Résumé
The aim of this study was to examine the effects of fibroblast growth factor-2 (FGF-2) on cancer cell invasion and on fibroblast proliferation in an <i>in vitro</i> model of invasion. Three kinds of human oral squamous cell carcinoma cell lines with different invasive activity were used: OSC-20, OSC-19 (lower invasive type), and HOC313 (higher invasive type). FGF-2 and its high-affinity receptors FGFR-1 and FGFR-2 were detected by western blotting. The expression of FGF-2 and FGFRs mRNA was examined in cultured human oral squamous cell carcinoma cells by reverse transcriptase polymerase chain reaction (RT-PCR). Furthermore, recombinant human FGF-2 (rhFGF-2) was reacted with each cell line, and the invasion rate was determined by invasion assay. We also observed the behavior of cancer cell invasion in the collagen gel invasion model in the presence or absence of FGF-2-neutralizing antibody (anti-FGF-2). HOC313 cells showed higher expression of FGF-2 than OSC-20 and OSC-19 cells. The addition of rhFGF-2 promoted not only the proliferation of fibroblasts, but also the invasion of all cancer cell lines. In contrast, the addition of anti-FGF-2 completely inhibited the invasion of OSC-20 and OSC-19 cells. These results suggest that a higher invasiveness of squamous carcinoma cells is associated with higher production of FGF-2, which acts in an autocrine fashion to promote cancer cell invasion, and in a paracrine fashion to promote fibroblast proliferation.
Résumé
Retinoic acid plays an important role in embryogenesis, by regulating morphogenesis, cell proliferation, differentiation, and extracellular matrix production. Also retinoic acid is a potent teratogen and induces a variety of limb and craniofacial malformations including cleft palate, that is the most common congenital malformation. Fibroblast growth factor 2 (FGF2) and fibroblast growth factor receptor 2 (FGFR2) are an important role in the secondary induction for the epithelial-mesenchymal transformation during development. Mutations in them, produce a congenital malformation in the skeletal system and the craniofacial tissue. It was of interest to explore the hypothesis of an inhibitory effect exerted by retinoic acid on the cell proliferating activity and the expression of FGF2 and FGFR2 in the developing palate in vivo. In the present study, author observed the expression of PCNA as a marker for the cell proliferating activity, FGF2 and FGFR2 to compare with developmental stages and locations in normal and retinoic acid-induced cleft palate. Retinoic acid was administered orally at gestational day (GD) 10 to ICR mice. The pregnant mice were sacrificed on GD 12, 13, 14, 15 to obtain the fetuses. Scanning electron microscope and immunohistochemistry was performed. In the retinoic acid-treated fetuses, palatal shelves did not elevate and cleft palate was induced. On GD 12, 13 in the palatal mesenchyme of the retinoic acid treated-fetuses, expression of the PCNA decreased. On GD 12 in the palatal epithelium of the retinoic acid-treated fetuses, expression of FGFR2 decreased, but after GD 13, the patterns of expression of FGFR2 were not affected. On GD 12, 13 in the palatal epithelium and mesenchyme of the retinoic acid-treated fetuses, expression of FGF2 decreased dramatically, but after GD 14, it was similar to that in the normal fetal palate. These results suggest that retinoic acid inhibits the cell proliferating activity and the expression of FGF2, FGFR2 in the palatal mesenchyme on GD 12, 13, which is critical in the developing palate, and elevation of palatal shelves is delayed and impaired. Moreover, it seems that retinoic acid inhibits the epithelial-mesenchymal transformation of epithelium. Finally, cleft palate is induced.