Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C1140680 (ovarian cancer)
 28,141 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effect of N-(3,4-dimethoxyphenyl) N-methyl-2-(naphthyl)-m-dithiane-2-propylamine hydrochloride (RO11-2933), an analog of the calcium channel blocker tiapamil, on doxorubicin (DOX)-induced cytotoxicity and DNA damage in human ovarian cancer cells sensitive and resistant to DOX was investigated. A2780-DX2, A2780-DX3, and A2780-DX6 cell sublines were characterized by 7-, 26-, and 48-fold resistance after 2 h DOX exposure and 30-, 50-, and 500-fold resistance after 72 h DOX exposure, respectively. Increased drug efflux resulting in a lower intracellular drug accumulation, decreased DOX-induced DNA single-strand breaks (DNA SSBs), and rapid DNA repair correlated with the degree of resistance. In addition, DNA SSBs were rapidly repaired within 8 h in A2780-DX3 cells, whereas no significant repair of DNA SSBs was observed in sensitive cells. In comparison with verapamil, RO11-2933 was found to reverse DOX resistance at lower and nontoxic concentrations (2 microM as compared with 10 microM verapamil). This reversion was complete in cells with a low degree of resistance (A2780-DX1 and A2780-DX2) but partial in highly resistant cells (A2780-DX3 and A2780-DX6), and continuous exposure to RO11-2933 was essential for optimal reversal of drug resistance. Interestingly, RO11-2933 was found to inhibit the repair of DNA SSBs induced by DOX but not those induced by X-ray. These results suggest that the potentiation of DNA SSBs and the specific inhibition of DNA repair by RO11-2933 in multidrug-resistant cells could be of particular value in overcoming MDR in the clinic.
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PMID:Relationship between cytotoxicity, drug accumulation, DNA damage and repair of human ovarian cancer cells treated with doxorubicin: modulation by the tiapamil analog RO11-2933. 259 2

New 2-[2'-(dimethylamino)ethyl]-3H-dibenz[de,h]isoquinoline-1,3-diones with substituents at the 6- and 7-positions were prepared. Nucleophilic aromatic displacement was a key reaction in the syntheses. Ten of the new compounds were more potent than the unsubstituted compound, azonafide, in a panel of tumor cells including human melanoma and ovarian cancer and murine sensitive and MDR L1210 leukemia. They also were less cardiotoxic in cell culture. Four of these compounds were not cross-resistant with the MDR leukemia, and one of them, 6-ethoxyazonafide, was nearly as potent against solid tumor cells as leukemia cells. These compounds also had good potency against human breast, colon, and lung cancer cells, including doxorubicin and mitoxantrone resistant cell lines. Advantages of the new analogues over azonafide were less in vivo, but 6-ethoxyazonafide was more effective against L1210 leukemia and subcutaneous B16 melanoma in mice. Although correlations of antitumor potency in cells and physicochemical properties of substituents were not found, there were statistically significant correlations of DNA melt transition temperature (delta Tm) with potency in solid tumor cells and sensitive and MDR resistant L1210 leukemia cells for 6-substituted azonafides and with solid tumors for 7-substituted azonafides.
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PMID:6- and 7-substituted 2-[2'-(dimethylamino)ethyl]-1,2-dihydro-3H-dibenz[de,h] isoquinoline-1,3-diones: synthesis, nucleophilic displacements, antitumor activity, and quantitative structure-activity relationships. 864

The expression of different genes potentially involved in DNA repair and in cell responses to chemotherapy was evaluated in 33 previously untreated ovarian cancer patients. In biopsies of the same patients the expression of repair genes O6-methylguanine DNA methyltransferase (MGMT), 3-methyladenine DNA glycosylase (MAG), ERCC1, MDR-1, DNA topoisomerase I, DNA topoisomerase IIalpha, and glutathione S-transferase-pi (GST-pi) was assessed by Northern blot analysis. No direct statistical correlation was found between the expression of these genes and the response to chemotherapy (mainly platinum-based with or without doxorubicin and cyclophosphamide). Univariate analysis showed a weak negative correlation (P = 0.037) between the expression of ERCC1 and mortality, whereas no statistically significant correlation was found for other parameters. The MDR-1 gene encoding for the P-glycoprotein P-170 was mostly undetectable in these patients (as assessed by Northern blotting), whereas relatively high levels of MAG and MGMT were found in the majority of patients. A statistically significant correlation was found between the expression of DNA topoisomerase I and the expression of either ERCC1 (P = 0.0026) or GST-pi (P = 0.0279).
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PMID:Expression of genes of potential importance in the response to chemotherapy and DNA repair in patients with ovarian cancer. 910 2

Extensive research has led to accumulation of common hereditary evidence concerning ovarian and breast cancer, suggesting that these two cancers can be considered as one type. Subsequently, women with breast cancer are susceptible to the risk of developing ovarian cancer. Highly expressed oncogenes such as bcl-2, HER2/neu and others or mutated suppressor genes such as p53 or BRCA1 have been characterised as hereditary susceptibility genes leading to syndromes such as breast/ovarian cancer syndrome, Li-Fraumeni and others. Furthermore, these genetic alterations can cause potent chemoresistance by inhibiting induction of apoptosis after DNA damage caused by chemotherapy and/or radiotherapy. Presently, molecular onco-biology has enabled us not only to detect susceptibility to ovarian and breast cancer but also ways to inhibit their further progression or even circumventing chemoresistance mechanisms after their development by gene therapy using delivery vectors such as liposomes or viruses, by which we can replace wild-type tumour suppressor genes or by using antigene, antisense oligonucleotides and antisense RNA leading to reduced oncogene expression, enabling induction of apoptosis after DNA damage into chemoresistant tumour cells. Furthermore efflux-genes such as MDR-1 or MRP can be circumvented, suicide-genes can be employed which can facilitate sensitivity by encoding enzymes capable of converting inactive forms of a drug into toxic antimetabolites and immunotherapy can be achieved, by transfection of tumour cells with adenoviral vectors encoding immunomodulators such as IL-2 or MHC molecules. Thus, molecular biology appears to be a very strong element for the screening, diagnosis, therapy and prognosis of ovarian and breast cancer. However, consistent future research is greatly needed because many points concerning ovarian and breast cancer genetics are still unknown. Finally, we strongly believe that gene therapy could be extremely useful when is combined with conventional therapy against ovarian and breast tumours.
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PMID:Molecular aspects of breast and ovarian cancer. 937 59

CI-980 is a synthetic mitotic inhibitor that binds to the colchicine binding site of tubulin. It demonstrates broad activity against human and murine tumor models and shows no cross resistance with tumor models whose mechanism of resistance is mediated by P-glycoprotein (MDR-1). A phase I study was completed in 25 patients with solid tumors using a 24-hour infusion schedule, with courses repeated every 3 weeks. Eight dose levels were tested between 1.2 and 15.6 mg/m2. The maximum tolerated dose was 14.4 mg/m2. Neutropenia was dose-related but not dose-limiting; thrombocytopenia was infrequent. CNS toxicities were dose-limiting and consisted of dizziness, headache, loss of coordination, loss of consciousness, nervousness, and other symptoms. These events occurred near the end of the infusion and were reversible, usually within 24 hours. One patient who was to be treated at dose level 8 (intended dose was 19.2 mg/m2; actual dose was 15.6 mg/m2) became encephalopathic prior to completion of the infusion. Other adverse events included gastrointestinal toxicities (nausea, vomiting, anorexia, constipation, stomatitis, dyspepsia, bleeding, cheilitis), IV site erythema, fever, and fatigue. A partial response was observed in one patient with colon cancer and reductions in CA-125 levels were observed in 2 patients with ovarian cancer. Pharmacokinetics were linear and dose-proportional. Results indicate high systemic clearance and wide tissue distribution. Mean pharmacokinetic parameter values: T1/2 = 5.52 hours, plasma clearance 1163 mL/min/m2, and Vdss 376 L/m2.
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PMID:A phase I trial and pharmacokinetic evaluation of CI-980 in patients with advanced solid tumors. 938 46

We recently demonstrated a correlation between the expression levels of the PKC eta isozyme and the MDR1 or MRP genes in blasts from AML patients, and in primary breast cancers. In order to extend these findings we analysed ovarian cancer cells from 14 ascites aspirates from 8 patients using a cDNA-PCR approach. 5 patients were examined in follow up studies. 4 out of these 5 patients received continuous chemotherapy. The relative increases in MDR1, MRP, LRP or PKC eta mRNA expression levels were monitored. In one of these patients combined significant increase in MDR1, MRP, LRP and PKC was seen. One follow up sample was obtained after chemotherapy was discontinued. In this case significant relative decreases of MDR1, LRP and PKC eta mRNA expression levels were found. Furthermore, a significant positive correlation was determined for the relative mRNA expression levels of MRP and PKC eta. These results point to a multifactorial emergence of MDR in this type of tumor with a possible involvement of the PKC eta isozyme.
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PMID:Expression analysis of protein kinase C isozymes and multidrug resistance associated genes in ovarian cancer cells. 961 8

The multidrug resistant protein MDR-1 has been associated with the resistance to a wide range of anti-cancer drugs. Taxol is a substrate for this transporter system and is used in the treatment of a wide range of human malignancies including lung, breast and ovarian cancer. We have generated a series of ovarian cell lines resistant to this compound, all of which overexpress MDR-1 through gene amplification. We present novel evidence that a constitutive activation of the ERK1/2 MAP kinase pathway was also observed although the level of active JNK and p38 remained unchanged. Inhibition of the ERK1/2 MAP kinase pathway using UO126 or PD098059 re-sensitised the Taxol resistant cells at least 20-fold. Importantly, when Mdr-1 cDNA was stably expressed in the wild-type cell line to generate a highly Taxol-resistant sub-line, 1847/MDR5, ERK1/2 MAP kinases again became activated. This result demonstrated that the increased activity of the signalling pathway in the Taxol-resistant lines was directly attributable to MDR-1 overexpression and was not due to the effects of Taxol itself. Additionally, we demonstrated that inhibition of the P13K pathway with LY294002 sensitised the MDR-1-expressing 1847/TX0.5 cells and 1847/MDR5 cells at least 10-fold but had no effect in the wild-type cells. This finding suggests a possible role for this pathway, also, in the generation of resistance to Taxol.
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PMID:Cross-talk between signalling pathways and the multidrug resistant protein MDR-1. 1171 Aug 32

For the treatment of ovarian cancer, gene therapy is increasingly viewed as the fourth therapeutic concept (in addition to surgery, chemotherapy, and irradiation). Many approaches that use viral and nonviral delivery systems have been employed to introduce genes into tumor cells, thus changing their malignant phenotype. The development of tissue-specific promoters has enhanced the specificity of adenoviral transduction, the most commonly used transfer method. Phase I clinical trials (targeting p53, BRCA1, Her2/neu, Bcl-2, MDR, EIA, and HSV-TK genes) have been performed to test the relative safety of different strategies. Further studies are needed to evaluate the effectiveness of these treatments. New studies must evaluate gene therapy alone and in combination with cytostatic regimens because preclinical studies have shown the chemosensitizing effects of several target genes. The increasing knowledge about the genetic background of ovarian cancer will provide many targets for novel gene therapy approaches.
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PMID:Gene therapy of ovarian cancer. 1211 82

The development of a molecular screening method for cancer patients is of great importance, since it would contribute to the selection of the most effective chemotherapy regimen for each patient. In the present study we applied such a method, semi-quantative RT-PCR analysis, and we examined the expression of the multidrug resistance gene MDR-1, the metastasis suppressor gene nm23-H1 and the non-MDR drug resistant gene H Sema E in 53 ovarian and breast cancer specimens. Moreover, we have correlated the expression profile of these genes with the histopathological findings and clinical outcome of the examined patients. The majority of specimens were found to be positive for MDR-1 and H Sema E gene expression, while nm23-H1 was detected in less than 50% of the patients. Correlation and statistical analysis of the molecular data with clinicopathological features showed that nm23-H1 could serve as a good prognostic factor for ovarian cancer patients. In breast cancer patients, nm23-H1 expression was associated with a 6.1 higher death risk. Ovarian cancer patients who express nm23-H1, but not MDR-1 and H Sema E, tend to have longer survival than patients with any other gene combination. Finally, breast cancer patients with advanced disease showed a better response when they were negative for all the three genes studied. In conclusion this work proposes that the combined study of the expression of different genes may be a useful approach for evaluating patients' response to therapy.
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PMID:Correlation of MDR-1, nm23-H1 and H Sema E gene expression with histopathological findings and clinical outcome in ovarian and breast cancer patients. 1217 14

HMN-176 ((E)-4-[[2-N-[4-methoxybenzenesulfonyl]amino]stilbazole]1-oxide) is an active metabolite of HMN-214 ((E)-4-[2-[2-(N-acetyl-N-[4-methoxybenzenesulfonyl]amino)stilbazole]]1-oxide), which has a potent antitumor activity in mouse xenograft models. In this study, we show that HMN-176 circumvents multidrug resistance in a K2 human ovarian cancer subline selected for Adriamycin resistance (K2/ARS). Upon treatment of K2/ARS cells with 3 microM HMN-176, the GI(50) of Adriamycin for the cells decreased by approximately 50%. To explore the molecular mechanism of this effect, we assessed the expression of the multidrug resistance gene (MDR1), which is constitutive in K2/ARS cells, at both the protein and the mRNA level. Western and reverse transcription-PCR analysis revealed that the expression of MDR1 was significantly suppressed by treatment with HMN-176. Furthermore, when administered p.o., HMN-214 suppressed the expression of MDR1 mRNA in a mouse xenograft model implanted with KB-A.1, an Adriamycin-resistant cell line. Luciferase reporter fusion gene analysis demonstrated that HMN-176 inhibited the Y-box-dependent promoter activity of the MDR1 gene in a dose-dependent manner. Moreover, we show by electrophoretic mobility shift assay that HMN-176 inhibits the binding of NF-Y, which is thought to be an essential factor for the basal expression of MDR1, to its target Y-box consensus sequence in the MDR-1 promoter. Inhibition of MDR-1 expression was achieved with pharmacological concentrations of HMN-176, suggesting that HMN-176 may act by two different mechanisms-cytotoxicity and MDR1 down-regulation-simultaneously. The data presented strongly suggest that the antitumor mechanism of HMN-176 (or its prodrug HMN-214 in vivo) is quite different from those of known antitumor agents.
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PMID:HMN-176, an active metabolite of the synthetic antitumor agent HMN-214, restores chemosensitivity to multidrug-resistant cells by targeting the transcription factor NF-Y. 1458 95


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