Targeting myoferlin in ER/Golgi vesicle trafficking reprograms cancer-associated fibroblasts in pancreatic cancer.

Pancreatic cancer cells exploit vesicle trafficking proteins such as myoferlin to fuel tumor aggressiveness, yet the presence and function of myoferlin-dependent vesicles in cancer-associated fibroblasts (CAFs) remain unknown. By combining PDAC whole-tumor and single-cell transcriptomic analyses with immunohistochemistry and 2D/3D in vitro models, we link stromal myoferlin to tumor aggressiveness. We identify CAF-specific functions of myoferlin, as MYOF-depleted CAFs present reduced activity and impaired extracellular matrix (ECM) production. Analysis of intracellular vesicles identifies a TGFß-receptor 1 (TGFBR1) trafficking blockade at the ER/Golgi interface upon myoferlin depletion, leading to altered TGFBR1 activation, impaired signal transduction, loss of ECM production and reduced CAF contractility. The genetic depletion of myoferlin in the murine tumor stroma and the pharmacological targeting of myoferlin alike reduced tumor desmoplasia in orthotopic KPC mice. Overall, we propose TGFBR1 trafficking as innovative target to reprogram CAFs, control desmoplasia and tackle these aggressive features in pancreatic cancer. Overall design: Human PDAC CAFs originating from 4 donors were transfected with irrelevant (GL3) or myoferlin specific siRNA. Cells were collected 48h after cell transfection and submitted to bulk RNA-seq.