HnRNP-F promotes cell proliferation by regulating TPX2 in bladder cancer

Heterogeneous nuclear ribonucleoprotein F (hnRNP-F) is crucial for gene expression and signal transduction as a tumor-promoting molecule with the ability to promote cell proliferation in various cancers. However, the role and mechanism of hnRNP-F in bladder cancer (BC) remain unclear. Therefore, we investigated the effect of hnRNP-F on the proliferation of BC cells and the potential mechanism. In this study, hnRNP-F was found to be upregulated in BC tissues and cells by western blotting. The knockdown of hnRNP-F could inhibit proliferation and delay cell cycle progression in EJ and UMUC-3 cells. Mechanistically, hnRNP-F was shown to bind to Targeting protein for Xenopus kinesin-like protein 2 (TPX2) by mass spectrometry and coimmunoprecipitation. Furthermore, Pearson correlation analysis showed that the expression of hnRNP-F was positively associated with that of TPX2 in BC tissues (P<0.001, r=0.8180). Notably, TPX2 was correspondingly markedly decreased in cells upon hnRNP-F knockdown. In addition, the decrease in TPX2 after hnRNP-F knockdown further decreased cyclin D1 protein expression and evoked p21 protein expression, eventually resulting in cell cycle arrest and proliferation inhibition in BC cells. Moreover, the overexpression of TPX2 protein was found to reverse the effect of hnRNP-F knockdown on the cell cycle and cell proliferation in BC cells. In conclusion, these findings suggest that hnRNP-F could promote cell proliferation and drive cell cycle progression by regulating TPX2 in BC, which may serve as a potential target for the treatment of BC patients.