FUS inactivation promotes leptomeningeal metastasis of lung cancer through the up-regulation of CD36.

Abstract

The prognosis of non-small cell lung cancer (NSCLC) with leptomeningeal metastasis (LM) is dismal. The regulators of LM progression remain elusive, thus impeding effective clinical intervention. Here, we performed in vivo genome-wide CRISPR-based screens and found that fused in sarcoma (FUS) ablation promoted LM in both PC9 and A549 cells. FUS repressed CD36 expression by directly interacting with and destabilizing <i>PPARA</i> (<i>peroxisome proliferator-activated receptor</i> α) messenger RNA. CD36 augmented fatty acid uptake and oxidative phosphorylation in NSCLC cells. Matrix metallopeptidase 2 (MMP2) was up-regulated through CD36-mediated fatty acid metabolism, which enabled NSCLC cells to disrupt the endothelial barrier. FUS-deficient NSCLC cells increased the expression of neuroendocrine differentiation (NED)-related markers, including SRY-box transcription factor 2 (SOX2), microtubule-associated protein 2 (MAP2), enolase 2 (NSE), and synaptophysin (SYP). They also exhibited neurite-like extensions and expanded in cerebrospinal fluid-supplemented medium in a CD36-dependent manner. Mechanistically, fatty acid uptake increased acetyl-coenzyme A and H3K27ac modifications to promote the expression of NED signature genes and MMP2 in NSCLC cells. Genetic or pharmacological inhibition of CD36 or inhibition of NED-related markers in NSCLC cells hindered LM and prolonged survival in mice. In patients with NSCLC, down-regulation of FUS or up-regulation of CD36 or SYP was associated with progression to LM. Thus, CD36-mediated fatty acid metabolism and NED signature are crucial for progression to LM in NSCLC, highlighting CD36 as a promising therapeutic target to limit the progression of LM.