Calcipotriol Enhances Efficacy of Imatinib and Nilotinib on Cells Derived from Plexiform Neurofibroma

Abstract

Background/Aim: Plexiform neurofibromas (PNFs) are benign tumors composed mainly of tumorous Schwann cells and non-tumorous fibroblasts. This study examined the possible enhancing effect of vitamin D on the efficacy of drugs used for the treatment of PNF in vitro. Materials and Methods: Paired Schwann cells and fibroblasts were cultured from 10 PNFs and treated with imatinib and nilotinib in the absence and presence of calcipotriol, an analogue of the active metabolite of vitamin D. IC₅₀ values for cell proliferation were calculated. Results: Calcipotriol reduced the IC₅₀ of the two drugs in both tumorous Schwann cells and non-tumorous fibroblasts by 40 to 45%. Conclusion: Calcipotriol enhanced the efficacy of imatinib and nilotinib on PNF-derived cells in vitro, though rather non-specifically. Nevertheless, sustaining vitamin D at 100-200 nM, the physiological range, may be beneficial for reducing the dose of drugs without scarifying efficacy.