This is a guest post from Erin M. Hall. Erin is the Technical Leader at Genetica DNA Laboratories, Inc. located in Cincinnati, OH. Do you have a response to Erin’s post? Respond in the comments section below.
It is estimated that 18-36% of all actively growing cell line cultures are misidentified and/or cross-contaminated with another cell line (1). For researchers in any field of biomedical science, this could mean that a significant amount of the experimental data published in current and past journals is of questionable value. Every year, millions of dollars of public money are spent on potentially wasted research and this is happening not just here in the United States but around the world as well.
Cell line misidentification and cross-contamination has been around for more than 50 years. It was finally brought to light in 1966 by Stanley Gartler, who reported that 19 supposedly independent human cell lines were in fact HeLa cells(2), which are known to be extremely robust, fast growing and able to contaminate other cultures by aerosol droplets. There was much resistance to his findings and scientists didn’t want to admit that the research done using those contaminated cell lines may be questionable and potentially irreproducible. Walter Nelson-Rees was one scientist who supported Gartler’s findings. Nelson-Rees highlighted the papers and the scientists who were publishing experimental data using misidentified cell lines and for this, in 1981, he lost his contract with the National Institutes of Health (NIH) because his behavior was deemed “unscientific”(3). From 1981 and on, misidentification went unchecked and even cell line repositories continued to distribute lines under their false names (3).
To exacerbate the problem, certain cell culture practices may be aiding cell misidentification and cross-contamination, including the practice of assessing the phenotypic characteristics, such as protein expression, as the only way to properly identify the cell population. It has been proven that phenotypic expression can change with an increased passage number or even with changes in growth medium or other cell culture conditions(4). The modern way of assessing the correct identity of the cell line (“cell line authentication”) is to perform short tandem repeat (STR) DNA testing. The STR DNA profile of a human cell line is similar to a person’s fingerprint; it is unique to that individual. STR testing is now the “gold standard” of human identification testing and is routinely used by the FBI in profiling convicted offenders (CODIS). STR profiling is a straightforward and effective way to confirm that the cell line you think you have been using for the past 5 years, is in fact, the genuine cell line.
The reason the problem continues today is because it has not been properly brought to the attention of researchers. Many researchers learn about the service the hard way, i.e. at the last minute when the journal requests confirmation of authentication before considering your article for publication. In a survey that profiled 483 researchers who actively use cell cultures, only 33% authenticate their cell lines and 35% obtained their lines from other laboratories rather than a cell line repository, such as American Type Culture Collection (ATCC) (3). We, as researchers, expect to use only the best reagents and supplies but the one aspect of the experiment that may be the most important, i.e. the cell line, is consistently and explicitly overlooked. ATCC recommends verifying the identity of all cell lines before you start your experiments, every two months during active growth, and just prior to publication.
The NIH now officially recognizes that cell line misidentification is a serious problem in the scientific community. They state in a formal notice issued on their website (NOT-OD-08-017) that grant applications that fail to employ acceptable experimental practices would not be looked upon favorably and would potentially not fare well in the journal review process. The NIH encourages all peer reviewers and researchers to consider this problem carefully “in order to protect and promote the validity of the science [they] support”. Many journals, such as those published by the American Association for Cancer Research (AACR) require a statement in the “Materials and Methods” section as to whether cells used in the submitted manuscript were authenticated. Not properly authenticating the lines may prohibit the article from being published when peer reviewed. To continue the advancement towards the elimination of the problem of cell line misidentification and cross-contamination, ATCC, in early 2012, released a set of guidelines written by the international Standard Development Organization (SDO) workgroup; these guidelines provide researchers with information on the use of STR DNA profiling for the purpose of cell line authentication. In the near future, with the help of all of these influential supporters, cell line authentication will become a routine quality control check in every laboratory in the United States and around the world.
I would love to hear other thoughts and comments on this topic. Tell us about your experiences with cell line authentication – good or bad!
(1) Editorial – Nature 457, 935-936 (2009).
(2) Gartler, SM. Second Decennial Review Conference on Cell Tissue and Organ Culture: 167-195 (1967).
(3) ATCC SDO Workgroup. Cell line misidentification: the beginning of the end: 441- 448 (2010).
(4) Kerrigan, L. Authentication of human cell-based products: the role of a new consensus standard: 255-260 (2011).
About the author:
Erin is the Technical Leader at Genetica DNA Laboratories, Inc. located in Cincinnati, OH. She is responsible for the technical operations of the laboratory, as well as, all aspects of the daily casework involving DNA identity sample processing and quality assurance. She received her Master’s degree in Forensic Science from PACE University in NYC and her Bachelor’s degree in Molecular Biology from the College of Mount Saint Joseph in Cincinnati, OH. For more information on Genetica, visit www.genetica.com or their website dedicated to cell line authentication, www.celllineauthentication.com .
Prior to joining Genetica, Erin worked in New York City as a laboratory manager and researcher in the Pharmacology department at Cornell University’s Medical School. She designed and executed complex experiments that examined the effects of environmental toxins on liver enzyme production utilizing HPLC, UV/vis spectroscopy, Western blotting and PCR analysis. Her work contributed to several published journal papers (under Erin Labitzke, if you want to read them!), most recently including being cited as first author on a paper related to enzymes present in mitochondria.
Erin may be contacted at firstname.lastname@example.org.