The effect of cyclosporin A on the activity of matrix metalloproteinases during the healing of rat molar extraction wounds

Cyclosporin A (CyA) is a cyclic peptide used as an immunosuppressive agent because it can block the synthesis of interleukin-2 and other cytokines produced by CD4+ lymphocytes. It is widely used for the prevention of allograft rejection and treatment of autoimmune diseases. Several side-effects of CyA treatment have been reported, among which are chronic nephrotoxicity, hepatotoxicity and neurotoxicity, lymphoproliferative neoplasms, hypertension, thromboembolic complications and gingival overgrowth. Here, using a rat molar model, it is demonstrated that CyA immunosuppression inhibits the activity of matrix metalloproteinases 2 and 9 in the early phase of granulation tissue in the healing dental socket. These observations suggest that CyA may interfere with the wound healing following dental extractions.

Hereditary gingival fibromatosis: report of three cases

Three cases of generalized and severe HGF in young patients of the same family without other features are reported. The purpose of this article is to present documented cases and discuss the identification, treatment, and control of the disease. The histopathological characteristics of HGF are emphasized.

Basaloid squamous carcinoma of the oral cavity: report of 2 cases and study of AgNOR, PCNA, p53, and MMP expression

Basaloid squamous carcinoma (BSC) is an uncommon aggressive variant of squamous cell carcinoma (SCC) with a predilection for the head and neck. In the English literature, approximately 40 cases of BSC in the oral cavity have been described. In this study, the clinicopathologic features of 2 cases of BSC affecting the buccal mucosa are reported. In addition, we compare the proliferative and invasive potential of BSC cells with that of poorly differentiated SCC cells matched for age, sex, site, and TNM status. Proliferative activity was studied through use of the argyrophilic nuclear organizer region (AgNOR) method and immunohistochemical quantification of proliferating cell nuclear antigen (PCNA). The invasive potential was evaluated through use of the semiquantitative reverse transcriptase-polymerase chain reaction (RT-PCR) for matrix metalloproteinases (MMPs). Alterations of p53 were also investigated through use of immunohistochemistry. The tumors showed many clinical and histopathologic similarities to tumors in cases previously reported. The AgNOR and PCNA indices were significantly higher in the 2 cases of BSC than in the cases of SCC. Immunostaining for p53 protein showed a higher percentage of positive cells and more intense staining in the BSC tissues than in the SCC tissues. RT-PCR studies clearly demonstrated that the expression of MMP-1, MMP-2, and MMP-9 was higher in cells from BSCs than in cells from SCCs. Taken together, the data described here are compatible with the concept that BSC has a more aggressive biologic behavior than conventional SCC.

Non-natural CBP2 binding peptides and peptomers modulate carcinoma cell adhesion and invasion

A combinatorial approach that utilized a repertoire of bacteriophage-peptides has identified a number of non-natural CBP2 binding peptides. Moreover, co-localization of some of these peptides with CBP2 in a number of tumor cell lines demonstrated that the peptides were directed to an intracellular location spatially coincident with the normal distribution of CBP2 [Sauk et al., 2000]. From among these sequences WHYPWFQNWAMA and LDSRYSLQAAMY were the most effective CBP2 binding peptides and best fulfilled the combinatorial motif containing deep hydrophobic pockets. When the hydropathic profiles of collagen alpha1(IV) and alpha2 (IV) were compared with these dodecapeptides, the hydropathic profiles of WHYPWFQNWAMA and LDSRYSLQAAMY closely matched those of alpha1(IV) 414-452 and alpha1(IV)531-543. These peptides were shown to be functional peptidomimics and possessed the ability to alter cell adhesion and invasion of human squamous cell carcinoma cell lines. Peptomers were formed of these non-natural peptides to explore the role that a repetitive peptide may have on cell adhesion. The enhanced cell adhesion observed with the peptomers required both CBP2 antibodies and integrin antibodies for inhibition. The enhanced adhesion observed even in the face of combined antibody inhibition was consistent with such complexes possessing correspondingly slower dissociation rates. Thus, suggesting that peptomers may function in a like manner to multimeric peptide MHC complexes (tetramers) binding more than one cell receptor on a specific cell. These findings evoke both peptidomimics of native ligands and their peptomers as potential reagents by which to target tumor cells for chemotherapy, imaging, or retargeting viral vectors for gene therapy.

Increase in expression of Hsp47 and collagen in hereditary gingival fibromatosis is modulated by stress and terminal procollagen N-propeptides

HGF is a rare oral condition characterized by a slow, progressive enlargement of the gingiva, involving both the maxilla and mandible. HGF provides a model for the study of regulatory features of conditions characterized by connective tissue hyperplasia. In this study, the culture characteristics of gingival fibroblasts derived from patients of the same family with HGF (n = 4) were similar with regard to cell cycle analysis. Flow cytometric DNA content analysis revealed uniform DNA diploidy for fibroblasts cultured from NG and HGF. NG cells showed a low S-phase fraction (19.8%) and G2/M fraction (5.8%) and a relatively high G1 phase fraction (74%). In contrast, HGF cells from all members of the tested kindred, exhibited diploid cells with a higher S-phase (40.9%) and G2/M (10.1%) fraction and a relatively low G1 phase fraction (40.9%). Furthermore, we demonstrated that the expression and production of Hsp47 parallels the increased levels of collagen secretion observed in HGF. In addition, we show that Hsp47 and collagen are coordinately regulated following stress via a feedback mechanism mediated by N-terminal procollagen propeptides. Utilizing confocal microscopy and antibodies directed against GST-fusion proteins encompassing the pro alpha1(I) N-propeptide globular domain (NP1) (residues 23-108), it was apparent that this regulatory mechanism does not involve significant interaction with Hsp47's chaperoning of procollagen.

Binding motifs of CBP2 a potential cell surface target for carcinoma cells

Previously we have shown (Hebert et al. [1999] J. Cell Biochem. 73:248-258) that among many cell lines the CBP2 gene product, Hsp47, eludes its retention receptor, erd2P, resulting in the appearance of Hsp47 on the cell surface associated with the tetraspanin protein CD9. Since Hsp47 possesses a highly restricted binding cleft, random peptide display libraries were used to characterize peptides binding to Hsp47 and then to target this protein on carcinoma cell lines in vitro. Comparison of the clones obtained from panning revealed little specific homology based on sequence alone. To determine whether carcinoma cells expressing Hsp47 could selectively take up the selected bacteriophages, traditional immunofluorescence and confocal microscopy were employed. These studies revealed that phage-displaying Hsp47 binding peptides bound to cell lines expressing Hsp47 and that the peptides were rapidly taken up to a location coincident with Hsp47 staining. These observations were confirmed by cytometric analyses. These data indicate that CBP2 product may provide a molecular target for chemotherapy and/or imaging of malignancies.

Alteration in expression of MMP-1 and MMP-2 but not TIMP-1 and TIMP-2 in hereditary gingival fibromatosis is mediated by TGF-beta 1 autocrine stimulation

Hereditary gingival fibromatosis (HGF) is characterized by an excess accumulation of extracellular matrix (ECM) resulting in a generalized and fibrotic enlargement of the gingiva. To investigate some of the regulatory features of this condition, gingival fibroblasts from normal gingiva (NG) and HGF were examined for the expression and production of matrix metalloproteinases (MMPs) and their inhibitors, tissue matrix metalloproteinases inhibitor (TIMPs). Our results, obtained from 2 different assays, semi-quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) and enzymography, clearly demonstrated that the expression and production of MMP-1 and MMP-2 was significantly lower in fibroblasts from HGF than from NG. Interestingly, TIMP-1 and TIMP-2 expression from NG cells was shown to be slightly higher to those from HGF. Addition of antibodies against transforming growth factor-beta 1 (TGF-beta 1), which is produced in greater amounts by HGF fibroblasts, resulted in a slight increase in MMP-1 and a decrease in MMP-2 expression, whereas TIMP-1 and TIMP-2 expressions were unaffected. These patterns of expression and production suggest that enhanced TGF-beta 1 production reduce the proteolytic activities of HGF fibroblasts, which favor the accumulation of ECM.

Differential proliferation of fibroblasts cultured from hereditary gingival fibromatosis and normal gingiva

Hereditary gingival fibromatosis (HGF) is an oral condition characterized by the enlargement of the gingiva of both the maxilla and mandible. To study the cell proliferation index of fibroblasts from HGF and normal gingiva (NG), cell cultures from 4 members of the same family with HGF and from 4 healthy patients were established. Our results obtained from 6 different cell proliferation assays clearly showed that the cell proliferation rate was significantly higher in fibroblasts from HGF than from normal gingiva. HGF and control fibroblasts in subconfluent culture densities were typically spindle, but in saturation density HGF cells were shorter than control cells. These data suggest that the higher proliferative index of HGF fibroblasts possibly has a role in the pathogenesis of gingival outgrowth in HGF patients.

Regional odontodysplasia. Report of two cases

Two cases of regional odontodysplasia in girls are reported; one affected the lower incisors, and the other the left maxilla. The first case was radiographically followed over a 6-year period, during which time the ghost teeth exhibited significant dentin formation, along with a resultant decrease in pulp size and relative normalization of the radicular anatomy. The second case involved the deciduous molars and the first permanent molar. In addition to tooth alterations, both cases exhibited many odontogenic epithelial islands and extensive areas of calcification in the mucosa. Diagnosis, causes, and treatment are discussed in the light of recent data.