Morphologically and karyotypically atypical cells of 'normal' human bronchial epithelial cell line (Beas-2B)

Beas-2B is an adenovirus 12-SV40-transfected cell line of normal human bronchial epithelial cells. This cell line was able to replace normal human bronchial epithelial cells, which are currently unavailable, and served as a model for related studies in numerous toxicology and cancer transformation experiments. In any experiment involving toxins or carcinogens, the basic morphology of Beas-2B should be well characterized prior to exposure, but this has never been properly reported. In this study, atypical cells of the Beas-2B cell line in early passage culture were observed using light and electron microscopy, and the cells were further investigated for abnormal karyotypes by flow cytometry. This Beas-2B cell line could be morphologically categorized into two cell types, A and B. Type A contains a large nucleus and abundant cytoplasm (type A > 95%) and type B contains a small nucleus with dense and scarce cytoplasm (type B < 5%). Both atypical cell types had atypical and multilobed/multinucleated cells, including a high percentage (>30%) of mitotic figures, and were Ki-67 positive (100%). Karyotyping also revealed that 40.4% of the cells had atypical karyotyped chromosomes. In light of these findings, this cell line is no longer a normal cell, and experiments performed using this cell line can be questioned for non-default results. Experimenters should consider this error in future experiments.

Automated summary

The Beas-2B cell line, which is used as a model in toxicology and cancer transformation experiments, was found to contain atypical cells with abnormal karyotypes. These findings indicate that the Beas-2B cell line is no longer a normal cell line and should be used with caution in future experiments.