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)

Peripheral T-cell lymphomas (PTCLs) are aggressive tumors in which the current therapy based on multiagent chemotherapy is not successful. Since cytochrome P450 3A subfamily (CYP3A) enzymes are involved in the inactivation of chemotherapy drugs, we hypothesized that CYP3A and P-glycoprotein (MDR1) expression in these lymphomas could result in a poor clinical response. We measured tumoral CYP3A and MDR1 mRNA content in 44 T-cell lymphomas, finding a large variation in CYP3A expression. Multiplex polymerase chain reaction (PCR) analysis and fluorescence in situ hybridization (FISH) analysis showed genomic gains affecting CYP3A and MDR1 genes in T-cell lines and primary tumors, suggesting that this could be the mechanism underlying the tumoral expression variation. To test whether the tumoral expression of CYP3A and/or MDR1 could influence PTCL treatment outcome, their expression levels were compared with the clinical response and survival of the patients, finding that a high tumoral expression of CYP3A4 was significantly associated with a lower complete remission rate. This was further investigated with cell lines stably expressing CYP3A4 that exhibited an increased resistance to doxorubicin and etoposide. In conclusion, a high CYP3A4 tumoral expression could be useful to predict poor response to the standard PTCL chemotherapy; in these cases alternative chemotherapy combinations or doses should be explored.
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PMID:Expression of CYP3A4 as a predictor of response to chemotherapy in peripheral T-cell lymphomas. 1763 10

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