Mutant p53 and NOX4 are modulators of a CCL5-driven pro-migratory secretome.

Previously, we showed wild-type (WT) and mutant (mt) forms of p53 differentially regulate ROS generation by NADPH oxidase-4 (NOX4). We found that WT-p53 suppresses TGF-β-induced NOX4, ROS production, and cell migration, whereas tumor-associated mt-p53 proteins enhance NOX4 expression and cell migration by TGF-β/SMAD3-dependent mechanisms. In this study, we investigated the role of mutant p53-induced NOX4 on the cancer cell secretome and the effects NOX4 signaling have on the tumor microenvironment (TME). We found conditioned media collected from H1299 lung epithelial cells stably expressing either mutant p53-R248Q or R273H promotes the migration and invasion of naïve H1299 cells and chemotactic recruitment of THP-1 monocytes. These effects were diminished with conditioned media from cells co-transfected with dominant negative NOX4 (P437H). We utilized immunoblot-based cytokine array analysis to identify factors in mutant p53 H1299 cell conditioned media that promote cell migration and invasion. We found CCL5 was significantly reduced in conditioned media from H1299 cells co-expressing p53-R248Q and dominant negative NOX4. Moreover, neutralization of CCL5 reduced autocrine-mediated H1299 cell mobility. Furthermore, CCL5 and TGF-beta from M2-polarized macrophages have a significant role in crosstalk and H1299 cell migration and invasion. Collectively, our findings provide further insight into NOX4-based communication in the tumor microenvironment and its potential as a therapeutic target affecting metastatic disease progression.