Cellular transformation

Benzyl chloride also induced in vitro cellular transformation in Syrian hamster embryo cultures and DNA alkylation in several organs of the male mouse following iv adrninistration. In summary, lARC states there is limited evidence that benzyl chloride is carcinogenic in experimental animals epidemiological data was inadequate to evaluate carcinogenicity to humans (67). 

Table 6. Some Tumor Viruses Which Cause Cellular Transformation...

Goff, L. J. H. and Coleman A. W. (1995), Fate of parasite and host organelle DNA during cellular transformation of red algae by their parasites , Plant Cell, 7, 1899-1911... 

Taken together, these biochemical and cellular transformations within the degenerating IVD result in macroscopic changes manifest as a dehydrated and fibrous NP, disorganized AF lamellae, and an inconspicuous boundary between the NP and AF. Concentric and/or radial annular tears, and NP fissure formations are also observed within the severely degenerated IVD, and an overall reduction in the central disc height may occur [11, 31]. Additionally, blood vessels and nerve endings have been found to infiltrate into the center of the disc, which may harbor inflammatory cells and their mediators. 

DNA viruses, such as adenoviruses and papovaviruses (e.g. polyoma and SV40), induce cellular transformation in rodents. Other viruses have been implicated in human cancers. Epstein-Barr virus, for example, has been implicated with nasopharyngeal carcinoma, (3-cell lymphomas and Hodgkin s lymphoma. Human papilloma virus is linked to most cervical cancers. 

Cellular-transforming factors Associated tumour antigen... 

Although Epstein-Barr virus is capable of inducing cellular transformation, few antibody-producing B-lymphocytes display the viral cell surface receptor. Most, therefore, are immune... 

For example, c-Fos is heavily phosphorylated on a series of serine residues in the C-terminal domain of the protein by several types of protein kinases. The likely functional importance of these phosphorylation sites is indicated by the fact that the difference between c-Fos (the normal cellular form of the protein) and v-Fos (the viral oncogene product) is a frameshift mutation in the v-Fos protein, which obliterates the phosphorylated serine residues. It is speculated that the loss of these phosphorylation sites removes one mechanism by which the cell can regulate the protein, thereby leading to cellular transformation. 

In the proper cellular context in B cells, NK cells and mast cells, Syk kinase has been shown to transduce cell growth and survival signals by activating PI3K/Akt and Ras/mitogen-activated protein kinase pathways [3,46]. When deregulated, Syk activity can promote myelodysplasias, leukemogenesis, and perhaps viral-media ted cellular transformations [47,48]. By contrast, Syk has also been proposed to function as a tumor suppressor [49]. This is however, based on... 

Costa, M., Heck, J. D. and Robison, S. H. (1982). Selective phagocytosis of crystalline metal sulfide particles and DNA strand breaks as a mechanism for the induction of cellular transformation, Cancer Res., 42, 2757-2763. 

Xiong, Y., H. Zhang, and D. Beach. 1993. Subunit rearrangement of the cyclin-dependent kinases is associated with cellular transformation. Genes Dev 7(8) 1572-83. 

Howlett, C. j. and S. M. Robbins, Membrane-anchored Cbl suppresses Hck protein-tyrosine kinase mediated cellular transformation. Oncogene,... 

Oncogene a gene found in viruses or as part of a normal genome that is involved in eliciting cellular transformation. 

Several cancer cell types are characterized by expressing a truncated EGF receptor. The related viral oncogene, V-er B, also encodes a truncated receptor which lacks most of the extracellular domain (the EGF receptor is also known as C-erbB). Mutant receptors that display inappropriate constitutive activity can lead to cellular transformation, due to the continuous generation of mitogenic signal. 

Although Epstein-Barr virus (EBV) is capable of inducing cellular transformation, few antibody-producing B lymphocytes display the viral cell surface receptor. Most, therefore, are immune to EBV infection. Even upon successful transformation, most produce low-affinity IgM antibodies, and the cells are often unstable. Having said that, one monoclonal antibody approved for medical use (Humaspect, Table 10.4) is produced by a human lymphoblastoid cell line originally transformed by EBV. 

NT005 West, K. A., I. R. Linnoila, S. A. Belinsky, C. C. Harris, and P. A. Dennis. Tobacco carcinogen-induced cellular transformation increases activation of the phosphatidylinositol 3 -kinase/Akt pathway in vitro and in vivo. Cancer Res 2004 64(2) 446-451. 

Arylnitrenium ions are considered to be key intermediates in carcinogenic DNA damage by metabolically activated amines. The enzymatic activation of amines and the propogation of DNA-amine adducts into mutations and cellular transformations is beyond the specific scope of this chapter. Presented here is an outline of the key mechanistic issues relevant to the interaction of DNA components with various arylnitrenium ions. 

Tumorigenesis is a multistep process that begins with cellular transformation, progresses to hyperproliferation and culminates with the acquisition of invasive potential, angiogenic properties and establishment of metastatic lesions [256]. 

Cellular transformation in Syrian hamster embryo eells in vitro Cell transformation, Syrian hamster embryo eells, elonal assay Cell transformation, C3H10T14 mouse eells Inhibition of gap-junetional intereellular eommunieation, Chinese hamster V79 eells and Syrian hamster embryo eells in vitro... 

Ruley, H.E. (1983). Adenovirus early r on lA enables viral and cellular transforming genes to transform primary cells in culture, Nature 304,602. 

The one-hit 7 model. This is ultra conservative as it assumes that cancer involves only one stage, and a single molecular event is sufficient to induce a cellular transformation. 

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