Up-regulation of EMT-related gene VCAN by NPM1 mutant-driven TGF-β/cPML signalling promotes leukemia cell invasion

Acute myeloid leukemia (AML) with mutated nucleophosmin (NPM1) is acknowledged as a distinct leukemia entity in the 2016 updated World Health Organization (WHO) classification. NPM1-mutated AML patients are correlated with higher extramedullary involvement. Epithelial-mesenchymal transition (EMT) is one of the key steps which cause distant metastasis in tumor. However, whether EMT-related programs contribute to cell invasion in NPM1-mutated AML remains unclear. In this study, we identified the EMT-related gene versican (VCAN) in NPM1-mutated AML across three patient datasets. Further experiments validated the elevated VCAN expression in NPM1-mutated AML primary blasts and OCI-AML3 cells with NPM1 mutation. Mechanistic studies revealed that increased VCAN expression was at least partially regulated by NPM1 mutant via TGF-beta/cPML/Smad signalling. Functional evaluations showed that silencing VCAN by shRNA significantly suppressed cell migration and invasion capacity, whereas increased VCAN by overexpressing NPM1-mA enhanced migration and invasion ability of leukemia cells. Finally, we found that high expression of VCAN was associated with poor prognosis in AML patients. These findings provide insights into the involvement of EMT-related gene VCAN in the pathogenesis of NPM1-mutated leukemia, which suggests that VCAN is an attractive target for novel diagnostic and therapeutic strategies in NPM1-mutated AML.