UC Davis

SbIII and AsIII are known to exhibit similar chemical properties, but the degree of similarity in their effects on biological systems merits further exploration. Present work compares the responses of human epidermal keratinocytes, a known target cell type for arsenite-induced carcinogenicity, to these metalloids after treatment for a week at environmentally relevant concentrations. Previous work with these cells has shown that arsenite and antimonite have parallel effects in suppressing differentiation, altering levels of several critical enzymes and maintaining colony forming ability. More globally, protein profiling now reveals parallels in SbIII and AsIII effects. The more sensitive technique of transcriptional profiling also shows considerable parallels. Thus, gene expression changes were almost entirely in the same directions for the two treatments, although the degree of change was sometimes significantly different. Inspection of the changes revealed that RYR1 and LRIG1 were among the genes strongly suppressed, consistent with reduced calcium-dependent differentiation and maintenance of EGF-dependent proliferative potential. Moreover, levels of miRNAs in the cells were altered in parallel, with nearly 90% of the 198 most highly expressed ones being suppressed. Among these was miR-203, which is known to decrease proliferative potential. Finally, both SbIII and AsIII were seen to attenuate bone morphogenetic protein 6 induction of dual specificity phosphatases 2 and 14, consistent with maintaining epidermal growth factor receptor signaling. These findings raise the question whether SbIII, like AsIII, could act as a human skin carcinogen.