Tumour cell cultures

Baguley BC, Marshall ES, Holdaway KM, et al. Inhibition of growth of primary human tumour cell cultures by a 4-anilinoquinazoline inhibitor of the epidermal growth factor receptor family of tyrosine kinases. EurJ Cancer 1998 34 1086-1090. 

It has also been demonstrated that tumour cells cultured in vitro often release tumour-associated antigens into the growth medium. Similar antigens can be detected in the blood of patients with advanced cancer. The development of monoclonal antibodies should make possible the detection of (tissue specific) antigens in quite small amounts and methods are now being developed to improve diagnosis. 

During ischaemia, NOS is activated by calcium influx or by cytokines like tumour necrosis factor (TNF) or by lipopolysaccharide (LPS) and NO is produced in excess. It has been proposed that the excitotoxic effect of glutamate, which contributes to ischaemia-induced neuronal damage, is mediated by increased production of NO via a chain of events that includes increases in intracellular calcium (via glutamate activation of NMDA receptors), calcium activation of NOS, production of NO and peroxynitrite, and induction of lipid peroxidation. In fact, N-nitro-L-atginine, a selective inhibitor of NOS, has been shown to prevent glutamate-induced neurotoxicity in cortical cell cultures (Dawson rf /., 1991). 

The mitochondrial dysfunctionality seen in manganese neurotoxicity might be related to the accumulation of reactive oxygen species (Verity, 1999). Mitochondrial Mn superoxide dismutase (MnSOD) is found to be low or absent in tumour cells and may act as a tumour suppressor. It is induced by inflammatory cytokines like TNF, presumably to protect host cells. In a rat model, iron-rich diets were found to decrease MnSOD activity, although a recent study reported that in rat epithelial cell cultures iron supplementation increased MnSOD protein levels and activity, but did not compromise the ability of inflammatory mediators like TNF to further increase the enzyme activity (Kuratko, 1999). 

Some tumour cells possess the enzyme glutamine synthetase and so are able to synthesise glutamine from glutamate as expected, proliferation of these tumour cells is not dependent upon the presence of glutamine in the culture medium. 

Nystrom ML, Thomas GJ, Stone M et al (2005) Development of a quantitative method to analyse tumour cell invasion in organotypic culture. J Pathol 205 468-475... 

Drapier, J. C., Pellat, C., and Henry, Y. (1992). Characterization of the nitrosyl-iron complexes generated in tumour cells after co-culture with activated macrophages. In The Biology of Nitric Oxide. 2. Enzymology, Biochemistry and Immunology. (S. Moncada, M. A. Marietta, J. B. Hibbs, Jr., and E. A. Higgs, eds.), pp. 72-76, Portland Press, London. 

Another method of removing fast growing fibroblasts is to prepare primary cultures from a tumour and after a short time return them to an animal where they will reform a tumour. By repeated alternation of growth in vivo and in vitro it was hoped to select for tumour cells and this has proved successful in isolating differentiated cell lines from adrenal, pituitary and neural tissue (Buonassisi et al., 1962 Augusti-Tocco and Sato, 1969). 

Mycoplasma can be eliminated from cell culture by treatment with immune serum (Pollock and Kenny, 1963) and passage through an animal is often effective in removing mycoplasma from tumour producing cell lines. 

Although most cultured cell populations come to rest in Gl, i.e. between cell division and DNA synthesis, a proportion of mouse ear epidermal cells are thought to be arrested in G2 (Gelfant, 1959, 1963), although recent evidence casts doubt on these conclusions (Sauerbom et al., 1978). There is some evidence that human embryonic fibroblasts maintained in culture for 48 passages (i.e. in the terminal phase) may arrest in G2 (Maciero-Coelho et al., 1966) but these are so abnormal as to be of no value in studies of G2. As mentioned in 11.6, some tumour cells arrest in G2 on medium exhaustion, but again many metabolic processes are affected and the cells cannot be considered as typical of G2-phase cells. 

Viruses produce CPEs on cells and are the agents for many diseases in humans and other animals. In addition, many viruses (e.g. oncoma viruses, herpes type II, adenovirus and polyoma and SV40) are believed to be agents responsible for tumour formation in animals. Moreover, due to their ability to pass through bacteriological filters it is difficult to exclude viruses from uninfected cell cultures if the viruses are present in suspension in the air of the culture room. For these reasons it is recommended practice to take special precautions when using viruses. 

Tumour cells are allowed to attach to gelatin-coated tissue culture dishes (see 2.4.1) when many different kinds of cells including embryonal cells grow out. These latter cells may eventually outgrow the differentiated cells and they may then be cloned (Chapter 7) (Rosenthal et al., 1970 Bernstine et al., 1973). Lines isolated in this way tend after some time to lose their ability to differentiate. 

Bennis, S. Chapey, C. Couvreur, P. Robert, J. Enhanced cytotoxicity of doxorubicin encapsulated in polyiso-hexylcyanoacrylate nanospheres against multidrug-resistant tumour cells in culture. Eur. J. Cancer 1994, 1, 89-93. 

One of the most active associations in B-ring is -3 - OH, 4 - OMe. The four most active flavonoids in Beutler et al. [21] have this association of substituents and they say that the requirements for the B-ring may be quite stringent and when these substituents are reversed (-3 - OMe, 4 -OH) cytotoxicity decreases notably. We can observe the same results in two flavonoids assayed on six tumour cell lines by Shi et al. [53]. The first one has -3 - OH, 4 - OMe in its B-ring and shows, for example, IC50 values of 0.045 and 0.055 pM on KB and P-388 respectively and the second one, with the only difference of these substituents reversed, show IC50 values of 8.38 and 6.52 pM on the same cell lines. Cushman and Nagarathnam [14], who studied 55 flavones in five cancer cell cultures, said that all five flavones with -3% 5 - OMe, 4 [(t-... 

Wright WC, Daniels WP Fogh J (1981) Distinction of seventy one cultured human tumour cell lines by polymorphic enzyme analysis. Journal of the National Cancer Institute 66 239-247. 

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