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

In spite of important progress in the local treatment of uveal melanoma, the most frequent primitive intraocular tumor, 15%-30% of patients still die because of tumor metastasis. This tumor is characterized by constitutive chemoresistance, thwarting any attempt to control it using the usual chemotherapy protocols. The chemoresistance of uveal melanoma is mainly due to the typical multidrug resistance phenotype (MDR), which is linked to overexpression of membrane proteins that actively extrude anticancer drugs from the cell. Typical MDR is particularly complex in this tumor since several chemoresistance-related proteins are simultaneously produced. The negative prognostic significance of the overexpression of P-glycoprotein, the main representative among the typical MDR-related proteins, was shown in uveal melanoma. The atypical MDR phenotype, which refers to other chemoresistance mechanisms such as resistance to apoptosis also contributes to the chemoresistance of uveal melanoma. Thanks to the recent progress in molecular biology, the chemosensitization strategies of gene therapy approaches, which aim at weakening the pathological activity of MDR genes in cancer cells, are currently on the rise. This approach will disrupt current therapeutic strategies and necessarily improve and standardize the methods used to characterize the chemoresistance profile of this cancer. Indeed, we will have to know the genes to be targeted for each melanoma in order to induce cell chemosensitivity.
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PMID:[Multidrug resistance in uveal melanoma]. 1614 33

Trabectedin [Ecteinascidin 743, Yondelis, ET 743, NSC 684766] is a tetrahydroisoquinoline alkaloid derived from the Caribbean marine tunicate, Ecteinascidia turbinata. The drug is being developed by PharmaMar (Zeltia) in partnership with Johnson & Johnson Pharmaceutical Research & Development LLC. It was synthetically isolated and developed by the University of Illinois and licensed to PharmaMar; the company has completed the hemisynthesis of agent. Trabectedin interacts with the minor groove of DNA and alkylates guanine at the N2 position, which bends towards the major groove. In this manner, it is thought that the drug affects various transcription factors involved in cell proliferation, particularly via the transcription-coupled nucleotide excision repair system. Trabectedin blocks the cell cycle at the G(2) phase, while cells at the G(1 )phase are most sensitive to the drug. It also inhibits overexpression of the multidrug resistance-1 gene (MDR-1) coding for the P-glycoprotein that is a major factor responsible for cells developing resistance to cancer drugs. The agent is also thought to interfere with the nucleotide excision repair pathways of cancer cells, suggesting that it could be effective in the treatment of many cancer types including melanoma and sarcoma, as well as lung, breast, ovarian, endometrial and prostate cancers; clinical evaluations are underway in these indications. PharmaMar and Ortho Biotech Products (Johnson & Johnson) entered into an agreement in August 2001 for the joint development and commercialisation of trabectedin. PharmaMar retains commercialisation rights in Europe, including Eastern Europe. Ortho Biotech will market the product in the US, Japan and the rest of the world; Tibotec Therapeutics (a division of Ortho Biotech) will commercialise it in the US. PharmaMar will receive an initial payment from Ortho Biotech plus future milestone and royalty payments linked to development targets and sales; the upfront payment would be approximately 20 million US dollars with royalties contributing 10-20% of total sales of the drug. Although details of the licensing transaction for trabectedin were undisclosed, analysts estimate the figure to be around 100 million US dollars. Previously, PharmaMar signed an agreement granting Bristol-Myers Squibb the option to evaluate and develop as many as 12 of PharmaMar's marine-derived anticancer compounds on an exclusive worldwide basis. However, it appears that Bristol-Myers Squibb had chosen not to exercise the option. Trabectedin is undergoing clinical trials in soft tissue sarcoma (Sarcoma in the Phase table), ovarian, breast, endometrial, prostate and non-small-cell lung cancers. PharmaMar indicated in January 2004 that it intends to launch trabectedin in one of these indications in 2006. PharmaMar raised funds from a round of financing in June 2005 that will be used to fund further clinical trials of its anticancer products, including trabectedin. The US FDA granted trabectedin orphan drug status for ovarian cancer in April 2005. Trabectedin also received orphan drug status from the European Commission for the treatment of ovarian cancer in October 2003. This followed a positive opinion by the Committee for Orphan Medicinal Products (COMP) of the EMEA. Trabectedin has undergone a phase II study for the second- or third-line treatment of ovarian cancer in Europe (England and Belgium), the US and Canada. The trial was initiated in October 2002 and evaluated a weekly schedule of trabectedin (0.58 mg/m(2)) via IV infusion for 3 weeks followed by a week of rest. Final results from this study have been presented. A separate phase II trial evaluating the antitumour activity of trabectedin as a second-line therapy in advanced ovarian cancer was conducted by researchers at the Southern Europe New Drugs Organization (SENDO) in Milan, Italy. PharmaMar and Johnson & Johnson are conducting a pivotal (STS-201) trial to compare a weekly and daily dosing regimen of trabectedin among patients with advanced or metastatic soft tissue sarcoma who are unresponsive to standard chemotherapy of doxorubicin and ifosfamide. The randomised, multicentre, open-label trial has completed enrolment of 270 patients during the second quarter of 2005. Positive data from the STS-201 trial have been announced. An independent data monitoring committee has found that interim data supports a positive trend in time to disease progression favouring patients receiving the daily dosing regimen. Consequently, all patients have been offered the option of switching to the daily regimen. Final results from the STS-201 trial will form the basis of MAA re-submission with European regulatory authorities. PharmaMar has held a pre-submission meeting with the EMEA and has presented a formal letter of intent to file for approval of trabectedin for soft tissue sarcoma. Previously, PharmaMar first filed for EU registration of trabectedin for treatment of advanced soft tissue sarcoma in November 2001, which was accepted for review by the EMEA and Swiss Health Authorities. However, the CPMP confirmed its recommendation not to grant trabectedin marketing authorisation in November 2003 following PharmaMar's appeal against the CPMP's negative opinion first announced in July 2003; the opinion was adopted by a majority vote rather than by consensus. Trabectedin was granted orphan drug status in Europe for recurrent soft tissue sarcoma in 2001. It was also granted orphan drug status by the FDA for the same indication in October 2004. Phase I studies are being conducted to evaluate trabectedin in combination with doxorubicin and liposomal doxorubicin for the treatment of soft tissue sarcoma. PharmaMar is also conducting a phase I study of sequential paclitaxel followed by trabectedin in patients with soft tissue sarcoma. At additional dose levels, patients with other tumour types will be enrolled to assess the antitumour activity of the combination. The US NCI has approved and is partially funding a phase I clinical programme to determine the feasibility of using trabectedin to treat children with soft tissue sarcoma and bone sarcoma who are resistant to conventional therapies. PharmaMar has reported that trabectedin can be safely administered to children at doses up to 1100mg given as a 3-hour infusion, and that this dose will be used in further paediatric studies. Trabectedin has completed phase II studies for small round cell sarcoma and rhabdomyosarcoma, which are aggressive tumours occurring predominantly in children. A phase II study evaluating two dosing schedules of trabectedin has been conducted in patients with leiomyosarcomas or liposarcomas refractory to standard doxorubicin + ifosfamide chemotherapy. The study was conducted in Australia, Canada, Russia and the US.
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PMID:Trabectedin: Ecteinascidin 743, Ecteinascidin-743, ET 743, ET-743, NSC 684766. 1692 93

The molecular chaperone heat shock protein 90 (HSP90) has emerged as an exciting molecular target. Derivatives of the natural product geldanamycin, such as 17-allylamino-17-demethoxy-geldanamycin (17-AAG), were the first HSP90 ATPase inhibitors to enter clinical trial. Synthetic small-molecule HSP90 inhibitors have potential advantages. Here, we describe the biological properties of the lead compound of a new class of 3,4-diaryl pyrazole resorcinol HSP90 inhibitor (CCT018159), which we identified by high-throughput screening. CCT018159 inhibited human HSP90beta with comparable potency to 17-AAG and with similar ATP-competitive kinetics. X-ray crystallographic structures of the NH(2)-terminal domain of yeast Hsp90 complexed with CCT018159 or its analogues showed binding properties similar to radicicol. The mean cellular GI(50) value of CCT018159 across a panel of human cancer cell lines, including melanoma, was 5.3 mumol/L. Unlike 17-AAG, the in vitro antitumor activity of the pyrazole resorcinol analogues is independent of NQO1/DT-diaphorase and P-glycoprotein expression. The molecular signature of HSP90 inhibition, comprising increased expression of HSP72 protein and depletion of ERBB2, CDK4, C-RAF, and mutant B-RAF, was shown by Western blotting and quantified by time-resolved fluorescent-Cellisa in human cancer cell lines treated with CCT018159. CCT018159 caused cell cytostasis associated with a G(1) arrest and induced apoptosis. CCT018159 also inhibited key endothelial and tumor cell functions implicated in invasion and angiogenesis. Overall, we have shown that diaryl pyrazole resorcinols exhibited similar cellular properties to 17-AAG with potential advantages (e.g., aqueous solubility, independence from NQO1 and P-glycoprotein). These compounds form the basis for further structure-based optimization to identify more potent inhibitors suitable for clinical development.
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PMID:In vitro biological characterization of a novel, synthetic diaryl pyrazole resorcinol class of heat shock protein 90 inhibitors. 3060 24

There is no accepted standard of care for the chemotherapy treatment of metastatic brain tumors, which has been generally limited to lipophilic alkylators, which may not have efficacy against the tumor that metastasized to the brain. More than 50% of chemotherapy agents are natural product drugs, which are rarely used in the treatment of metastatic brain tumors because they are thought to not cross the blood-brain barrier (BBB). A major protein constituent in the BBB is P-glycoprotein (P-gp), which pumps natural product chemotherapy drugs and toxins out of the CNS. However, P-gp expression in the neovasculature of metastatic brain tumors is similar to the P-gp expression in the neovasculature of the primary, extracranial tumor. In contrast, gliomas have higher P-gp expression in their neovasculature, similar to the greater intrinsic expression of P-gp in normal brain vasculature. This decreased immunohistochemical expression of P-gp in the neovasculature of metastatic tumors, as well as our recent pharmacologic demonstration of increased tissue concentrations of paclitaxel in metastatic brain tumors compared with gliomas, support the idea that the choice of chemotherapy agents should be based on the histologic origin of the metastatic brain tumor and not on the lipophilicity of the drug. Our hypothesis is that metastatic brain tumors from tumors with intrinsically low P-gp expression (eg, lung, melanoma, and untreated breast) may be more permeable to natural product chemotherapy drugs than gliomas. This information could lead to a paradigm shift in the use of natural product drugs for metastatic brain tumors.
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PMID:Increased permeability of the blood-brain barrier to chemotherapy in metastatic brain tumors: establishing a treatment paradigm. 1753 77

Malignant melanoma shows high levels of intrinsic drug resistance associated with a highly invasive phenotype. In this study, we investigated the role of the drug transporter P-glycoprotein (Pgp) in the invasion potential of drug-sensitive (M14 WT, Pgp-negative) and drug-resistant (M14 ADR, Pgp-positive) human melanoma cells. Coimmunoprecipitation experiments assessed the association of Pgp with the adhesion molecule CD44 in multidrug resistant (MDR) melanoma cells, compared with parental ones. In MDR cells, the two proteins colocalized in the plasma membrane as visualized by confocal microscopy and immunoelectron microscopy on ultrathin cryosections. MDR melanoma cells displayed a more invasive phenotype compared with parental cells, as demonstrated by quantitative transwell chamber invasion assay. This was accomplished by a different migration strategy adopted by resistant cells ("chain collective") previously described in tumor cells with high metastatic capacity. The Pgp molecule, after stimulation with specific antibodies, appeared to cooperate with CD44, through the activation of ERK1/2 and p38 mitogen-activated protein kinase (MAPK) proteins. This activation led to an increase of metalloproteinase (MMP-2, MMP-3, and MMP-9) mRNAs, and proteolytic activities, which are associated with an increased invasive behavior. RNA interference experiments further demonstrated Pgp involvement in migration and invasion of resistant melanoma cells. A link was identified between MDR transporter Pgp, and MAPK signaling and invasion.
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PMID:The multidrug transporter P-glycoprotein: a mediator of melanoma invasion? 1794 88

Overexpression of the multidrug resistance 1 (MDR1) gene, encoding P-glycoprotein (P-gp), facilitates resistance to diverse chemotherapeutic drugs and current P-gp inhibitors display high toxicity. We studied the effects of melanoma differentiation associated gene-7/interleukin-24 (mda-7/IL-24), which exhibits cancer-specific apoptosis-inducing properties, in drug-sensitive (SW620) and drug-resistant (SW620/Dox) colorectal carcinoma cells. Adenovirus administered mda-7/IL-24, Ad.mda-7, effectively reversed resistance to doxorubicin-induced apoptosis in SW620/Dox cells by increased intracellular accumulation and decreased efflux of doxorubicin. Unexpectedly, P-gp-overexpressing cells (SW620/Dox) displayed increased apoptosis following Ad.mda-7 infection compared with parental SW620 cells, which correlated with more MDA-7/IL-24 protein in SW620/Dox than SW620 cell and potentially explains the increased sensitivity of P-gp-overexpressing cells to mda-7/IL-24. Transient overexpression of MDR1 in SW620 cells significantly increased apoptosis, decreased anchorage-independent growth, and increased MDA-7/IL-24 protein following Ad.mda-7 infection, whereas down-modulation of MDR1 in SW620/Dox cells by small interfering RNA decreased apoptosis following Ad.mda-7 infection. The increased mda-7/IL-24 sensitivity observed in SW620/Dox cells was partly due to increased reactive oxygen species generation and lower mitochondrial membrane potential. These findings confirm that mda-7/IL-24 is a potent MDR reversal agent, preferentially causing apoptosis in P-gp-overexpressing MDR cells, suggesting significant expanded clinical implications for the use of mda-7/IL-24 in treating neoplasms that have failed chemotherapy mediated by the P-gp MDR mechanism.
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PMID:Melanoma differentiation associated gene-7/interleukin-24 reverses multidrug resistance in human colorectal cancer cells. 1802 83

Oral chemotherapy has many advantages over parenteral chemotherapeutics administration. To use the advantages of the oral chemotherapy and maximize anti-tumor effects of the chemotherapeutic agent, we designed HM30181A (a P-glycoprotein inhibitor) and a paclitaxel oral co-administration chemotherapeutic method. HM30181A is used to aid paclitaxel absorption from gut lumen into blood and to inhibit paclitaxel exclusion out of the brain tumor mass by endothelial cells, which inhibits paclitaxel access to tumor cells in the brain parenchyma. We applied HM30181A and paclitaxel oral co-administration methods to the treatment of tumors in the brain using the K1735 melanoma brain metastasis animal model and the U-87 MG glioblastoma animal model. Administrations were performed twice per week for 28 days and the therapeutic effect was examined using tumor volume change. We observed that 32 mg/kg HM30181A and 16 mg/kg of paclitaxel (dose ratio 2:1) oral co-administration showed significant therapeutic effects in both animal models, but when the doses or dose ratio was changed, the effects could not be observed. Therefore, adjustments of doses and dose ratio of the agents seems to be essential in realizing oral HM30181A and paclitaxel treatment in brain tumors. These results suggest that if the doses and dose ratio can be successfully adjusted, the oral co-administration of HM30181A and paclitaxel can be used to treat tumors in the brain.
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PMID:Oral paclitaxel chemotherapy for brain tumors: ideal combination treatment of paclitaxel and P-glycoprotein inhibitor. 1809 71

P-glycoprotein (P-gp), a factor responsible for the multidrug resistance of tumors, is specifically expressed in brain microenvironment. To test its roles in brain metastatic tumor chemoresistance, we implanted the paclitaxel-sensitive melanoma cell line, K1735, into the skin or brain of mice and examined its paclitaxel resistances. When implanted into the skin, paclitaxel inhibited tumor growth, however, it had no inhibitory effect on cells implanted into the brain. The paclitaxel resistance of the brain K1735 tumors was eliminated by combined treatment with a P-gp inhibitor, HM30181A, and paclitaxel. Previously we found that there is a defined therapeutic window for combined treatment of brain tumors with HM30181A and paclitaxel. To determine whether it is due to responses of the brain microenvironment we measured changes in P-gp expression and function of brain endothelial cells in response to HM30181A treatment in vitro and in vivo. They were significantly increased by high-dose HM30181A treatment and it was related with the therapeutic effect loss of high-dose HM30181A treatment. Therefore, P-gp in the brain microenvironment has crucial roles in the brain metastatic tumor chemoresistance and brain microenvironment responses to P-gp inhibitor treatment should be considered in the development of brain endothelial cell-targeted chemotherapy using P-gp inhibitor.
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PMID:Response of brain specific microenvironment to P-glycoprotein inhibitor: an important factor determining therapeutic effect of P-glycoprotein inhibitor on brain metastatic tumors. 1881 83

Nine halogenated monoterpenes isolated from the red alga Plocamium cartilagineum have been evaluated for their cytotoxic effects on the tumor cell lines CT26 (murine colon adenocarcinoma), SW480 (human colon adenocarcinoma), HeLa (human cervical adenocarcinoma) and SkMel28 (human malignant melanoma) with several multidrug resistance mechanisms and the mammalian non-tumor cell line CHO (Chinese hamster ovary cells). The activities of these compounds were compared with those of the insecticide gamma-hexachlorocyclohexane (lindane) due to chemical structure similarities. Compounds 1, 2, 3, and 5 exhibited selective cytotoxicity against colon and cervical adenocarcinoma cells. Interestingly, the effect of compound 3 was specific and irreversible to human colon adenocarcinoma SW480 cells, which overexpress the transmembrane P-glycoprotein often related to chemoresistance. None of the anti-tumor doses of these compounds was cytotoxic against CHO cells. Furthermore, analysis of cellular extracts after incubation with the test compounds and rotenone (positive uptake control) demonstrated the intracellular accumulation of 1, 2, 3, and 5.
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PMID:Cytotoxic activity of halogenated monoterpenes from Plocamium cartilagineum. 1899 98

The unresponsiveness of multidrug resistant tumor cells to antineoplastic chemotherapy is often associated with reduced cellular drug accumulation accomplished by overexpressed transport molecules. Moreover, intracellular drug distribution in resistant cells appears to be remarkably different when compared to their wild type counterparts. In the present paper, we report observations on the intracellular accumulation and distribution of doxorubicin, an antitumoral agent widely employed in chemotherapy, in sensitive and resistant cultured tumor cells. The inherent fluorescence of doxorubicin allowed us to follow its fate in living cells by laser scanning confocal microscopy. This study included flow cytometric analysis of drug uptake and efflux and analysis of the presence of the well known drug transporter P-glycoprotein. Morphological, immunocytochemical and functional data evidentiated the Golgi apparatus as the preferential intracytoplasmic site of drug accumulation in resistant cells, capable of sequestering doxorubicin away from the nuclear target. Moreover, P-glycoprotein has been found located in the Golgi apparatus in drug induced resistant cells and in intrinsic resistant cells, such as melanoma cells. Thus, this organelle seems to play a pivotal role in the intracellular distribution of doxorubicin.
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PMID:Intracellular distribution of anthracyclines in drug resistant cells. 1900 86


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