CD147 promotes NSCLC metastasis by inducing secretory autophagy-dependent exosome secretion via TRIM56-mediated ubiquitination and degradation of GCN2

Abstract Tumor-derived exosome secretion dynamically correlates with malignant progression, although the mechanisms by which tumor-associated antigens regulate exosome production remain unclear. Here, we found that the number of plasma exosomes increased significantly with the progression of non-small-cell lung cancer (NSCLC) patients and identified that CD147 as a crucial mediator of exosome secretion using mass spectrometry. CD147 exhibited a positive correlation with exosomes release in NSCLC patients and various cell lines and it drove the release of exosome to promote tumor metastasis in vitro and in vivo. Transcriptomic profiling of transgenic CD147 models identified differential gene expression patterns enriched in autophagy-related pathways. Intriguingly, CD147 was found to specifically enhance autophagosome and amphisome biogenesis to promote exosomes release by using transmission electron microscopy, high-sensitivity structured light microscope, RFP-GFP-LC3 adenovirus reporters and immunofluorescence, which indicated the role of CD147 in mediating non-canonical autophagy processes. Mechanistically, CD147 activated the GCN2/EIF2α/ATG12 signaling axis to drive autophagosome assembly but blocked autolysosome maturation by inhibiting VAMP8/STX17/SNAP29-dependent fusion, leading to amphisome accumulation. Proteomics identified TRIM56 as a novel E3 ligase mediating K619 ubiquitination-dependent GCN2 proteasomal degradation. Subsequently, we found that CD147 suppresses TRIM56 expression, thereby stabilizing GCN2 to activate the GCN2/EIF2α/ATG12 axis. Meanwhile, CD147-induced IP3R3-mediated calcium overload facilitated the fusion of autophagosomes with multivesicular bodies to form amphisomes, thus enhancing exosome release. Collectively, our findings reveal a novel mechanism whereby CD147 promotes crinophagy-mediated exosome secretion through dual regulation of GCN2 stability and calcium homeostasis, thereby accelerating NSCLC progression. Our work establishes a new molecular link between autophagy modulation and cancer progression.