Sunday, September 18, 2016

Forensic DNA analysis checks the origin of cultured cells

"A cell line consists of cultured cells that often originate from a tumor."Unlike other cultured cells, cell line of tumor cells can be cultured for many years because these cells divide continually. A cell line U87MG used by the brain tumor type glioma was studied by the researchers at Uppsala university about fifty years ago. Marie Allen is an expert in DNA fingerprinting. DNA fingerprinting is used for finding out genetic identity such as in crime investigation scenes. Marie and her collegues genetically compared the cell lines with each other. It was found by that the U87MG cell line from the American Type Culture Collection (ATCC) had a different DNA profile than the original cell line in Uppsala. 
The material from the original tumor was saved as thin sections on microscope slides when the cell line was established in 1960s. The researchers could compare the two current cell lines with the tumor from which the cell line was established by using a very sensitive DNA analysis technique. This technique can also be used when very small quantities of DNA from old tissues are present. Consequently, the U87MG cell line from ATCC had a different and unknown origin while the Uppsala cell line was genetically similar to the original tumor. Bengt Westermark says, " We do not know at which point during the fifty years of culturing the mix-up occured but we have been able to show that the ATCC U87MG line is most likely from a human glioma tumor." Researchers who report results based on cell line experiment should use DNA profiling to establish the identity of used cells. Proper identification of a cell line requires that the DNA profile should match the origin of tissues. This is important if someone wants to assert that the cells are true representatives of original tumor through the research results. 
In my opinion, DNA profiling of human cell lines, which if applied routinely in cell culture experiment can significantly improve the recognition of cellular cross-contamination and thus results in more precise analysis. Human cell lines have been used as models for diseases such as cancer, production of vaccines and recombinant proteins. However, we need to moderate the accelerated use of human cell lines to prevent the cellular cross contamination.

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