Cytokines secreted by inflamed oral mucosa: implications for oral cancer progression.

The oral mucosa has an essential role in protecting against physical, microbial, and chemical harm. Compromise of this barrier triggers a wound healing response. Key events in this response such as immune infiltration, re-epithelialization, and stroma remodeling are coordinated by cytokines that promote cellular migration, invasion, and proliferation. Cytokine-mediated cellular invasion and migration are also essential features in cancer dissemination. Therefore, exploration of cytokines that regulate each stage of oral wound healing will provide insights about cytokines that are exploited by oral squamous cell carcinoma (SCC) to promote tumor development and progression. This will aid in identifying potential therapeutic targets to constrain SCC recurrence and increase patient survival. In this review, we discuss cytokines that overlap in oral wounds and SCC, emphasizing how these cytokines promote cancer progression.

Cancer-associated keratinocytes: new members of the microenvironment in head and neck cancer.

The tumor microenvironment is a complex ecosystem of malignant and nonmalignant cells and extracellular proteins that work together to enhance tumor progression. We identified a mechanism in which adjacent nonmalignant epithelium enhances invasion of squamous cell carcinoma, thereby expanding the tumor microenvironment to include cancer-associated keratinocytes.

Squamous cell carcinoma subverts adjacent histologically normal epithelium to promote lateral invasion.

Recurrent and new tumors, attributed in part to lateral invasion, are frequent in squamous cell carcinomas and lead to poor survival. We identified a mechanism by which cancer subverts adjacent histologically normal epithelium to enable small clusters of cancer cells to burrow undetected under adjacent histologically normal epithelium. We show that suppression of DMBT1 within cancer promotes aggressive invasion and metastasis in vivo and is associated with metastasis in patients. Cancer cells via TGFß1 and TNFα also suppress DMBT1 in adjacent histologically normal epithelium, thereby subverting it to promote invasion of a small population of tumor cells. The sufficiency of DMBT1 in this process is demonstrated by significantly higher satellite tumor nests in Dmbt1-/- compared with wild-type mice. Moreover, in patients, invasion of small tumor nests under adjacent histologically normal epithelium is associated with increased risk for recurrence and shorter disease-free survival. This study demonstrates a crucial role of adjacent histologically normal epithelium in invasion and its important role in the tumor microenvironment and opens new possibilities for therapeutic strategies that reduce tumor recurrence.

Activin A triggers angiogenesis via regulation of VEGFA and its overexpression is associated with poor prognosis of oral squamous cell carcinoma.

Poor prognosis associated with the dysregulated expression of activin A in a number of malignancies has been related to with numerous aspects of tumorigenesis, including angiogenesis. The present study investigated the prognostic significance of activin A immunoexpression in blood vessels and cancer cells in a number of oral squamous cell carcinoma (OSCC) cases and applied in vitro strategies to determine the impact of activin A on angiogenesis. In a cohort of 95 patients with OSCC, immunoexpression of activin A in both blood vessels and tumor cells was quantified and the association with clinicopathological parameters and survival was analyzed. Effects of activin A on the tube formation, proliferation and migration of human umbilical vein endothelial cells (HUVECs) were evaluated in gain­of­function (treatment with recombinant activin A) or loss­of­function [treatment with activin A­antagonist follistatin or by stable transfection with short hairpin RNA (shRNA) targeting activin A] conditions. Conditioned medium from an OSCC cell line with shRNA­mediated depletion of activin A was also tested. The profile of pro­ and anti­angiogenic factors regulated by activin A was assessed with a human angiogenesis quantitative PCR (qPCR) array. Vascular endothelial growth factor A (VEGFA) and its major isoforms were evaluated by reverse transcription­qPCR and ELISA. Activin A expression in blood vessels demonstrated an independent prognostic value in the multivariate analysis with a hazard ratio of 2.47 [95% confidence interval (CI), 1.30­4.71; P=0.006) for disease­specific survival and 2.09 (95% CI, 1.07­4.08l: P=0.03) for disease­free survival. Activin A significantly increased tubular formation of HUVECs concomitantly with an increase in proliferation. This effect was validated by reduced proliferation and tubular formation of HUVECs following inhibition of activin A by follistatin or shRNA, as well as by treatment of HUVECs with conditioned medium from activin A­depleted OSCC cells. Activin A­knockdown increased the migration of HUVECs. In addition, activin A stimulated the phosphorylation of SMAD2/3 and the expression and production of total VEGFA, significantly enhancing the expression of its pro­angiogenic isoform 121. The present findings suggest that activin A is a predictor of the prognosis of patients with OSCC, and provide evidence that activin A, in an autocrine and paracrine manner, may contribute to OSCC angiogenesis through differential expression of the isoform 121 of VEGFA.

Use of a Non-Crosslinked Collagen Membrane During Guided Bone Regeneration Does Not Interfere With the Bone Regenerative Capacity of the Periosteum.

PURPOSE: To assess whether the use of a non-crosslinked porcine collagen type I and III bi-layered membrane inter-positioned between the periosteum and a bone defect would interfere with the bone regenerative capacity of the periosteum. MATERIALS AND METHODS: Sixty rats, each with 1 critical-size calvarial defect (CSD; diameter, 5 mm) in the parietal bone, were randomly allocated to 1 of 3 equal-size groups after CSD creation: 1) the periosteum was excised and the flap was repositioned without interposition of a membrane (no-periosteum [NP] group); 2) the flap including the periosteum was repositioned (periosteum [P] group); and 3) a non-crosslinked collagen membrane was inter-positioned between the flap, including the periosteum, and the bone defect (membrane [M] group). Micro-computed tomography, qualitative histology, immunohistochemistry, and reverse transcription real-time quantitative polymerase chain reaction were performed at 3, 7, 15, and 30 days postoperatively. RESULTS: A markedly increased radiographic residual defect length was observed in the NP group compared with the P group at 30 days. The NP group also presented a smaller radiographic bone fill area than the P group at 15 and 30 days and then the M group at 30 days. The P and M groups exhibited considerably greater expression of bone morphogenetic protein-2 and osteocalcin than the NP group at 7 days; expression of transforming growth factor-ß1 was considerably greater in the NP group at 15 days. Further, the P group presented considerably higher gene expression levels of Runx2 and Jagged1 at 7 days and of alkaline phosphatase at 3 and 15 days compared with the M and NP groups. CONCLUSION: Interposition of this specific non-crosslinked collagen membrane between the periosteum and the bone defect during guided bone regeneration interferes only slightly, if at all, with the bone regenerative capacity of the periosteum.