Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.6.3.44 (P-glycoprotein)
 13,344 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The current World Health Organization (WHO) classification includes two types of natural killer (NK)-cell lymphomas: extranodal NK/T-cell lymphoma, nasal type (ENKL), and aggressive NK-cell leukemia (ANKL). These diseases are mostly endemic to East Asia and Latin America. The Epstein-Barr virus (EBV) is usually detected in tumor cells, suggesting that EBV plays an important role in lymphomagenesis. At the site of origin, ENKL can be divided into two major subtypes: nasal and extranasal diseases. The advanced disease presentation, highly aggressive clinical course, and poor prognosis of the latter are analogous to ANKL. It is well known that P-glycoprotein, which is a product of the multi-drug resistance (MDR1) gene, is expressed on neoplastic cells of ENKL or ANKL. This is a major cause of the refractoriness of malignant lymphoma to conventional chemotherapeutic regimens containing anthracycline. Recent studies, however, have identified that L-asparaginase-containing regimens, such as SMILE (steroid, methotrexate, ifosfamide, L-asparaginase and etoposide), are effective for ENKL. Considering the myelotoxicity of SMILE, its use in the treatment of ANKL needs some modifications, but this treatment scheme is promising in improving the prognosis of NK-cell lymphomas.
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PMID:NK/T-cell lymphomas: pathobiology, prognosis and treatment paradigm. 2263 6

To identify molecular determinants of histone deacetylase inhibitor (HDI) resistance, we selected HuT78 cutaneous T-cell lymphoma (CTCL) cells with romidepsin in the presence of P-glycoprotein inhibitors to prevent transporter upregulation. Resistant sublines were 250- to 385-fold resistant to romidepsin and were resistant to apoptosis induced by apicidin, entinostat, panobinostat, belinostat, and vorinostat. A custom TaqMan array identified increased insulin receptor (INSR) gene expression; immunoblot analysis confirmed increased protein expression and a four- to eightfold increase in mitogen-activated protein kinase (MAPK) kinase (MEK) phosphorylation in resistant cells compared with parental cells. Resistant cells were exquisitely sensitive to MEK inhibitors, and apoptosis correlated with restoration of proapoptotic Bim. Romidepsin combined with MEK inhibitors yielded greater apoptosis in cells expressing mutant KRAS compared with romidepsin treatment alone. Gene expression analysis of samples obtained from patients with CTCL enrolled on the NCI1312 phase 2 study of romidepsin in T-cell lymphoma suggested perturbation of the MAPK pathway by romidepsin. Immunohistochemical analysis of Bim expression demonstrated decreased expression in some skin biopsies at disease progression. These findings implicate increased activation of MEK and decreased Bim expression as a resistance mechanism to HDIs, supporting combination of romidepsin with MEK inhibitors in clinical trials.
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PMID:MAPK pathway activation leads to Bim loss and histone deacetylase inhibitor resistance: rationale to combine romidepsin with an MEK inhibitor. 2353 32

Epstein-Barr virus (EBV)-associated natural killer (NK)/T-cell lymphomas show a geographical predilection for Asian and South American populations and are rare in Western countries. They predominantly occur in extranodal sites, including the nasal or paranasal areas, and less frequently in the localized nodal lesion. Most of the tumor cells exhibit a cytotoxic phenotype, characterized primarily by the expression of granzyme B and perforin. EBV is usually detected in tumor cells by using EBV-encoded small RNA in situ hybridization (EBER), suggesting that EBV plays an important role in lymphomagenesis. In this chapter, we have described 2 diseases: 1) extranodal NK/T-cell lymphoma, nasal type (ENKL), representative of extranodal EBV-associated NK/T-cell lymphoma; and 2) nodal cytotoxic molecule-positive EBV-positive peripheral T-cell lymphoma, not specified type (CM + EBV + PTCL-N), representative of nodal lymphoma. Both ENKL and nodal CM + EBV + PTCL-N are intractable to standard chemotherapy. Although ENKL is sensitive to radiotherapy, it shows a poorer response to chemotherapeutic agents than other lymphomas because of P-glycoprotein expression. P-glycoprotein is a product of the multidrug resistance (MDR1) gene, which is a major cause of the refractoriness of malignant lymphomas to conventional chemotherapeutic regimens containing anthracycline. l-asparaginase-containing regimens such as SMILE (steroid, methotrexate, ifosfamide, l-asparaginase, and etoposide) are effective for ENKL. Evaluation of effective chemotherapy for nodal CM + EBV + PTCL-N is ongoing.
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PMID:Epstein-Barr virus-associated natural killer/T-cell lymphomas. 2376 37

Extranodal natural killer (NK)/T-cell lymphoma, nasal type (ENKL) is one of the uncommon subtypes of malignant lymphoma, and predominantly occurs in the nasal or paranasal areas and less frequently in the skin. Previously, its prognosis was poor due to the expression of P-glycoprotein, which actively exports several anticancer agents outside the lymphoma cells. However, in recent years, novel therapeutic approaches such as simultaneous chemoradiotherapy or l-asparaginase-based regimens including SMILE (steroid, methotrexate, ifosfamide, l-asparaginase, and etoposide) improved the response to therapy and survival of ENKL patients. Epstein-Barr virus (EBV) is present in lymphoma cells of almost all patients, accounting for the pathogenesis of ENKL. Fragmented EBV-DNA is released from tumor cells, and can be detected in the peripheral blood of patients. The EBV-DNA copy numbers are associated with tumor burden, and can predict the prognosis of ENKL, as well as the toxicity against chemotherapy. Based on this recent progress, ENKL is currently categorized as a lymphoma with intermediate prognosis, but the overall treatment results are not satisfactory. Further improvement of the prognosis of ENKL is therefore warranted, including the optimal use of hematopoietic stem cell transplantation (HSCT).
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PMID:Pathogenesis and treatment of extranodal natural killer/T-cell lymphoma. 2446 15

Histone deacetylase (HDAC) inhibitors are becoming a novel and promising class of antineoplastic agents that have been used for cancer therapy in the clinic. Two HDAC inhibitors, vorinostat and romidepsin, have been approved by the Food and Drug Administration to treat T-cell lymphoma. Nevertheless, similar to common anticancer drugs, HDAC inhibitors have been found to induce multidrug resistance (MDR), which is an obstacle for the success of chemotherapy. The most common cause of MDR is considered to be the increased expression of adenosine triphosphate binding cassette (ABC) transporters. Numerous studies have identified that the upregulation of ABC transporters is often observed following treatment with HDAC inhibitors, particularly the increased expression of P-glycoprotein, which leads to drug efflux, reduces intracellular drug concentration and induces MDR. The present review summarizes the key ABC transporters involved in MDR following various HDAC inhibitor treatments in a range of cancer cell lines and also explored the potential mechanisms that result in MDR, including the effect of nuclear receptors, which are the upstream regulatory factors of ABC transporters.
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PMID:HDAC inhibitor-induced drug resistance involving ATP-binding cassette transporters (Review). 2562 82

Three new dimeric naphthoquinones, 5,4'-dihydroxy-1'-methoxy-6,6'-dimethyl-7,3'-binaphthyl-1,4,5',8'-tetraone (1), 5',8'-dihydroxy-5-methoxy-6,6'-dimethyl-7,3'-binaphthyl-1,4,1',4'-tetraone (2) and 8,5',8'-trihydroxy-6,6'-dimethyl-7,3'-binaphthyl-1,4,1',4'-tetraone (3), were isolated from the roots of Diospyros lotus. Their structures were elucidated by spectroscopic techniques, including 1D and 2D NMR, such as HSQC, HMBS, NOESY, and J-resolved. Compounds 1-3 were evaluated for their effects on the reversion of multidrug resistance (MDR) mediated by P-glycoprotein through use of the rhodamine-123 exclusion screening test on human ABCB1 gene transfected L5178Y mouse T-cell lymphoma. Compounds 1-3 were also assessed for their antiproliferative and cytotoxic effects on L5178 and L5178Y mouse T-cell lymphoma lines. Both 1 and 2 exhibited promising antiproliferative and MDR-reversing effects in a dose-dependent manner. The effects of the tested compounds on the activity of doxorubicin were observed to vary from slight antagonism to antagonism.
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PMID:A Rare Class of New Dimeric Naphthoquinones from Diospyros lotus have Multidrug Reversal and Antiproliferative Effects. 2673 80

Phytochemical investigation of Pistacia integerrima has highlighted isolation of two known compounds naringenin (1) and dihydrokaempferol (2). A crude extract and these isolated compounds were here evaluated for their effects on reversion of multidrug resistance (MDR) mediated by P-glycoprotein (P-gp). The multidrug resistance P-glycoprotein is a target for chemotherapeutic drugs from cancer cells. In the present study rhodamine- 123 exclusion screening test on human mdr1 gene transfected mouse gene transfected L5178 and L5178Y mouse T-cell lymphoma cells showed excellent MDR reversing effects in a dose dependent manner. In-silico molecular docking investigations demonstrated a common binding site for Rhodamine123, and compounds naringenin and dihydrokaempferol. Our results showed that the relative docking energies estimated by docking softwares were in satisfactory correlation with the experimental activities. Preliminary interaction profile of P-gp docked complexes were also analysed in order to understand the nature of binding modes of these compounds. Our computational investigation suggested that the compounds interactions with the hydrophobic pocket of P-gp are mainly related to the inhibitory activity. Moreover this study s a platform for the discovery of novel natural compounds from herbal origin, as inhibitor molecules against the P-glycoprotein for the treatment of cancer.
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PMID:Reversal of Multidrug Resistance in Mouse Lymphoma Cells by Extracts and Flavonoids from Pistacia integerrima. 2683 54

A new compound namely (13-(3,3-dihydroxypropyl)-1,6-dihydroxy-3,4-dihydro-1H-isochromen-8(5H)-one (1) was isolated from an ethyl acetate extract of the borne fungi Screlotium rolfsii. Its chemical structure was elucidated by spectroscopic analysis. Screlotiumol 1 were evaluated for their effects on the reversion of multidrug resistant (MDR) mediated by P-glycoprotein (P-gp) of the soil borne fungi. The multidrug resistant P-glycoprotein is a target for chemotherapeutic drugs in cancer cells. In the present study rhodamine-123 exclusion screening test on human mdr1 gene transfected mouse gene transfected L5178 and L5178Y mouse T-cell lymphoma which showed excellent MDR reversing effect in a dose dependent manner against mouse T-lymphoma cell line. Moreover, molecular docking studies of compound-1 also showed better results as compared with the standard. Therefore the preliminary results obtained from this study suggest that screlotiumol 1 could be used as a potential agent for the treatment of cancer.
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PMID:Isolation and Structure Elucidation, Molecular Docking Studies of Screlotiumol from Soil Borne Fungi Screlotium rolfsii and their Reversal of Multidrug Resistance in Mouse Lymphoma Cells. 2722 99

Treatment outcomes of malignant lymphoma have improved due to the discovery of novel chemotherapeutic and molecular targeted agents as well as advances in their combination uses. However, the prognosis of T-cell lymphoma remains poorer than that of B-cell lymphomas, and progress is slow. The reasons include their chemotherapeutic resistant nature and the absence of effective antibody agents for T-cell lymphomas. The number of T-cell lymphoma subtypes increased from 21 in the WHO classification 2008 to 29 in the WHO classification 2016. This means that T-cell lymphomas are heterogeneous. T-cell lymphomas can be divided to ALK-positive anaplastic lymphoma (ALCL) with a good prognosis and others with poorer prognoses. ALK-positive ALCL can be successfully treated with CHOP, but the others cannot. P-glycoprotein resistant anthracyclines, etoposide, or hematopoietic stem cell transplantations are increasingly applied to improve outcomes, but no standard treatment approach has yet been established. Regarding relapsed/refractory T-cell lymphoma, many novel agents are currently under development. The treatment outcomes of T-cell lymphoma need to be improved by applying innovative strategies including further novel agents.
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PMID:Progress in the treatment of mature T-cell lymphoma. 2779 7

Natural killer/T-cell (NK/T-cell) lymphomas are rare in children and adolescents and consist predominantly of nasal-type extranodal NK/T-cell lymphomas. More than half of pediatric/adolescent patients with NK/T-cell lymphomas present with localized nasal/sinus involvement, but the disease may involve many organs. NK/T-cell lymphoma cells are cytotoxic and associated with necrosis and angioinvasion; they express CD56, CD2, cytoplasmic CD3 epsilon, and to a variable degree CD30. The cells contain Epstein-Barr virus (EBV)-encoded RNA. Loss of chromosome 6q is frequent, and multiple other genetic changes may occur. The Janus kinase/signal transducers and activators of transcription (JAK/STAT) and other pathways are activated in NK/T-cell lymphoma. Adults with stage I/II disease receive radiation with or without chemotherapy, whereas adults with advanced disease receive multiagent chemotherapy, including asparaginase and drugs not affected by P-glycoprotein-mediated resistance. Outcomes data for pediatric patients come from retrospective reviews and retrospective case series. The overall survival of pediatric patients is 77% for those with stage I/II disease and 36% to 59% for those with advanced disease. Bone marrow transplant (BMT) is used in children, but with little evidence regarding the indications and rationale for type of transplant. BMT achieves better outcomes for adult patients in remission, but with high levels of morbidity and mortality. Improved understanding of the biology of this disease will allow the development of targeted approaches, including JAK/STAT inhibitors, checkpoint inhibitors, anti-CD30 agents, epigenetic modifiers, and reduced-intensity conditioning for BMT, to improve outcomes in pediatric patients.
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PMID:Natural killer/T-cell lymphomas in pediatric and adolescent patients. 2839 75


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