Cancer cells produce liver metastasis via gap formation in sinusoidal endothelial cells through proinflammatory paracrine mechanisms

Menée à l'aide de lignées cellulaires, d'un modèle murin et d'échantillons tumoraux provenant de patients atteints d'un carcinome hépatocellulaire, cette étude met en évidence un mécanisme par lequel les cellules cancéreuses infiltrent le parenchyme hépatique en induisant, via des mécanismes paracrines pro-inflammatoires, la formation d'un espace intracellulaire dans les cellules endothéliales sinusoïdales du foie

Résumé en anglais

Intracellular gap (iGap) formation in liver sinusoidal endothelial cells (LSECs) is caused by the destruction of fenestrae and appears under pathological conditions; nevertheless, their role in metastasis of cancer cells to the liver remained unexplored. We elucidated that hepatotoxin-damaged and fibrotic livers gave rise to LSECs-iGap formation, which was positively correlated with increased numbers of metastatic liver foci after intrasplenic injection of Hepa1-6 cells. Hepa1-6 cells induced interleukin-23–dependent tumor necrosis factor–α (TNF-α) secretion by LSECs and triggered LSECs-iGap formation, toward which their processes protruded to transmigrate into the liver parenchyma. TNF-α triggered depolymerization of F-actin and induced matrix metalloproteinase 9 (MMP9), intracellular adhesion molecule 1, and CXCL expression in LSECs. Blocking MMP9 activity by doxycycline or an MMP2/9 inhibitor eliminated LSECs-iGap formation and attenuated liver metastasis of Hepa1-6 cells. Overall, this study revealed that cancer cells induced LSEC-iGap formation via proinflammatory paracrine mechanisms and proposed MMP9 as a favorable target for blocking cancer cell metastasis to the liver. An alternative pathway for liver metastasis was discovered showing that cancer cells invade via intraendothelial gap formation.