Caspase-14 expression reduced tumorigenicity of human salivary cancer cells

Treatment of salivary gland cancer is often associated with disfigurement and loss of glandular function, which inflict traumatic impact to the patients. Exploration of novel approaches with innovative therapies is needed to combat such cancers. We previously reported that caspase-14, a green tea polyphenol-targeted gene that expresses during terminal differentiation of certain epithelial cells, is able to induce cell death and reduce tumorigenicity in skin cancer cells. However, whether caspase-14 expression induces similar effects in human salivary gland cancer cells is not determined. OBJECTIVES: to transfect HSG cells with plasmid containing full length cDNA of human caspase-14, and determine the effects of caspase-14 expression on cell growth, cell death, and tumorigenicity. METHODS: the human salivary gland cancer cell line HSG was transfected with pCMV plasmid containing human caspase 14 cDNA. Control cells were transfected with pCMV empty vector. Expression of caspase 14 was confirmed by Western blotting. Cell morphology was monitored by microscopic photography, cell growth was measured by BrdU assay, and cell viability was determined by MTT assay. In addition, the transfected HSG cells were xenografted into athymic mice to determine the tumorigenicity. RESULTS: expression of caspase-14 induced an undefined cell death in HSG cells compared to the control cells. Cell growth and cell viability were inhibited significantly by caspase-14 expression. Xenograft of caspase-14-expressing HSG cells into athymic mice resulted in reduced tumorigenicity. CONCLUSION: HSG cells undergo growth inhibition and cell death when exogenous caspase-14 was expressed in these undifferentiated tumor cells. Caspase-14 expression in HSG cells also reduced tumorigenicity in vivo. Further effort is warranted to explore if caspase 14 could be used as a potential therapeutic approach to treat human salivary gland cancer. This study was supported in part by the Dental Research Foundation of the Medical College of Georgia.