Tumor Suppressive Function of NQO1 in Cutaneous Squamous Cell Carcinoma (SCC) Cells.

Cutaneous squamous cell carcinoma (SCC) is a common cancer that significantly decreases the quality of life. It is known that external stimulus such as ultraviolet (UV) radiation induces cutaneous SCC via provoking oxidative stress. NAD(P)H dehydrogenase 1 (NQO1) is a ubiquitous flavoenzyme that functions as a guardian against oxidative stress. However, the effect of NQO1 on cutaneous SCC is not clearly elucidated. In this study, we investigated the effect of NQO1 on cutaneous SCC cells using the recombinant adenoviruses that can upregulate and/or downregulate NQO1 expression. Overexpression of NQO1 resulted in significant decrease of cell proliferation and colony forming activity of SCC lines (SCC12 and SCC13 cells). By contrast, knockdown of NQO1 increased the cell proliferation and colony forming activity. Accordingly, the levels of proliferation-related regulators, such as Cyclin D1, Cyclin E, PCNA, SOX2, and p63, were decreased by the overexpression of NQO1, while those were increased by knockdown of NQO1. In addition, NQO1 affected the invasion and migration of SCC cells in a very similar way, with the regulation of epithelial-mesenchymal transition- (EMT-) related molecules, including E-cadherin, N-cadherin, Vimentin, Snail, and Slug. Finally, the overexpression of NQO1 decreased the level of phosphorylated AKT, JNK, and p38 MAPK, while the knockdown of NQO1 increased the level of phosphorylated signaling molecules. Based on these data, NQO1 has tumor suppressive function in cutaneous SCC cells.

Antitumor Effect of Albendazole on Cutaneous Squamous Cell Carcinoma (SCC) Cells.

Drug repurposing and/or repositioning is an alternative method to develop new treatment for certain diseases. Albendazole was originally developed as an anthelmintic medication, and it has been used to treat a variety of parasitic infestations. In this study, we investigated the antitumor effect of albendazole and putative action mechanism. Results showed that albendazole dramatically decreased the cell viability of SCC cell lines (SCC12 and SCC13 cells). Albendazole increased apoptosis-related signals, including cleaved caspase-3 and PARP-1 in a dose-dependent fashion. The mechanistic study showed that albendazole induced endoplasmic reticulum (ER) stress, evidenced by increase of CHOP, ATF-4, caspase-4, and caspase-12. Pretreatment with ER stress inhibitor 4-PBA attenuated albendazole-induced apoptosis of SCC cells. In addition, albendazole decreased the colony-forming ability of SCC cells, together with inhibition of Wnt/ß-catenin signaling. These results indicate that albendazole shows an antitumor effect via regulation of ER stress and cancer stemness, suggesting that albendazole could be repositioned for cutaneous SCC treatment.

Inhibition of Poly(I:C)-Induced Inflammation by Salvianolic Acid A in Skin Keratinocytes.

BACKGROUND: Skin keratinocytes participate actively in inducing immune responses when external pathogens are introduced, thereby contributing to elimination of pathogens. However, in condition where the excessive inflammation is occurred, chronic skin disease such as psoriasis can be provoked. OBJECTIVE: We tried to screen the putative therapeutics for inflammatory skin disease, and found that salvianolic acid A (SAA) has an inhibitory effect on keratinocyte inflammatory reaction. The aim of this study is to demonstrate the effects of SAA in poly(I:C)-induced inflammatory reaction in skin keratinocytes. METHODS: We pre-treated keratinocytes with SAA then stimulated with poly(I:C). Inflammatory reaction of keratinocytes was verified using real-time polymerase chain reaction, enzyme-linked immunosorbent assay and Western blot. RESULTS: When skin keratinocytes were pre-treated with SAA, it significantly inhibited poly (I:C)-induced expression of inflammatory cytokines including interleukin (IL)-1ß, IL-6, IL-8, tumor necrosis factor-α, and CCL20. SAA inhibited poly(I:C)-induced activation of nuclear factor-κB signaling. And SAA also inhibited inflammasome activation, evidenced by decrease of IL-1ß secretion. Finally, SAA markedly inhibited poly(I:C)-induced NLRP3 expression. CONCLUSION: These results demonstrate that SAA has an inhibitory effect on poly(I:C)-induced inflammatory reaction of keratinocytes, suggesting that SAA can be developed for the treatment of inflammatory skin diseases such as psoriasis.

Inhibition of Insulin-Like Growth Factor-1-Induced Sebum Production by Bilobetin in Cultured Human Sebocytes.

BACKGROUND: Sebocytes are the major cells of sebaceous gland. The essential role of sebocytes is the production of sebum, a specific lipid mixture, that covers the body surface and provides the barrier function. At puberty, sebum production increases under the effects of various stimuli including androgens and insulin-like growth factor-1 (IGF-1). Excessive sebum production changes the microenvironment surrounding hair follicle, often leading to the onset of acne. OBJECTIVE: We previously performed screening test using cultured human sebocytes, and found that bilobetin had a potential for inhibiting lipid production. The aim of this study is to demonstrate the effects of bilobetin on IGF-1-induced lipogenesis in sebocytes. METHODS: We pretreated simian virus 40 T (SV40T)-transformed sebocytes with bilobetin then stimulated with IGF-1. Effects of bilobetin on lipogenesis of sebocytes were examined by thin layer chromatography and Western blot. RESULTS: Bilobetin markedly inhibited IGF-1-induced lipid production in sebocytes, especially in terms of production of squalene and wax ester. Supporting these results, bilobetin showed significant inhibitory effect on squalene synthase promoter activity. In addition, bilobetin significantly down-regulated lipogenic transcription factors such as sterol response element binding protein (SREBP)-1 and SREBP-2. To delineate the possible action mechanism, we investigated the effect of bilobetin on intracellular signaling. As a result, bilobetin inhibited IGF-1-induced phosphorylation of AKT. CONCLUSION: Together, these results suggest that bilobetin has an inhibitory potential on sebum production in sebocytes, being applicable for acne treatment.

Inhibition of collagen synthesis by IWR-1 in normal and keloid-derived skin fibroblasts.

AIMS: Keloid is a benign tumor that is characterized by the hyperproliferation of dermal fibroblasts and excessive deposition of extracellular matrix (ECM) especially the collagen. Aberrant activation of Wnt/ß-catenin signaling is implicated in the pathogenesis of keloid. In this study, we investigated the effects of IWR-1, a small molecule inhibitor for Wnt/ß-catenin signaling via the inhibition of tankyrase, on production of collagen and matrix metalloproteinase (MMP) in dermal fibroblasts. MAIN METHODS: We cultured human normal skin- and keloid-derived fibroblasts, then treated with IWR-1. The effects of IWR-1 on collagen and MMP production were determined by Western blot, ELISA and zymography. KEY FINDINGS: IWR-1 significantly suppressed the proliferation and migration of both the normal and keloid fibroblasts. IWR-1 also inhibited the production and secretion of type I collagen from the fibroblasts. In addition, IWR-1 significantly increased the expression of MMPs, such as MMP-1, MMP-3 and MMP-13, along with the increase of gelatinase activity. These results suggest that inhibitory effect of IWR-1 on collagen production may be related with the increased MMP activity. SIGNIFICANCE: This study provides the possible action mechanism of IWR-1 on regulation of collagen expression, on which to base further investigation for preventing skin fibrotic diseases such as keloid.

Rosmarinic acid inhibits poly(I:C)-induced inflammatory reaction of epidermal keratinocytes.

AIMS: Keratinocytes are the predominant cells in the epidermis, exerting their primary role of physical barrier through sophisticated differentiation process. In addition, keratinocytes contribute to the activation of innate immunity, providing the surveillant role against external pathogens. It has been known that chronic skin inflammatory disease such as psoriasis can be provoked by viral pathogens including double-stranded RNA. In this study, we demonstrated that rosmarinic acid (RA) has an inhibitory potential on inflammatory reaction induced by double-stranded RNA mimic poly(I:C) in epidermal keratinocytes. MAIN METHODS: We cultured human epidermal keratinocytes and induced inflammatory reaction by poly(I:C) treatment. The effect of RA on inflammatory reaction of keratinocytes was determined by RT-PCR and Western blot. KEY FINDINGS: RA significantly inhibited poly(I:C)-induced expression of inflammatory cytokines including IL-1ß, IL-6, IL-8, CCL20, and TNF-α, and downregulated NF-κB signaling pathway in human keratinocytes. In addition, RA significantly inhibited poly(I:C)-induced inflammasome activation, in terms of secretion of active form of IL-1ß and caspase-1. Furthermore, RA markedly inhibited poly(I:C)-induced NLRP3 and ASC expression. SIGNIFICANCE: These results indicate that RA can inhibit poly(I:C)-induced inflammatory reaction of keratinocytes, and suggest that it may be a potential candidate for the treatment of psoriasis.

Glycyrrhizin improves p75NTR-associated sciatic nerve regeneration in a BALB/c mouse model.

Glycyrrhizin has a role in immune regulation in the central nervous system, but its impact on sciatic nerve injury had not previously been reported. In this study, a BALB/c mouse model of sciatic nerve injury was used to explore the role of glycyrrhizin in sciatic nerve repair and its underlying mechanism. Glycyrrhizin with intragastric gavage of 10 and 20 mg/kg weight per day (mid- and high-dose, respectively) inhibited p75 neurotrophin receptor (p75NTR) expression at the protein and mRNA levels versus the 5 mg/kg (low-dose) group and control (0.9% NaCl solution) at one, two, four and eight weeks following sciatic nerve injury, and simultaneously improved the action potential amplitude and motor nerve conductive velocity. Combined Marsland, Glees and Erikson's silver stain and Luxol fast blue staining results indicated that high- and mid-dose glycyrrhizin promoted improved sciatic nerve myelination compared with the low-dose or control groups eight weeks after injury. Immunofluorescence staining demonstrated that glycyrrhizin had an inhibitory effect to a certain degree on local hypertrophic scar and inflammatory responses in the mouse model. In conclusion, glycyrrhizin can promote sciatic nerve regeneration and functional repair, in which doses of 10 and 20 mg/kg per day are more effective than lower doses, and such regeneration is associated with the downregulation of p75NTR.