Activated protein C promotes human lung cancer progression through the release of tumor extracellular vesicles and transfer of microRNA-200a.

Blood coagulation and cancer are intricately related. Hypercoagulation associated with cancer leads to aberrant thrombin generation, which contributes to thrombosis. Thrombin also activates anticoagulant protein C and the activated protein C (aPC), in addition to regulating the coagulation pathway, it also elicits cell signaling by binding to endothelial cell protein C receptor (EPCR) and activating protease-activated receptor 1 (PAR1)-mediated cell signaling. Earlier studies showed that aPC promotes lung adenocarcinoma survival and metastasis. However, the underlying mechanism remains largely unknown. Our present study provides mechanistic insight into how aPC promotes lung adenocarcinoma survival, metastasis, and drug resistance. Our study shows that aPC, through EPCR-PAR1-driven activation of RhoA-ROCKII-JNK1/2-MLC2 signaling, triggers extracellular vesicle (EV) release from lung adenocarcinoma cells. aPC-EVs, via the transfer of microRNA (miR)-200a, promote proliferation, migration, and invasion of normal lung epithelial cells. They also confer resistance to lung cancer against chemotherapeutic agents. Inhibition of miR-200a functions through the incorporation of anti-miR-200a abrogates aPC-EVs-mediated tumorigenic effects. Furthermore, loading miR-200a mimic into control EVs showed similar phenotypic responses to that of aPC-EVs. miR-200a is shown to target SOX17 in the recipient cells, leading to tumorigenesis. miR-200a upregulation and SOX17 downregulation are consistently observed in lung cancer tissues in the UALCAN portal database of clinical specimens. Consistent with these findings, our in vivo studies in BALB/c nude mice showed that aPC-EVs from lung cancer cells promote tumor growth, metastasis, and drug resistance through miR-200a transfer. Targeting EV biogenesis, EV's miR-200a, and/or EV uptake mechanisms may offer novel therapeutic strategies in limiting lung tumorigenesis, thereby increasing patients' survival.