Cytotoxic effect of tobacco extracts on human oral squamous cell carcinoma cell-line

Summary Cancer is a public health problem worldwide. Incidences of oral carcinomas are increasing in the last decades, and the developed countries are the most affected. Current therapeutic options for this type of cancer are aggressive and/or invasive, including surgery, radiotherapy and chemotherapy. In addition, they have not yet translated into an improvement of life quality or expectancy to patients. In this scenario, new therapeutics are urgently needed and actively sought after. The goal of this study was to investigate the cytotoxic effects of tobacco crude extract (TCE) and two fractions thereof in the human lineage of oral squamous cell carcinoma, OSCC-3. Exposure of human oral cancer cells to TCE-induced cell death and decreased cell viability in a dose-dependent manner. Of the fractions tested, one was able to induce significant cell death (over 50%) after 48 h treatment. DNA fragmentation and caspase-3 activation indicated that the type of cell death induced by TCE and its fraction was apoptosis. Our results indicate that tobacco contains compounds that could be useful in inducing apoptosis in cancer cells. More specifically, because of the neutral chemical nature of the fraction capable of inducing apoptosis, we postulate that the putative compound responsible for the cell death is non-polar. Further investigation is needed to uncover its chemical nature and structure.