DKK1, a negative regulator of Wnt signaling, is a novel inducer of neuroblastoma differentiation

BackgroundThis study aimed to analyze the role of Dickopff1 [DKK1] as a potential differentiating agent for the neuroblastoma cell line SHSY5Y and neurospheres derived from it. Materials and MethodsSHSY5Y neurospheres were formed from undifferentiated adherent cultures. The cellular properties and gene expression were used to study the effect of DKK1 on SHSY5Y-formed neurospheres. Its effect on SHSY5Y neuronal differentiation was also studied. ResultsSHSY5Y adherent undifferentiated cells were grown as neurospheres. Treatment of neurospheres resulted in their fragmentation. It also resulted in reduced mRNA expression of markers of cancer stem cells, pluripotency, and proliferation [p[≤]0.05]. DKK1 treatment also resulted in reduced mRNA expression of {beta}-catenin and TCF genes. There was significantly higher expression of neuronal differentiation genes in SHSY5Y adherent cells grown in complete DMEM media containing DKK1 as compared to cells grown without DKK1. We also found DKK1 synergized with retinoic acid-induced differentiation of neuroblastoma cells. ConclusionDKK1 was able to convincingly abrogate neurosphere formation and promote neuronal differentiation of SHSY5Y cells, including synergy with retinoic acid. This was accompanied by corresponding changes in mRNA markers of cancer stem cells, pluripotency and proliferation. These results may have implications for neuroblastoma stemness and differentiation.