Patient-derived exosomes facilitate therapeutic targeting of oncogenic MET in advanced gastric cancer.

Gastric cancer (GC) with peritoneal metastases and malignant ascites continues to have poor prognosis. Exosomes mediate intercellular communication during cancer progression and promote therapeutic resistance. Here, we report the significance of exosomes derived from malignant ascites (EXO) in cancer progression and use modified exosomes as resources for cancer therapy. EXO from patients with GC stimulated invasiveness and angiogenesis in an ex vivo three-dimensional autologous tumor spheroid microfluidic system. EXO concentration increased invasiveness, and blockade of their secretion suppressed tumor progression. In -amplified GC, EXO contain abundant MET; their selective delivery to tumor cells enhanced angiogenesis and invasiveness. Exosomal MET depletion substantially reduced invasiveness; an additive therapeutic effect was induced when combined with MET and/or VEGFR2 inhibition in a patient-derived -amplified GC model. Allogeneic MET-harboring exosome delivery induced invasion and angiogenesis in a non-amplified GC model. -amplified patient tissues showed higher exosome concentration than their adjacent normal tissues. Manipulating exosome content and production may be a promising complementary strategy against GC.