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)

To date no hematopoietic progenitors of dendritic Langerhans' cells (DLC), which represent an highly efficient class of antigen presenting cells, have been identified or the cytokines they elaborate have been defined. Here we describe an acute leukemia patient whose blasts (90-96% in peripheral blood and bone marrow) had a phenotype consistent with putative progenitors of DLC. The patient was treated with ara-C and VP-16 but did not achieve remission. The blasts had lobulated nuclei, no cytoplasmic vacuolation or Auer rods and were weakly positive for acid phosphatase and non-specific esterase and negative for PAS, granzyme A, dipeptidyl aminopeptidase IV, ATPase/ADPase and lysozyme production. The blasts were positive for CD1a, CD4, CD16, CD35, HLADR, HLADQ, CD11b, CD11c, CD14, CD33, CD34, CD11a, CD71, CD19, CD25, IL-2R beta and negative for CD2, CD7, CD8, CD10, CD22, CD56, CD57, surface or cytoplasmic CD3, TCR delta and TCR beta, HTLV-1p19 and P-glycoprotein. On liquid culture with or without 5 x 10(-9) M 12-O-tetradecanoylphorbol-13-acetate (TPA) for 3 days, the blasts formed aggregates of proliferating and elongating cells on the wall of the flasks with a decline in CD34, numerous dendritic processes appeared on the cells and there was strong positivity for ATPase/ADPase, but no other changes in phenotype. No macrophages were observed, indicating derivation from separate DLCs. Cytogenetic analysis showed chromosomal abnormalities and electron microscopy showed Birbeck granules. Southern blotting of DNA showed rearrangement of one allele for both JH and TCR beta but no HTLV-1 related sequences. Culture supernatants from blasts cultured with or without TPA showed the production of large amounts of IL-8, IL-6, TNF-alpha, MIP-1 alpha, IL-10 and interferon gamma and modest amounts of IL-1 alpha, GM-CSF and stem cell factor. The presence not only of CD1a, HLADR, HLADQ and many other characteristics including Birbeck granules, but also differentiation along the lines of DLC with appearance of dendritic processes on the cells and expression of ATPase/ADPase activity, indicate that the leukemic blasts in our patient represented a leukemic counterpart of normal progenitors of DLC and the leukemia a new entity which could possibly be classified as AML-M8. Lastly, many pro-inflammatory cytokines produced by DLC could contribute to inflammation and IL-10 to immunosuppression.
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PMID:Phenotype, genotype and cytokine production in acute leukemia involving progenitors of dendritic Langerhans' cells. 791 55

Reversal of multidrug resistance (MDR) may offer a means of increasing the effectiveness of tumour chemotherapy. A variety of recent evidence indicates that cytokines may be particularly useful in this endeavour. To investigate the molecular mechanism by which cytokines may sensitise multidrug-resistant colon carcinoma cells, HCT15 and HCT116, to treatment with MDR-related drugs, we evaluated the effects of the human cytokines tumour necrosis factor alpha (TNF alpha), interleukin 2 (IL-2) and interferon gamma (IFN gamma) on mdr1 gene expression at the mRNA level by reverse transcription-polymerase chain reaction (RT-PCR) and at the protein level with monoclonal antibodies by immuno flow cytometry. P-glycoprotein function was examined after accumulation of the fluorescent drug, doxorubicin, by flow cytometry. Chemosensitivity to doxorubicin and vincristine was analysed using the XTT assay. All three cytokines were found to modulate the MDR characteristics on mdr1 expression levels, P-glycoprotein function and measured chemosensitivity to MDR-associated anti-cancer drugs. This cytokine-induced reversal of MDR was strongly time dependent, with maximal effects after 48 and 72 h of cytokine treatment. If similar modulation of MDR phenotype can be obtained in in vivo models, it may be possible to verify the time course for modulation by cytokine treatment and to design appropriate clinical trials of this strategy for MDR reversal.
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PMID:Modulation of mdr1 expression by cytokines in human colon carcinoma cells: an approach for reversal of multidrug resistance. 891 33

Antigenic marker expression was studied in a series of eight small cell lung carcinoma (SCLC) cell lines, according to their histological subtype, classic or variant. These lines were obtained from human tumors xenografted into nude mice, originally derived from heterotransplanted tumor biopsy samples. We looked at an altered expression of HLA class I antigens, a battery of neuroendocrine antigens and the P-glycoprotein (Pgp) responsible for MDR1 encoded multidrug resistance, as markers of tumor malignancy. Three cell lines out of four of the classic subtype and two cell lines out of four of the variant subtype showed a lack or a low expression of HLA class I antigen. Recombinant interferon gamma (rIFN-gamma) treatment (100 U/ml, for 48 h) increased HLA class I expression of the cell lines differently, but did not induce an imbalance between HLA-A and HLA-B molecules as described in other tumor models. Neuroendocrine antigens were tested in six out of these eight lines, using a family of monoclonal antibodies developed against the cell membrane antigens of low passage cell lines derived from pleural effusions (de Leij et al, Cancer Res 45: 2192-2200, 1985). Globally, these antigens were more highly expressed in classic subtypes of SCLC. Neuroendocrine antigens corresponding to MOC-21 and MOC-32 monoclonal antibodies were weakly expressed in variant forms. Pgp expression was detectable with the JSB1 monoclonal antibody on the three variant SCLCs out of the six lines. Comparing two cell lines originated from the same patient before and after therapy, we showed that neuroendocrine reactivity to MOC-21 and MOC-32 was lost simultaneously with a gain of Pgp expression, and with a classic to variant histological transition. With regard to the clinical evolution, HLA class I expression and stimulation by rIFN-gamma was not related to malignancy. It appears that for variant forms, a low expression of neuroendocrine antigens detected by MOC-21 and MOC-32 monoclonal antibodies and a high level of Pgp predict for a poor prognosis.
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PMID:HLA class I and neuroendocrine antigen expression in multidrug resistant small cell lung carcinoma cell lines. 2154 55