Metastatic tumor growth in steatotic liver is promoted by HAS2-mediated fibrotic tumor microenvironment

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Abstract

Steatotic liver enhances liver metastasis of colorectal cancer (CRC), but this process is not fully understood. Steatotic liver induced by a high-fat diet increases cancer-associated fibroblast (CAF) infiltration and collagen and hyaluronic acid (HA) production. We investigated the role of HA synthase 2 (HAS2) in the fibrotic tumor microenvironment in steatotic liver using Has2ΔHSC mice, in which Has2 is deleted from hepatic stellate cells. Has2ΔHSC mice had reduced steatotic liver–associated metastatic tumor growth of MC38 CRC cells, collagen and HA deposition, and CAF and M2 macrophage infiltration. We found that low–molecular weight HA activates Yes-associated protein (YAP) in cancer cells, which then releases connective tissue growth factor to further activate CAFs for HAS2 expression. Single-cell analyses revealed a link between CAF-derived HAS2 and M2 macrophages and CRC cells through CD44; these cells were associated with exhausted CD8+ T cells via programmed death–ligand 1 and programmed cell death protein 1 (PD-1). HA synthesis inhibitors reduced steatotic liver–associated metastasis of CRC, YAP expression, and CAF and M2 macrophage infiltration, and improved response to anti–PD-1 antibody. In conclusion, steatotic liver modulates a fibrotic tumor microenvironment to enhance metastatic cancer activity through a bidirectional regulation between CAFs and metastatic tumors, enhancing the metastatic potential of CRC in the liver.

Authors

Yoon Mee Yang, Jieun Kim, Zhijun Wang, Jina Kim, So Yeon Kim, Gyu Jeong Cho, Jee Hyung Lee, Sun Myoung Kim, Takashi Tsuchiya, Michitaka Matsuda, Vijay Pandyarajan, Stephen J. Pandol, Michael S. Lewis, Alexandra Gangi, Paul W. Noble, Dianhua Jiang, Akil Merchant, Edwin M. Posadas, Neil A. Bhowmick, Shelly C. Lu, Sungyong You, Alexander M. Xu, Ekihiro Seki