KLF7 promotes neuroblastoma differentiation through regulation neuroblast differentiation-associated protein AHNAKs and is a marker of clinical outcome

Abstract

Background Recent studies have revealed that neuroblastomas share a close transcriptional similarity with developing adrenal neuroblasts which were often overlooked in previous studies andconfirmed that the neuroblast identity of the neuroblastoma cells. Accumulated data suggest that a differentiation arrest in sympathoadrenal neuroblasts contributes to the formation of neuroblastoma. It has been proposed that KLF7 is a neuroblastoma super-enhancer-associated transcription factor gene. Moreover, KLF7 strongly active in postmitotic neuroblasts of the developing nervous system during embryogenesis. However, the role of KLF7 in the differentiation of neuroblast or neuroblastoma is unknown. Methods Human neuroblastoma cells were used to assess the effects of KLF7 on the proliferation and differentiation biological behaviors of neuroblastoma. CHIP-seq and RNA-seq were used to detect the target gene of KLF7 in neuroblastoma. Luciferase assay, GTPase activity assayand Immunoblotting were utilized to determine the protein–promoter interactions and related molecular mechanisms. Results Firstly, we find a strong association between high KLF7 expression and favorable clinical outcomes in neuroblastoma. Moreover, we find that KLF7 not only inhibits proliferation but also induces differentiation of neuroblastoma cells, surpassing the effects of previously reported neuroblastoma differentiation genes. Furthermore, we are the first one to report that KLF7 binds directly to the promoters of neuroblast differentiation-associated protein (AHNAK and AHNAK2) and regulates their expression to influence the MAPK pathway and GTPase activity and then induces differentiation of neuroblastoma which also indicates that KLF7 plays a crucial role in neuroblast differentiation through regulating neuroblast differentiation-associated protein AHNAKs expression. As reported that KLF7 was a neuroblastoma super-enhancer-associated transcription factor gene, we also observe that depletion of KLF7 in neuroblastoma cells promotes the adrenergic-to-mesenchymal transition, accompanies by changes in enhancer-mediated gene expression. Conclusion we are the first one to report that KLF7 binds directly to the promoters of neuroblast differentiation-associated protein (AHNAK and AHNAK2) and regulates their expression to influence the GTPase activity and then induces differentiation of neuroblastoma which also indicates that KLF7 plays a crucial role in neuroblast differentiation. Our results reveal KLF7 as an inducer of neuroblast or neuroblastoma differentiation with prognostic significance and potential therapeutic value.