4-(5-benzo(1-3)dioxol-5-yl-4-pyridin-2-yl-1h-imidazol-2-yl)benzamide and Mouth-Neoplasms

Heterogeneity of carcinoma-associated fibroblasts (CAF) has long been recognized, but the functional significance remains poorly understood. Here, we report the distinction of two CAF subtypes in oral squamous cell carcinoma (OSCC) that have differential tumor-promoting capability, one with a transcriptome and secretome closer to normal fibroblasts (CAF-N) and the other with a more divergent expression pattern (CAF-D). Both subtypes supported higher tumor incidence in nonobese diabetic/severe combined immunodeficient (NOD/SCID) Ilγ2(null) mice and deeper invasion of malignant keratinocytes than normal or dysplasia-associated fibroblasts, but CAF-N was more efficient than CAF-D in enhancing tumor incidence. CAF-N included more intrinsically motile fibroblasts maintained by high autocrine production of hyaluronan. Inhibiting CAF-N migration by blocking hyaluronan synthesis or chain elongation impaired invasion of adjacent OSCC cells, pinpointing fibroblast motility as an essential mechanism in this process. In contrast, CAF-D harbored fewer motile fibroblasts but synthesized higher TGF-β1 levels. TGF-β1 did not stimulate CAF-D migration but enhanced invasion and expression of epithelial-mesenchymal transition (EMT) markers in malignant keratinocytes. Inhibiting TGF-β1 in three-dimensional cultures containing CAF-D impaired keratinocyte invasion, suggesting TGF-β1-induced EMT mediates CAF-D-induced carcinoma cell invasion. TGF-β1-pretreated normal fibroblasts also induced invasive properties in transformed oral keratinocytes, indicating that TGF-β1-synthesizing fibroblasts, as well as hyaluronan-synthesizing fibroblasts, are critical for carcinoma invasion. Taken together, these results discern two subtypes of CAF that promote OSCC cell invasion via different mechanisms.

Topics: Animals; Benzamides; Carcinoma, Squamous Cell; Cell Movement; Dioxoles; Epithelial-Mesenchymal Transition; Fibroblasts; Gene Expression; Hyaluronic Acid; Kaplan-Meier Estimate; Mice; Mice, Inbred NOD; Mice, SCID; Mouth Neoplasms; Neoplasm Invasiveness; Neoplasm Transplantation; Receptors, Transforming Growth Factor beta; Transcriptome; Transforming Growth Factor beta1; Tumor Cells, Cultured

Podoplanin, a transmembrane sialomucin-like glycoprotein, is known to express at high frequency in oral squamous cell carcinomas (OSCC) and possess metastasis-promoting activity such as increased invasion and platelet-aggregating activity. However, the regulatory mechanism of podoplanin expression in OSCC remains unknown.. In the present study, we investigated the podoplanin expression in both clinical specimens from total 80 patients (50 OSCC and 30 pharyngeal SCC) and in 4 OSCC cell lines in vitro.. Immunohistochemical analysis of surgically resected specimens of OSCC revealed podoplanin expression in 70% of OSCC cases with localization primarily in the basal layer of squamous cancer nest and the expression was inversely correlated with squamous cell differentiation. In vitro analysis of OSCC cell lines revealed 36 that podoplanin expression was decreased in response to the squamous cell differentiation (Cytokeratin 10 expression as a marker) induced by treatment with histone deacetylase (HDAC) inhibitors such as sodium butyrate and trichostatin. Furthermore, transforming growth factor-β (TGF-β) significantly enhanced podoplanin expression in OSCC cell lines in line with increased phosphorylation of Smad2. A TGF-β type I receptor inhibitor (SB431542) significantly inhibited such induction of podoplanin expression by TGF-β at both the protein and mRNA level. However, in a subset of OSCC cell line, its expression was only weakly dependent on TGF-β and squamous differentiation.. These results suggest that regulation of podoplanin is not simple, but in the majority of OSCC cell lines, its expression is positively and negatively regulated by TGF-β receptor/Smad signaling pathway and epigenetic mechanism leading to squamous differentiation, respectively.

Topics: Adult; Aged; Aged, 80 and over; Animals; Benzamides; Biomarkers, Tumor; Butyrates; Carcinoma, Squamous Cell; Cell Differentiation; Cell Line, Tumor; Dioxoles; Female; Histone Deacetylase Inhibitors; Humans; Hydroxamic Acids; Immunohistochemistry; Keratin-10; Lymphatic Metastasis; Male; Membrane Glycoproteins; Mice; Mice, Nude; Middle Aged; Mouth Neoplasms; Neoplasm Invasiveness; Pharyngeal Neoplasms; Signal Transduction; Smad2 Protein; Tongue Neoplasms; Transforming Growth Factor beta