agar and Cell-Transformation--Viral

Transgenic mice expressing the Notch 4 intracellular domain (ICD) (Int3) in the mammary gland have two phenotypes: arrest of mammary alveolar/lobular development and mammary tumorigenesis. Notch4 signaling is mediated primarily through the interaction of Int3 with the transcription repressor/activator Rbpj. We have conditionally ablated the Rbpj gene in the mammary glands of mice expressing whey acidic protein (Wap)-Int3. Interestingly, Rbpj knockout mice (Wap-Cre(+)/Rbpj(-/-)/Wap-Int3) have normal mammary gland development, suggesting that the effect of endogenous Notch signaling on mammary gland development is complete by day 15 of pregnancy. RBP-J heterozygous (Wap-Cre(+)/Rbpj(-/+)/Wap-Int3) and Rbpj control (Rbpj(flox/flox)/Wap-Int3) mice are phenotypically the same as Wap-Int3 mice with respect to mammary gland development and tumorigenesis. In addition, the Wap-Cre(+)/Rbpj(-/-)/Wap-Int3-knockout mice also developed mammary tumors at a frequency similar to Rbpj heterozygous and Wap-Int3 control mice but with a slightly longer latency. Thus, the effect on mammary gland development is dependent on the interaction of the Notch ICD with the transcription repressor/activator Rbpj, and Notch-induced mammary tumor development is independent of this interaction.

Topics: Adenocarcinoma, Papillary; Agar; Animals; Basic Helix-Loop-Helix Transcription Factors; Cell Cycle Proteins; Cell Transformation, Viral; Female; Homeodomain Proteins; Mammary Glands, Animal; Mammary Neoplasms, Experimental; Mammary Tumor Virus, Mouse; Mice; Mice, Knockout; Mice, Nude; Milk Proteins; Neoplasm Proteins; Pregnancy; Protein Structure, Tertiary; Proto-Oncogene Proteins; Receptor, Notch4; Receptors, Notch; Recombinant Fusion Proteins; Repressor Proteins; Terminal Repeat Sequences; Transcription Factor HES-1; Tumor Cells, Cultured

Topics: 3T3 Cells; Agar; Animals; Antigens, Polyomavirus Transforming; Cell Adhesion; Cell Communication; Cell Count; Cell Division; Cell Line; Cell Transformation, Neoplastic; Cell Transformation, Viral; Culture Media; Cytopathogenic Effect, Viral; Methylcellulose; Mice; Mice, Nude; Mutation; Neoplasm Transplantation; Polyhydroxyethyl Methacrylate; Rats; Simian virus 40; Virology

We showed earlier that cellular retinol-binding protein (CRBP) expression is downregulated in a subset of human breast cancers. We have now investigated the outcome of ectopic CRBP expression in MTSV1-7 cells, a SV40 T antigen-transformed human breast epithelial cell line devoid of endogenous CRBP expression. We found that: (i) CRBP did not inhibit adherent cell growth but suppressed foci formation in post-confluent cultures and colony formation in soft agar; (ii) this effect was due to CRBP inhibition of cell survival, as demonstrated by viability and TUNEL assays of cells in soft-agar or plated on polyHEMA-coated dishes; (iii) CRBP inhibited protein kinase B/Akt activation in cells in suspension but not in adherent cells and the CRBP suppression of anchorage-independent growth was mimicked by cell treatment with the phosphatidylinositol-3 kinase (PI3K) inhibitor LY294002; (iv) CRBP enhanced retinyl ester formation and storage but did not regulate retinoic acid synthesis or retinoic acid receptor activity. Ectopic CRBP-mediated inhibition of anchorage-independent cell survival and colony formation in the absence of significantly altered responses to either retinol or retinoic acid was also documented in T47D human breast cancer cells. In conclusion, the data suggest two novel and linked CRBP functions in mammary epithelial cells: inhibition of the PI3K/Akt survival pathway and suppression of anchorage-independent growth.

Topics: Agar; Apoptosis; Breast; Breast Neoplasms; Carrier Proteins; Cell Adhesion; Cell Division; Cell Line, Transformed; Cell Transformation, Viral; Chromones; Contact Inhibition; Enzyme Activation; Enzyme Inhibitors; Fatty Acid-Binding Protein 7; Fatty Acid-Binding Proteins; Female; Humans; Morpholines; Neoplasm Proteins; Phosphatidylinositol 3-Kinases; Phosphoinositide-3 Kinase Inhibitors; Protein Serine-Threonine Kinases; Proto-Oncogene Proteins; Proto-Oncogene Proteins c-akt; Receptors, Retinoic Acid; Retinol-Binding Proteins; Retinol-Binding Proteins, Cellular; Signal Transduction; Simian virus 40; Tretinoin; Tumor Stem Cell Assay; Tumor Suppressor Proteins; Vitamin A

Human herpesvirus 8 (HHV8) infects Kaposi's sarcoma (KS) spindle cells in situ, as well as the lesional endothelial cells considered to be spindle cell precursors. The HHV8 genome contains several oncogenes, suggesting that infection of endothelial and spindle cells could induce cellular transformation and tumorigenesis and promote the formation of KS lesions. To investigate the potential of HHV8 infection of endothelial cells to contribute to the development of KS, we have developed an in vitro model utilizing dermal microvascular endothelial cells that support significant HHV8 infection. In contrast to existing in vitro systems used to study HHV8 pathogenesis, the majority of dermal endothelial cells are infected with HHV8 and the viral genome is maintained indefinitely. Infection is predominantly latent, with a small percentage of cells supporting lytic replication, and latency is responsive to lytic induction stimuli. Infected endothelial cells develop a spindle shape resembling that of KS lesional cells and show characteristics of a transformed phenotype, including loss of contact inhibition and acquisition of anchorage-independent growth. These results describe a relevant model system in which to study virus-host interactions in vitro and demonstrate the ability of HHV8 to induce phenotypic changes in infected endothelial cells that resemble characteristics of KS spindle cells in vivo. Thus, our results are consistent with a direct role for HHV8 in the pathogenesis of KS.

Topics: Agar; Antigens, Viral; Cell Culture Techniques; Cell Division; Cell Transformation, Viral; Cells, Cultured; Culture Media; Endothelium, Vascular; Herpesvirus 8, Human; Humans; Nuclear Proteins; Phenotype; Sarcoma, Kaposi; Time Factors; Virus Latency; Virus Replication

Periodontal ligament (PDL) cells are thought to be important for establishing and maintaining a stable interface between bone and teeth. In addition, PDL cells are thought to play critical roles in both the pathogenesis of periodontal disease and the regeneration of periodontal ligament tissues. The purpose of this study was to develop a continuous or stable human PDL cell line as an in vitro model for the investigation of cellular mechanisms involved in periodontal regeneration and destruction. Human PDL cells, derived from a primary cell culture, were transfected with simian virus 40 (SV40) T antigen-containing virus with a neomycin resistance gene. The transformed cells expressed the SV40 T antigen mRNA as assayed by reverse transcription polymerase chain reaction (RT-PCR). This cell line was also characterized for morphological changes and growth characteristics compared to primary PDL cell cultures. The transformed cells were shown to form a multilayer pattern and distinct colonies on tissue culture surfaces. However, no colony formation was found in soft agar. The transformed PDL cell line was found to have a greater rate of proliferation in 10% fetal bovine serum than primary culture, and continued to proliferate in low serum concentrations capable of producing quiescence in primary cells. Interleukin-1 beta (IL-1 beta) was shown to produce a 7-fold elevation in collagenase (MMP-1) mRNA levels, consistent with primary PDL cells. In addition, IL-1 beta was shown to produce a decrease in alkaline phosphatase activity in a concentration-dependent manner. The transformed cell line has been maintained for over 30 generations of cell culture. In conclusion, a stable human PDL cell line has been established to serve as a model for future in vitro investigations into periodontal pathogenic mechanisms and to evaluate therapies directed at the regeneration of periodontal ligament.

Topics: Adult; Agar; Alkaline Phosphatase; Alveolar Process; Animals; Anti-Bacterial Agents; Antigens, Viral, Tumor; Blood; Cattle; Cell Division; Cell Line, Transformed; Cell Transformation, Viral; Cells, Cultured; Collagenases; Culture Media; Culture Techniques; Drug Resistance; Female; Gene Expression Regulation, Enzymologic; Gene Expression Regulation, Viral; Humans; Interleukin-1; Mice; Mice, Inbred BALB C; Mice, Nude; Neomycin; Periodontal Diseases; Periodontal Ligament; Regeneration; RNA, Messenger; Simian virus 40; Tooth; Transfection

Expression of the early regions of several primate polyomaviruses (SV40, BKV, JCV, and LPV) in hamster cells induces transformation, manifested by the ability to grow in soft agar. Hamster cells transformed by SV40 contain complexes between the SV40 T antigen and the cellular tumor suppressor protein p53. We detected analogous complexes between p53 and the BKV T antigen in hamster cells transformed by the BKV early region, where the half life of p53 increased 16-fold. However, neither a LPV-transformed hamster fibroblast cell line [LPV-HE (F); K. K. Takemoto and T. Kanda, 1984, J. Virol. 50, 100-105] nor BHK-21 cells transformed by the LPV early region contained detectable complexes between the LPV T antigen and p53, nor was the stability of p53 in LPV transformed BHK-21 cells altered. Association between hamster p53 and the LPV T antigen expressed as glutathione S-transferase fusion protein could not be detected in vitro. These data indicate that alteration of the amount or stability of p53 is not required for transformation of hamster cells by LPV. However, as viruses such as SV40 and BKV whose T antigens bind p53 are oncogenic in hamsters, whereas LPV is not, the alteration of p53 amount or stability may be required for tumorigenesis.

Topics: Agar; Animals; Antigens, Viral, Tumor; Cell Line; Cell Transformation, Neoplastic; Cell Transformation, Viral; Cricetinae; Culture Media; Glutathione Transferase; Lymphoid Tissue; Organ Specificity; Polyomavirus; Transcription, Genetic; Tumor Suppressor Protein p53

Tumorigenesis is a multistep process involving both genetic and epigenetic changes resulting in altered cellular gene expression. While many phenotypic attributes of transformed cells have been described, the cellular genes responsible for these phenotypes are largely unknown. In this study, we show that the interferon-stimulated gene (ISG) ISG15 is expressed in all adenovirus type 5 (Ad5)-transformed rodent cells tested, in an E1A-dependent manner. We find that the level of ISG15 mRNA correlates with the level of the transcription factor ISGF3, which has been postulated to be the transcriptional activator of ISGs. Consistent with the activation of the interferon transduction pathway in Ad5-transformed cells, beta interferon mRNA is expressed in all but the parental untransformed cell line. The level of ISG15 mRNA in Ad5-transformed cells correlated inversely with the ability of these cells to proliferate in soft agar. This appears to have functional significance, since the phenotype of poor growth in agar could be conferred upon a cell line that grows efficiently in soft agar by using conditioned media from cells that grow poorly in soft agar. The same effect could be mimicked by applying rat interferon. We conclude that the degree of activation of the interferon signal transduction pathway explains differences in the transformation phenotypes among Ad5-transformed cell lines.

Topics: Adenoviruses, Human; Agar; Animals; Base Sequence; Blotting, Northern; Cell Line; Cell Transformation, Viral; Cloning, Molecular; Culture Media; DNA; Gene Expression Regulation; HeLa Cells; Humans; Interferon-beta; Molecular Sequence Data; Rats; RNA, Messenger; Signal Transduction

Cloning efficiency in hard agar (0.6%) and high chemotactic migration toward fibroblast conditioned medium have been shown to characterize metastatic tumor cells. We studied growth in 0.6% agar and chemotaxis of two lines of Rous Sarcoma virus-transformed Balb/c3T3 cells, B77/3T3 (low metastatic) and AA12 (high metastatic), and compared them to their non-transformed counterpart, in order to verify whether these properties were maintained during several subcultivations. Cells were cryopreserved at early passages and thawed for experiments. Both assays were performed on freshly thawed cells (4-6 weeks in culture) and on cells which had been cultured 15-20 weeks after thawing. B77/3T3, which are tumorigenic but low metastatic and which have a very low cloning efficiency in hard agar (0.1-1%), showed a chemotactic response to Balb/c3T3 conditioned medium about two-fold higher than control Balb/c3T3. This response did not change with time in culture. AA12 cells, a genetic unstable variant of B77/3T3 selected for its growth in hard agar (0.6%), had a high cloning efficiency in hard agar and showed a high chemotactic motility (three-fold the controls). High growth in 0.6% agar and high chemotaxis of AA12 were lost in late passages, where cells behaved as the controls. It seems that besides the already reported variation in anchorage-independent growth, genetically unstable tumor cells can also have important variations in chemotactic motility during subcultivations.

Topics: Agar; Animals; Avian Sarcoma Viruses; Cell Transformation, Viral; Chemotaxis; Fibroblasts; Mice; Mice, Inbred BALB C; Neoplasm Metastasis; Tumor Cells, Cultured; Tumor Stem Cell Assay

The effect of fibroblast growth factor (FGF) on the growth of chondrocytes in soft agar was examined. FGF induced colony formation by chick embryo and rabbit chondrocytes. The colony-forming efficiency of FGF-exposed chondrocytes was similar to that of Rous sarcoma virus-transformed chondrocytes (15-20%). Other mitogenic agents tested, such as epidermal growth factor, insulin, insulin-like growth factor-l, and platelet-derived growth factor, induced very low levels of colony formation. The induction of growth in soft agar of chondrocytes by FGF was not due to cells' phenotypic transformation, because chondrocytes grown in soft agar with FGF retained the ability to synthesize cartilage-characteristic proteoglycan. FGF did not induce growth in soft agar of chondrocytes whose phenotypic expression was suppressed by retinoic acid or 5-bromodeoxyuridine. In addition, FGF did not induce growth in soft agar of primary fibroblasts and normal rat kidney (NRK) cells. These results suggest that FGF selectively stimulates growth of differentiated chondrocytes in soft agar.

Topics: Agar; Animals; Avian Sarcoma Viruses; Cartilage; Cell Differentiation; Cell Transformation, Viral; Chick Embryo; Fibroblast Growth Factors; Fibroblasts; Osmolar Concentration; Proteoglycans; Rats; Stem Cells; Stimulation, Chemical

A retrovirus isolated from experimentally induced sheep lung carcinoma (SPCTV) was propagated in chronically infected Himalayan tahr ovarian cells and in normal sheep lung cells. Follow-up of infection of the cells with SPCTV showed the appearance of syncytium, plaque formation, partial recovery and the establishment of a chronic infection. Virus-associated reverse transcriptase activity in the medium fluctuated but remained at a constantly high level at the stage of chronic infection. Stages of type-C virus morphogenesis were demonstrated by electron microscopy. The viral genome was detected in both the nucleus and cytoplasm by in situ hybridization. Chronically infected cells formed colonies when plated in soft agar. Following subcutaneous inoculation of chronically infected cells (of fibroblast origin) into nude mice, lymphoid tumors developed at the site of inoculation and in vital organs.

Topics: Agar; Animals; Cell Line; Cell Transformation, Viral; Cytopathogenic Effect, Viral; Female; Lung; Lung Neoplasms; Mice; Mice, Inbred BALB C; Mice, Nude; Ovary; Retroviridae; RNA-Directed DNA Polymerase; RNA, Viral; Sheep; Sheep Diseases; Tumor Virus Infections; Virion; Virus Replication

Hamster embryo cells were transformed by African green monkey lymphotropic papovavirus (LPV). The transformed cells contained intranuclear T-antigens demonstrable by fluorescent antibody staining with hamster anti-LPV serum. Analysis of uncloned and cloned lines of transformed cells for LPV sequences revealed that the viral DNA was present as free nonintegrated and integrated genomes; there were approximately 10 copies of free DNA and about one to two copies of integrated genomes per cell. The cells were highly tumorigenic when inoculated into hamsters and produced progressively growing tumors in 100% of newborn or 10-day-old hamsters that were inoculated with LPV-transformed cells. The serum from tumor-bearing hamsters reacted with LPV-transformed cells and also showed a weak reaction with simian virus 40-, BK virus-, and JC virus-transformed cells, thereby showing an antigenic relationship with the T-antigens of other primate polyomaviruses. The large T-antigen of LPV was found to be an 84,000-molecular-weight protein which was immunoprecipitated by hamster anti-LPV (antiviral) as well as by tumor serum.

Topics: Agar; Animals; Antigens, Viral, Tumor; Blood; Cell Division; Cell Line; Cell Transformation, Neoplastic; Cell Transformation, Viral; Clone Cells; Cricetinae; Culture Media; DNA, Viral; Embryo, Mammalian; Neoplasms, Experimental; Polyomavirus; Tumor Virus Infections

Thymidine kinase-deficient syrian hamster cells were cotransfected with recombinant plasmids containing the thymidine kinase (TK) gene of Herpes Simplex Virus Type 1, and either intact or partially deleted SV40 T antigen-coding genes. The transformants were selected by their ability to grow in gHAT medium. After selection and cloning, the TK-positive transformants that also expressed T antigen were tested for the extent of their transformation with respect to a number of characteristics, which included saturation density, ability to grow in soft agar, resistance to butyrate and to dibutyryl-cAMP, and plating efficiency. The combined results of these various tests indicate that cells containing partially deleted SV40 T antigen-coding genes are less transformed than cells containing an intact SV40 T antigen-coding gene. However, the amounts of T antigen are lower in cells transformed by deletion mutants than in cells transformed by wild-type T antigen-coding gene. Our data indicate that both the quantity and the quality of T antigen may be important in determining the degree of transformation in Syrian hamster cells.

Topics: Agar; Animals; Antigens, Viral, Tumor; Bucladesine; Butyrates; Butyric Acid; Cell Count; Cell Division; Cell Line; Cell Transformation, Viral; Chromosome Deletion; Cricetinae; Culture Media; Genes, Viral; Mesocricetus; Mutation; Simian virus 40; Transfection

Growth factors with the two characteristic properties of sarcoma growth factor, the ability to stimulate anchorage-independent growth of normal mouse or rat fibroblasts and the ability to compete with 125I-labeled epidermal growth factor for receptor binding, can be isolated from 12- to 13-day-old normal mouse embryos of various strains. Two size classes of the transforming factor from embryo cells can be isolated with apparent molecular weights of 20,000 and 10,000. The lower-molecular-weight factor has been purified several hundred-fold and has the same properties as the peptides with a molecular weight of 10,000 produced by mouse sarcoma virus-transformed 3T3 cells. Whole-mouse embryos contain approximately 10% as much sarcoma growth factor per g of tissue as do the murine sarcoma virus-transformed cells; how it is distributed among the embryonic tissues remains to be determined.

Topics: Agar; Animals; Cell Line; Cell Transformation, Viral; Embryo, Mammalian; ErbB Receptors; Female; Gestational Age; Growth Substances; Mice; Mice, Inbred BALB C; Molecular Weight; Rats; Receptors, Cell Surface; Sarcoma Viruses, Murine; Tumor Virus Infections

The availability of many SV40 mutants, in which the ability of the virus to transform fibroblasts is variously affected, has prompted us to investigate the effect of treating SV40-infected cells with known tumor promoters on the expression of the transformed phenotype. Using mouse Swiss 3T3 cells and various SV40 tsA mutants unable to transform these cells at 39 degrees C, we have observed a dramatic effect of the potent phorbol ester promoter, 12-O-tetradecanoyl-phorbol-13-acetate, on the formation of macroscopic colonies in soft-agar at the restrictive temperature of 39 degrees C. The efficiency of other phorbol esters and various substances such as anthralin, saccharin, sodium cyclamate, mellitin, griseofulvin and benzoyl peroxide, was in agreement with their reported promoting activities suggesting that mouse Swiss 3T3 cells infected with SV40 tsA mutants could provide a quick and easy test to detect promoters.

Topics: Agar; Animals; Carcinogens; Cell Division; Cell Transformation, Viral; Cells, Cultured; Mice; Phorbol Esters; Simian virus 40; Viral Proteins

Topics: Agar; Animals; Antigens, Neoplasm; Antigens, Viral; Antigens, Viral, Tumor; Cell Adhesion; Cell Transformation, Viral; Cells, Cultured; Embryo, Mammalian; Fibroblasts; Growth; Kidney; Kirsten murine sarcoma virus; Peptides; Rats; Sarcoma, Experimental; Simian virus 40

Simian virus 40 tsA-transformed BALB/c-3T3 cells isolated as foci of overgrowth in liquid medium were compared with those isolated as colonies in soft agar. Efficiencies of transformation were equivalent in the two procedures. Cells isolated as foci were able to grow in agar and vice versa. No difference in temperature sensitivity of the transformed phenotype was detected when tsA transformants selected in agar were compared with those selected as foci. The use of the two different transformation procedures, then, did not form the basis for generation of different transformed phenotypes, and transformants generated in both ways were dependent upon expression of the A gene for maintenance of the transformed state.

Topics: Agar; Animals; Cell Line; Cell Transformation, Neoplastic; Cell Transformation, Viral; Culture Media; Fibroblasts; Mice; Mice, Inbred BALB C; Mutation; Phenotype; Simian virus 40; Temperature; Virus Replication

Infection of long-term BDF1 marrow cultures with Friend leukaemia virus complex (FLV) induced transformed cells with myelomonocytic characteristics, which were isolated only 14 days after the viral infection. Criteria for transformation were growth in suspension cultures and high plating efficiency in agar. The lymphatic leukaemia virus (LLV) replicates in these suspension cultures, but the spleen focus-forming virus (SFFV) component of the FLV complex has not been detected. Injection of the transformed cells into syngeneic neonatal or adult mice leads to the development of leukaemia which can be demonstrated to be of donor origin by the presence of two metacentric marker chromosomes which are also seen in the cultured cells.

Topics: Agar; Animals; Bone Marrow; Cell Division; Cell Line; Cell Transformation, Neoplastic; Cell Transformation, Viral; Colony-Forming Units Assay; Friend murine leukemia virus; Genetic Markers; Leukemia, Experimental; Leukemia, Myeloid; Mice; Neoplasm Transplantation; Time Factors; Transplantation, Isogeneic

Monolayer cultures of human prostatic epithelial cells were exposed to SV40 virus at 35th population doubling. Clones were isolated from infected plates after growth had ceased on the control plates. The nuclei of these clones were virtually all positive for viral T-antigen by immunofluorescence. When the properties of three of these lines were compared to those of normal cells, they were found to have altered morphology, ultrastructure, chromosomes, and growth behavior. All transformed lines had reduced serum dependence and were capable of growing in soft agar. However, their reduced serum dependence was not due to reduced growth factor requirements because each subline's response to growth factors was different.

Topics: Agar; Antigens, Polyomavirus Transforming; Blood Physiological Phenomena; Calcium; Cell Division; Cell Size; Cell Transformation, Viral; Clone Cells; Culture Media; Epidermal Growth Factor; Epithelial Cells; Fibroblast Growth Factors; Fibroblasts; Growth Substances; Humans; Karyotyping; Magnesium; Male; Microscopy, Electron; Ploidies; Prostate; Simian virus 40

Fisher rat fibroblasts (FR 3T3), transformed with the tsA30 mutant of simian virus 40 and selected by colony formation in soft agar, maintained the transformed phenotype at high temperature, whereas most transformants isolated from foci were found to undergo a phenotypic reversion toward the normal state in their saturation density, ability to grow in soft agar, and rate of 2-deoxyglucose transport. The temperature-independent phenotype observed in agar-selected transformants was not due to a reversion of the viral mutation. These results, similar to those previously obtained with polyoma virus tsa mutants, further suggest that two distinct mechanisms may operate in both cases for maintaining the transformed phenotype. Immunofluorescence studies suggested a different regulation of T antigen synthesis in these two classes of transformants.

Topics: Agar; Animals; Antigens, Viral; Cell Line; Cell Transformation, Neoplastic; Cell Transformation, Viral; Deoxyglucose; Mutation; Phenotype; Rats; Simian virus 40; Temperature; Virus Replication

Topics: Agar; Animals; Avian Sarcoma Viruses; Caseins; Cell Transformation, Neoplastic; Cell Transformation, Viral; Chick Embryo; Culture Techniques; Fibroblasts; Genes, Viral; Plasminogen Activators; Virus Replication

Infection of normal rat fibroblasts (FR 3T3) with the early tsa mutant of polyoma virus may lead to either the A or the N phenotype, tsa-A transformants, originally derived by agar selection, are not temperature dependent for maintenance of the transformed phenotype, whereas tsa-N transormants revert at high temperature to normal growth control. A transformants did not result from an independent cellular mutation selected in agar medium, but rather from a transformation process distinct from that leading to the N state. It occurred in both liquid and agar media when the infected cells were maintained under growth-restricting conditions, such as absence of anchorage and contact inhibition at confluency. N transformation occurred in cells maintained in active growth after virus infection (sparse cultures on a solid substratum). Physiological conditions during a critical period after virus infection thus appear to be a crucial parameter of the transformation process.

Topics: Agar; Animals; Cell Division; Cell Line; Cell Transformation, Neoplastic; Cell Transformation, Viral; Clone Cells; Fibroblasts; Mutation; Phenotype; Polyomavirus; Rats; Temperature

A human revertant cell line, derived from non-producer human osteosarcoma cells (NP/KHOS) induced by Kirsten murine sarcoma virus, was treated in vitro with various levels of polycyclic aromatic hydrocarbons (3-methylcholanthrene, 7,12-dimethylbenz(alpha)anthracene, and benzo(alpha)pyrene [BP] or dimethyl sulfoxide (control). Cells treated only with 3-methylcholanthrene and 7,12-dimethylbenz(alpha)anthracene underwent morphological alteration in vitro, and produced tumors when injected into NIH nude mice. These human revertant cells may be a useful in vitro tool in screening for the potential chemical carcinogens in human cell systems.

Topics: 9,10-Dimethyl-1,2-benzanthracene; Agar; Benzopyrenes; Carcinogens; Cell Aggregation; Cell Line; Cell Transformation, Neoplastic; Cell Transformation, Viral; Cytotoxicity Tests, Immunologic; Humans; Methylcholanthrene; Polycyclic Compounds