Transcription factor HOXB2 upregulates NUSAP1 to promote the proliferation, invasion and migration of nephroblastoma cells via the PI3K/Akt signaling pathway.

The transcription factor homeobox protein Hox­B2 (HOXB2) and its downstream factor nucleolar and spindle­associated protein 1 (NUSAP1) play important regulatory roles in cell proliferation, invasion and migration. However, their effects and specific mechanisms in nephroblastoma have not been previously investigated, to the best of our knowledge. Therefore, in the present study, the mRNA and protein expression levels of HOXB2 and NUSAP1 were determined in nephroblastoma cells using reverse transcription­quantitative PCR and western blot analyses, respectively. Furthermore, cell transfection experiments were carried out to knock down NUSAP1 and overexpress HOXB2 in nephroblastoma cell lines. The proliferative, invasive and migratory abilities of nephroblastoma cells were assessed by MTT, EdU, colony formation, wound healing and Transwell assays. In addition, the JASPAR website was used to predict the association between HOXB2 and NUSAP1, which was further verified by dual­luciferase reporter and chromatin immunoprecipitation assays. Finally, the expression levels of the PI3K/Akt signaling pathway­related proteins were measured by western blot analysis. The results showed that the expression of NUSAP1 was abnormally upregulated in nephroblastoma cell lines. However, NUSAP1 silencing attenuated the proliferation, invasion and migration abilities of nephroblastoma cells. The results also suggested that HOXB2 could transcriptionally activate NUSAP1. Therefore, HOXB2 overexpression abrogated the inhibitory effect of NUSAP1 silencing on the proliferation and metastasis of nephroblastoma cells, possibly via the PI3K/Akt signaling pathway. The aforementioned findings indicated that HOXB2 may upregulate NUSAP1 to promote the proliferation, invasion and migration of nephroblastoma cells via the PI3K/Akt signaling pathway.