Extracellular vesicle packaged LMP1-activated fibroblasts promote tumor progression via autophagy and stroma-tumor metabolism coupling

Several reports have demonstrated that Epstein-Barr virus (EBV) encoded latent membrane protein 1 (LMP1), which is transferred by extracellular vesicles (EVs) or exosomes, can promote cancer progression. However, its mechanism is still not fully understood. In the present study, we demonstrated that EV packaged LMP1 can activate normal fibroblasts (NFs) into cancer-associated fibroblasts (CAFs). The NF-kappa B p65 pathway is the key signal that promotes the activation of NFs to CAFs in nasopharyngeal carcinoma (NPC). In activated CAFs, aerobic glycolysis and autophagy were increased. Moreover, glucose uptake and lactate production were decreased, and mitochondrial activity in tumor cells was enhanced, which supported the Reverse Warburg Effect (RWE). During this process, upregulation of MCT4 in CAFs and MCT1 in tumor cells was observed. The NF-kappa B p65 pathway also plays an important role in the regulation of MCT4. Furthermore, co-culture with CAFs promoted the proliferation, migration and radiation resistance of NPC cells. And EV packaged LMP1 promoted tumor proliferation and pre-metastatic niche formation by activating CAFs in vivo. Our findings indicate that EV packaged LMP1-activated CAFs promote tumor progression via autophagy and stroma-tumor metabolism coupling.