Viral transformation

The streptovaricins inhibit the reverse transcriptase of some RNA oncogenic vimses that may be involved in the process of viral transformation (see Antiviral agents). The atropisostreptovaricins again have similar activities to the corresponding natural isomers. The streptovals and streptovarone exhibit gready improved activity against reverse transcriptase relative to the streptovaricins (85), but their in vitro activities were low (86). The damavaricins also inhibit reverse transcriptase (4) as well as tumor cell growth (87). 

Casto BC, Meyers J, DiPaolo JA. 1979. Enhancement of viral transformation for evaluation of the carcinogenic potential of inorganic metal salts. Cancer Res 39 193-198. 

On the other hand, mercuric chloride, at a concentration of 50 /iM, also has been shown to enhance viral transformation of Syrian hamster embryo cells [252],... 

Water-soluble nickel salts enter the cells with relative ease but are less effective than crystalline particulates in the cell transformation assay, when using hamster cells [429, 430]. However, an enhancement of viral transformation of cells has been found [431, 432], In addition, a synergistic effect of cigarette smoke extracts, benzo[a]pyrene and nickel sulphate on the morphological transformation of hamster embryo cells has also been obtained [433], It was suggested that nickel salts are more potent as promoters than they are as initiators [434],... 

Hatch GG, Mamay PD, Ayer ML, et al. 1983. Chemical enhancement of viral transformation in Syrian hamster embryo cells by gaseous and volatile chlorinated methanes and ethanes. Cancer Res 43 1945-1950. 

Seliger, B., Ritz, U., and Ferrone, S., 2006, Molecular mechanisms of HLA class 1 antigen abnormalities following viral transformation, Int. J. Cancer 118 129 138. 

Electron-microscope examination did not, however, reveal changes in the organization of the microfilaments or microtubules, but the endoplasmic reticulum was dilated in a sac-like fashion.541 Decreased proportions of fibronectin were observed, both for control and virally transformed cells. In cells that had heen exposed to tunicamycin,... 

Hatch, G.G. Anderson. T.M. (1985) Assays for enhanced DNA viral transformation of primary Syrian hamster embryo (SHE) cells. Prog. Mutat. Res., 5, 629-638... 

Casto. B.C. (1981) Chemical-viral interactions enhancement of viral transformation by chemical carcinogens. In Stich, H.F. San, R.H.C., eds, Short-term Tests for Chemical Carcinogens, Berlin, Springer-Verlag, pp. 350-361... 

Phenyl glycidyl ether induced mutations in bacteria and transformation in mammalian cells in vitro (in a Syrian hamster embryo cell clonal assay and in an assay for the enhancement of viral transformation), but did not induce chromosomal aberrations in animal cells in vitro or either micronuclei or chromosomal aberrations in vivo. It did not induce dominant lethal effects in rats (IARC, 1989). 

An immunogen induces antibodies from many B cell clones, producing a polyclonal antibody response. In contrast, the propagation of an isolated B cell clone produces an antibody of single specificity. However, the problem is that in tissue culture medium, B cells die within a few days of their isolation from, for example, a mouse spleen. To circumvent this problem, immortality can be conferred on B cells by means of viral transformation Epstein-Barr virus can be used. Alternatively, fusion to cancerous cells is carried out to generate hybrids or hybridomas. Generally, the former procedure is used to immortalize peripheral blood B cells and produce human monoclonal antibodies, while myeloma cells are used to produce murine monoclonal antibodies. 

Levels of HA that cells deposit must respond to various physiological states including growth phase,239 confluence, inversely related to cell density in both fibroblasts,240 and keratinocytes,241 mitosis and cell detachment from the substratum,242 calcium concentrations,149,243 anoxia and lactate,244 viral transformation,245 and serum stimulation.91,246 Preliminary immunolocalization data indicate that some of the HAS and hyaluronidases colocalize (A. Spicer et al., pers. commun.). All of this evidence supports, albeit indirect and tentative, the existence of the hyaluronasome structure. 

No cell transformation was detected. This lack of effect may be due to the short period of exposure. However, 1,1-dichloroethane increased the frequency of transformation induced by SA-7 virus in Syrian hamster embryo cells (Hatch et al. 1983). Embryo cell cultures were exposed in a sealed treatment chamber to volatilized 1,1- dichloroethane for 20 hours and then treated with SA7 virus for 3 hours. 1,1-Dichloroethane treatment significantly increased the viral transformation frequency in cells in a dose-dependent manner. The highest concentration (1,000 jg/mL) was cytotoxic. These results reflect the capacity of 1,1-dichloroethane to interact with cellular DNA in hamster embryo cells. 

Hatch G, Anderson T, Elmore E, et al. 1983. Status of enhancement of DNA viral transformation for determination of mutagenic and carcinogenic potential of gaseous and volatile compounds [Abstract]. Environ Mutag 5 422. 

Levels of HA deposition respond to the various physiological states of the cell. In cultures of normal animal cells, growth phase [34], and degrees of confluence are inversely related to HA levels in both fibroblasts [106] and keratinocytes [38]. HA has been correlated with the onset of mitosis and detachment from the substratum [35], calcium concentrations [107], anoxia and lactate levels [108], viral transformation [109], and serum stimulation [110,111]. 

The 16HBE14o- and BEAS-2B cells are viral transformed bronchial cell lines.52,57 P-gp is expressed in 16HBE14o- cells, tight junctions form, and transport experiments can be carried out in 8 to 10 days, but the cells lack a representative mucus layer. Apical microvilli and cilia can be produced when 16HBE14o- cells are grown at an air interface, but this may not be favorable due to the basal origin of the cells.51,57 The use of BEAS-2B cells for transport studies is limited by their low TEER.57... 

B. Locating Gene Functions - The goal of mapping a mutant is to determine what function is affected by the mutation, and where that function is located on the physical map. Consequently, the protein or protein region responsible for the function can be determined. The quest to Identify the gene function(s) required for viral transformation and how that function is controlled has been of special interest. 

Golden Syrian hamster (embryo cell Viral transformation No data + Hatch etal. 1983... 

Currently proposed mechanisms for neoplasia include gene mutation, epigenetic changes, viral transformation, and cell selection these will be discussed in the following sections. 

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