Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0029463 (osteosarcoma)
 16,637 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The synthesis and biological activity of three 7-substituted actinomycin D derivatives are reported. Three such derivatives, 7-nitro-, 7-amino-, and 7-hydroxyactinomycin D, were synthesized via new methods which were first tested successfully with a chromophore model system. Of these, 7-nitro- and 7-aminoactinomycin D were assayed for growth inhibitory activity against mammalian cells (CCRF-CEM human lymphoblastic leukemia) in vitro and against the Ridgway osteogenic sarcoma and the L1210, P1534, and P388 murine leukemias in vivo. In these systems, the inhibitory activity of the 7-substituted analogs was comparable to actinomycin D. In two bacterial systems ( (L. casei and L. arabinosus) in vitro, on the other hand, these compounds showed inhibitory profiles which are distinctly different from actinomycin D. These studies demonstrate that substitution at the 7 position, which does not interfere with DNA binding, is capable of yielding experimental antitumor agents with significant activity against a variety of tumors.
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PMID:7-substituted actinomycin D analogs. Chemical and growth-inhibitory studies. 105 73

We isolated four monoclonal antibodies (MAbs), M38, M101, M104, and C33, which were capable of inhibiting syncytium formation induced in a human T-cell line, MOLT-4-#8, by coculture with human T-cell leukemia virus type 1 (HTLV-1)-positive human T-cell lines. The MAbs had, however, no inhibitory activity on syncytium formation induced in a human osteosarcoma line, HOS, by HTLV-1-positive T-cell lines. They also did not inhibit syncytium formation induced in MOLT-4-#8 by human immunodeficiency virus type 1-positive MOLT-4. All MAbs reacted with various human cell lines of lymphoid and nonlymphoid origins, including HTLV-1-positive T-cell lines. Furthermore, they all reacted with a murine A9 clone containing human chromosome 11 fragment q23-pter. Two MAbs, M104 and C33, immunoprecipitated a membrane antigen with the same molecular size. The antigen (henceforth called C33 antigen) was about 40 to 55 kDa in HTLV-1-negative Jurkat, CEM, MOLT-4, and normal peripheral blood CD4-positive human T cells and about 40 to 75 kDa in HTLV-1-positive C91/PL, TCL-Kan, MT-2, and in fresh HTLV-1-transformed CD4-positive human T-cell lines. Pulse-chase experiments revealed that C33 antigen was synthesized as a 35-kDa precursor that was then processed to 41 to 50 kDa in MOLT-4 and to 44 to 70 kDa in C91/PL. In the presence of tunicamycin, a 28-kDa protein was synthesized. The conversion from 35 kDa to 41 to 50 kDa in MOLT-4 and to 44 to 70 kDa in C91/PL was inhibited by monensin. Treatment with N-glycanase alone, but not with sialidase and O-glycanase in combination, completely removed the sugar moiety of C33 antigen from both HTLV-1-negative Jurkat and HTLV-1-positive C91/PL. Therefore, C33 antigen has only N-linked carbohydrates, the modification of which appears to be substantially altered in the presence of the HTLV-1 genome.
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PMID:Identification of membrane antigen C33 recognized by monoclonal antibodies inhibitory to human T-cell leukemia virus type 1 (HTLV-1)-induced syncytium formation: altered glycosylation of C33 antigen in HTLV-1-positive T cells. 173 99

Methotrexate (MTX)-resistant sublines of malignant human cells were selected in vitro by stepwise increase in drug concentration in the medium. By this procedure a subline of Burkitt's lymphoma cells (RAJI) was made 290-fold resistant (RAJI/MTX-R), T-cell leukemia cells (CCRF-CEM) were obtained 210-fold resistant (CEM/MTX-R), and 3 MTX-resistant human osteosarcoma lines were selected: TE-85/MTX-R (19-fold resistant; relative to wild-type); MG-63/MTX-R (8-fold resistant); and SAOS-2/MTX-R (200-fold resistant). We also studied a B-cell lymphoblastoid line, WI-L2/m4, that was 13,000-fold resistant. Assay of cellular dihydrofolate reductase (DHFR) showed the following pattern of activity in resistant cell lines, relative to parental cell activity: RAJI/MTX-R, 550-fold increased; CEM/MTX-R, unchanged; TE-85/MTX-R, 4-fold increased; MG-63/MTX-R, 6-fold increased; SAOS-2/MTX-R, unchanged; and WI-L2/m4, 110-fold increased. Measurement of MTX membrane transport showed decreased uptake in CEM/MTX-R and SAOS-2/MTX-R, relative to parental cell lines. The other DHFR-overproducing cells all gave normal initial MTX uptake rates but increased total uptake. The DHFR-overproducing lines all had significant cross-resistance to both metoprine and trimetrexate; the two lines with defective MTX transport were not cross-resistant, and the CEM/MTX-R cells showed collateral sensitivity to these agents. Only minor cross-resistance to homofolic acid was found in all MTX-resistant lines. The highly MTX-resistant RAJI/MTX-R and WI-L2/m4 cells showed minor cross-resistance to the dual inhibitor of thymidylate synthetase and DHFR, CB3717 (5- and 15-fold, respectively). These studies demonstrated that, depending upon the mechanism of resistance, MTX-resistant human tumor cells may be effectively killed by antifolates with different routes of uptake into cells, or with a different enzyme target. Thus, there are at least three functionally distinct classes of folate antagonist with antitumor activity.
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PMID:Patterns of cross-resistance to the antifolate drugs trimetrexate, metoprine, homofolate, and CB3717 in human lymphoma and osteosarcoma cells resistant to methotrexate. 622 14

Deoxycytidine kinase (dCK) activates several clinically important drugs, including the recently developed antileukaemic compound 2-chlorodeoxyadenosine (CdA). The distribution of dCK in cells and tissues has previously been determined by activity measurements, which may be unreliable because of the presence of other enzymes with overlapping substrate specificities. Therefore we have measured dCK polypeptide levels in extracts of normal and malignant human peripheral blood mononuclear cells, gastrointestinal tissues and sarcomas, using a specific immunoblotting technique, as well as the phosphorylation of CdA in the same extracts. High levels of dCK were found in all major subpopulations of normal mononuclear leucocytes (120 +/- 19 ng dCK/mg protein) and in B-cell chronic lymphocytic leukaemia (81 +/- 30 ng/mg, n = 23). Hairy-cell leukaemia contained lower levels (28 +/- 23 ng/mg, n = 7), as did three samples of T-cell chronic lymphocytic leukaemia (18 +/- 14 ng/mg). Phytohaemagglutinin stimulation of normal lymphocytes did not lead to any substantial increase in either dCK activity or protein expression (less than 2.5-fold). The human CEM wt T-lymphoblastoid cell line contained 56 +/- 1 ng/dCK/mg protein, while in the CEM ddC50 and AraC8D mutants that lack dCK activity, no dCK polypeptide could be detected. In colon adenocarcinomas, the dCK content was significantly higher (20 +/- 9 ng/mg, n = 20) than in normal colon mucosa (8 +/- 3.5 ng/mg, n = 19, P < 0.05). A similar pattern of dCK expression was found in gastric adenocarcinomas (21 +/- 13 ng/mg, n = 5) and normal stomach mucosa (6 +/- 5 ng/mg, n = 5, P < 0.15). One leiomyosarcoma and one extra-skeletal osteosarcoma showed dCK levels comparable with those found in normal lymphocytes (84 +/- 6 and 109 +/- 4 ng/mg, respectively), while other sarcoma samples contained lower levels, comparable to the gastrointestinal adenocarcinomas (20 +/- 7 ng/mg, n = 12). Thus, dCK is expressed constitutively and predominantly in lymphoid cells, but it is also found in solid non-lymphoid tissues, with increased levels in malignant cells. The phosphorylation of CdA in crude extracts showed a close correlation to the dCK polypeptide level.
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PMID:Expression of deoxycytidine kinase and phosphorylation of 2-chlorodeoxyadenosine in human normal and tumour cells and tissues. 771 26

Multidrug-resistance (MDR) is largely caused by the efflux of therapeutics from the tumor cell by means of P-glycoprotein (P-gp), resulting in reduced efficacy of the chemotherapy. In order to overcome MDR, substances, such as verapamil and cyclosporin A (CsA), were employed. As these P-gp modulating agents did not seem promising in clinical practice, new compounds with a low degree of undesirable side effects, were introduced. In this study, bisindolic alkaloid voacamine was examined for its possible capability of enhancing the cytotoxic effect of doxorubicin (DOX) on drug resistant cells. Two different pairs of tumor cell lines were analyzed: the parental lymphoblastoid cell line CEM-WT and its MDR derivative CEM-R, the parental osteosarcoma cell line U-2 OS-WT and its resistant counterpart U-2 OS-R. These cell lines were characterized for their morphological features by scanning electron microscopy (SEM) and for the expression of the main drug transporters by flow cytometric analysis. The effects of voacamine on the cell survival and on both accumulation and efflux of DOX were then investigated. The intracellular distribution of DOX, given alone or in association with CsA or voacamine, was observed by laser scanning confocal microscopy. A differential effect of voacamine between sensitive and resistant cells on the intracellular DOX concentration and distribution was shown. In particular, voacamine induced a significant increase of drug retention and intranuclear location in resistant cells. The results of cell survival experiments revealed an enhancement of the cytotoxic effect of DOX induced by voacamine, confirmed by evident morphological changes observed by SEM. These findings suggest promising applications of this natural substance against MDR tumors.
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PMID:Voacamine, a bisindolic alkaloid from Peschiera fuchsiaefolia, enhances the cytotoxic effect of doxorubicin on multidrug-resistant tumor cells. 1461 20

Chemokines and their receptors are key factors in the onset and progression of AIDS. Among them, accumulating evidence strongly indicates the involvement of IL-8 and its receptors, CXCR1 and CXCR2, in AIDS-related conditions. Through extensive investigation of genetic variations of the human CXCR1-CXCR2 locus, we identified a haplotype of the CXCR1 gene (CXCR1-Ha) carrying two nonsynonymous single nucleotide polymorphisms, CXCR1_300 (Met to Arg) in the N terminus extracellular domain and CXCR1_142 (Arg to Cys) in the C terminus intracellular domain. Transfection experiments with CXCR1 cDNAs corresponding to the CXCR1-Ha and the alternative CXCR1-HA haplotype showed reduced expression of CD4 and CXCR4 in CXCR1-Ha cells in human osteosarcoma cells as well as in Jurkat and CEM human T lymphocytes. Furthermore, the efficiency of X4-tropic HIV-1(NL4-3) infection was significantly lower in CXCR1-Ha cells than in CXCR1-HA cells. The results were further confirmed by a series of experiments using six HIV-1 clinical isolates from AIDS patients. A genetic association study was performed by using an HIV-1(+) patient cohort consisting of two subpopulations of AIDS with extreme phenotypes of rapid and slow progression of the disease. The frequency of the CXCR1-Ha allele is markedly less frequent in patients with rapid disease onset than those with slow progression (P = 0.0003). These results provide strong evidence of a protective role of the CXCR1-Ha allele on disease progression in AIDS, probably acting through modulation of CD4 and CXCR4 expression.
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PMID:A haplotype of the human CXCR1 gene protective against rapid disease progression in HIV-1+ patients. 1736 Jun 50

Dihydrofolate reductase (DHFR) is an essential enzyme involved in de novo purine and thymidine biosynthesis. For several decades, selective inhibition of DHFR has proven to be a potent therapeutic approach in the treatment of various cancers including acute lymphoblastic leukemia, non-Hodgkin's lymphoma, osteogenic sarcoma, carcinoma of the breast, and head and neck cancer. Therapeutic success with DHFR inhibitor methotrexate (MTX) has been compromised in the clinic, which limits the success of MTX treatment by both acquired and intrinsic resistance mechanisms. We report that benzamide riboside (BR), via anabolism to benzamide adenine dinucleotide (BAD) known to potently inhibit inosine monophosphate dehydrogenase (IMPDH), also inhibits cell growth through a mechanism involving downregulation of DHFR protein. Evidence to support this second site of action of BR includes the finding that CCRF-CEM/R human T-cell lymphoblasic leukemia cells, resistant to MTX as a consequence of gene amplification and overexpression of DHFR, are more resistant to BR than are parental cells. Studies of the mechanism by which BR lowers DHFR showed that BR, through its metabolite BAD, reduced NADP and NADPH cellular levels by inhibiting nicotinamide adenine dinucleotide kinase (NADK). As consequence of the lack of NADPH, DHFR was shown to be destabilized. We suggest that, inhibition of NADK is a new approach to downregulate DHFR and to inhibit cell growth.
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PMID:A second target of benzamide riboside: dihydrofolate reductase. 2295 84

Virus-like particles based on polyomaviruses (PVLPs) are promising delivery devices for various cargoes, including nucleic acids, imaging probes, and therapeutic agents. In biological environments, the major coat protein VP1 interacts with ubiquitously distributed sialic acid residues, and therefore PVLPs show a broad tropism. For selective targeting, appropriate engineering of the PVLP surface is needed. Here, we describe a chemical approach to retarget PVLPs to cancer cells displaying abnormally high levels of transferrin receptor. We created an array of transferrin molecules on the surface of PVLPs by combining a high-yielding bioconjugation approach with specific point modification of transferrin. This artificial surface protein architecture enables (i) suppression of natural VP1-specific interactions by blocking the surface conformational epitope on the VP1 protein, (ii) unusually high cellular uptake efficiency, and (iii) selective retargeting of PVLPs to osteosarcoma (U2OS) and lymphoblastoid leukemia (CCRF-CEM) cells.
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PMID:Retargeting Polyomavirus-Like Particles to Cancer Cells by Chemical Modification of Capsid Surface. 2803 16