The response of human ectomesenchymal dental pulp stem cells to cisplatin treatment

Abstract

Aim: To determine the response of dental pulp stem cells (DPSCs) to DNA-damaging cytostatic cisplatin and compare it with the response of normal human dermal fibroblasts (HDFs).

Methodology: Dental pulp stem cells were exposed to 5, 10, 20 or 40 μmol L(-1) of cisplatin. The proliferation of affected cells was assessed by a Z2 Counter and viability was assessed by means of a Vi-Cell XR using Trypan blue exclusion staining. Cell cycle analysis and induction of apoptosis were performed by flow cytometry. Induction of apoptosis was determined by monitoring the activities of caspases. The expression of proteins was detected by electrophoresis and Western blotting. The descriptive statistics of the results was analyzed by Student's t-test.

Results: Dental pulp stem cells had a greater genotoxic stress response to cisplatin compared to HDFs. All three main Mitogen-activated protein kinases (MAPK) families - extracellular signal-regulated kinases (ERK), c-Jun-N-terminal kinase (JNK) and p38 were activated after treatment of DPSCs with cisplatin. The activation of MAPK pathways was not observed in HDFs exposed to cisplatin. The exposure of DPSCs and HDFs to cisplatin provoked an increase in p53 and p21 expression and p53 phosphorylation of serine 15. Higher concentrations of cisplatin reduced the viability of DPSCs and HDFs and induced the activation of caspases 3/7 and 9.

Conclusion: Dental pulp stem cells had a greater genotoxic stress response to cisplatin compared to HDFs. Cisplatin in higher concentrations triggered activation of MAPK and apoptosis in DPSCs but not in HDFs.