Mechanisms of Cytotoxicity of Chemical Agents to Giant Cell Tumors: An In Vitro Study.

Background: Various chemical agents have been used as an adjuvant treatment for giant cell tumor (GCT). However, the comparative effect of these chemicals remains unclear.

Methods: Multinucleated and spindle cells from cultured GCT patients, characterized by Nanog and Oct4 expression with RT-PCR, were directly administered, in vitro, with concentrations of 1%, 3%, and 5% of HO and 75%, 85%, and 95% of ethanol for 10 minutes and concentrations of 0.003%, 0.005%, 0.01%, 0.03%, 0.1%, and 0.3% of HO for 5 minutes and were incubated for 24 hours. Cell morphology, cell viability, and flow cytometry after various concentrations of HO and ethanol exposure were assessed.

Results: HO in all concentrations caused loss of cell viability. The number of viable cells after HO exposure was related to the concentration-dependent effect. The initial viable spindle-shaped cell, multinucleated giant cell, and round-epithelioid cell had morphological changes into fragmented nonviable cells after exposure to HO. Flow cytometry using Annexin V showed cell death due to necrosis, with the highest concentration amounting to 0.3%.

Conclusion: Administering local chemical adjuvants of HO in vitro caused loss of viable GCT cells. The number of viable cells after HO exposure was related to the concentration-dependent effect, whereas reducing concentration of HO may cause loss of viability and morphology of cultured GCT cells with the apoptotic mechanism.