Fig. 1: CDC6 is upregulated in psoriatic skin and is required for keratinocyte proliferation.

a Expression analysis of CDC6 in clinical psoriasis samples using public GEO data (GEO ascension GDS4602). ***p < 0.001. b CDC6 protein levels in lesional skin of psoriasis relative to those in paired adjacent nonlesional skin were determined by optical density analysis of the results of western blot. c The statistical analysis of IHC staining for CDC6 in psoriatic lesional skin (10 patients) or healthy controls (11 subjects). Values represent the means ± SD. ***p < 0.001. d Representative IHC staining of CDC6 in the normal and psoriatic lesional plaque skin. Bar = 200 μm. Normal control skin with weak basal CDC6 expression (a), psoriatic lesional skin showing moderate (b), or intense full thickness CDC6 expression (c). e HaCaT cells were transfected with 50 nM negative control (NC) siRNA or CDC6 targeting siRNAs (siCDC6). Seventy-two hours later, the CDC6 protein levels were analyzed by western blot. f–h HaCaT cells were transfected with indicated siRNAs, and cell proliferation, DNA replication, and cell apoptosis were determined by CCK8 assays (F), EdU assays (G), and flow cytometry (H). **p < 0.01, compared to that of NC cells. i, j HaCaT cells were treated with 100 ng/ml IL-22 for 48 h and mRNA and protein levels of CDC6 were analyzed by western blot (I) and qRT-PCR (J). **p < 0.01, compared to that of untreated cells. k, l HaCaT cells were treated with or without 3 μM Stattic either alone or together with 100 ng/ml IL-22 for 48 h. CDC6 protein levels were determined by western blot (K), and mRNA levels of CDC6 were determined by qRT-PCR (L). **p < 0.01, compared to that of DMSO-treated cells