Agrin para-secreted by PDGF-activated human hepatic stellate cells promotes hepatocarcinogenesis in vitro and in vivo

Abstract

Evaluating the process and mechanism of fibrogenesis is essential in hepatocellular carcinoma (HCC), especially in hepatocyte transformation and oncogenic signaling. We evaluated the oncogenic role of agrin secreted by platelet-derived growth factor (PDGF)-induced hepatic stellate cell (HSC) in HCC. Cells were co-cultured to investigate the effect of activated HSC on hepatocytes. Liquid chromatography and protein profiling analysis were used to search the distinct proteins secreted in HSC supernatant. Sprague Dawley rats with Diethylnitrosamine (DEN)-induced HCC were used to simulate human liver cancer and sorafenib was administered to investigate its effect on hepatocarcinogenesis. A paired “two-tailed” Student t-test and chi-square tests was used for statistical analysis. PDGF acted as an activator of the HSC and sorafenib inhibits the activation by blocking the combination of PDGF and PDGF receptor. The supernatant of activated HSCs promoted the proliferation, metastasis, and invasion of HL-7702 and SMMC-7721, as well as epithelial-mesenchymal transition (EMT). Agrin found in the HSC supernatant showed the same effect on SMMC-7721 as to the supernatant of activated LX-2. Furthermore, downregulation of agrin by siRNA could decrease the proliferation, metastasis, and invasion of SMMC-7721, and promote MET. Sorafenib prevented DEN-induced hepatocarcinogenesis and could alleviate the liver inflammation and fibrosis. Sorafenib could improve the liver function of Sprague Dawley rats by decreasing the serum levels of ALT and AST. These results demonstrate thatPDGF is an effective activator of HSC and sorafenib could inhibit the activation. In vivo experiment suggested sorafenib could alleviate the hepatocarcinogenesis mediated through agrin secretion and could be potential candidate for treatment of cirrhosis.

Proteoglycans Are Attractive Biomarkers and Therapeutic Targets in Hepatocellular Carcinoma

“…Agrin is secreted from human hepatic stellate cells activated by platelet-derived growth factor (PDGF) and induces the EMT in HCC cells [ 77 ]. Interestingly, the multi-kinase inhibitor sorafenib, which targets the PDGF receptor (PDGFR), not only inhibits the hepatocarcinogenesis mediated through agrin secretion, but also alleviates liver inflammation and fibrosis, suggesting that it might be a potential candidate for the treatment of cirrhosis.…”

A Role of Agrin in Maintaining the Stability of Vascular Endothelial Growth Factor Receptor-2 during Tumor Angiogenesis

“…The C terminus of Agrin binds to low-density lipoprotein receptor-related protein 4 (Lrp4) to activate muscle-specific tyrosine kinase (MuSK), thereby forming a multi-protein complex (Glass et al, 1996;Kim et al, 2008;Ruegg and Bixby, 1998;Zhang et al, 2008). Distinct from its role at NMJs, Agrin is secreted in hepatocellular carcinoma (HCC) and regulates liver tumorigenesis (Chakraborty et al, 2015;Lv et al, 2017). As a potent regulator of cancer-cell-ECM mechanics, Agrin binds to Lrp4, MuSK, and Integrin b1, thereby sustaining Cell Reports 28, 949-965, July 23, 2019 ª 2019 The Author(s).…”

Agrin Mediates Angiogenesis in the Tumor Microenvironment

“…Although elementary at this stage, increasing evidence encourages the use of novel combinations of antibodies scavenging Agrin, and inhibitors against VEGFR2 and FAK for limiting cancer angiogenesis. In accordance, both sorafenib, which inhibits VEGFR2 signaling, and the FAK-PyK2 inhibitor PF562271, suppress Agrin-mediated angiogenesis and tumorigenesis [8,9]. Hence, recognizing the role of Agrin as an extrinsic regulator of angiogenesis and the cumulative role of Agrin and perlecan in the tumor ECM, that control tumor growth and metastasis, may offer fresh perspectives to restrain tumor vascularization.…”

“…Presently, it remains unclear as to how the TME sustains and/or enhances Agrin expression. For instance, Agrin secreted by platelet-derived growth factor (PDGF)-activated hepatic stellate cells (HSCs) supports HCC development in a paracrine fashion [9]. Therefore, it is likely that Agrin produced cumulatively by hepatocytes, HSCs, and stromal cells affects liver endothelium by creating more vascular infiltration during HCC development ( Figure 1B).…”