Antitumor Effect of Calcium-Mediated Destabilization of Epithelial Growth Factor Receptor on Non-Small Cell Lung Carcinoma.

Despite the development of numerous therapeutics targeting the epithelial growth factor receptor (EGFR) for non-small cell lung carcinoma (NSCLC), the application of these drugs is limited because of drug resistance. Here, we investigated the antitumor effect of calcium-mediated degradation of EGFR pathway-associated proteins on NSCLC. First, lactate calcium salt (LCS) was utilized for calcium supplementation. Src, α-tubulin and EGFR levels were measured after LSC treatment, and the proteins were visualized by immunocytochemistry. Calpeptin was used to confirm the calcium-mediated effect of LCS on NSCLC. Nuclear expression of c-Myc and cyclin D1 was determined to understand the underlying mechanism of signal inhibition following EGFR and Src destabilization. The colony formation assay and a xenograft animal model were used to confirm the in vitro and in vivo antitumor effects, respectively. LCS supplementation reduced Src and α-tubulin expression in NSCLC cells. EGFR was destabilized because of proteolysis of Src and α-tubulin. c-Myc and cyclin D1 expression levels were also reduced following the decrease in the transcriptional co-activation of EGFR and Src. Clonogenic ability and tumor growth were significantly inhibited by LSC treatment-induced EGFR destabilization. These results suggest that other than specifically targeting EGFR, proteolysis of associated molecules such as Src or α-tubulin may effectively exert an antitumor effect on NSCLC via EGFR destabilization. Therefore, LCS is expected to be a good candidate for developing novel anti-NSCLC therapeutics overcoming chemoresistance.

The Hot-Water Extract of Smilacis Chinae Rhizome Suppresses 2,4-Dinitrochlorobenzene and House Dust Mite-Induced Atopic Dermatitis-Like Skin Lesions in Mice.

Smilacis Chinae Rhizome (SCR) has been used as an oriental folk medicine for various biological activities. However, its effect on atopic dermatitis (AD) remains undetermined to date. We assessed the effect of orally administered hot-water extract of SCR on AD-like skin lesions in mice and its underlying mechanisms. AD-like murine model was prepared by repeated alternate application of house dust mite (Dermatophagoides farinae) extract (DFE) and 2,4-dinitrochlorobenzene (DNCB) for 4 weeks, topically to the ears. Daily oral administration of SCR for 3 and 4 weeks significantly reduced inflammatory ear thickening, with the effect being enhanced at the earlier start and longer period of administration. This effect was accompanied by a significant decrease in both Th2 and Th1 serum antibodies (total IgE, DFE-specific IgE, and IgG2a). Histological analysis showed that SCR markedly decreased the epidermal/dermal ear thickening and the dermal infiltration of inflammatory cells. Furthermore, SCR suppressed DFE/DNCB-induced expression of IL-4, IL-13, IL-17, IL-18, TSLP, and IFN-γ genes in the ear tissue. Taken together, our observations demonstrate that chronic oral administration of SCR exerts beneficial effect in mouse AD model, suggesting that SCR has the therapeutic potential as an orally active treatment of AD by modulating both Th1 and Th2 responses.

Investigation of the preventive effect of calcium on inflammation-mediated choroidal neovascularization.

AIMS: Age-related macular degeneration (AMD) is a leading cause of irreversible blindness in elderly people. The pathogenesis of neovascular AMD is known but is closely related to inflammation and choroidal neovascularization (CNV). The aim of this study was to investigate the anti-inflammatory and anti-angiogenic effects of calcium on neovascular AMD. MAIN METHODS: Human retinal pigment epithelial cells (ARPE-19) were used to identify protein markers of inflammation induced by differentiated macrophages. Choroidal neovascularization (CNV) mouse model was established by rupturing the Bruch's membrane using laser photocoagulation in C57BL/6 mice. Mice were divided into the following groups: untreated control and calcium supplemented. The expression levels of toll-like receptor isotype (TLR) 4, nuclear factor kappa B (NF-κB), hypoxia-inducible factor-1α (Hif-1α), and vascular endothelial growth factor (VEGF) were investigated to check whether calcium supplementation results in suppression of inflammation and has an anti-angiogenic effect. CNV was evaluated by immunofluorescence staining on choroidal flat mounts. KEY FINDING: The inflammation-induced expression of TLR4, NF-κB, and Hif-1α was decreased in ARPE-19 cells after calcium supplementation. Inhibition of the transcriptional activation of ARPE-19 cells by Hif-1α suppression resulted in decreased VEGF expression. In the laser-induced CNV mouse model, calcium supplementation inhibited inflammatory mediators and neovascularization in the retinal tissue. SIGNIFICANCE: Supplementation with calcium seems to constrain inveterate symptoms of neovascular AMD by inhibiting inflammation and angiogenesis in the laser-induced CNV mouse model.