Deletion of Cd44 Inhibits Metastasis Formation of Liver Cancer in Nf2-Mutant Mice

Abstract

Primary liver cancer is the third leading cause of cancer-related death worldwide. An increasing body of evidence suggests that the Hippo tumor suppressor pathway plays a critical role in restricting cell proliferation and determining cell fate during physiological and pathological processes in the liver. Merlin (Moesin-Ezrin-Radixin-like protein) encoded by the NF2 (neurofibromatosis type 2) gene is an upstream regulator of the Hippo signaling pathway. Targeting of Merlin to the plasma membrane seems to be crucial for its major tumor-suppressive functions; this is facilitated by interactions with membrane-associated proteins, including CD44 (cluster of differentiation 44). Mutations within the CD44-binding domain of Merlin have been reported in many human cancers. This study evaluated the relative contribution of CD44- and Merlin-dependent processes to the development and progression of liver tumors. To this end, mice with a liver-specific deletion of the Nf2 gene were crossed with Cd44-knockout mice and subjected to extensive histological, biochemical and molecular analyses. In addition, cells were isolated from mutant livers and analyzed by in vitro assays. Deletion of Nf2 in the liver led to substantial liver enlargement and generation of hepatocellular carcinomas (HCCs), intrahepatic cholangiocarcinomas (iCCAs), as well as mixed hepatocellular cholangiocarcinomas. Whilst deletion of Cd44 had no influence on liver size or primary liver tumor development, it significantly inhibited metastasis formation in Nf2-mutant mice. CD44 upregulates expression of integrin β2 and promotes transendothelial migration of liver cancer cells, which may facilitate metastatic spreading. Overall, our results suggest that CD44 may be a promising target for intervening with metastatic spreading of liver cancer.

RNAseq analysis reveals transcriptome changes associated with the progression of non-alcoholic liver disease in livers fromEfcab4bknockout mice

“…Accordingly the upregulation of CD44 is observed in HFD diet fed animals displaying inflammation, fibrosis and is particularly significantly associated with the malignant transformation of hepatocytes in NAFLD 52 53 . The deletion of CD44 inhibits metastasis formation in mice 54 and in obese patients, hepatic CD44 and serum sCD44 strongly correlated with NASH 55 . Indeed, CD44 is considered a cancer stem cell marker 56 where immunohistochemical analysis of human HCC samples demonstrate increased expression of CD44.…”

Targeting LRRC41 as a potential therapeutic approach for hepatocellular carcinoma

“…Ho et al identified a CD24/CD44-enriched cell subpopulation within EpCAM cells through single-cell transcriptomics, indicating a novel stemness-related cell subclone in HCC ( Ho et al, 2019 ). Deletion of CD44 significantly inhibited metastasis formation of HCC in Nf2-mutant mice ( Gerardo-Ramirez et al, 2023 ). Furthermore, the importance of SOX9 in HCC prognosis has been verified in several studies.…”

RNA-seq analysis reveals transcriptome changes associated with the progression of non-alcoholic liver disease in livers from Efcab4b knockout mice

“…Accordingly the upregulation of CD44 is observed in HFD diet fed animals displaying inflammation, fibrosis and is particularly significantly associated with the malignant transformation of hepatocytes in NAFLD 47 48 . The deletion of CD44 inhibits metastasis formation in mice 49 and in obese patients, hepatic CD44 and serum sCD44 strongly correlated with NASH 50 . Indeed, CD44 is considered a cancer stem cell marker 51 where immunohistochemical analysis of human HCC samples demonstrate increased expression of CD44.…”