Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0025202 (melanoma)
 69,561 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

2-(Diethylamino-2-ethyl)9-hydroxyellipticinium-chloride, HCl (DHE), a new congener of the antitumor agent elliptinium acetate (Celiptium) (NMHE), has recently been selected for phase I clinical trials. NMHE has a methyl group at nitrogen 2 on the ellipticine ring while DHE possesses a basic diethylaminoethyl chain at this position. Compared to NMHE, the presence of the diethylaminoethyl side chain results in the following: a significant increase in the lipophilicity of the drug; no significant modification in either the binding constant values to DNA or the ability to intercalate between DNA base pairs; a marked decrease in the unwinding angle value of supercoiled DNA; and no significant change in the alteration of the catalytic activity of topoisomerase II in vitro. DHE appears to act as a simple reversible intercalating agent as shown by the selective mutagenic effect on Salmonella TA 1977 tester strain and by its inability to induce the SOS functions in a sfiA lac fusion containing Escherichia coli strain. From a pharmacological point of view, the presence of the diethylaminoethyl chain results in a 2-fold increase in the cytotoxicity to L1210 cultured cells, a strong increase in the antitumor efficiency on experimental murine tumors such as L1210 and P388 leukemia, B16 melanoma, M 5076 reticulosarcoma, and colon 38 adenocarcinoma, and finally an objective decrease in the acute and subacute toxicity in mice, rat, and macaque. The absence of significant differences in the interaction of NMHE and DHE with their potential targets in vitro leads to the hypothesis that the superiority of DHE in terms of cytotoxicity and antitumor efficiency may be due to an increase in the diffusion across cellular membrane and a more favorable biodistribution in vivo.
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PMID:Physicochemical and pharmacological properties of the antitumor ellipticine derivative 2-(diethylamino-2-ethyl)9-hydroxy ellipticinium-chloride, HCl. 367 74

A series of DNA-intercalating 9-anilinoacridines, namely 9-phenoxyacridines, 9-(phenylthio)acridines, and 9-(3',5'-disubstituted anilino)acridines, were synthesized as potential antitumor agents with inhibitory effects on DNA topoisomerase II. Unlike amsacrine (m-AMSA), these agents were designed to avoid the oxidative metabolic pathway. These acridine derivatives were, therefore, expected to have long half-life in plasma. Both 9-phenoxyacridines and 9-(phenylthio)acridines were found to have moderate cytotoxicity against mouse leukemia L1210 and human leukemic HL-60 cell growth in culture. Among 9-(3',5'-disubstituted anilino)acridines, 3-(9-acridinylamino)-5-(hydroxymethyl)aniline (AHMA) was found to be a potent topoisomerase II inhibitor and exhibited significant antitumor efficacy both in vitro and in vivo. Chemotherapy of solid-tumor-bearing mice with 10, 10, and 5 mg/kg (QD x 4, ip) AHMA, VP-16, and m-AMSA, respectively, resulted in more tumor volume reduction by AHMA than by VP-16 or m-AMSA for E0771 mammary adenocarcinoma and B-16 melanoma. For Lewis lung carcinoma, AHMA was as potent as VP-16 but more active than m-AMSA. Structure-activity relationships of AHMA derivatives are discussed.
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PMID:9-substituted acridine derivatives with long half-life and potent antitumor activity: synthesis and structure-activity relationships. 765 Jun 75

The human melanoma cell line FEM-X was selected in multiple steps with VP-16 (etoposide) and an inhibitor of P-glycoprotein (Campain et al., 1993). The resulting clones, FVP1b and FVP3, are highly resistant to the nonintercalative epipodophyllotoxins and exhibit moderate levels of resistance to doxorubicin. The topoisomerase II activity present in crude nuclear extracts from mutant and wild-type cells is similar in amount and equally sensitive to VP-16. However, in live cells, the topoisomerase II from FVP1b and FVP3 is much less susceptible to drug-induced cleavable complex formation than is that from FEM-X. Using reverse transcription followed by the polymerase chain reaction (RT-PCR), we have cloned and sequenced the entire cDNA for topoisomerase II alpha from FEM-X and FVP3. The only sequence change unique to the cDNA from drug-resistant cells is a 3 bp deletion of nucleotide 1320-1322, resulting in a deletion of Ala429. Three FEM-X sublines of increasing resistance were tested, and the prevalence of the mutant RNA over wild-type increases in these cells in parallel with their resistance to VP-16. In FVP3, the most highly resistant line, expression of the wild-type allele is barely detectable. Analysis of genomic DNA shows that FEM-X is homozygous for the wild-type topoisomerase II alpha sequence and that each of the drug-resistant clones possesses both wild-type and mutant alleles. Although not definitive, these genetic results suggest that the deletion of Ala429 from topoisomerase II alpha makes the enzyme less susceptible to drug-induced cleavable complex formation and confers a growth advantage upon cells in the presence of VP-16.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:A novel mutant topoisomerase II alpha present in VP-16-resistant human melanoma cell lines has a deletion of alanine 429. 772 83

N-[2-(Dimethylamino)ethyl]acridine-4-carboxamide (DACA), a DNA intercalator that exerts its antitumour action through the enzyme topoisomerase II, has previously been shown to be curative against the transplantable Lewis lung adenocarcinoma growing as lung tumour nodules in mice. On the basis of this finding as well as its high in vitro activity against multidrug-resistant cell lines, DACA has been chosen for clinical trial under the auspices of the Cancer Research Campaign, United Kingdom. In the present study the activity of DACA was assessed against advanced (5-mm diameter) s.c. colon 38 adenocarcinomas in BDF1 mice using tumour-growth delay as an end point. Its activity was found to be related positively to the total dose given and negatively to the total duration of the dose schedule. Adoption of a split-dose i.p. administration schedule or slow i.v. infusion allowed the administration of large doses without toxicity. The activity of DACA was comparable with that of 5-fluorouracil and superior to that of doxorubicin, cyclophosphamide and the experimental amsacrine analogue CI-921. Mitoxantrone, amsacrine, etoposide, teniposide and daunorubicin showed minimal activity. DACA also demonstrated significant activity against the NZM3 melanoma human cell line growing as a xenograft in athymic mice.
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PMID:Experimental solid tumour activity of N-[2-(dimethylamino)ethyl]-acridine-4-carboxamide. 778 Nov 46

We investigated the ability of camptothecin (CPT), an inhibitor of topoisomerase (topo) I, and etoposide (VP-16), an inhibitor of topo II, to potentiate X-radiation response and to inhibit the repair of potentially lethal damage (PLDR) and sublethal damage (SLDR) in confluent cultures of a radioresistant (Sk-Mel-3) and a radiosensitive (HT-144) human melanoma cell line. CPT or VP-16 were present both during irradiation and during the subsequent delayed plating period allowed for repair of X-radiation damage. When the direct toxicities of CPT or VP-16 were corrected for, we found that a dose of either drug that killed approximately 15% of the clonogenic cells potentiated the effects of radiation differentially on the cell lines. CPT and VP-16 inhibited the increase in survival brought about by delayed plating of HT-144 but not Sk-Mel-3 cells. In both cell lines, CPT inhibited SLDR but not PLDR. VP-16 also inhibited SLDR in both cell lines, however, in contrast with CPT, it also inhibited PLDR in HT-144 cells. Our results therefore suggest that either topo I and II are both implicated in the repair of X-radiation damage, or that the lesions formed by CPT and VP-16 with DNA are able to impair the processing of X-radiation repair. In addition, we found that in the absence of the topo inhibitors, the two cell lines repaired similar amounts of PLD from an isosurvival level. Sk-Mel-3, however, repaired significantly increased SLD from an isosurvival level (about three-fold, p < 0.05) compared with HT-144.
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PMID:Inhibition of potentially lethal and sublethal damage repair by camptothecin and etoposide in human melanoma cell lines. 802 12

The topoisomerase II inhibitor, VP-16 (etoposide), is an important component in many chemotherapeutic regimens. To characterize resistance to this drug, the human melanoma cell line, FEM-X, was selected in multiple steps with VP-16. To prevent the development of typical multidrug resistance, an inhibitor of P-glycoprotein, the tiapamil analog, RO-11-2933, was added to the selections. The resultant clone FVP3 is 56-fold resistant to VP-16 and cross-resistant to doxorubicin (Adriamycin) (9-fold) and VM-26 (27-fold). These cells are also two- to four-fold resistant to m-AMSA, daunorubicin, and mitoxantrone. FVP3 is not resistant to the P-glycoprotein substrates vinblastine, does not express the MDR1 gene at detectable levels, and does not show reduced 3H-VP-16 accumulation. Unlike other cell lines that exhibit resistance to inhibitors of topoisomerase II, FVP3 has the same level of topoisomerase II expression and activity as FEM-X. Using live cells treated with VP-16, band depletion assays and KCI/SDS precipitation assays show that topoisomerase II from FVP3 is much less susceptible to drug-induced cleavable complex formation than is that from FEM-X. This difference in sensitivity to VP-16 is also detected using lysates from disrupted cells, but not with isolated nuclei devoid of cytoplasmic and membrane components. In addition, the topoisomerase II present in nuclear extracts from FVP3 is not resistant to the effects of VP-16 as measured by: (1) inhibition of strand passing activity during decatenation of kinetoplast DNA, (2) drug-induced linearization of plasmid DNA, and (3) immunodepletion by VP-16. These results suggest that some component of the cytoplasm or cellular membranes, or a factor depleted from nuclei during their isolation, is responsible for the resistance to VP-16 in FVP3.
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PMID:Characterization of an unusual mutant of human melanoma cells resistant to anticancer drugs that inhibit topoisomerase II. 809 46

We have analyzed five human melanoma cell lines, displaying variable doxorubicin resistance (1- to 6-fold), for drug-induced DNA breaks, topoisomerase II activity and mRNA expression. Enhanced drug efflux was not the reason for doxorubicin resistance of these tumor cells although they overexpressed the transmembrane 170 kDa P-glycoprotein. Doxorubicin-induced DNA lesions (2-fold) and topoisomerase II activity (7-fold) were higher in HM-1 and G361 cells than in the less doxorubicin-sensitive NH and FCCM-9 cells. Topoisomerase II mRNA expression was also 2-fold higher in HM-1 and G361 cells. Doxorubicin-induced DNA breaks and topoisomerase II activity inversely correlated with the degree of doxorubicin sensitivity. Southern blot analysis showed variation in the hybridization pattern of topoisomerase II gene in doxorubicin-resistant cells when compared to sensitive cells. This study portrays the low doxorubicin sensitivity of NH and FCCM-9 cells as "atypical" and emphasizes the importance of DNA damage and topoisomerase II activity in cellular low doxorubicin resistance.
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PMID:Doxorubicin-induced DNA breaks, topoisomerase II activity and gene expression in human melanoma cells. 838 63

Several possible mechanisms of the synergistic interactions of IL-1 alpha and VP-16 against A375-C6 human melanoma cells were investigated. Studies indicate that IL-1 alpha did not increase topoisomerase II-dependent VP-16-mediated DNA damage, nor did IL-1 alpha inhibit the repair of VP-16-induced DNA damage in these cells. Furthermore, IL-1 alpha by itself or in combination with VP-16 did not cause significant fragmentation of cellular DNA into oligomers, indicating programmed cell death (apoptosis) was not involved in the mechanism of synergy. In contrast, an IL-1-specific receptor antagonist significantly decreased IL-1 alpha toxicity toward the melanoma cells and nearly eliminated the synergistic interactions of IL-1 alpha with VP-16. These results strongly indicate that synergism of IL-1 alpha with VP-16 was dependent upon an IL-1-receptor-mediated processes. DNA-strand breakage was unlikely to be a primary intracellular target for IL-1 alpha cytotoxicity and synergism with VP-16.
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PMID:Synergistic interactions of etoposide and interleukin-1 alpha are not due to DNA damage in human melanoma cells. 842 27

Mutants of the human melanoma cell line, FEM-X, selected in multiple steps with VP- 16 (etoposide), are cross resistant to the epipodophyllotoxins and doxorubicin. Complementary DNA's for topoisomerase IIalpha were cloned from both FEM-X and FVP3, the most resistant mutant. Deletion of nucleotides 1320-1322 (or Ala429 from the resulting topoisomerase IIalpha protein) was unique to the cDNA from the drug resistant cell line. Expression of the mutant mRNA increases in parallel with VP-16 resistance in this series of cell lines. Restriction analysis and Southern analysis with allele-specific oligonucleotide probes were used to quantify the ratio of wild-type to mutant topoisomerase IIalpha alleles present in DNA amplified by PCR from both FEM-X and the drug resistant sublines. This analysis shows that in cell lines of increasing drug resistance, the number of mutant topoisomerase IIalpha alleles increases incrementally along with a concomitant decrease in the number of wild-type alleles. By quantitative Southern analysis of genomic DNA the total number of topoisomerase IIalpha alleles in FVP3 is approximately 2-fold that in the parental cells. Fluorescence in situ hybridization with a chromosome l7 paint reveals that amplification of the topoisomerase IIalpha locus in FVP3 correlates with an increase in the number of chromosome 17's, specifically the long arm. Cytogenetic analysis demonstrates that FEM-X contains three copies of chromosome 17, two of which are morphologically normal. During drug selection, FVP3 has gained 2-3 additional copies of the long arm of chromosome 17, the chromosomal location of the topoisomerase IIalpha locus. In this subline it is likely that three copies of the topoisomerase IIalpha gene are found on normal chromosome 17's and two on an isochromosome of the long arm of 17. By pulsed field gel electrophoresis, we were able to detect changes in the restriction pattern of the region of the long arm of chromosome 17 around the topoisomerase IIalpha locus that correlate with observed cytogenetic changes in FVP3. These results suggest that the acquisition of the mutant allele of topoisomerase IIalpha confers a selective advantage to cells in the presence of VP-16. As the drug concentration increased during the selection process, surviving sublines show preferential expression of the mutant topoisomerase IIalpha mRNA over that of the wild-type which is associated with a concomitant increase in the number of mutant topoisomerase IIalpha alleles.
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PMID:Acquisition of multiple copies of a mutant topoisomerase IIalpha allele by chromosome 17 aneuploidy is associated with etoposide resistance in human melanoma cell lines. 860 May 72

As a continuation of our structure--activity relationship study of substituted 2-phenyl-4-quinolones and flavonoids as antitumor and antiviral agents, a series of 5,6,7,8-substituted-2-phenylthiochromen-4-ones has been synthesized by condensation of substituted thiophenols and ethyl benzoylacetates. Target compounds were evaluated for biological activity. Among them, compounds 7, 10, 12, and 13 displayed significant growth inhibitory action against a panel of tumor cell lines including human ileocecal carcinoma (HCT-8), murine leukemia (P-388), human melanoma (RPMI), and human central nervous system tumor (TE671) cells. Compounds 10, 12, and 19 displayed DNA topoisomerase I inhibitory activity in vitro and compound 11 was an in vitro, inhibitor of DNA topoisomerase II. Compound 11 was most active (ED50 value, 0.65 microM) against HIV in acutely infected H9 lymphocytes and had a therapeutic index of about 5.
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PMID:Antitumor agents. 166. Synthesis and biological evaluation of 5,6,7,8-substituted-2-phenylthiochromen-4-ones. 864 56


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