Gene expression profiles of cell adhesion molecules, matrix metalloproteinases and their tissue inhibitors in canine oral tumors

Perturbation of cell adhesion can be essential for tumor cell invasion and metastasis, but the current knowledge on the gene expression of molecules that mediate cell adhesion in canine oral tumors is limited. The present study aimed to investigate changes in the gene expression of cell adhesion molecules (E-cadherin or CDH1, syndecan 1 or SDCI, NECTIN2 and NECTIN4), matrix metalloproteinases (MMPs) and their tissue inhibitors (TIMPs), in canine oral tumors, including benign tumors, oral melanoma (OM) and non-tonsillar oral squamous cell carcinoma (OSCC), by quantitative real-time reverse transcription PCR. When compared with the normal gingival controls, decreased CDH1, SDC1 and NECTIN4 expression levels were observed in OSCC and OM, reflecting a possible role as cell adhesion molecules and tumor suppressors in canine oral cancers in contrast to the upregulation of MMP2 expression. Downregulated MMP7 was specifically revealed in the OM group. In the late stage OM, the positive correlation of MMP7 and CDH1 expression was noticed as well as that of SDCI and NECTIN4. Enhanced TIMP1 expression was shown in all tumor groups with prominent expression in the benign tumors and the early-stage OM. MMPI4 expression was notable in the early-stage OM. Higher MMP9 and TIMPI expression was observed in the acanthomatous ameloblastoma. In conclusion, this study revealed that the altered expression of cell adhesion molecules, MMP7 and MMP2 was correlated with clinicopathologic features in canine oral cancers whereas TIMPI and MMP14 expression was probably associated with early-stage tumors; therefore, these genes might serve as molecular markers for canine oral tumors.