Expression of intercellular adhesion molecule-1 in the livers of rats treated with diethylnitrosamine

Involvement of proliferation of atypical hepatocytes and CDT 1 in the liver cancer of rats administered the diethylnitrosamine

We have reported that extent of proliferation of atypical hepatocytes (POAH) in non-cancerous liver in hepatocellular carcinoma and chromatin licensing and DNA replication factor 1 (CDT1) are associated with postoperative recurrence. Here, we investigated whether extent of POAH and expression of CDT1 in liver are also associated with chemically induced liver cancer in rats. Male Fisher strain rats were orally administered diethylnitrosamine (DEN) in their drinking water and sacrificed at 6, 8, 12, or 14 weeks after start of DEN administration. We serially monitored changes in extent of POAH, CDT1 expression by immunohistochemistry (IHC), and CDT1 mRNA expression in liver by real-time quantitative PCR. The extent of POAH in liver progressed in a time-dependent manner after start of DEN administration. CDT1 expression was higher at 8 weeks than at 6 weeks by IHC, suggesting that CDT1 expression may be a marker of POAH severity. CDT1 mRNA expression in liver was significantly higher at 12 weeks than at 6 weeks (p<0.0001). We found that extent of POAH and the expression of CDT1 are also important factors in the development of chemical carcinogen-induced hepatocarcinogenesis. Furthermore, the association with POAH and CDT1 expression in carcinogenic process is important regardless of the cause of hepatocarcinogenesis.

Role of the BrafV637E mutation in hepatocarcinogenesis induced by treatment with diethylnitrosamine in neonatal B6C3F1 mice

The BrafV637E mutation is frequently reported in mouse hepatic tumors, depending on the mouse strain, and corresponds to the human BrafV600E mutation. In this study, we detected the BrafV637E mutation by whole‐exome analysis in 4/4 hepatic tumors induced by neonatal treatment with diethylnitrosamine (DEN) in male B6C3F1 mice. We also detected the BrafV637E mutation in 54/63 (85.7%) hepatic lesions, including microscopic foci and grossly visible tumors, by PCR‐direct sequencing. Although the mutation was detected in 5/7 (71.4%) hepatic tumors induced by neonatal DEN treatment followed by repeated CCl₄ administration, it was not detected in 24 tumors induced by CCl₄ treatment without DEN or in eight spontaneous lesions in B6C3F1 mice, suggesting that the mutation is induced by the genotoxic action of DEN. The DEN‐induced tumors exhibited hyperphosphorylation of ERK1 and Akt, suggesting that the BrafV637E mutation might activate the MAPK and Akt pathways. Moreover, the DEN‐induced tumors overexpressed mRNAs for the oncogene‐induced senescence (OIS) markers such as p15^Ink4b and p19^Arf as well as pro‐survival/pro‐proliferative cytokines/chemokines such as complement C5/C5a, ICAM‐1, IL‐1 receptor antagonist and CXCL9, suggesting that the BrafV637E mutation influences the expression of genes involved in either OIS or cellular growth/survival. Liver‐specific expression of mutated Braf under control of the albumin enhancer/promoter resulted in an enlarged liver that consisted entirely of small basophilic hepatocytes resembling DEN‐induced preneoplastic hepatocytes with ERK1/Akt hyperphosphorylation and C5/C5a overexpression. These results indicate that the BrafV637E mutation induces hepatocytic changes in DEN‐induced hepatic tumors. © 2016 The Authors. Molecular Carcinogenesis published by Wiley Periodicals, Inc.

Expression and role of icam-1 in the occurrence and development of hepatocellular carcinoma

Intercellular adhesion molecule-1 (ICAM-1) is a member of the immunoglobulin superfamily, its main function being to participate in recognition and adhesion between cells. ICAM-1 is considered closely related to occurrence, development, metastasis and invasion process of hepatocellular carcinoma (HCC). A variety of inflammatory cytokines and stimulus affect its expression through the nuclear factor-kappa B (NF-κB) signal transduction pathway. In the initial stage of inflammation, hepatocirrhosis and tumor development, ICAM-1 is expressed differently, and has varied effects on different cells to promote occurrence of malignancy and metastasis. ICAM-1 has diagnostic significance for AFP-negative or suspected HCC, and may be a prognositic significance. It is thus widely used in studies as a biomarker which reflects cancer cells metastasis as well as curative effect of drugs. Many new treatments of HCC may be based on the effects of ICAM-1 on different levels of function.