Mechanisms of Cd-Induced Cytotoxicity in Normal Human Skin Keratinocytes: Implication for Human Health

Abstract

Cadmium (Cd) is one of the toxic heavy metals found widely in the environment. Skin is an important target organ of Cd exposure. However, the adverse effects of Cd on human skin are still not well known. In this study, normal human skin keratinocytes (HaCaT cells) were studied for changes in cell viability, morphology, DNA damage, cycle, apoptosis, and the expression of endoplasmic reticulum (ER) stress-related genes (XBP-1, BiP, ATF-4, and CHOP) after exposure to Cd for 24 h. We found that Cd decreased cell viability in a concentration-dependent manner, with a median lethal concentration (LC50) of 11 µM. DNA damage induction was evidenced by upregulation of the level of γ-H2AX. Furthermore, Cd induced G0/G1 phase cell cycle arrest and apoptosis in a dose-dependent manner and upregulated the mRNA levels of ER stress biomarker genes (XBP-1, BiP, ATF4, and CHOP). Taken together, our results showed that Cd induced cytotoxicity and DNA damage in HaCaT cells, eventually resulting in cell cycle arrest in the G0/G1 phase and apoptosis. In addition, ER stress may be involved in Cd-induced HaCaT apoptosis. Our data imply the importance of reducing Cd pollution in the environment to reduce its adverse impacts on human skin.

Exploring the Functions of Mutant p53 through TP53 Knockout in HaCaT Keratinocytes

“…HaCaT keratinocytes, a line of spontaneously immortalized human keratinocytes, represent a convenient model for research in this field [5]. Although HaCaT cells are traditionally defined as normal non-tumoral keratinocytes and are commonly used as an alternative to primary keratinocytes [6][7][8], they also bear two UV-signature gain-of-function (GOF) mutations in both alleles of TP53 (R282Q and H179Y) [9]. The novel properties of p53 obtained through mutations are manifested in its capacity to bind atypical response elements and its altered affinity to other transcription factors, which in turn results in the suppression of their biological functions [10].…”