Authentication of newly established human esophageal squamous cell carcinoma cell line (YM-1) using short tandem repeat (STR) profiling method

Abstract

Cross-contamination during or early after establishment of a new cell line could result in the worldwide spread of a misidentified cell line. Therefore, newly established cell lines need to be authenticated by a reference standard method. This study was conducted to investigate the authenticity of a newly established epithelial cell line of human esophageal squamous cell carcinoma (ESCC) called YM-1 using short tandem repeat (STR) DNA profiling method. Primary human ESCC epithelial cells were cultured from the fresh tumor tissue of an adult female patient. Growth characteristics and epithelial originality of YM-1 cells were studied. Genomic DNA was isolated from YM-1 cells harvested at passage 22 and ESCC donor tumor sample on two different days to prevent probable DNA contamination. STR profiling was performed using AmpFℓSTR® Identifiler® Plus PCR Amplification Kit. To address whether YM-1 cells undergo genetic alteration as the passage number increases, STR profiling was performed again on harvested cells at passage 51. YM-1 cells grew as a monolayer with a population doubling time of 40.66h. Epithelial originality of YM-1 cells was confirmed using ICC/IF staining of cytokeratins AE1/AE3. The STR profile of the ESCC donor tumor sample was the same with YM-1 cells at passage 22. However, STR profile of the donor tumor sample showed an off-ladder (OL) allele in their D7S820 locus. Also, re-profiling of YM-1 cells at passage 51 showed a loss of heterozygosity (LOH) at D18S51 locus. This suggests that long-term culture of cell lines may alter their DNA profile. Comparison of the DNA fingerprinting results in DSMZ, and ATCC STR profiling databases confirmed unique identity of YM-1 cell line. This study provides an easy, fast, and reliable procedure for authentication of newly established cell lines, which helps in preventing the spread of misidentified cells and improving the reproducibility and validity of experiments, consequently.