Influence of vitamin D on cisplatin sensitivity in testicular germ cell cancer-derived cell lines and in a NTera2 xenograft model

▸ Effects of co-treatment with 1,25(OH)2D3 and cisplatin compared with cisplatin monotherapy were investigated in testicular germ cell cancer models in vitro and in vivo. ▸ In vitro, combined treatment with 1,25(OH)2D3 and cisplatin augmented effects on cell survival and viability when compared to cisplatin monotherapy. ▸ In vivo, 1,25(OH)2D3 and cholecalciferol co-treatment with cisplatin did not augment the effect on tumor reduction compared to high dose cisplatin treatment alone. ▸ 1,25(OH)2D3 mediated upregulation of cell cycle regulators in vitro and in vivo, indicates that 1,25(OH)2D3 might improve cisplatin sensitivity when using lower dose regimes.