Effects of rottlerin on in vitro proliferation of and expressions of interleukin-17C, CCL20 and nuclear factor-κB in a human keratinocyte cell line HaCaT

Objective To investigate the effects of rottlerin on in vitro proliferation of and expressions of interleukin (IL) - 17C, CCL20 chemokine, and nuclear factor (NF) - κB in cultured human HaCaT keratinocytes. Methods Some HaCaT cells were divided into several test groups treated with rottlerin at concentrations of 0.5, 1.0, 2.0 and 4.0 μmol/L, a solvent group treated with RPMI 1640 culture solution containing the same volume of dimethyl sulfoxide (DMSO) as that of 4.0 μmol/L rottlerin, and a control group treated with RPMI 1640 culture solution. Cell counting kit-8 (CCK8) assay was conducted to estimate the proliferative activity of HaCaT cells after 24-, 48- and 72-hour culture, RT-PCR to determine the mRNA expressions of IL-17C and CCL20 after 48-hour culture, and Western blot to measure the protein expressions of IL-17C, CCL20 and NF-κB after 48-hour culture. Statistical analysis was carried out by using repeated-measures analysis of variance, one-way analysis of variance and Pearson correlation analysis with the SPSS16.0 software. Results Rottlerin showed an inhibitory effect on the proliferation of HaCaT cells, and the inhibitory effect increased over time (F=126.936, P < 0.05) and with the increase of rottlerin concentrations (F=838.308, P < 0.05), with a significant interaction effect between rottlerin concentrations and treatment duration (F=15.961, P < 0.05). After 48-hour treatment, a significant decrease was observed in the mRNA and protein expressions of IL-17C (F=206.041, 233.887, respectively, both P < 0.05) and CCL20 (F=143.883, 162.431, respectively, both P < 0.05), as well as in the protein expression of NF-κB (F=577.915, P < 0.05) in the test groups with the increase in rottlerin concentrations. Conclusions Rottlerin can inhibit the proliferation of HaCaT cells in vitro, and decrease the mRNA and protein expressions of IL-17C and CCL20 likely by downregulating the protein expression of NF-κB. Key words: Keratinocytes; Cell proliferation; NF-kappa B; Interleukin-17; Chemokine CCL20; Psoriasis; HaCaT cells; Rottlerin