seryl-leucyl-isoleucyl-glycyl--arginyl-leucinamide and Carcinoma--Squamous-Cell

Oral cancer is the sixth most common cause of death from cancer with an estimated 400,000 deaths worldwide and a low (50%) 5-year survival rate. The most common form of oral cancer is oral squamous cell carcinoma (OSCC). OSCC is highly inflammatory and invasive, and the degree of inflammation correlates with tumor aggressiveness. The G protein-coupled receptor protease-activated receptor-2 (PAR-2) plays a key role in inflammation. PAR-2 is activated via proteolytic cleavage by trypsin-like serine proteases, including kallikrein-5 (KLK5), or by treatment with activating peptides. PAR-2 activation induces G protein-α-mediated signaling, mobilizing intracellular calcium and Nf-κB signaling, leading to the increased expression of pro-inflammatory mRNAs. Little is known, however, about PAR-2 regulation of inflammation-related microRNAs. Here, we assess PAR-2 expression and function in OSCC cell lines and tissues. Stimulation of PAR-2 activates Nf-κB signaling, resulting in RelA nuclear translocation and enhanced expression of pro-inflammatory mRNAs. Concomitantly, suppression of the anti-inflammatory tumor suppressor microRNAs let-7d, miR-23b, and miR-200c was observed following PAR-2 stimulation. Analysis of orthotopic oral tumors generated by cells with reduced KLK5 expression showed smaller, less aggressive lesions with reduced inflammatory infiltrate relative to tumors generated by KLK5-expressing control cells. Together, these data support a model wherein KLK5-mediated PAR-2 activation regulates the expression of inflammation-associated mRNAs and microRNAs, thereby modulating progression of oral tumors.

Topics: Animals; Carcinoma, Squamous Cell; Cell Line, Transformed; Cell Line, Tumor; Gene Expression Regulation, Neoplastic; Humans; Inflammation; Kallikreins; Keratinocytes; Male; Mice; Mice, Nude; MicroRNAs; Mouth Neoplasms; Neoplasm Transplantation; NF-kappa B; Oligopeptides; Precancerous Conditions; Receptor, PAR-2; Signal Transduction; Transcription Factor RelA

Both neurotrophins and chemorepellents are involved in the elongation and sprouting of itch-associated C-fibers in the skin. Nerve growth factor (NGF) and semaphorin 3A (Sema3A) are representatives of these two types of axon-guidance factors, respectively.. We investigated the effects of calcium concentration and histamine on the expression of NGF and Sema3A in normal human epidermal keratinocytes (NHEK) and normal human fibroblasts (NHFb).. NHEK and NHFb were cultured under different calcium concentrations (0.15-0.9 mM) with or without histamine, and the expression of mRNA for NGF and SEMA3A was assessed by real-time PCR analysis. An immunohistochemical study was performed for Sema3A using normal skin and skin cancer specimens.. In NHEK, SEMA3A expression was elevated by high calcium concentration and reduced by low calcium condition, while NGF expression was not dependent on calcium. Their expressions were unchanged by calcium in NHFb. Immunohistochemically, keratinocytes in the prickle layer of normal epidermis and squamous cell carcinoma cells were positive for Sema3A, sparing basal cells and suprabasal cells. The addition of histamine to NHEK at 10 μg/ml enhanced SEMA3A expression but depressed NGF expression. In NHFb, however, histamine decreased both NGF and SEMA3A levels.. Sema3A inhibits C-fiber elongation/sprouting in the upper layers of the epidermis, where calcium concentration is high, thereby determining the nerve endings. Histamine reduces Sema3A production by fibroblasts, allowing C-fibers to elongate in the dermis. In contrast, the histamine-augmented keratinocyte production of Sema3A might suppress C-fiber elongation and exaggerated pruritus.

Topics: Calcium; Carcinoma, Basal Cell; Carcinoma, Squamous Cell; Cells, Cultured; Fibroblasts; Granulocyte-Macrophage Colony-Stimulating Factor; Histamine; Humans; Interleukin-8; Keratinocytes; Nerve Fibers, Unmyelinated; Nerve Growth Factor; Oligopeptides; RNA, Messenger; Semaphorin-3A; Skin