Blocking CEMIP2-mediated low-molecular-weight hyaluronic acid -TGFβ signaling inhibits chemotherapy-associated lymphatic metastasis in gastric cancer.

Chemotherapy-associated metastasis is a major cause of failure of cancer treatment, especially neoadjuvant chemotherapy. Extracellular matrix (ECM) remodeling aways accompany with chemotherapy, but its role in chemotherapy-associated metastasis is still unclear. Here, we reveal hyaluronidase-driven degradation of hyaluronic acid (HA) as a key mechanism underlying chemotherapy-associated lymphatic metastasis in gastric cancer. We found that chemotherapy-associated lymphatic metastasis of gastric cancer occurred during neoadjuvant chemotherapy in both patients and nude mice. The proportion of HA increased significantly in ECM during chemotherapy. We also found that cell migration inducing hyaluronidase 2 (CEMIP2) is the most highly expressed hyaluronidase to degrade HA into its effective type, low molecular weight HA (LMWHA), and promoted chemotherapy-associated lymphatic metastasis of gastric cancer. Mechanistically, CEMIP2-generated LMWHA activates CD44-ATF3 signaling to transcriptionally upregulate TGFβ receptor TGFBR1, driving metastasis. CEMIP2 is highly expressed in gastric epithelium naturally. To specifically target CEMIP2 and inhibit chemotherapy-associated lymphatic metastasis of gastric cancer, we developed bioengineered RGD-conjugated exosomes mimics (EMs) for targeted delivery of CEMIP2 siRNA. This strategy potently suppressed chemotherapy-associated lymphatic metastasis in vivo. Crucially, our results position CEMIP2 as a therapeutic target to inhibit chemotherapy-associated metastasis of gastric cancer.