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Query: UMLS:C0027651 (tumor)
 685,946 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The growth and metastatic behavior of three human tumor cell lines and a human colon carcinoma previously passaged in vivo were compared between nude mice and scid mice after xenotransplantation. The three human tumor lines included a bladder carcinoma (T24B), a melanoma (RPMI 7931) and a lacZ gene-transduced breast cancer (MDA-MB-435 BAG). The lacZ gene codes for beta-galactosidase, which can be stained blue with chromogenic substrate X-gal, thus allowing the highly sensitive detection and quantitative examination of human cancer metastasis in host mice. Adult (7-14 weeks) NMRI nude and C.B-17 SCID mice were inoculated with 0.5-5 x 10(6) tumor cells s.c. Comparable take rate, latent period and growth rate of implanted tumors were observed in nude and scid mice for each of the cell lines tested. At the time of autopsy, which varied from 6 to 11 weeks after inoculation, a significantly higher incidence of spontaneous lung metastasis was discovered in scid mice (96%) than in age-matched nude mice (27%, total P less than 0.001). In vitro assays for NK cell-mediated cytotoxicity revealed no significant differences between the two strains of mice. Our results suggest that nude and scid mice are equally suitable for propagating human tumors. However, the metastatic capacity of human tumor cells appears to be better expressed in scid mice. Scid mice may therefore provide an advantageous model for the study of human tumor metastasis.
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PMID:Comparative studies between nude and scid mice on the growth and metastatic behavior of xenografted human tumors. 158 90

The L1 and L2 proteins of BPV-2 have been produced in Escherichia coli as beta-galactosidase fusion proteins. The fusion proteins have been used to vaccinate calves both prophylactically and therapeutically. The L1 fusion protein prevented tumor formation when administered before challenge with BPV-2, while the L2 fusion protein was very effective in promoting tumor rejection, independently from whether it was administered before or after challenge. Animals vaccinated with L1, but not with L2, responded rapidly with production of serum neutralizing antibodies, showing that this peptide contains B-cell-specific epitopes. The massive infiltration of lymphocytes in the tumors of L2-vaccinated animals suggests that the peptide contains epitopes specific for T-cells. The two structural proteins of BPV-2 therefore interact with both efferent arms of the immune system, and this observation allows the choice between two different types of antiviral vaccination.
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PMID:Studies on vaccination against papillomaviruses: prophylactic and therapeutic vaccination with recombinant structural proteins. 165 94

Mediation of cellular interactions by protein (lectin)-carbohydrate recognition presupposes the expression of respective surface determinants. Due to the importance of cellular contacts between bone marrow stromal cells, recently shown to express cell surface lectins, and tumor or normal progenitor cells for biosignaling and marrow egress, quantitation of cell surface sugar receptor expression by a panel of chemically glycosylated enzymes (tetrameric E. coli beta-galactosidase) for human leukemia/lymphoma cells was initiated. Cells of the new B lymphoblastoid line Croco II that are partially positive for the CD15-specific epitope expressed receptors for various sugar specificities on their surface, fulfilling an indispensable prerequisite for establishment of glycobiological interactions. Binding studies with increasing neoglycoenzyme concentrations up to saturation in four cases disclosed values for apparent affinity constants in the range of 25-200 nM with 0.25-3 x 10(5) bound probes per cell. The presence of receptors for constituents of carbohydrate chains of cellular glycoconjugates was also ascertained biochemically, namely for beta-galactosides, alpha-mannosides, alpha-fucosides and N-acetylgalactosaminides. Expression of this property was modulated by changes in the culture conditions, as revealed by binding studies with cells, derived from growth in medium containing different serum concentrations. These findings indicate that cell surface sugar receptors of tumor cells warrant further attention with respect to recognitive interactions.
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PMID:Establishment, characterization and determination of cell surface sugar receptor (lectin) expression by neoglycoenzymes of a human myeloid marker-expressing B lymphoblastoid cell line. 171 80

Primary cultures of mouse colonic epithelial cells have been obtained that are typically epithelial by morphology and moreover express keratins and endogenous beta-galactosidase; this latter activity was also demonstrated in the epithelial lining of the mouse colonic mucosa. The proliferative response of the primary colonic epithelial cells to epidermal growth factor, insulin, and the bile acid, deoxycholic acid, has been studied. Using primary cultures maintained at suboptimal growth conditions, which yielded 96 to 100% quiescent cells, epidermal growth factor, insulin, and the bile acid, deoxycholic acid, at concentrations at which it normally occurs in the aqueous phase of human feces, stimulated proliferation as measured by autoradiography. Exposure of the cells to combinations of these factors resulted in additive increases in growth. In conclusion, cells from the normal mouse colon can now be cultured while retaining at least two normal marker functions and moreover respond to some known mitogens and the potential tumor promoter deoxycholic acid. The cells can also be subcultivated while maintaining their epithelial morphology and marker functions for at least 3 passages.
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PMID:Proliferative potential and expression of cell type specific functions in primary mouse colonic epithelial cells. 172 7

The structure of the linkage region of chondroitin sulfate chains attached to the hybrid proteoglycans of the Engelbreth-Holm-Swarm mouse tumor was investigated. The peptidoglycan fraction which contains oversulfated chondroitin sulfate rich in the GlcA beta 1-3GalNAc-4,6-diO-sulfate unit and undersulfated heparan sulfate rich in GlcA beta 1-4GlcNAc and GlcA beta 1-4GlcN-2N-sulfate units was isolated after exhaustive protease digestion of the acetone powder of the tumor tissue, (GlcA, glucuronic acid; GalNAc, 2-deoxy-2-N-acetylamino-D-galactose). Glycosaminoglycans were released by beta-elimination using NaB3H4 and digested with chondroitinase ABC. The linkage region fraction was separated from heparan sulfate by gel filtration and fractionated by HPLC on an amine-bound silica column. Six radiolabeled compounds (L1-L6) were obtained and structurally analyzed by cochromatography with authentic hexasaccharide alditols recently isolated by us from the linkage region, and by digestion using chondroitinase ACII, alkaline phosphatase and beta-galactosidase in conjugation with HPLC. These compounds shared the conventional hexasaccharide backbone structure: delta GlcA beta 1-3GalNAc beta 1-4GlcA beta 1-3Gal beta 1-3Gal beta 1-4Xyl-ol, (delta GlcA, delta 4.5-GlcA or D-gluco-4-enepyranosyluronic acid). L1 was not sulfated or phosphorylated. L2 and L4 were monosulfated at C-6 and C-4 of the GalNAc residue, respectively. Upon alkaline phosphatase digestion, L3, L5 and L6 were converted to L1, L2 and L4, respectively. Analysis of the periodate oxidation products indicated that the phosphate group in L3, L5 and L6 is located at C-2 of Xyl-ol. These results suggest that Xyl-2-O-phosphate is associated with both 4-O-sulfated and 6-O-sulfated GalNAc units and does not directly determine the sulfation pattern of chondroitin sulfate.
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PMID:The phosphorylated and/or sulfated structure of the carbohydrate-protein-linkage region isolated from chondroitin sulfate in the hybrid proteoglycans of Engelbreth-Holm-Swarm mouse tumor. 174 Jan 53

Recent technological advances made in molecular biology and in vitro culture of human and other mammalian cells have led to broad medical and scientific acceptance of the feasibility of gene therapy for genetic diseases. Cancer might practically be one of the attractive targets for such therapy. For the treatment of cancer, it is important to manipulate the gene of interest such that it is expressed solely in cancer cells. We have developed a tissue-specific gene expression system, based on a tissue-specific promoter on a retroviral vector. A murine ecotropic retroviral vector was constructed in which the Escherichia coli beta-galactosidase gene served as a reporter; it was expressed under control of the albumin enhancer element and promoter. The tissue specificity of this vector was first assessed in vitro, and beta-galactosidase activity was detected exclusively in hepatoma cell lines. This recombinant retrovirus was injected directly into a subcutaneous tumor composed of transplantable murine MH-134 hepatoma cells, and expression of the gene was observed in vivo. Then this recombinant retrovirus was injected via the spleen or directly into the liver, resulting in the gene expression in dividing hepatocytes in partially hepatectomized mice, but not in nondividing hepatocytes in normal mice. Gene transfer specific to dividing hepatocytes and expression by means of retroviral vectors should possess high potential for selective elimination of hepatoma cells surrounded by nondividing normal hepatocytes.
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PMID:A potential approach for gene therapy targeting hepatoma using a liver-specific promoter on a retroviral vector. 181 47

Sera from 26 rats bearing tumours induced by wild-type (wt) and mutant human adenovirus type 12 (Ad12), or by cells transformed with these viruses, were analysed for antibodies against the early region 1 (E1) transforming proteins. Six Ad12-beta-galactosidase fusion proteins encoding different regions of the Ad12 E1 proteins were constructed. The sera from the tumour-bearing animals reacted most strongly with the fusion protein encoding the N terminus of the E1A protein. Tumour-bearing rats exposed to the E1B 54K and 19K proteins showed strong reactions with the N terminus of the 54K protein and the C terminus of the 19K protein. Monospecific polyclonal antisera were raised against five of the fusion proteins by immunization of rats and rabbits; these sera cross-reacted with the purified native protein. No antibodies could be obtained which recognized a fusion protein containing amino acids 136 to 268 of the 54K protein. The fusion proteins were also used to purify monospecific antisera from tumour-bearer sera using affinity chromatography.
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PMID:The use of beta-galactosidase fusion proteins encoding the early region 1 transforming proteins of adenovirus type 12 to examine the humoral response in tumour-bearing animals. 184 78

Chemically induced mammary carcinomas often contain the activated Ha-ras oncogene. The role of this oncogene in the multistage process of carcinogenesis remains undefined. In order to model the role of ras in mammary carcinogenesis, gene transfer into adult rat mammary epithelial cells was accomplished by infusing helper-free, replication-defective retrovirus vectors into the central duct of each gland. In the initial experiments, the beta-galactosidase reporter gene was used to optimize the efficiency of this in situ gene transfer method. Stable infection of greater than 0.1% of mammary cells could be achieved following exposure to the beta-galactosidase gene-expressing vector. v-Ha-ras was then introduced into in situ adult rat mammary epithelial cells using this method. Cellular infection frequencies of less than 1% resulted in the frequent and rapid appearance of mammary carcinomas without any further treatment. Tumors arising following v-Ha-ras oncogene transfer resembled those induced by chemical carcinogens in both the kinetics of their development and histopathological spectrum. These observations support the hypothesis that ras activation can act as an initiation event in chemically induced mammary carcinogenesis. However, only a small percentage of v-Ha-ras infected cells, even with hormonal promotion, were neoplastically transformed, suggesting that ras-driven transformation is not a one-step event.
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PMID:Carcinoma induction following direct in situ transfer of v-Ha-ras into rat mammary epithelial cells using replication-defective retrovirus vectors. 202 42

We used a recombinant retrovirus to study cell lineage in the chicken optic tectum. The virus inserts the Escherichia coli lacZ (beta-galactosidase) gene into the genome of an infected cell; a histochemical stain marks the progeny of infected cells with a blue precipitate. We had previously shown that individual clones frequently contain diverse neuronal types. Now we asked whether individual clones contain glia as well as neurons. To this end, we constructed a virus in which lacZ is fused to a nuclear localization signal sequence from the simian virus 40 large tumor antigen. Cells infected with this virus are marked with blue nuclei instead of blue somata. In embryos injected with a mixture of the two retroviruses, individual clusters contained cells with only one label type (nuclear or cytoplasmic), thus verifying that clusters of cells were clones. Furthermore, it was possible to immunostain the somata of cells that had blue nuclei, whereas the blue cytoplasmic precipitate hampered immunostaining. Together, these methods allowed us to show that some clones contained neurons (neurofilament-positive) and two types of glia (glutamine synthetase-positive and glial fibrillary acidic protein-positive). This result demonstrates the existence of a common progenitor for neurons and glia in optic tectum.
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PMID:Neurons and glia arise from a common progenitor in chicken optic tectum: demonstration with two retroviruses and cell type-specific antibodies. 210 84

Proliferation-competent and differentiation-competent adult rat hepatocytes in primary culture were investigated for their ability to express reporter genes (firefly luciferase, bacterial chloramphenicol acetyltransferase, and bacterial beta-galactosidase) driven by tumor virus or eucaryotic promoters that vary in transcriptional efficiency and tissue specificity. Supercoiled plasmid DNA molecules were introduced into the cells by the calcium phosphate coprecipitation protocol of C. Chen and H. Okayama (Mol. Cell. Biol. 7:2745-2752, 1987). Reporter gene expression was virtually restricted to hepatocytes and was efficient (2 to 20% of the cells). The patterns and absolute levels of reporter gene expression depended on assay conditions employed (plasmid concentration [optimal at 2.4 micrograms of DNA per ml] and duration of exposure [optimal between 5 and 10 h]), culture growth cycle stages (lag, log, or stationary phase), properties and tissue specificity of the promoter(s) tested, and composition (and timing of fluid change) of the culture medium with or without the hepatocyte mitogen human transforming growth factor-alpha. Initial observations suggest that during hepatocellular growth transitions, human transforming growth factor-alpha differentially regulates exogenously introduced promoters associated with hepatocyte-specific function and proliferation. These findings provide a simple, fast, and powerful approach to analyzing the molecular and cellular biology of hepatocyte growth control.
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PMID:DNA-mediated gene transfer into adult rat hepatocytes in primary culture. 210 58


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