Cancer-associated fibroblast-derived extracellular vesicles facilitate metastasis in hepatocellular carcinoma by delivering CTGF.

[PURPOSE] The tumor microenvironment (TME) plays a crucial role in cancer progression. Cancer-associated fibroblasts (CAFs) are key components of the TME and play critical roles in tumor development and metastasis. However, the mechanisms by which CAFs influence hepatocellular carcinoma (HCC) metastasis are not fully understood.

[METHODS] Extracellular vesicles (EVs) from CAFs and normal fibroblasts (NFs) were characterized via western blotting, transmission electron microscopy, and nanoparticle tracking analysis. An iTRAQ-based proteomic sequencing analysis was conducted to quantify proteins in the EVs from these cells. Colony formation assays and Transwell assays were used to assess tumor cell proliferation and migration. Xenograft tumor models were established in nude mice to evaluate tumor progression in vivo. Coimmunoprecipitation and molecular docking were performed to explore the interactions between CTGF and Notch1.

[RESULTS] A high CAF abundance is associated with poor prognosis in HCC patients. EVs from CAFs significantly enhanced the proliferative and invasive abilities of HCC cells in vitro and in vivo. Connective tissue growth factor (CTGF) was found to be highly upregulated in CAF-derived EVs, and CTGF knockdown in CAF-derived EVs attenuated their tumor-promoting capacities. Mechanistically, CTGF derived from CAF-EVs activated the Notch1/Snail1 signaling pathway in recipient cells via interaction with the Notch1 receptor, enhancing HCC cell proliferation and invasion. Furthermore, high CTGF expression was significantly correlated with poor clinicopathological features in HCC patients.

[CONCLUSION] Our findings revealed that CTGF derived from CAF-EVs promoted the proliferation and invasion of HCC cells via activation of the Notch1/Snail1 pathway, highlighting CTGF derived from CAF-EVs as a prognostic biomarker and therapeutic target in HCC.