Cell culture standards--time for a rethink?

Rapid authentication of animal cell lines using pyrolysis mass spectrometry and auto-associative artificial neural networks

Pyrolysis mass spectrometry (PyMS) was used to produce biochemical fingerprints from replicate frozen cell cultures of mouse macrophage hybridoma 2C11-12, human leukaemia K562, baby hamster kidney BHK 21/C13, and mouse tumour BW-O, and a fresh culture of Chinese hamster ovary CHO cells. The dimensionality of these data was reduced by the unsupervised feature extraction pattern recognition technique of auto-associative neural networks. The clusters observed were compared with the groups obtained from the more conventional statistical approaches of hierarchical cluster analysis. It was observed that frozen and fresh cell line cultures gave very different pyrolysis mass spectra. When only the frozen animal cells were analysed by PyMS, auto-associative artificial neural networks (ANNs) were employed to discriminate between them successfully. Furthermore, very similar classifications were observed when the same spectral data were analysed using hierarchical cluster analysis. We demonstrate that this approach can detect the contamination of cell lines with low numbers of bacteria and fungi; this approach could plausibly be extended for the rapid detection of mycoplasma infection in animal cell lines. The major advantages that PyMS offers over more conventional methods used to type cell lines and to screen for microbial infection, such as DNA fingerprinting, are its speed, sensitivity and the ability to analyse hundreds of samples per day. We conclude that the combination of PyMS and ANNs can provide a rapid and accurate discriminatory technique for the authentication of animal cell line cultures.

Modulatory Effects of Resveratrol, Citroflavan-3-ol, and Plant-Derived Extracts on Oxidative Stress in U937 Cells

Phytochemicals and plant extracts, present in fruit, vegetables, plants, herbs, and beverages, have been shown to have antioxidant potential that may modulate the etiology of certain chronic diseases. The objective of the present study was to determine the concentration of compound that inhibited cell growth by 50% (IC(50)) of a range of phytochemicals and plant extracts and to investigate their antioxidant and genoprotective effects under conditions of oxidative stress in U937 cells. Two phytochemicals-resveratrol and citroflavan-3-ol-and four plant extracts-grapeseed polyphenols, olive leaf extract, bearberry, and Echinacea purpurea-were examined. Viability was assessed by the fluorescein diacetate/ethidium bromide assay. The IC(50) was calculated. To examine their antioxidant and genoprotective effects, U937 cells were pretreated with the test compounds at levels below the IC(50) and then exposed to oxidants: 0.5 microM etoposide or 100 microM hydrogen peroxide (H(2)O(2)) or 400 microM tert-butylhydroperoxide (tBOOH). Cellular reduced glutathione levels were measured as an indicator of oxidative stress. DNA damage was assessed by the alkaline single-cell gel electrophoresis assay or comet assay. Resveratrol demonstrated the highest IC50 value of 13.7 microg/mL, with Echinacea the lowest at 9,400 microg/mL. Etoposide-induced oxidative stress was strongly reduced by olive leaf extract and bearberry. Grapeseed polyphenols and bearberry strongly protected against H2O2- and tBOOH-induced DNA damage. In conclusion, these results provide evidence that non-nutrient dietary constituents may act as significant bioactive compounds and that plant extracts, such as bearberry, grapeseed polyphenols, and olive leaf extract, strongly protect against oxidative stress.

DNA fingerprinting transforms the art of cell authentication

The increasing diversity of new cell cultures is seriously stretching the capabilities of traditional methods of identification. DNA fingerprinting is set to play an important role in increasing confidence in the authenticity of cultures in research and industry.

The quality control of cell banks using DNA fingerprinting

Reproducibility in animal cell culture technology requires careful preparation and characterisation of banks of cell cultures. The two standard techniques used in the quality control of such banks are isoenzyme analysis and cytogenetics which require complex and time-consuming procedures to enable cell line identification. However, DNA fingerprinting is potentially a more powerful method of analysis which can detect mutation and intra-species cross-contamination. At the European Collection of Animal Cell Cultures (ECACC) multilocus fingerprint analysis using probes 33.6 and 33.15 has been assessed in the quality control of cell banks. This method has confirmed consistency between master and working banks, has proven useful over a wide species range and can differentiate closely related cell lines. The key advantage of this method is its ability to detect cross-contamination by cell lines from a wide range of species using a straightforward and economical test. In addition the reproducibility of DNA fingerprints indicates their possible role in cell line authentication procedures which are important for patent and product licence applications.