Transformed cells, characterization

Daar, I., Paules, R. S and Vande Woude, G. F. (1991). A characterization of cytostatic factor activity from Xenopus eggs and c-mor-transformed cells. J. Cell Biol. 114 329-335. 

As was the case for most other cytokines, medical appraisal/use of IL-2 was initially impractical due to the minute quantities in which it is normally produced. Some transformed cell lines, most notably the Jurkat leukaemia cell line, produces IL-2 in increased quantities, and much of the IL-2 used for initial characterization studies was obtained from this source. Large-scale IL-2 production was made possible by recombinant DNA technologies. Although the IL-2 gene/cDNA has now been expressed in a wide variety of host systems, it was initially expressed in E. coli, and most products being clinically evaluated are obtained from that source. As mentioned previously, the absence of glycosylation on the recombinant product does not alter its biological activity. 

The characterization of the cells isolated after transformation with a gene that alters the proliferative properties of the primary cells is approached at several different levels. The first stage is the verification that the cells are transformed and have altered growth properties when compared with primary cells. The next stage is the verification that the transformed cells are epithelial in origin. Finally, the cells can be characterized for specific genotypic and/or phenotypic endpoints that are of interest. 

The final stage in the characterization of a transformed cell line is an extension of the verification of epithelial origin and likely the most relevant in assessing the usefulness of a given cell line for the study of features and pathways associated with differentiated functions. The cells can be evaluated... 

The appearance of any such cancer-associated antigen should thus be capable of inducing an immune response which, if successful, should eradicate the transformed cells. The exact elements of immunity responsible for destruction of transformed cells remain to be fully characterized. Both a humoral and cell-mediated response can be induced, although the T cell response appears to be the most significant. 

Mountford, C.E., Grossman, G., Reid, G., Fox, R.M. (1982). Characterization of transformed cells and tumors by proton nuclear magnetic resonance spectroscopy. Cancer Res. 42,2270-2276. 

Our understanding on the underlying mechanism of this novel cancer treatment was significantly advanced by the discovery in 1975 that bacterial endotoxin induced the production and release of an anti-tumor activity from host cells like macrophages. This activity caused hemorrhagic necrosis of transplanted tumors in mice and killed transformed cell lines (Carswell et al, 1975). The promise of TNF as a cancer cure prompted many laboratories to search the molecular identity of TNF, which eventually led to the purification, characterization and cloning of TNF (Beutler and Cerami, 1986 Pennica et al., 1984 Shirai et al., 1985 Wang et al, 1985). 

Neuronal cultures derived from human stem cells can possibly serve as renewable source of normal (non-transformed) cells with the capacity to differentiate into any cell type present in the nervous system. The major advantage of human cell types-based in vitro models is that the results do not require extrapolation from animal data to the human situation. The detailed characterization of human stem/progenitor cell-based assays for neurodevelop-mental toxicity testing is described in Chap. 16 of this book by E. Eritsche. 

Linzer DI, Levine AJ (1979) Characterization of a 54 K Dalton cellular SV40 tumor antigen present in SV40-transformed cells and uninfected embryonal carcinoma cells. Cell 17 43-52... 

The importance of maintaining genomic stability is evidenced by the fact that transformed cells often contain a variety of chromosomal abnormalities such as eu-ploidy, translocations, and inversions. Gene amplification is a well-characterized hallmark of genomic instability, and is thought to result from recombination events following the formation of doublestrand, chromosomal breaks. Therefore,... 

Increasing Energy Dissipation Characterizes the Cell Attachment Process. The process of cell attachment as monitored by the QCM is rather lengthy, involving many hours of change before steady state invariant behavior is observed. We have followed this process for normal ECs as well as for other transformed cell types, but our most detailed studies have been performed... 

Pottenger, L. and Jefcoate, C. R. (1990) Characterization of a novel cytochrome P450 from the transformable cell line C3H/10T1/2. Carcinogensis 11 321 327. 

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