Arecoline induces upregulated expression of MMP-9 in gingival epithelial cells

Objectives: Carcinoma of the oral cavity is one of the 10 most frequent malignant tumors worldwide, with major predominance in Southeast Asia. Oral squamous cell carcinoma and oral pre-malignancies appear to be related to the habit of betel quid chewing in these countries. One of major components in the betel quid is Arecoline which is a byproduct of areca nut and slaked lime. In the present study, we examined genome-wide analysis of transcriptional levels of in human gingival epithelial cells (HGEP) stimulated with Arecoline.
Methods: HGEP were grown in Epithelial Culture Medium. The culture of HGEP was repeated, alternating 3 days with Arecoline (Sigma, 50 μg/ml) and 3 days without Arecoline for 1 month. A global analysis of mRNA expression was carried out using DNA microarray (human SurePrint G3 Human GE Microarray) in an experimental model. Since alteration of matrix metalloproteinase (MMP) is a key phenomenon in the process of cancer-causing transformation, expression levels of MMP genes from the data were confirmed by quantitative RT-PCR. Results were compared by Mann-Whitney U test with P-value <0.05 accepted as statistically significant.

Results: The microarray array revealed that there were 502 genes with 4-fold greater expression in the stimulation with Arecoline. We found an upregulated expression of MMP-9 in the microarray data. The expression level of MMP-9 mRNA in the experimental group was significantly higher than in the control (p<0.05).
Conclusions: The upregulated expression of MMP-9 in the cells stimulated with Arecoline may be involved in the oral cancer and pre-cancerous lesions induced by betel quid chewing.