Identification of a keratinocarcinoma cell line expressing AQP3

Background information. AQP3 (aquaporin 3) in the skin is important for skin moisture as demonstrated by the studies of AQP3-null mice, which have accelerated skin drying. Prevention of dry skin is important not only from a cosmetic but also from a clinical point of view. Primary keratinocyte cultures are cumbersome for screening substances that modulate AQP3 expression. Results. A human keratocarcinoma cell line was found to express AQP3 mRNA and protein, which responded to hypertonic stimulation with sorbitol, suggesting that the AQP3 expression is normally regulated in this cell line. This cell line also expressed the type 1 keratinocyte transglutaminase gene. The AQP3 expression was unaffected by all-trans-retinoic acid up to 10^-6 M. Similarly, the retinoic acid did not increase the AQP3 expression up to 1% concentration in rat skin. Conclusion. This cell line is useful for the screening of candidate substances that modulate AQP3 expression.