Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0023418 (leukemia)
 93,477 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A series of glaucarubinone analogues, obtained from natural sources as well as synthesized by us, were studied both in vitro and in vivo. The focus of the in vitro assessment was to define solid tumor-selective compounds by quantitating differential cytotoxic activity between murine and human solid tumor cells and either murine leukemia or normal cells. Subsequent in vivo studies were aimed at determining the therapeutic efficacy of these analogues against the murine models. Structure-activity analysis consequent to both the in vitro and in vivo studies demonstrated that few changes could be made in the parent glaucarubinone structure (outside of the C-15 position) without abrogating either cytotoxicity or potency. However, significant changes could be made at the C-15 position which modified, either enhanced or diminished, in vitro differential cytotoxicity, potency, human solid tumor selectively, and differential cytotoxicity to a MDR-expressing murine mammary tumor.
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PMID:Anticancer activity of glaucarubinone analogues. 977 91

The synthesis and antitumor evaluation of 2, 5-disubstituted-indazolo[4,3-gh]isoquinolin-6(2H)-ones (9-aza-APs) are described. The key intermediates in the synthesis are benz[g]isoquinoline-5,10-diones which are substituted at positions 6 and 9 with groups of different nucleofugacity for SNAr displacements. The initial displacement of fluoride by a substituted hydrazine leads to the pyrazole analogues. Substitution of the remaining leaving group by an amine or BOC-protected amines leads to the 9-aza-APs 12. These analogues were converted into their maleate or hydrochloride salts 13. In two cases, namely, 13x and 13z, sidearm buildup was also employed in the synthetic pathway. In vitro evaluation of 9-aza-APs against the human colon tumor cell line LoVo uncovered for most of the compounds a cytotoxic potency lower than that of DuP-941 or mitoxantrone and comparable to that of doxorubicin. Only analogues 13c, 13n, and 13ff were as cytotoxic as DuP-941. Interestingly, while DuP-941 was highly cross-resistant in the LoVo cell line resistant to doxorubicin (LoVo/Dx), the 9-aza-APs carrying a distal lipophilic tertiary amine moiety in both chains were capable of overcoming the MDR resistance induced in this cell line. The 9-aza-APs show outstanding in vivo antitumor activity against both systemic P388 murine leukemia and MX-1 human mammary carcinoma transplanted in nude mice. At their optimal dosages, congeners 13a-c, 13f, 13n, 13q, 13x, and 13dd were highly effective against P388 leukemia with T/C% of 200-381, while the T/C% value of DuP-941 was 147. In the MX-1 tumor model, 24 compounds elicited percentages of tumor weight inhibitions (TWI) ranging from 50% to 99%. Congeners 13d, 13k, 13l, 13x, 13z, and 13ee emerged as the most effective ones, with TWI% 96, simliar to that of DuP-941 (TWI% = 95). On the basis of their efficacy profile in additional experimental tumors and lack of cardiotoxicity in preclinical models, two congeners have surfaced as potential clinical candidates.
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PMID:Synthesis and antitumor evaluation of 2,5-disubstituted-indazolo[4, 3-gh]isoquinolin-6(2H)-ones (9-aza-anthrapyrazoles). 987 13

A series of derivatives belonging to a new class of compounds (R4-todit) were highly cytotoxic to a panel of leukaemia- and solid tumour-derived cell lines (IC50 = 0.06-20 microM). The most potent compound was the butyl4 derivative (IC50 = 0.06-5.1 microM); T leukaemia and melanoma cells were the most susceptible cells to this inhibitor (IC50 0.06 microM and 0.1 microM, respectively). The effect of butyl4-todit was irreversible, and led to progressive cell death. The compound showed a comparable potency against exponentially growing and stationary phase cells, and against cell lines expressing the MDR phenotype. The cytotoxicity of butyl4-todit in human normal PBL was up to 20 fold lower than that shown against T leukaemia cells. When tested for antiangiogenic activity in vivo, 1.5 mg/Kg butyl4-todit resulted in over 70% inhibition of the angiogenesis process induced in mice by Kaposi's sarcoma cell secreted products.
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PMID:Antitumor activity of 4,5,6,7-tetrathiocino (1,2-b: 3,4-b') diimidazolyl-1,3,8,10-tetrasubstituted-2,9-dithiones (R4-todit). 989 5

P-glycoprotein (PGP), lung resistance-related protein (LRP) and multidrug resistance associated protein (MRP) expression and the blast cells' intracellular daunorubicin accumulation (IDA) were evaluated in 96 previously untreated cases of de novo acute non-lymphocytic leukaemia (ANLL). 47/96 patients (49%) were classified as PGP+ 44/ 96 (46%) as LRP+, and 8/96 (8%) as MRP+. The more frequent MDR clusters were PGP-/LRP-/MRP- (32/96 cases, 33%) and the PGP+/LRP+/MRP- (27/96 cases, 28%) followed by PGP+/LRP-/MRP- (15/96 cases, 16%) and PGP-/LRP+/MRP- (14/96 cases, 14%). A favourable karyotype was observed more frequently in PGP- and LRP-cases. A highly significant correlation was found between either PGP or LRP overexpression and leukaemic blast cell IDA. All the patients received standard induction and consolidation treatments containing MDR-related (idarubicin, mitoxantrone, etoposide) and other (arabinosyl cytosine) drugs. Multivariate analysis showed that PGP overexpression was significantly associated with a poor response to treatment, both in terms of primary resistance or shorter survival. Other independent prognostic factors were age and cytogenetics. LRP overexpression did not reach statistical significance, although for LRP+ cases the trend was unfavourable. Due to small numbers, no conclusion could be made regarding MRP overexpression, but 5/8 cases showed unfavourable karyotypic abnormalities, 8/8 had a defective IDA and 6/8 failed to achieve remission. This study showed that both PGP and LRP overexpression are common features in de novo ANLL at onset whereas MRP overexpression is more rare. It suggested that overexpression of one of the MDR related proteins was associated with a defective IDA, and confirmed that, in addition to age and cytogenetics, PGP retains an independent prognostic value. It also suggested that LRP did not affect clinical outcome when patients were treated with idarubicin or mitoxantrone and arabinosyl cytosine.
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PMID:P-glycoprotein, lung resistance-related protein and multidrug resistance associated protein in de novo acute non-lymphocytic leukaemias: biological and clinical implications. 1005 Jul 16

The multidrug transporter P-glycoprotein (Pgp), which is frequently overexpressed in multidrug resistant leukemia, has many proposed physiological functions including involvement in transmembraneous transport of certain growth-regulating cytokines. Therefore, we studied cell growth of three pairs of drug resistant and sensitive leukemia cell lines (KG1a, K562 and HL60) exposed to three different inhibitors of Pgp. The resistant KG1a and K562 sublines, which expressed high levels of Pgp, responded to low doses of the cyclosporin SDZ PSC 833, the cyclopeptolide SDZ 280-446, and the cyclopropyldibenzosuberane LY335979 with a dose-dependent growth inhibition. In the resistant variants of KG1a and K562 cells the mean half-maximal growth inhibitory doses (GI50) of SDZ PSC 833 were 312 (SE 41) and 414 (SE 50) nM, those of SDZ 280-446 were 685 (SE 51) and 578 (SE 54) nM, and those of LY335979 were 66 (SE 1) and 48 (SE 8) nM, respectively. Exposure to 1 microM SDZ PSC 833 resulted in tetraploidization, cytokinesis failure and apoptosis of the KG1a and K562 MDR variants. Conversely, parental cells with no or low levels of Pgp and the non-Pgp resistant variant of HL60 cells were not receptive to these cytotoxic effects. We conclude that inhibition of Pgp may exercise selective cytotoxicity in Pgp-rich leukemia cells indicating a possible therapeutic target in multiresistant leukemia.
Leukemia 1999 May
PMID:Growth inhibition, cytokinesis failure and apoptosis of multidrug-resistant leukemia cells after treatment with P-glycoprotein inhibitory agents. 1037 82

Expression of the mdr1 (multidrug resistance), mrp (multidrug resistance associated protein), and lrp (lung resistance related protein) genes is associated with transport related MDR (multidrug resistance). We quantified mRNA levels of these genes using competitive reverse transcription polymerase chain reaction (RT-PCR) in 128 samples of leukaemic cells from 92 patients with acute myelogenous leukaemia (AML). There was a wide variation between the samples in mRNA levels of all three genes. The mean mdr1 mRNA level was 1.3 transcripts per cell (range undetectable to 15.8), the mean mrp level was 7.9 (range 0.1-36.2) and mean lrp 3.9 (range 0.1-29). Lrp mRNA levels were higher in samples drawn at diagnosis from the 15 patients with resistant disease than from the 37 with chemosensitive disease (4.9 SD 3.1 v 2.9 SD 2.3, P = 0.016). Neither mdr1 nor mrp mRNA levels were predictive for response to chemotherapy. In samples from patients who had received chemotherapy, those that had received mitoxantrone (n = 24) had higher lrp mRNA levels (mean 4.8, SD 2.5) than those that had not (n = 20, mean 2.8, SD 2.4, P = 0.012). In conclusion, the results indicate that lrp expression is associated with inferior response to chemotherapy in AML and that lrp expression increases after exposure to mitoxantrone.
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PMID:High levels of lung resistance related protein mRNA in leukaemic cells from patients with acute myelogenous leukaemia are associated with inferior response to chemotherapy and prior treatment with mitoxantrone. 1046 50

The synthesis of dihydroxybenzoperimidine derivatives, which are chromophore-modified dihydroxyanthracenediones with an additional pyrimidine ring incorporated into the chromophore, is reported. These derivatives are structurally related to the antitumor agent mitoxantrone. Their synthesis was carried out by the reaction of 6-amino-8,11-dihydroxy-7H-benzo[e]perimidin-7-one (5) or 6,8, 11-trihydroxy-7H-benzo[e]perimidin-7-one (10) with a number of respective (alkylamino)alkylamines. The dihydroxybenzoperimidine derivatives exhibited in vitro cytotoxic activity against murine leukemia L1210 and human leukemia HL60 cell lines comparable to that of mitoxantrone. These compounds also exhibited a range of in vitro activity against the human MDR-type resistant leukemia K562R cell line with the MDR phenotype. The most active compound of this series, namely 6a, exhibited potent in vitro cytotoxic activity against a panel of human cell lines. Furthermore, in contrast to both mitoxantrone and doxorubicin, it displayed little cross-resistance in cell lines characterized by a MDR phenotype. Cell cycle analysis in the sensitive HT-29 and mitoxantrone-resistant HT-29/Mx (not identified resistance mechanism) cell lines has revealed that both mitoxantrone and 6a induce a G2/M block. However, while the proportion of apoptotic cells after mitoxantrone treatment is similar for both sensitive and resistant cell lines, it is much lower for 6a. Compound 6a tested against P388 murine leukemia in vivo displayed a significant antitumor effect (%T/C 196 at an optimal dose of 10 mg/kg). The property of overcoming the cross-resistance was maintained also in in vivo efficacy studies, where no difference was observed in the antitumor activity of compound 6a against the A2780 human tumor xenograft and its MDR A2780/Dx subline. We conclude that benzoperimidines, if properly substituted, constitute a novel class of compounds that can overcome multidrug resistance.
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PMID:8,11-dihydroxy-6-[(aminoalkyl)amino]-7H-benzo[e]perimidin-7-ones with activity in multidrug-resistant cell lines: synthesis and antitumor evaluation. 1047 82

Drug resistance is a well recognized problem in cancer therapy. Despite the current dogma that drug resistance is always an obstacle for treatment, here I show that it provides opportunities for selective protection of non-resistant cells with killing of drug-resistant cancer cells. According to the proposed 'two-drug' strategy, the first drug should be ineffective against a target drug-resistant cell (ie the drug is a substrate of MRP or Pgp pumps). In addition, it must be cytostatic but not cytotoxic. The second drug, which is applied in sequence, must be a cycle-dependent apoptotic drug to which the target cell is not cross-resistant. Thus, low doses of adriamycin, etoposide and actinomycin D, used as the first drugs, were cytostatic to parental HL60 cells. Therefore, these drugs precluded Bcl-2/Raf-1 phosphorylation, PARP cleavage and cell death which are otherwise induced by paclitaxel, a mitosis-selective apoptotic drug for HL60 cells. In contrast, HL60/ADR cells which express MRP, a transporter which pumps out the first drugs from a cell, were insensitive to the first drugs and therefore readily underwent apoptosis following the second drug. This strategy also allowed a selective killing of HL60/TX cells which express MDR-1, with the only difference being that the second drug, paclitaxel, was substituted for epothilones, non-Pgp substrates. Lack of protection by the first drug, a Pgp substrate, resulted in HL60/TX killing by the second drug, whereas parental HL-60 cells were fully protected. Therefore, drug resistant cells can be selectively killed by a combination of drugs not killing sensitive cells. Lack of toxicity against normal cells will be clinically translated in reduction of adverse side-effects of chemotherapy against drug-resistant malignancies.
Leukemia 1999 Dec
PMID:Drug-resistance enables selective killing of resistant leukemia cells: exploiting of drug resistance instead of reversal. 1060 25

Although the prognosis for adults with acute myelogenous leukemia (AML) has improved over the past 10 years, overall results remain modest. Current research areas in the treatment of AML include dose-intensive therapy and stem-cell transplantation (SCT), immunotherapy, modulation of leukemia resistance (eg, multidrug resistance [MDR] Inhibitors), differentiation therapy (eg, retinolds), exploitation of different disease pathophysiology (eg, angiogenesis inhibitors, apoptosis-inducing agents), targeted therapy (eg, monoclonal antibodies, gene therapy), and the development of additional active chemotherapeutic agents with different mechanisms of action. Topotecan, a topoisomerase-I Inhibitor, may potentially enhance the activity of standard induction chemotherapy with cytosine arabinoside (cytarabine) and topoisomerase-II inhibitors. Topotecan is being investigated as salvage and front-line therapy for AML in combination with etoposide, cytarabine, or cyclophosphamide. The role that topotecan will eventually play In the treatment of AML is not yet clear, but encouraging results from triple combination induction therapy In patients with unfavorable prognoses warrant further investigation.
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PMID:New developments in the treatment of acute myeloid leukemia: focus on topotecan. 1062 25

The photosensitizing dye merocyanine 540 (MC540) has been used in preclinical models and in a phase I clinical trial in the U.S.A. for the extracorporeal purging of autologous bone marrow grafts contaminated with leukemia or lymphoma. In this communication, we report MC540-mediated photodynamic therapy (PDT) was effective in purging leukemic cells expressing P-gp. When K562 and K562/ADM were exposed to MC540 (15 micrograms/ml) and white light (145.8 kJ/m2), the concentration of K562 and K 562/ADR was reduced by 1.8 and 3.0 log, respectively. Using flow cytometry and confocal laser scan microscopy, MC540 and calcein-AM were bound intracellularly and effluxed by P-gp in K562/ADM. In K562/ADM, calcein-AM efflux was inhibited by P-gp modulator, cyclosporin A (5 microM) and verapamil (15 micrograms/ml). In contrast, MC540 efflux was inhibited by cyclosporin A but not verapamil. Furthermore, MC540-mediated PDT inhibited efflux of calcein-AM and MC540, and induced the accumulation of dyes in K562/ADM. We conclude that MC540 is a substrate of P-gp and that MC540-mediated PDT is useful for purging MDR cells through inhibition of P-gp activity.
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PMID:[Merocyanine 540-mediated photodynamic therapy inhibits P-glycoprotein (P-gp) activity in adriamycin-resistant K562 cells]. 1063 4


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