Cell Line Stability

The StabiHty of cell lines will be dependent not only on the characteristics of the cell Hne and gene inserts, but also on culture conditions. Bird et al. [36] presented evidence that stability of a GS-NSO cell Hne was reduced under conditions where 

The mechanisms underlying instabihty in recombinant cell hnes are poorly understood. Barnes et al. [37, 38] determined that there may be molecular features of transfectants that predicate instabihty. These authors studied a series of GS-NSO cell lines making an anti-CD38 monoclonal antibody. Although copy number remained constant in these cell lines, there was a loss in expression of mRNA during prolonged culture. This did not result in loss of productivity in all of the cell lines. It seems that productivity was not influenced provided that levels of antibody mRNA remained above a critical threshold value. 

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Schenerman, M. A., Hope, J. N., Kletke, C. et al. Comparability testing of a humanized monoclonal antibody (Synagis0) to support cell line stability, process validation, and scale-up for manufacturing. Biologicals 27 203-215 (1999). 

Process Validation. A description and documentation of the validation studies should be included. If the process was changed or scaled up for commercial production and this involved changes in the fermentation steps, the revalidation of cell line stability during growth should be described, as in the previous section, and the data and results provided. A description and documentation of the validation studies for the cell growth and harvesting process that identify critical parameters of routine products should be submitted. Similarly, description and documentation of the validation of the purification process should be included. Finally, the subsection should describe and document the validation studies or any processes used for media sterilization and inactivation of cells prior to their release to the environment (if such inactivation is required). 

Select 3 cell lines for fnrtlier analysis, including cell line stability study... 

Some of the [Au(N,0)Cl2] derivatives, namely 58a, 59a and 59b, which have been tested for cytotoxic activity against various human tumor cell lines, have shown significant effects [144]. Compound 57 is a potential alternative to dimethylgold (III) P diketonates and can be used as a starting material for gold coatings by the CVD method [140]. Recent studies have shown that the long-term stability of these... 

In cell culture, lycopene is a highly oxidizable nonpolar hydrocarbon supplied in an aqueous medium and is incubated at body temperature for 12-72 h. The amount of intact lycopene or its oxidation products delivered to and absorbed by various cell types is an important factor to keep in mind when evaluating the effects of lycopene on various cellular processes. Before reviewing cell culture studies designed to characterize the effects of lycopene on prostate cell biology, the characteristics of prominent prostate cell lines, and the stability and uptake of lycopene by various prostate cell lines are reviewed. 

The extent to which the cell line supports appropriate expression of the cDNA. The level of expression achieved is determined by interactions of the vector/ expressed protein with the cell. These interactions include the strength of the promoter (weaker promoters can be compensated for by using a vector which is present at high copy number), the adequacy of the selective agent (not all agents are toxic to all cells), the stability of the expressed protein (some proteins may be rapidly degraded in some cells), and whether the expressed protein exerts any deleterious effects on the viability of host cells (some efflux transporters could deplete the cell of essential components). Finally, transporters must be expressed in a polarized manner in the host cell (i.e., preferentially on either the basolateral or apical side of the cell). 

Epothilones A, B and E (4,5 and 6) (Fig. 2) are representative members of a new class of bacterially derived natural products which exhibit potent biological activity. Isolated by Hofle and coworkers [6] from a soil sample collected near the Zambesi river, the compounds have provided a great deal of excitement in the scientific community due to their potent cytotoxicity against a number of multiple drug-resistant tumor cell lines and because of the mechanism by which they exert this effect. Like Taxol [7], the epothilones promote the combination of a- and 3-tubulin subunits and stabilize the resulting microtubule structures. This mode of action inhibits the cell division process and is, therefore, an attractive strategy for cancer chemotherapy [7,8]. 

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