Method: The DPSCs were shown to express high levels of the mesenchymal stem cell markers CD73, CD90 and CD105 and very low levels of CD34 and CD45, common hematopoietic lineage markers. Moreover, DPSCs had the potential to differentiate into osteocytes and adipocytes. The effect of a range of PSV concentrations (5, 10, 50 and 100 µg/ml) against HSC-4 and DPSCs was determined by the MTT assay. Additionally, the effect of peptide on cell death was assayed by light microscopy and RT-PCR.
Result: PSV treatment on HSC-4 oral cancer cell resulted in a significantly dose-dependent growth inhibition with medium cytotoxic concentration (IC50) is approximately 30 µg/ml after 24 hours treatment. Under a microscope, HSC-4 cells had shrunken in size and lost their ability to adhere to surfaces. The peptide induced apoptosis in HSC-4 cells as evidenced by down expression of bcl-2 nRNA and increase of activated caspases 3, 7, 9 transcripts. Interestingly, PSV peptide showed no growth inhibitory or apoptosis-inducing effects in DPSCs.
Conclusion: These results suggest that the PSV peptide possessed a selective toxicity against oral cancer cells without affecting dental stem cells. Therefore, the peptide derived from scorpion venom might provide an effective therapy in pre-clinical oral cancer.