Claudin-1 mediates progression by regulating EMT through AMPK/TGF-ß signaling in head and neck squamous cell carcinoma.

Claudin-1 (CLDN1), a major component of tight junction complexes in the epithelium, maintains cellular polarity, and plays a critical role in cell-to-cell communication as well as epithelial cell homeostasis. Although the role of CLDN1 has been widely studied in cancer, its role in the progression and the exact regulatory mechanisms, remain controversial. Using next-generation sequencing, we first analyzed the expression profiles of tumor/non-tumor paired tissue in patients with head and neck squamous cell carcinoma (HNSC) from public and local cohorts and found out that CLDN1 is upregulated in tumors compared to normal tissues. Next, its correlation with lymph node metastasis and poor prognosis was validated in the retrospective cohort, which collectively suggests CLDN1 as an oncogene in HNSC. As expected, the knockdown of CLDN1 inhibited invasive phenotypes by downregulating epithelial-to-mesenchymal transition (EMT) in vitro. To ascertain the regulatory mechanism of CLDN1 in HNSC analysis of GO term enrichment, KEGG pathways, and curated gene sets were used. As a result, CLDN1 was negatively associated with AMP-activated protein kinase (AMPK) and positively associated with transforming growth factor-ß (TGF-ß) signaling. In vitro mechanistic assay showed that CLDN1 inhibited AMPK phosphorylation by regulating AMPK upstream phosphatases, which led to inhibition of Smad2 activity. Intriguingly, the invasive phenotype of cancer cells increased by CLDN1 overexpression was rescued by AMPK activation, indicating a role of the CLDN1/AMPK/TGF-ß/EMT cascade in HNSC. Consistently in vivo, CLDN1 suppression significantly inhibited the tumor growth, with elevated AMPK expression, suggesting the novel observation of oncogenic CLDN1-AMPK signaling in HNSC.

Head and Neck Cancer Cell Death due to Mitochondrial Damage Induced by Reactive Oxygen Species from Nonthermal Plasma-Activated Media: Based on Transcriptomic Analysis.

Mitochondrial targeted therapy is a next-generation therapeutic approach for cancer that is refractory to conventional treatments. Mitochondrial damage caused by the excessive accumulation of reactive oxygen species (ROS) is a principle of mitochondrial targeted therapy. ROS in nonthermal plasma-activated media (NTPAM) are known to mediate anticancer effects in various cancers including head and neck cancer (HNC). However, the signaling mechanism of HNC cell death via NTPAM-induced ROS has not been fully elucidated. This study evaluated the anticancer effects of NTPAM in HNC and investigated the mechanism using transcriptomic analysis. The viability of HNC cells decreased after NTPAM treatment due to enhanced apoptosis. A human fibroblast cell line and three HNC cell lines were profiled by RNA sequencing. In total, 1 610 differentially expressed genes were identified. Pathway analysis showed that activating transcription factor 4 (ATF4) and C/EBP homologous protein (CHOP) were upstream regulators. Mitochondrial damage was induced by NTPAM, which was associated with enhancements of mitochondrial ROS (mtROS) and ATF4/CHOP regulation. These results suggest that NTPAM induces HNC cell death through the upregulation of ATF4/CHOP activity by damaging mitochondria via excessive mtROS accumulation, similar to mitochondrial targeted therapy.

Effect of S100A8 and S100A9 on expressions of cytokine and skin barrier protein in human keratinocytes.

Atopic dermatitis (AD) is an inflammatory skin disorder caused by immunological dysregulation and genetic factors. Whether the expression levels of cytokine and skin barrier protein were altered by S100 calcium binding protein A8 (S100A8) and S100A9 in human keratinocytic HaCaT cells was examined in the present study. Alterations of cytokine expression were examined by ELISA following treatment with S100A8/9 and various signal protein­specific inhibitors. Activation of the mitogen activated protein kinase (MAPK) pathway and nuclear factor (NF)­κB was evaluated by using western blotting and an NF­κB activity test, respectively. The expression levels of interleukin (IL)­6, IL­8 and monocyte chemoattractant protein­1 increased following treatment with S100A8 and S100A9, and the increase was significantly blocked by specific signaling pathway inhibitors, including toll­like receptor 4 inhibitor (TLR4i), rottlerin, PD98059, SB203580 and BAY­11­7085. Extracellular signal­regulated kinase (ERK) and p38 MAPK pathways were activated in a time­dependent manner following treatment with S100A8 and S100A9. Phosphorylation of ERK and p38 MAPK were blocked by TLR4i and rottlerin. S100A8 and S100A9 induced translocation of NF­κB in a time­dependent manner, and the activation of NF­κB was inhibited by TLR4i, rottlerin, PD98059 and SB203580. In addition, S100A8 and S100A9 decreased the expression of skin barrier proteins, filaggrin and loricrin. These results may help to elucidate the pathogenic mechanisms of AD and develop clinical strategies for controlling AD.

Inhibitory effect of Patrinia scabiosifolia Link on the development of atopic dermatitis-like lesions in human keratinocytes and NC/Nga mice.

ETHNOPHARMACOLOGICAL RELEVANCE: Atopic dermatitis (AD) is a chronic pruritic and inflammatory disease occurring in skin. Patrinia scabiosifolia Link (PS), a member of the Patrinia genus (Caprifoliaceae family), has traditionally been used in folk medicines to treat various inflammatory diseases such as acute appendicitis, ulcerative colitis, and pelvic inflammation in Korea and other parts of East Asia. AIM OF THE STUDY: This study investigated the anti-inflammatory effects of PS on AD in vitro and in vivo. MATERIALS AND METHODS: Whole PS plants were dried, powdered, and then underwent extraction with DMSO. Both ELISA and western blotting were performed to evaluate cytokine concentration and the expression and activation of filaggrin and signaling proteins. Five-week-old female NC/Nga mice were used as an AD-like mouse model by treating them with 2,4-dinitrochlorobenzene (DNCB). RESULTS: In human keratinocytic HaCaT cells, PS extract inhibited the production of IL-8, and TARC, which had been increased by TNF-α and IFN-γ. The TNF-α and IFN-γ suppressed filaggrin expression was associated with phosphorylation of JNK1 and JNK2, and NF-κB translocation. PS recovered the inhibition of filaggrin expression induced by TNF-α and IFN-γ by blocking the activation of JNK1/2, and NF-κB by the IFN-γ and TNF-α treatment. The in vivo experiment results showed that, compared to DNCB treatment PS administration reduced thickening of the epidermis and infiltration of inflammatory cells into the dermis. Moreover, the decrease of filaggrin expression due to DNCB treatment was recovered by PS administration. The serum IgE level was decreased by PS treatment. Additionally, secretions of IL-4, IL-5, IL-13, and eotaxin in splenocytes were lower in the PS-treated group than in the DNCB group. CONCLUSION: PS may attenuate the development of AD-like lesions by increasing filaggrin expression and lowering IgE and inflammatory cytokine levels. These results indicate the potential for development of a PS-based drug treatment for AD.