Involvement of epithelial-mesenchymal transition in adenoid cystic carcinoma metastasis.
ABSTRACT The high frequencies of recurrence and distant metastasis of adenoid cystic carcinoma (AdCC) are significant obstacles for the long-term cure of patients with AdCC and emphasize the need for better understanding of the biological factors associated with these outcomes. To identify proteins that mediate AdCC metastasis, we established three AdCC cell lines expressing green fluorescent protein (GFP) from the ACCS cell line using orthotopic transplantation and in vivo selection in nude mice: Parental ACCS-GFP, highly tumorigenic ACCS-T GFP and metastatic ACCS-M GFP. ACCS-GFP and ACCS-M GFP were subjected to DNA microarray analysis and the results were used for data mining studies. DNA microarray analysis revealed significantly altered biological processes in the ACC-M GFP cells, including events related to cell adhesion (three categories) and signaling (three categories). In particular, a significant down-regulation of cell adhesion molecules, such as cadherins and integrin subunits was observed. The loss of E-cadherin and integrins and the gain of vimentin in ACCS-M GFP cells were confirmed by immunoblotting. These results suggest that epithelial-mesenchymal transition (EMT) is a putative event in AdCC metastasis that induces tumor cell dissemination from the primary tumor site. In summary, in this study we established a useful nude mouse metastasis model which will enable further AdCC metastasis research and clinical treatment trials and we also provide evidence that EMT is significantly involved in the AdCC metastatic process.
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ABSTRACT: BACKGROUND: ERBB3 binding protein 1 (EBP1) gene transfer into human salivary adenoid cystic carcinoma cells has been shown to significantly inhibit cell proliferation and reduce tumor metastasis in mouse models. In the current study, to evaluate if EBP1 is a novel biomarker capable of identifying patients at higher risk of disease progression and recurrence, we examined the EBP1 expression profile in adenoid cystic carcinoma (ACC) patients and analyzed its clinicopathological relevance. To understand the underlying anti-metastatic mechanism, we investigated if EBP1 regulates invasion-related molecules. METHODS: We performed immunohistochemical analysis on 132 primary adenoid cystic carcinoma and adjacent non-cancerous tissues using commercial EBP1, MMP9, E-cadherin and ICAM-1 antibodies. Results were correlated to clinicopathological parameters, long-term survival and invasion-related molecules by statistical analysis. Cell motility and invasiveness of vector or wild-type EBP1-transfected ACC-M cell lines were evaluated using wound healing and Boyden chamber assays. MMP9, E-cadherin and ICAM-1 proteins in these cell lines were detected using western blot assay. RESULTS: The expression of EBP1 was significantly higher in non-cancerous adjacent tissues compared with corresponding cancer tissues. The intensity and percentage of cells that reacted with EBP1 antibodies were significantly higher in cases with tubular pattern than those with solid pattern (P<0.0001). We also found adenoid cystic carcinoma with local lymphatic metastasis had significantly lower EBP1 expression than ACC with no local lymphatic node metastasis (P<0.0001). Similar findings were observed in ACC with lung metastasis compared with cases with no lung metastasis (P<0.0001), in particular, in cases with perineural invasion compared with cases with no perineural invasion (P<0.0001). Furthermore, a decrease in EBP1 expression was positively associated with a reduction in overall survival of ACC patients. Of note, EBP1 inhibits migration and invasiveness of ACC cells by upregulating E-cadherin but downregulating MMP9. In clinical adenoid cystic carcinoma patients, higher EBP1 expression was positively correlated with E-cadherin levels (P<0.001) but negatively correlated with MMP9 expression (P=0.0002). CONCLUSIONS: EBP1 expression is reduced in adenoid cystic carcinoma, indicating unfavorable prognosis of ACC patients. Its regulation of MMP9 and E-cadherin protein levels suggests a critical therapeutic potential.BMC Cancer 10/2012; 12(1):499. · 3.33 Impact Factor