Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0027819 (neuroblastoma)
 27,800 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A methodology for rapid isolation of neuroblastoma (NB) cells from marrow with metastatic NB cells was developed using a cocktail of five antibodies and magnetic microspheres coated with secondary antibodies. Cells bound to microspheres were released by brief exposure to chymopapain, followed by repeated culture of released cells in serum supplemented DMEM medium and selection for adherent cells. Using this methodology, over 35 primary cell lines were obtained free of contaminating normal cells. Detailed analyses of over 14 cell lines revealed gross differences in cell phenotype, size, morphology development of neurite processes, and doubling time (40h-80 h). All cell lines expressed the 145 kDa neurofilament (NF) and a few expressed the 200 kDa NF, with very little or no expression of the 68 kDa NF. DNA analyses revealed 80% near diploid cell lines. High expression of the MDR-1 protein was detected in 6/22 of the cell lines tested.
 ...
PMID:A novel methodology for the establishment of neuroblastoma cell lines from metastatic marrow. Expression of surface markers, neurofilaments, MDR-1 and myc proteins. 134 78

P-glycoprotein, the product of the multidrug resistance (MDR1) gene, is an ATP-driven transmembrane pump that increases the resistance of cells by actively exporting toxic chemicals. In addition to transporting anticancer drugs, P-glycoprotein has been reported to extrude a variety of lipophilic drugs, such as calcium channel blockers, phenothiazines, cyclosporines etc. Interestingly, recent experiments suggest that steroid hormones may be physiologic substrates for P-glycoprotein. In addition, there exists a family of transporter genes with high structural homology to P-glycoprotein, the so-called ABC (ATP-binding casette) family. Although the physiological ligands for most of these transporters are unknown, there is increasing evidence that peptides may be transported by some of these proteins. Thus, the a-factor, a farnesylated pheromone with 13 amino acids, is exported from yeast cells by the product of the STE6 gene, a transporter protein with high homology to P-glycoprotein. Recently, we have cloned a novel member of the ABC-transporter gene family from neuroblastoma x glioma hybrid (NG-108-15) cells. This putative transporter gene ("NG-TRA") is expressed in the adrenal gland, kidney and in the brain. High amounts of NG-TRA mRNA are found in a variety of human brain tumors. Whether NG-TRA and/or other MDR-related transporters are involved in the transport of steroids, peptide hormones or growth factors remains to be established. If so, the cellular export of hormones by active pumps may represent a new mechanism of hormone secretion.
 ...
PMID:New mechanisms of hormone secretion: MDR-like gene products as extrusion pumps for hormones? 135

A methodology for rapid isolation of neuroblastoma cells from marrow with metastatic neuroblastoma cells was developed using a cocktail of five antibodies and magnetic microspheres coated with secondary antibodies. Cells bound to microspheres were released by brief exposure to chymopapain, followed by repeated culture of released cells in serum-supplemented Dulbecco's modified Eagle's medium and selection for adherent cells. Using this methodology, over 35 primary cell lines were obtained free of contaminating normal cells. Detailed analyses of over 14 cell lines revealed gross differences in cell phenotype, size, morphology development of neurite processes, and doubling time (40 to 80 h). All cell lines expressed the M(r) 145,000 neurofilament, and a few expressed the M(r) 200,000 neurofilament, with very little or no expression of the M(r) 68,000 neurofilament. Eight % of all cells lines had near-diploid DNA content. High expression of the MDR-1 protein was detected in six of the 22 cell lines tested. Great heterogeneity was observed in the expression of N-myc oncoprotein, with ten of 13 patients overexpressing the protein. c-myc oncoprotein was also expressed in all cell lines; however, the level of expression was 4- to 10-fold lower than the N-myc oncoprotein. Localization studies of c-myc and N-myc oncoproteins on the level of light microscopy and electron microscopy revealed exclusive nuclear localization of c-myc, whereas N-myc was localized to the nucleus and to the cytoplasm.
 ...
PMID:Expression of N-myc, c-myc, and MDR-1 proteins in newly established neuroblastoma cell lines: a study by immunofluorescence staining and flow cytometry. 137 83

Acquired resistance to doxorubicin and other anti-cancer drugs is generally dependent on gene amplification of a specific nucleotide sequence, the MDR1 gene. Verapamil, cyclosporin and other drugs have been used to circumvent the resistance in experimental models in vitro and/or in vivo. We have attempted to reverse the MDR phenotype by treating human adenocarcinoma resistant cells with 20 mers of synthetic unmodified oligodeoxynucleotide MDR1 antisenses. Five ODNs towards different mRNA regions and three different schedules of ODN antisense administration were tested. We found that FCS concentration greatly influenced the stability of ODN, whereas heat-inactivated FCS had no effect. The kinetics of ODN cellular uptake suggest the presence of a saturable receptor. Among the five antisense ODNs used, the most efficient was the oligomer (ODN-1) complementary to 20 bases upstream of the AUG initiation codon. No effect was observed with antisense complementary to the nucleotide binding sites. Administration of ODN-1 every 12 hr for 72 hr partially reversed the MDR phenotype. Approximately 60% of the cells lost their resistance to doxorubicin and did not form colonies in the presence of the drug. The MDR1 mRNA was transiently down-regulated so that the level of gp170 was slightly reduced. The incomplete switch off of MDR1 gene expression may be ascribed to the large abundance and great stability of MDR1 messenger RNA. Moreover, the inactivity of the two ODNs complementary to the NBS protein domains suggests that translation inhibition is ineffective. It is likely that ODN-4 and ODN-5 complement a large number of mRNAs competing for duplex formation, because these sequences are highly conserved among many proteins.
 ...
PMID:An oligomer complementary to the 5' end region of MDR1 gene decreases resistance to doxorubicin of human adenocarcinoma-resistant cells. 144 3

Immunohistological detection of P-glycoprotein (P-gp) with monoclonal antibody C219 was performed on serial sections of 37 neuroblastoma specimens representative of the different forms of the disease, from stage 1 ganglioneuroma to stage 4 neuroblastoma. Malignant cells, irrespective of their degree of maturation varying from neuroblasts to ganglion cells, were negative on all specimens. The expression of P-glycoprotein was detected in nine specimens, but it was restricted to normal cells within the tumour. In four specimens, C219 reacted with normal infiltrating cells in the stroma (i.e. monocytes, histiocytes or fibroblasts) representing 5 to 10% of the total population within the section; in three specimens, the residual adrenal gland was strongly positive, and in two ganglioneuromas, a weak reactivity of C219 was observed on a few satellite cells and schwann cells. Three of 15 biopsies obtained at diagnosis contained normal P-gp positive cells: two were classified as stage 1 ganglioneuromas; one was a typical stage 4 composite tumours with positive histiocytes and fibroblasts in the well-differentiated counterpart. Six of 22 biopsies obtained after patients had received our current protocol of chemotherapy contained normal P-gp positive cells: five were partially differentiated and necrotic under the effect of chemotherapy; only one positive specimen was classified as undifferentiated neuroblastoma. Among negative specimens from previously treated patients, one was obtained from a patient in relapse after high-dose chemotherapy and ABMT, two were obtained from patients who had not responded to induction therapy, and six from patients in partial remission after induction therapy. The clinical evolution was very similar in both groups of patients with P-gp negative or positive biopsies. These findings suggest that the quantitative assessment of MDR RNA by northern blotting on fresh homogenates is likely to overestimate its expression on neuroblastoma cells, and that the mechanism of chemoresistance in widespread neuroblastoma is less likely to be associated with P-gp expression.
 ...
PMID:Expression of P-glycoprotein restricted to normal cells in neuroblastoma biopsies. 167 95

Experience has shown that markers created in research laboratories can be adapted to everyday surgical pathology practice for malignant melanomas. These studies are feasible and readily conducted on frozen tissue as is routinely done in typing of lymphoma. The demonstration of heterogeneity using this monoclonal antibody panel, and other antibodies yet to come, may be important for prognostication. Tumor cell heterogeneity of surface antigens reflects disruption of the tumor cell's patterned gene expression. This should be regarded as an indication of different clones of cells (subsets) with a tumor, whether primary or secondary. It is entirely possible that autologous immune cells can kill or at least restrict the growth of subsets of melanoma cells having certain surface antigenic phenotypes while they are incompetent to handle other subsets. This would enable a particular phenotype within a primary melanoma to survive and escape the immunologic regression known to occur in 3 to 6 percent of these tumors. Such patients may present years later with metastases in the brain, liver, gastrointestinal (GI) tract, or lymph nodes. There are also implications in chemotherapy and chemoimmunotherapy for melanoma in this regard. It could be theorized that these agents may dispose of or restrict the growth of some phenotypes, leaving others in a resistant state. Perhaps the MDR gene is activated. Alternatively a tumor suppressor gene(s) could be absent or inactivated, as in neuroblastoma and carcinoma of the breast and lung. Markers present at the cell membrane surfaces and in the membranes themselves constitute an important field for study in the understanding of tumorigenesis. Many of these markers are present in embryos as early as the 4-to-8-cell stage and in blastocysts. Embryonic antigens in the intercell mass of blastocysts are stage-specific embryonic antigens. They are signals for organ development and the differentiation of cells. At various stages of this development, these markers disappear, especially upon differentiation into tissue types and specific organs. These cell signals are therefore organogenesis markers. Detecting a given antigen is not simple because it may be present but not immunohistochemically detectable because glycosylation, acetylation, phosphorylation, or sulfation have not taken place, or have resulted in a structural conformation not recognized by monoclonal antibodies.(ABSTRACT TRUNCATED AT 400 WORDS)
 ...
PMID:Immunohistochemical phenotyping of malignant melanoma. A procedure whose time has come in pathology practice. 220 65

Widely disseminated neuroblastoma in children older than infancy remains a very poor prognosis disease. Even the introduction of marrow ablative chemotherapy with autologous rescue has not significantly improved the outlook for these children, presumably because of a failure to eradicate minimal residual disease. One additional approach which may hold promise is the use of immunomodulation with cytokines such as IL2 in the setting of minimal residual disease (MDR), for example after intensive chemotherapy and ABMT. However, considerable variability in the susceptibility of neuroblastoma cells to natural killer (NK) and lymphokine-activated (LAK) killing has been observed, and it is presently unclear how NK and LAK cells recognise neuroblastoma cells. In this paper we examine expression of cell adhesion molecules on neuroblastoma to determine which of these modify interaction with NK and LAK cells. We find that LFA-3 (CD58), the ligand for CD2 is of predominant importance in predicting susceptibility of neuroblastoma to the cytotoxic actions of NK and LAK cells, while expression of ICAM-1 (CD54) may also modify susceptibility. These findings were confirmed by blocking experiments in which co-culture of target cells with ICAM-1 and LFA-3 reduced LAK and NK cytotoxicity. Study of the immunophenotypic features of each patient's neuroblastoma cells before induction of MRD may be valuable in determining the likely effect of IL2 in predicting disease reactivation.
 ...
PMID:Mechanisms of selective killing of neuroblastoma cells by natural killer cells and lymphokine activated killer cells. Potential for residual disease eradication. 849 26

Annamycin (Ann) is a highly lipophilic anthracycline antibiotic that has been shown to circumvent MDR-1 both in vitro and in vivo. A liposomal formulation of Ann is currently in phase I clinical trials. The multidrug resistance-associated protein (MRP) has been found to be over-expressed in some human leukemias at relapse and to be a poor prognostic factor in neuroblastoma. We studied the in vitro cytotoxicity and the cellular uptake and efflux of Ann and doxorubicin (Dox) in 2 pairs of human cell lines, breast carcinoma MCF7 and small-cell lung cancer UMCC-1, and their MRP-expressing counterparts, MCF-7/VP and UMCC-1/VP. Resistance indexes were 1.1 and 1.4 for Ann vs. 6.9 and 11.6 for Dox. Ann cellular accumulation was 3- to 5-fold higher than that of Dox in both sensitive and resistant cells. No changes in drug efflux between sensitive and resistant cells were observed in the case of Ann, while Dox efflux at 1 hr was 20-25% higher in resistant than in sensitive cells. By confocal microscopy, the subcellular distribution of Ann was identical in sensitive and resistant cells, localizing mostly in the perinuclear structures, while that of Dox was exclusively nuclear in sensitive cells and nuclear and in the cell membrane in resistant cells. There was a good correlation between the extent of DNA breaks induced by each drug in the different cell lines and cytotoxic effect. Our results indicate that Ann may be effective in the treatment of malignancies in which MRP is a relevant mechanism of clinical resistance.
 ...
PMID:Annamycin circumvents resistance mediated by the multidrug resistance-associated protein (MRP) in breast MCF-7 and small-cell lung UMCC-1 cancer cell lines selected for resistance to etoposide. 909 63

Four rhabdomyosarcoma and three neuroblastoma cell lines were characterised for the presence of P-glycoprotein and MDR-1 expression using immunohistochemistry, northern analysis, RT-PCR and in situ mRNA hybridisation. None of the rhabdomyosarcoma lines were unequivocally positive in contrast to all three neuroblastoma lines. Chemosensitivity to cytotoxic agents was determined using the MTT assay and chemosensitisation by cyclosporin and verapamil was evaluated. In a single rhabdomyosarcoma line (HX 170) there was sensitisation to etoposide using verapamil but not to other drugs or using cyclosporin A. In contrast, in all three neuroblastoma lines both cyclosporin and verapamil sensitised to vincristine and doxorubicin. No evidence of sensitisation to etoposide was apparent. The sensitisation was most marked for vincristine, using either modulator and therefore the influence of modulator scheduling was evaluated with this drug in the neuroblastoma line SK N BE. Prolonged pre-exposure to modulator did not appear necessary and maximum sensitisation was apparent where either cyclosporin or verapamil was added 1-3 h prior to and post vincristine. Continuity of exposure was important and even a break of 30 min appeared to reduce sensitisation. These data confirm the potential for chemosensitisation in MDR-1 positive neuroblastoma cell lines and provide some basis for rational schedule design in clinical practice. Because of the probability that vincristine resistance is predominantly related to MDR-1 and less multifactorial than for other drugs such as doxorubicin or etoposide, this agent should be considered for inclusion in any clinical evaluation of MDR reversal strategies.
 ...
PMID:Multidrug resistance modulation in rhabdomyosarcoma and neuroblastoma cell lines. 953 41

In tumor specimens such as those from neuroblastoma, ovarian, and lung carcinoma patients, the prevalence of extrachromosomal circular DNA molecules harboring amplified genes has been well established. In some cases, the amplified genes have been identified as oncogenes, and their increased expression appears to contribute to the maintenance and progression of the malignancy. The aim of this study was to investigate the effect of fractionated radiation treatment, given in daily doses similar to those administered clinically, on the stability of extrachromosomal circular DNA molecules in cancer cells. Our studies were conducted with multidrug-resistant KB cells, which harbor extrachromosomal copies of the multidrug resistance gene (MDR1) almost exclusively on circular DNA molecules of approximately 750 and 1500 kb pairs. This size range is representative of extrachromosomal circular DNA molecules that have been shown to harbor amplified oncogenes in vivo. Exponentially growing MDR KB cells were exposed to 1400 and 2800 cGy ionizing radiation administered in 7 and 14 fractions, respectively, at 200 cGy per fraction/day. A statistically significant decrease in MDR1 extrachromosomal gene copy number was reproducibly detected in the irradiated cells compared with unirradiated cells passaged for the duration of the experiment in the absence of radiation treatment. This decrease was accompanied by a reduction in multidrug resistance and in P-glycoprotein levels, as determined by clonogenic dose-response assays and Western analyses, respectively. P-glycoprotein is a multidrug transporter encoded by the MDR1 gene. Fluorescence in situ hybridization studies further determined that extrachromosomal circular DNA loss correlated to the entrapment of these DNA molecules in radiation-induced micronuclei. These results indicate that radiation-induced loss of extrachromosomally amplified genes from tumor cells via their entrapment in micronuclei contributes to the improved therapeutic response observed for some cancers.
 ...
PMID:Fractionated ionizing radiation accelerates loss of amplified MDR1 genes harbored by extrachromosomal DNA in tumor cells. 973 94


1 2 Next >>