > dexverapamil-HCl > GF 109203X. Similar interaction with the P-gp in the micromolar concentration range was revealed by competition of GF 109203X with photoincorporation of [3H]azidopine into P-gp-containing crude membrane preparations. No significant effect of the PKC inhibitor on MDR1 expression was seen, which was examined by cDNA-PCR. Thus, the bisindolylmaleimide GF 109203X probably influences MDR mostly via direct binding to P-gp. Our work identifies the bisindolylmaleimide GF 109203X as a new type of drug interacting with P-gp directly, but does not support the concept of a major contribution of PKC to a P-gp-associated MDR, at least using the particular cellular model systems and the selective, albeit general, PKC inhibitor GF 109203X.


Subject(s)
ATP Binding Cassette Transporter, Subfamily B, Member 1/physiology , Drug Resistance, Multiple , Enzyme Inhibitors/pharmacology , Indoles/pharmacology , Maleimides/pharmacology , Protein Kinase C/antagonists & inhibitors , 3T3 Cells , ATP Binding Cassette Transporter, Subfamily B, Member 1/genetics , Animals , Azides/metabolism , Dihydropyridines/metabolism , Dihydropyridines/pharmacology , Gene Expression , Humans , Mice , Phosphorylation , Verapamil/pharmacology
6.
Anticancer Res ; 16(1): 289-96, 1996.
Article in English | MEDLINE | ID: mdl-8615623

ABSTRACT

We investigated whether the expression of protein kinase C (PKC) isoenzymes, topoisomerase II alpha, II beta, multidrug resistance associated protein (MRP), p53 or the activity of glutathione-S- transferase (GST) are additional factors contributing to the resistance mediated by multidrug resistance gene 1 (mdr 1). the cell lines employed for these studies were human lymphoblastoid CCRF cells selected for resistance with actinomycin D, vincristine and adriamycin, KB-3-1 and matched resistant KB-8-5 and KB-C1 cells (selected with colchicine), and a HeLa cell line, in which the resistance was obtained by transfection with the mdr1-gene. Analysis of PKC isozymes showed that there is no correlation of a specific isoenzyme with resistance, although minor differences in the expression were observed. In vincristine and adriamycin selected cells, topoisomerase II alpha- and II beta-MRNA levels were reduced, and in vincristine selected cells the MRP-mRNA was elevated compared with the sensitive line. In KB cells the levels of topoisomerase II alpha and II beta mRNA were increasing with the resistance. Expression of p53 did not correlate with Pgp levels. In summary, MRP and topoisomerase II may contribute to the mdr1 -mediated resistance in some cell lines, but PKC, p53 and GST seem to be of minor or no importance.


Subject(s)
ATP-Binding Cassette Transporters/metabolism , Antimetabolites, Antineoplastic/pharmacokinetics , DNA Topoisomerases, Type II/metabolism , Drug Resistance, Multiple , Glutathione Transferase/metabolism , Isoenzymes/metabolism , Protein Kinase C/metabolism , Rhodamines/pharmacokinetics , Tumor Suppressor Protein p53/metabolism , ATP Binding Cassette Transporter, Subfamily B, Member 1/metabolism , Antigens, Neoplasm , Blotting, Western , DNA-Binding Proteins , HeLa Cells , Humans , KB Cells , Multidrug Resistance-Associated Proteins , Precursor Cell Lymphoblastic Leukemia-Lymphoma/drug therapy , Precursor Cell Lymphoblastic Leukemia-Lymphoma/metabolism , Rhodamine 123 , Transfection , Tumor Cells, Cultured/drug effects
7.
Dtsch Med Wochenschr ; 120(23): 826-30, 1995 Jun 09.
Article in German | MEDLINE | ID: mdl-7781523

ABSTRACT

A pilot study was undertaken to test whether combining the polymerase chain reaction with restriction fragment length polymorphism is suitable for the routine diagnosis of carcinoma of the pancreas. The method makes it possible to recognize point mutations in codon 12 of the Ki-ras oncogene. 60 cytological specimens from the pancreatobiliary tract, the bronchopulmonary system (by bronchoalveolar lavage or from pleural effusion) and ascites were tested. Results from nine pancreas carcinoma cell lines served as control. A PCR product was successfully amplified in all cell lines and 47 of the clinical specimens. In all eight samples in which a mutated Ki-ras oncogene was demonstrated, there was at least a suspicion of malignancy by cytological examination. A mutation was also found in four of five pancreas carcinomas. But no mutation was found in one, clinically certain, case of pancreas carcinoma. The described method is an elegant and, most of all, rapid means to complement and optimize any cytological diagnosis.


Subject(s)
Genes, ras/genetics , Pancreatic Neoplasms/genetics , Point Mutation , Polymerase Chain Reaction/methods , Ascitic Fluid/cytology , Biomarkers, Tumor/isolation & purification , Cell Line , Humans , Pleural Effusion/cytology , Sensitivity and Specificity
8.
Biochem Pharmacol ; 49(5): 603-9, 1995 Mar 01.
Article in English | MEDLINE | ID: mdl-7887974

ABSTRACT

It has previously been shown that dexniguldipine-HCl (B8509-035) is a potent chemosensitizer in multidrug resistant cells [Hofmann et al., J Cancer Res Clin Oncol 118: 361-366, 1992]. It is shown here that dexniguldipine-HCl causes a dose-dependent reduction of the labeling of the P-glycoprotein by azidopine, indicating a competition of dexniguldipine-HCl with the photoaffinity label for the multidrug resistance gene 1 (MDR-1) product. Exposure to dexniguldipine-HCl results in a dose-dependent accumulation of rhodamine 123 in MDR-1 overexpressing cells. In the presence of 1 microM dexniguldipine-HCl, rhodamine 123 accumulated in multidrug resistant cells to similar levels as in the sensitive parental cell lines. At this concentration, dexniguldipine-HCl enhances the cytotoxicities of Adriamycin and vincristine. The resistance modulating factors (RMF), i.e. IC50 drug/IC50 drug + modulator, were found to be proportional to the expression of MDR-1, ranging from 8 to 42 for Adriamycin and from 16 to 63 for vincristine. Transfection with the MDR-1 gene was found to be sufficient to sensitize cells to the modulation by dexniguldipine-HCl. The compound does not affect the expression of the MDR-1 gene. Dexniguldipine-HCl has no effect on a multidrug resistant phenotype caused by a mutation of topoisomerase II. It is concluded that dexniguldipine-HCl modulates multidrug resistance by direct interaction with the P-glycoprotein.


Subject(s)
ATP Binding Cassette Transporter, Subfamily B, Member 1/metabolism , Dihydropyridines/pharmacology , Drug Resistance, Multiple , ATP Binding Cassette Transporter, Subfamily B, Member 1/genetics , Affinity Labels , Azides/metabolism , Cell Line/drug effects , Cell Survival/drug effects , DNA Topoisomerases, Type II/genetics , Dihydropyridines/metabolism , Dose-Response Relationship, Drug , Doxorubicin/pharmacology , Drug Interactions , Drug Resistance, Multiple/genetics , Humans , Rhodamine 123 , Rhodamines/metabolism , Transfection , Vincristine/pharmacology
9.
Int J Cancer ; 57(1): 104-10, 1994 Apr 01.
Article in English | MEDLINE | ID: mdl-7908658

ABSTRACT

Multidrug resistance (MDR) is frequently associated with overexpression of a 170-kDa P-glycoprotein (Pgp). Data suggest altered protein kinase C (PKC) activity in cells expressing the multidrug-resistant phenotype. The staurosporine derivative CGP 41251, an experimental anticancer drug, has been shown to exert selectivity for inhibition of protein kinase C activity and to exhibit antitumor activity in vitro and in vivo. Here we show that CGP 41251 is also able to reverse MDR. After treatment of the multidrug-resistant human lymphoblastoid cell line CCRF-VCR1000 with 500 nM Adriamycin, cell proliferation was reduced to 81% of untreated controls. A combination of 500 nM Adriamycin with a non-toxic concentration of 150 nM CGP 41251 (IC50 for inhibition of cell proliferation 420 nM CGP 41251) inhibits cell proliferation of CCRF-VCR1000 cells to 29% of untreated controls. In sensitive CCRF-CEM cells no enhancement of Adriamycin-induced cytotoxicity was observed upon addition of 150 nM CGP 41251. Strong synergism of the inhibition of cell proliferation was also observed after concomitant treatment of KB-8511 cells with CGP 41251 and Vinblastine or Adriamycin. Drug-sensitive KB-31 cells could not be further sensitized to Adriamycin or Vinblastine with CGP 41251 doses above 100 nM. Pretreatment with 50-1000 nM CGP 41251 for 30 min led to a dose-dependent increase in the intracellular accumulation of rhodamine 123, a substrate of P-glycoprotein. Treatment of multidrug-resistant CCRF-VCR1000 cells with CGP 41251 for 10 min was sufficient to inhibit the efflux of rhodamine 123. Preincubation with CGP 41251 for 12 or 24 hr did not alter multidrug resistance gene (mdrI)-mRNA levels. CGP 41251, a drug with antitumor efficacy in experimental systems, might offer an attractive combination partner for the treatment of tumors expressing the MDR phenotype.


Subject(s)
Alkaloids/pharmacology , Antineoplastic Agents/pharmacology , Protein Kinase C/antagonists & inhibitors , Staurosporine/analogs & derivatives , ATP Binding Cassette Transporter, Subfamily B, Member 1 , Carrier Proteins/metabolism , Carrier Proteins/physiology , Doxorubicin/pharmacology , Drug Resistance/genetics , Gene Expression/genetics , Humans , KB Cells , Lymphocytes/drug effects , Membrane Glycoproteins/metabolism , Membrane Glycoproteins/physiology , Rhodamine 123 , Rhodamines/pharmacokinetics , Tumor Cells, Cultured/drug effects , Vincristine/pharmacology
10.
Ann Hematol ; 69 Suppl 1: S1-6, 1994.
Article in English | MEDLINE | ID: mdl-8061107

ABSTRACT

The activity of several proteins involved in the development of antitumor drug resistance is regulated by protein phosphorylation. These proteins include the mdr-1-encoded P-glycoprotein (Pgp) and topoisomerase II (topo II). The corresponding evidence is reviewed and attempts to modulate multidrug resistance (MDR) by protein kinase C inhibitors are described. The expression of several proteins which are essential in drug resistance is regulated at the transcriptional level, involving protein phosphorylation by members of the protein kinase C (PKC) family, casein kinase II (CKII), and others. These proteins include mdr-1-encoded P-glycoprotein, metallothionein, glutathione S-transferase (GST), dTMP synthase, and the proteins Fos and Jun. The corresponding genes are under positive regulation of ras, which in turn requires the activation of a protein kinase cascade for its function. Protein kinases are therefore potentially useful targets in reducing the expression of proteins involved in the development of multifactorial drug resistance caused by the expression of transforming ras-genes. Attempts to inhibit the ras-induced fos expression by an inhibitor of protein kinase C (ilmofosine) are described. Protein kinase inhibitors are also able to synergistically enhance the cytotoxicity of cis-platinum, which is discussed as resulting from a reduction of PKC-dependent fos expression.


Subject(s)
Antineoplastic Agents/therapeutic use , Drug Resistance , Protein Kinases/physiology , Animals , Carcinoma 256, Walker/genetics , Cisplatin/therapeutic use , DNA Topoisomerases, Type II/metabolism , Drug Resistance/genetics , Genes, ras , Mice , Protein Kinase Inhibitors , Tumor Cells, Cultured
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