Tumor-produced and aging-associated oncometabolite, methylmalonic acid, promotes cancer-associated fibroblast activation to drive metastatic progression

The systemic metabolic shifts that occur during aging and the local metabolic alterations of a tumor, its stroma and their communication cooperate to establish a unique tumor microenvironment (TME) that fosters cancer progression. Here, we show that methylmalonic acid (MMA), an aging-increased oncometabolite that is also produced by aggressive cancer cells, activates fibroblasts in the TME and stimulates the release of extracellular vesicles (EVs) that drive cancer progression, drug resistance and metastasis. The cancer-associated fibroblast (CAF)-released EV cargo is modified as a result of reactive oxygen species (ROS) generation and activation of the canonical and noncanonical TGFβ signaling pathways in CAFs. EV-associated IL-6 functions as a stroma-tumor messenger that activates the JAK/STAT3 and TGFβ signaling pathways in tumor cells and promote an epithelial-to-mesenchymal transition (EMT) and drug resistance in vitro, and metastatic progression in vivo. Our findings reveal the role of MMA in the activation of CAFs to drive metastatic reprogramming, unveiling multiple potential therapeutic avenues to target MMA at the nexus of aging, the tumor microenvironment and metastasis. MRC5 lung fibroblasts were treated with 1mM MMA for 5days