Cancer-secreted exosomal miR-1246 promotes colorectal cancer liver metastasis by activating hepatic stellate cells

Colorectal cancer liver metastases (CRLM) are the primary cause of mortality in colorectal cancer (CRC) patients, highlighting the importance of understanding the underlying mechanisms. The tumor microenvironment (TME) and its interaction with tumor cells play a crucial role in CRLM progression. Notably, the stability and peak levels of tumor-derived exosomal miRNAs facilitate intercellular communication in the TME. Hepatic stellate cells (HSCs), key liver mesenchymal cells, constitute about 33% of the liver's nonsolid cell population and exhibit plasticity. However, the specific role of tumor-derived exosomal miRNAs in the crosstalk between HSCs and tumor cells during the CRLM process remains unclear. We studied CRC-secreted exosomal miR-1246 and its impact on HSCs, as well as its effects on CRC cell proliferation and metastasis. Our findings demonstrate that CRC-secreted exosomal miR-1246 can be internalized by HSCs, leading to their activation and facilitating the metastatic potential of CRC cells. Mechanistically, exosomal miR-1246 targets INSIG1, resulting in SREBP2 nucleation and cholesterol metabolism alterations. This accumulation of free cholesterol (FC) regulates the TLR4/NF-κB/TGF-β pathway, promoting HSC activation. Activated HSCs, in turn, enhance liver metastasis of CRC cells through the TNFSF13/TNFRSF13B axis. Our study reveals the role of CRC-secreted exosomal miR-1246 in triggering HSC activation and reprogramming the TME, ultimately facilitating liver metastasis in CRC patients. Exosomal miR-1246 could serve as a potential non-invasive biomarker for predicting colorectal cancer liver metastasis, enhancing our understanding of CRC-associated liver metastases.