Cells and cell lines are widely used in biological experiments as models to investigate biological activities and support medical research and development. When cells carry defined donor information, gene background, and disease state, they enable scientists to gain deeper insights into specific diseases.
However, issues such as mislabeling, cross-contamination, or cell line replacement could happen and make the result meaningless. In some cases, entire research projects have been compromised, or published papers retracted due to the use of misidentified cell lines. An increasing number of studies have been found to use misidentified cell lines (Figure 1); therefore, it is advised to perform cell authentication at the start, middle, and end of the project.
Figure 1. Numbers of contaminated literature (Horbach and Halffman, 2017)
Cell authentication is performed using Short Tandem Repeat (STR) analysis, a reliable method that combines multiplex PCR and capillary electrophoresis. STRs are regions in the genome composed of repeated sequences of 2-6 base pairs. The number of these consecutive repeating units can vary between people, making STRs ideal genetic markers for identification. During the assay, specific STR loci are targeted and amplified by PCR with fluorescence dye, generating billions of copies. These fluorescent copies are then separated by size and detected through capillary electrophoresis. By analyzing the resulting STR profiles, a unique DNA fingerprint is generated for each cell line, allowing accurate comparison and confirmation of cell identity.
Figure 2. The general process of cell authenciation using capillary electrophoresis.
Horbach, S. P., & Halffman, W. (2017). The ghosts of HeLa: How cell line misidentification contaminates the scientific literature. PloS one, 12(10), e0186281.
