ZNF224 is a Mediator of TGF-β Pro-oncogenic Function in Melanoma
Abstract Background: The zinc finger protein ZNF224 plays a dual role in human cancers, operating as both tumour suppressor and oncogenic factor depending on the cellular context and molecular partners. In this research, we investigated the role played by ZNF224 in the TGF-β signalling in malignant melanoma. Methods: Real-time qPCR, western blot, and chromatin immunoprecipitation assays were performed to examine the molecular mechanisms of ZNF224 in TGF-β signalling in melanoma. ZNF224-induced cell anchorage, independent growth, migration, and invasion were assessed by the colony formation, wound healing, and transwell assays.Results: Our findings showed that ZNF224, whose expression increased in melanoma cell lines after TGF-b stimulation, potentiated the activation induced by TGF-β on its target genes involved in epithelial-mesenchymal transition (EMT). Accordingly, overexpression of ZNF224 improved the tumourigenic properties of melanoma cells, promoting cell proliferation and invasiveness, while ZNF224 knockdown had the opposite effect. Moreover, ZNF224 promoted the transcriptional activation of TGF-β itself and its type 1 and 2 receptors (TβR1 and TβR2), thus highlighting a possible mechanism by which ZNF224 could enhance the endogenous TGFβ/Smad signalling. Conclusions: Our results provide evidence for the involvement of ZNF224 in TGF-β signalling as a mediator of TGF-β pro-oncogenic function and unveil a positive regulatory loop between TGF-β and ZNF224 to promote EMT, consequently increasing the tumour metastatic potential.