Immortalized keratinocyte cell lines for tissue engineered 3D skin and epidermal modeling: prospects, challenges, and limitations.

Immortalized human epidermal keratinocytes, including HaCaT, N/TERT-1, and N/TERT-2G keratinocytes, are increasingly being used as alternatives to primary human keratinocytes to produce epidermal and full-thickness skin equivalents. The use of immortalized cell lines requires a critical evaluation of their genotypes and functional characteristics to establish their suitability to model the epidermis in vitro. Here, we assess the accumulating evidence-based experimental data on HaCaT, N/TERT-1, and N/TERT-2G keratinocytes, as well as additional immortalized keratinocyte cell lines, to aid the skin biology community in choosing the most appropriate cells for modeling the epidermis and skin.