Tumors cell characterization

Dead or live bacteria may be effective to stimulate inflammatory reactions of phagocytic cells against tumor cells. The best-characterized treatment is the use of Bacillus Calmette Guerin (BCG) in the case of bladder cancer where activation of the immune response is capable of controlling tumor growth. 

A factor known as scatter factor has been characterized which causes the break up and stimulates motility of epithelial cell clumps (Stoker et al., 1987). This factor is identical to hepatocyte growth factor and increases the rate of locomotion of several other cell types. Motility factors elaborated from tumor cells are considered to play an important role in metastasis (see later). Guidance of cells by the physical topography of the substratum is another factor that profoundly affects the behavior of cells. 

A massive body of evidence has already been presented clearly indicating that the medicinal plants of the Pacific Rim elaborate a broad array of cytotoxic substances. Most of these have been characterized using experimental procedures designed to examine the cytotoxicity of natural products against human tumor cell lines. These procedures involve in vitro screening where the viability of cultured cells after exposure to an extract or a purified substance is measured. 

The synthesis and characterization of a somatostatin receptor-specific peptide H2N-(DPhe)-cyclo[Cys-Phe-(D-Trp)-Lys-Thr-Cys]-Thr-OH, labeled with an indo-dicarbo- and an indotricarbocyanine dye at the V-terminal amino group were described in [34], The ability of these fluorescent contrast agents to target the somatostatin receptor was demonstrated by flow cytometry in vitro, wherein the indotricarbocyanine conjugate led to elevated cell-associated fluorescence on somatostatin receptor-expressing tumor cells. The intracellular localization was visualized using NIR fluorescence microscopy. 

Yanagida, O., et al. Human L-type amino acid transporter 1 (LAT1) characterization of function and expression in tumor cell lines. 

The advent of personalized therapies that are dependent on the outcome of an immunohistochemical stain has increased the need for quantitative positive controls. When IHC was first introduced as an adjunct in surgical pathology diagnosis, the interpretation was largely qualitative. Specific markers were present or absent, thereby characterizing a tumor cell s lineage. The fact that IHC interpretation was qualitative, rather than semiquantitative, minimized... 

Numerous excellent reviews on the possible role of oxygen radicals in cancer and carcinogenesis have been published 10-20 years ago [147-153], Earliest studies have been much concerned with the role of SOD in tumor cells. Despite some contradictory results, it is general conclusion that tumor cells are usually characterized by lowered CuZnSOD activity and always by lowered MnSOD activity [147]. The origin of SOD declining in cancer cells is unknown. It has been suggested that MnSOD is not induced in cancer immortalized cells in response to oxidative stress, but the reason of this is uncertain [154],... 

Level 3 of the screen is designed to determine the cytotoxic selectivity of samples for tumor cells vs. normal cells. Where possible, the same patient s tissues are used. As in Level 2, six serial dilutions (of four- to five-fold each) are assayed in triplicate for each sample. The diluted samples are then added to the tumor cell and normal cell cultures, and the IC50 is determined. A "selectivity index" (SI) is determined based on the IC50 for normal cells/IC5Q for tumor cells. Samples with an SI of three or more are advanced to Level 4 of the screen. Additionally, only purified and well-characterized compounds are promoted for further testing. 

Goulet B, Watson P, Poirier M, Leduy L, Berube G, Meterissian S, Jolicoeur P, (2002) A Nepveu. Characterization of a tissue-specific CDP/Cux isoform, p75, activated in breast tumor cells. Cancer Res 62(22) 6625-6633... 

Gene mapping detection of heteromorphisms and determination of parental origin of heteromorphisms Detection of gene mutations Characterization of structural aberrations Identification of marker chromosomes Characterization of tumor cells Chromosome and karyotype evolution Spatial topography of chromosomes... 

Atkins et al, 2004). Our results could demonstrate a subtype-specific downregulation of the various APM components, in particular of TAP and tapasin as well as the LMP subunits, whereas P2-m and the MHC class 1 HC expression were not affected in this tumor type. Based on these results, the characterization of the underlying molecular mechanisms of MHC class I deficiencies of tumor cell is mandatory. 

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