Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P10415 (Bcl-2)
 33,771 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Using a quantitative reverse transcriptase PCR assay, the mRNA expression of five putative drug resistance-related genes were assessed in normal peripheral (n = 14) and bone marrow (n = 4) mononuclear cells from healthy donors and patients with acute myeloid leukaemia (n = 11). The mRNA levels of MDR1, the multidrug resistance-associated protein and glutathione-S-transferase pi were equally expressed in both compartments. Bcl-2 mRNA was slightly higher in the leukaemic marrow samples. However, topoisomerase II alpha mRNA levels were found to be much higher in normal and leukaemic marrow cells compared to peripheral blood (p < 0.01), which may, in part, reflect the different proliferation pattern of the mononuclear cells in the two compartments. Such findings could be important for researchers using bulk assays in a mix of samples from peripheral blood or bone marrow to investigate prognostic factors in patients with leukaemia.
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PMID:mRNA expression, measured by quantitative reverse transcriptase polymerase chain reaction, of five putative drug resistance parameters, in normal and leukaemic peripheral blood and bone marrow. 921 Sep 6

The aim of this study was to obtain insight into the role of the multidrug resistance (MDR) phenomenon in hormone-independent progressive prostate cancer. Using immunocytochemistry and Western blotting we determined the expression of P-glycoprotein (Pgp), multidrug resistance-associated protein (MRP), glutathione-S-transferase-pi (GST-pi), Bcl-2, Bax, topoisomerase (Topo) I, II alpha and II beta in the human prostate cancer cell lines PC3, TSU-Pr1, DU145 and LNCaP derivatives LNCaP-R, LNCaP-LNO and LNCaP-FGC. Proliferative activity was assessed by immunocytochemistry. MTT assays were used to determine the sensitivity to etoposide, doxorubicin and vinblastin. Pgp was not expressed in any of the cell lines. MRP was variably expressed. GST-pi was expressed in TSU-Pr1, PC3 and DU145. The expression of Bcl-2 was restricted to TSU-Pr1, whereas Bax was found in all cell lines. Topo II alpha was expressed at the highest level in the rapidly proliferating cell lines TSU-Pr1 and DU145. Topo I and II beta were equally expressed. Resistance profiles varied among the cell lines, with TSU-Pr1 being the most sensitive and LNCaP-LNO relatively resistant. Multiple MDR proteins were expressed in prostate cancer cell lines and may well influence response to chemotherapy. Future functional studies, using chemo-selected MDR models, may further help to determine the mechanism or combination of mechanisms underlying the resistance of prostate cancer to chemotherapy.
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PMID:Chemosensitivity of prostate cancer cell lines and expression of multidrug resistance-related proteins. 1049 44

With the growing understanding of cytostatic drug-induced programmed cell death new drug-resistance mechanisms based on the altered ability of cells to die by apoptosis have been defined. At first, the sensitive and P-glycoprotein (P-gp)-related resistant cell lines were tested to induce apoptosis by a non-P-gp transported drug, such as cytosine arabinoside (ara-C). It was demonstrated that ara-C induces apoptosis in sensitive as well as in P-gp-related resistant cell lines, as expected. Furthermore, the role of bcl-2 and bcl-xL apoptosis inhibitors as well as bax expression (apoptosis inducer) in human sensitive leukemic cell lines (CCRF-CEM and HL-60) as compared to their resistant variants such as CCRF-CEM/ACT400, CCRF-CEM/VCR1000, HL-60/IDA40, HL-60/DNR250 was evaluated. In addition to the P-gp-related resistance, a possible multidrug resistance-associated protein (MRP) and the lung resistance protein (LRP)-related resistance were assessed by flow cytometry using the monoclonal antibodies 4E3.16, MRPr1 and LRP56. Furthermore, the function of P-gp was determined with the rhodamine-123 (R-123) accumulation test. Bcl-2 and bax were analyzed by both flow cytometry and ECL Western blot, bcl-xL by ECL-Western blot alone. Comparison of the two sensitive cell lines demonstrated different bcl-2, bax and bcl-xL patterns. The common characteristic was the increased expression of one of the apoptosis inhibitor proteins, such as bcl-2 or bcl-xL. The sensitive CCRF-CEM showed a high bax level, where a decrease of about 75% in resistant variants was measured. Compared to their sensitive counterpart HL-60, a low bax expression was analyzed, which increased in the resistant variant. The common characteristic of all resistant cell lines was the decreased expression of bax compared to bcl-2 or bcl-xL. In the P-gp-related resistant HL-60/DNR250 only an increase in bcl-xL was seen, whereas in the LRP-expressing as well as P-gp and MRP negative resistant HL-60/IDA40 both apoptotic inhibitor proteins bcl-2 and bcL-xL showed maximum increase, compared to the other resistant cell lines. The P-gp-related resistant cell lines CCRF-CEM/ACT400 and CCRF-CEM/VCR1000 also showed an increased expression of both bcl-2 and bcl-xL. Summarizing these results, it was shown that the examined sensitive human leukemic cell lines and their resistant variants demonstrated a different pattern of markers for preventing and promoting apoptosis. An association between P-gp and possible LRP-expressing leukemic cells as well as apoptosis-preventing markers (bcl-2, bcl-xL) seems to exist. The clinical relevance of the coexpression of various resistance mechanisms remains to be confirmed in large leukemia patient groups.
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PMID:Bcl-2, bax and bcl-xL expression in human sensitive and resistant leukemia cell lines. 1055 64

We have established a paclitaxel-resistant mutant cell line called H460/TAX which was derived from human non-small cell lung cancer (NSCLC) H460. A 64-fold greater resistant was shown in our assay as compared with the parental cells. High specificity of drug resistance was also observed since this mutant was not cross-resistant to several other anticancer drugs. Drug accumulation in H460/TAX was significantly less than that in H460. Many endogenous protein profiles were intact, including the expression level of P-glycoprotein, multidrug resistance-associated protein, the 70 kDa heat shock proteins as well as the phosphorylation of Bcl-2 in H460/TAX cells, except that the total amount of alpha- and beta- tubulins was higher in H460/TAX than in H460 cells. Higher drug concentration and longer treatment for paclitaxel were required in H460/TAX to exert the phosphorylation of keratin 19 which was then accompanied by reorganization of the intermediate filament and the microtubule networks. Since all of the aforementioned factors involved in paclitaxel-resistance in other systems were not found to be significantly altered in H460/TAX, there must be other paclitaxel-resistance mechanisms(s) which remains to be identified in human lung cancers.
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PMID:Establishment and characterization of a paclitaxel-resistant human non-small cell lung cancer cell line. 1095 9

Aqueous extracts of Salvia miltiorrhizae Bunge have been extensively used in the treatment of cardiovascular disorders and cancer in Asia. Recently, a compound, 5-(3-hydroxypropyl)-7-methoxy-2-(3'-methoxy-4'-hydroxyphenyl)-3-benzo[b]furancarbaldehyde (salvinal), isolated from this plant showed inhibitory activity against tumor cell growth and induced apoptosis in human cancer cells. In the present study, we investigated the cytotoxic effect and mechanisms of action of salvinal in human cancer cell lines. Salvinal caused inhibition of cell growth (IC50 range, 4-17 microM) in a variety of human cancer cell lines. Flow cytometry analysis showed that salvinal treatment resulted in a concentration-dependent accumulation of cells in the G(2)/M phase. We observed, using Hoechst 33258 dye staining, that salvinal blocked the cell cycle in mitosis. In vitro and in vivo examinations showed that salvinal inhibited tubulin polymerization in a concentration-dependent manner. Immunocytochemical studies demonstrated that salvinal treatment caused the changes of cellular microtubule network, similar to the effect of colchicine. In addition, salvinal treatment resulted in upregulation of cyclin B1 levels, activation of Cdc2 kinase, and Cdc25c phosphorylation. Furthermore, elevation of levels of MPM-2 phosphoepitopes in salvinal-treated cells in a concentration-dependent manner was also observed. Similar to the effect of other antitubulin agent, hyperphosphorylation of Bcl-2, induction of DNA fragmentation and activation of caspase-3 activity occurred in salvinal-treated cells. In particular, salvinal exhibited similar inhibitory activity against parental KB, P-glycoprotein-overexpressing KB vin10 and KB taxol-50 cells, and multidrug resistance-associated protein (MRP)-expressing etoposide-resistant KB 7D cells. Taken together, our data demonstrate that salvinal inhibits tubulin polymerization, arrests cell cycle at mitosis, and induces apoptosis. Notably, Salvinal is a poor substrate for transport by P-glycoprotein and MRP. Salvinal may be useful in the treatment of human cancers, particularly in patients with drug resistance.
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PMID:Salvinal, a novel microtubule inhibitor isolated from Salvia miltiorrhizae Bunge (Danshen), with antimitotic activity in multidrug-sensitive and -resistant human tumor cells. 1472 39

To determine the antitumor effect of arsenic trioxide (As2O3) on multidrug-resistant cells, we applied 3 human leukemia cell lines: daunorubicin (DNR)-resistant cell line K562/D1-9, which overexpresses p-glycoprotein (Pgp); DNR and 1-beta-D-arabinofuranosylcytosine (Ara-C) double-resistant cell line HL60/AD, which overexpresses multidrug resistance-associated protein (MRP1); and Bcl-2-transfected pre-B lineage leukemia cell line 697/Bcl-2. Interestingly, K562/D1-9 showed collateral sensitivity. Only HL60/AD showed small cross resistance, but 697/Bcl-2 had no resistance to As2O3. An intracellular content of glutathione (GSH) played a critical role in sensitivity to As2O3. Buthionine-sulfoximine (BSO), which reduces the GSH content, not only increased the As2O3 sensitivity but also conquered the MRP1-related cross resistance in HL60/AD. In conclusion, As2O3 was effective in all 3 cell lines, suggesting that As2O3 may be a promising agent for the treatment of multidrug-resistant leukemia.
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PMID:Arsenic trioxide circumvents multidrug resistance based on different mechanisms in human leukemia cell lines. 1586 38

Multimodal therapies play important roles in the treatment of osteosarcoma (OS) and Ewing's family of tumors (EFTs), two most frequent malignant bone tumors. Although the clinical outcome of primary OS and EFTs is greatly improved, the relapsed cases often are associated with multidrug resistance of the tumors and the prognosis of these patients is still poor. Flavopiridol, a pan cyclin-dependent kinase (CDK) inhibitor is a novel antitumor agent that can induce cell cycle arrest and apoptosis in many cancer cells. However, there have been no studies about the effects of flavopiridol on drug-resistant OS and EFTs. Here, we demonstrated that flavopiridol induced the cleavage of poly-ADP-ribose polymerase (PARP) in a time and dose dependent manner in adriamycin-resistant OS and EFTs cells expressing P-glycoprotein (P-gp) and multidrug resistance-associated protein 1 (MRP(1)) as effectively as in their parental cells. Our data also showed that flavopiridol caused the release of mitochondrial cytochrome c and the activation of caspase-9, caspase-8 and caspase-3, with an increase ratio of the proapoptotic protein level (Bax) to the antiapoptotic protein level (Bcl-2 and Bcl-X(L)), while apoptosis was inhibited by pan caspase inhibitor (Z-VAD-FMK) and caspase-3 inhibitor (Z-DEVD-FMK), not by caspase-8 inhibitor (Z-IETD-FMK). The treatment with flavopiridol further inhibited the tumor growth in mouse models of the drug-resistant OS and EFTs. These results suggest that flavopiridol might be promising in clinical therapy for the relapsed OS and EFTs.
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PMID:Cyclin-dependent kinase inhibitor, flavopiridol, induces apoptosis and inhibits tumor growth in drug-resistant osteosarcoma and Ewing's family tumor cells. 1752 Jun 76

In the present work, we have investigated the antitumor activity of 6-(7-nitro-2,1,3-benzoxadiazol-4-ylthio)hexanol (NBDHEX) on aggressive small cell lung cancer. NBDHEX not only is cytotoxic toward the parental small cell lung cancer H69 cell line (LC(50) of 2.3 +/- 0.6 micromol/L) but also overcomes the multidrug resistance of its variant, H69AR, which overexpresses the ATP-binding cassette transporter multidrug resistance-associated protein 1 (MRP1; LC(50) of 4.5 +/- 0.9 micromol/L). Drug efflux experiments, done in the presence of a specific inhibitor of MRP1, confirmed that NBDHEX is not a substrate for this export pump. Interestingly, NBDHEX triggers two different types of cell death: a caspase-dependent apoptosis in the H69AR cells and a necrotic phenotype in the parental H69 cells. The apoptotic pathway triggered by NBDHEX in H69AR cells is associated with c-Jun NH(2)-terminal kinase and c-Jun activation, whereas glutathione oxidation and activation of p38(MAPK) is observed in the NBDHEX-treated H69 cells. In contrast to the parental cells, the higher propensity to die through apoptosis of the H69AR cell line may be related to the lower expression of the antiapoptotic protein Bcl-2. Therefore, down-regulation of a factor crucial for cell survival makes H69AR cells more sensitive to the cytotoxic action of NBDHEX, which is not a MRP1 substrate. We have previously shown that NBDHEX is cytotoxic toward P-glycoprotein-overexpressing tumor cell lines. Therefore, NBDHEX seems a very promising compound in the search for new molecules able to overcome the ATP-binding cassette family of proteins, one of the major mechanisms of multidrug resistance in cancer cells.
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PMID:6-(7-Nitro-2,1,3-benzoxadiazol-4-ylthio)hexanol, a specific glutathione S-transferase inhibitor, overcomes the multidrug resistance (MDR)-associated protein 1-mediated MDR in small cell lung cancer. 1828 20

Given that arsenic trioxide (As(2)O(3)) has been successfully used as a chemotherapeutic agent for refractory malignant tumors, this study is aimed at investigating the effect of As(2)O(3) on human Adriamycin resistant osteosarcoma cell line Saos-2. The mechanism underlying multi drug resistance (MDR) in osteosarcoma cells and the anti-tumor effect of As(2)O(3) on Adriamycin resistant osteosarcoma cells were analyzed. In our experiment, we first selected Adriamycin resistant osteosarcoma cell line by growing the classic osteosarcoma cell line Saos-2 in the medium with increasing drug concentrations. Then, we compared the IC50s of the osteosarcoma cells treated with different anticancer drugs by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Subsequently, we assessed the expression of classic MDR related molecules, Pgp, multidrug resistance-associated protein (MRP) and glutathione (GSH) activity in the wild type and Adriamycin resistant Saos-2 cells. Furthermore, the apoptosis was assessed by concerning DNA fragment and flow cytometry with Annexin-V staining. To elucidate the underlying mechanism of the apoptosis, related proteins Bcl-2, Bcl-xL, Bax, Bak, cleaved Caspase-3 and cleaved Caspase-9 were analyzed by western blotting. The data showed that the resistance to Adriamycin affected the sensitivity of osteosarcoma cell to other chemotherapeutic agents. The IC50s of Saos-2/ADM cells for methotrexate (1.74-fold), Cisplatin (1.43-fold) and As(2)O(3) (1.21-fold) were increased compared with Saos-2 control cells. The expression of Pgp was upregulated comparing with the control cells. No significant difference was detected about the MRP and the glutathione-S-transferase activity and intracellular GSH concentration among different treated osteosarcoma cells. Apoptosis was observed and proved. The western blotting showed that the expression of Bcl-2 and Bcl-xL was downregulated. Meanwhile, the level of Bax, Bak, cleaved Caspase-3 and cleaved Caspase-9 was upregulated after treated with As(2)O(3). The study suggests that Adriamycin resistant osteosarcoma cells have good response to As(2)O(3)-based chemotherapy in vitro, probably via the pathway of inducing apoptosis. And As(2)O(3) might serve as an excellent alternative candidate for adjuvant chemotherapeutic agent on this incurable pediatric sarcoma.
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PMID:Arsenic trioxide inhibits the growth of adriamycin resistant osteosarcoma cells through inducing apoptosis. 1970 92

In early studies, it was demonstrated that R-HZ08, S-HZ08 and the racemate had strong reverse efficacy of multidrug resistance in vitro and in vivo (Yan et al., 2008b). The effect was supposed to have direct interaction with multidrug resistance-associated protein (MRP1) in MCF-7/ADM and P-glycoprotein in K562/A02. According to our latest study, we found HZ08 could enhance chemotherapy induced apoptosis by synergistic action on reactive oxygen species generation, GSH depletion, mitochondrial membrane potential depolarization, cytochrome c release and caspase activation. Moreover, the potential selective effect of HZ08 on resistant cells suggested that HZ08 have specific targets for resistance reversal via apoptosis regulation. Therefore, we traced individual influence of HZ08, not only on apoptosis pathway per se but also on apoptosis related intracellular regulation systems. Then we found HZ08 could increase cells in G(0)/G(1) phase and regulate apoptosis related proteins (Bcl-2, Bax) as well as upstream functional molecules (c-Myc and c-Fos), which are usually abnormal in malignancy and responsible for multidrug resistance in MCF-7/ADM. Thereby, chemotherapy induced apoptosis was promoted. R-HZ08 showed better effect than S-HZ08 or the racemate did in most of targets above. Furthermore, HZ08 did not change the concentration of intracellular Ca(2+) which means it would not have side effect as verapamil does. Considering multidrug resistance is multifactorial, HZ08, especially R-HZ08, which could sensitize apoptosis by multiple improvements of upstream malignant characters, will be a promising drug to enhance the effect of chemotherapy in the treatment of multidrug resistant tumor.
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PMID:HZ08, a great regulator to reverse multidrug resistance via cycle arrest and apoptosis sensitization in MCF-7/ADM. 2081 13


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