Genetic lineage tracing analysis of the cell of origin of hepatotoxin‐induced liver tumors in mice

Abstract

The expression of biliary/progenitor markers by hepatocellular carcinoma (HCC) is often associated with poor prognosis and stem cell-like behaviors of tumor cells. Hepatocellular adenomas (HCA) also often express biliary/progenitor markers and frequently act as precursor lesions for HCC. However, the cell of origin of HCA and HCC that expresses these markers still remains unclear. Therefore, to evaluate if mature hepatocytes give rise to HCA and HCC tumors, and to understand the molecular pathways involved in tumorigenesis, we lineage-labeled hepatocytes by injecting adeno-associated virus (AAV) containing thyroxine-binding globulin (TBG) promoter driven-Cre into RosaYFP mice. Yellow fluorescent protein (YFP) was present in more than 96% of hepatocytes before exposure to carcinogens. We treated AAV-TBG-Cre;RosaYFP mice with diethylnitrosamine (DEN) followed by multiple injections of carbon tetrachloride (CCl4) to induce carcinogenesis and fibrosis, and found that HCA and HCC nodules were YFP+ lineage-labeled and also positive for osteopontin (Opn), SRY (sex determining region Y)-box 9 (Sox9), and epithelial cell adhesion molecule (EpCAM), and enriched for transcripts of biliary/progenitor markers such as Prom1, Cd44, and Dlk1. Next, we performed the converse experiment and lineage-labeled Foxl1-positive hepatic progenitor cells simultaneously with exposure to carcinogens. None of the tumor nodules expressed YFP, indicating that Foxl1-expressing cells are not the cell of origin for hepatotoxin-induced liver tumors. We confirmed that HCA and HCC cells are derived from mature hepatocytes and not from Foxl1-Cre-marked cells in a second model of toxin-induced hepatic neoplasia, using DEN and 3,3’,5,5’-tetrachloro-1,4-bis(pyridyloxy)benzene (TCPOBOP). Conclusion Our results indicate that hepatocytes are the cell of origin of HCA and HCC in DEN/CCl4 and DEN/TCPOBOP-induced liver tumors.

Hepatocyte-specific, PPARγ-regulated mechanisms to promote steatosis in adult mice

“…This model allows us to study the immediate impact of hepatocyte-specific loss of PPARγ in the adult liver and how this deficit impacts liver function overtime under different dietary conditions. As indicated in this study and supported by accumulating evidence (Ashpole, et al 2016; Shin, et al 2016; Yanger, et al 2014), injection of AAV8-TBGp-Cre is an efficient and reproducible method to knockdown a floxed allele only in hepatocytes, independent of age.…”

Reactive Ductules Are Associated With Angiogenesis and Tumor Cell Proliferation in Pediatric Liver Cancer

“…Expression of progenitor markers by HCC is likely to be associated with poor prognosis and recurrence after surgical resection and liver transplantation, and it has been proposed that HPCs are the cellular origin of liver cancer based on correlative data . However, using two mouse models of liver cancer induced by hepatotoxin treatment, we demonstrated that mature hepatocytes, not HPCs, are the cell of origin for tumors …”

Deregulated GATA6 modulates stem cell‐like properties and metabolic phenotype in hepatocellular carcinoma

“…In neoplastic conditions, there is compelling evidence showing the implication of cell plasticity as a prerequisite for HCC biology. In one recent report, the oncogenic reprogramming of hepatocytes was emphasized by lineage‐tracing experiments using Sox9, EpCAM and Yap1 as key molecular markers in this process . In this regard, our group previously reported on the in‐depth characterization of Sox9 in HCC.…”