NONO associates with PKM2 and directs histone H3 phosphorylation to promote tumor metastasis (RNA-Seq)

Dysregulation of transcriptional programming and epigenome has been identified as fundamental driver of cancer. However, the molecular mechanisms in such processes remain poorly understood. Here, we report that NONO (non-POU domain-containing octamer-binding protein) directly interacts with nuclear PKM2, which is critical for the activation of the NONO-driven transcriptional programme in triple-negative breast cancer (TNBC). We further demonstrate that plasminogen activator inhibitor 1 (PAI1) is a downstream target of NONO/PKM2 complex in TNBC cells through transcriptome analysis. In addition, we show that PKM2-mediated phosphorylation of histone H3 at threonine 11 (H3T11ph) collaborates with acetylation of histone H3 at lysine 27 (H3K27ac), which is due, at least in part, to PKM2 transcriptional activation of TIP60 expression. Importantly, NONO, H3T11ph, and H3K27ac signals are co-enriched at the PAI1 gene loci, which directly boosts PAI transcription. Consistent with above results, we also confirm that the expression of NONO and PKM2 are positively correlated with PAI1 expression in TNBC tissues. Thus, our findings reveal nuclear PKM2 as a novel NONO cofactor required for its biological function and suggest that the NONO/PKM2-PAI1 axis is an attractive therapeutic target in TNBC. To identify potential transcriptional targets of NONO/PKM2 complex and understand the mechanisms of their interaction in TNBC, we established MDA-MB-231 cell lines in which each target gene has been knocked down by siRNA.