Hepatic Stellate Cells Secreted Hepatocyte Growth Factor Contributes to the Chemoresistance of Hepatocellular Carcinoma

Guofeng Yu,Qiudong Zhao,Mengchao Wu,Lixin Wei,Qingmin Fan,Yang Yang,Fei Ye,Rong Li,Xingrui Kou,Yingying Jing,Lu Gao,Xin-Yuan Guan

doi:10.1371/journal.pone.0073312

Guofeng Yu, Qiudong Zhao + Show 10 more

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https://doi.org/10.1371/journal.pone.0073312

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Abstract

As the main source of extracellular matrix proteins in tumor stroma, hepatic stellate cells (HSCs) have a great impact on biological behaviors of hepatocellular carcinoma (HCC). In the present study, we have investigated a mechanism whereby HSCs modulate the chemoresistance of hepatoma cells. We used human HSC line lx-2 and chemotherapeutic agent cisplatin to investigate their effects on human HCC cell line Hep3B. The results showed that cisplatin resistance in Hep3B cells was enhanced with LX-2 CM (cultured medium) exposure in vitro as well as co-injection with LX-2 cells in null mice. Meanwhile, in presence of LX-2 CM, Hep3B cells underwent epithelial to mesenchymal transition (EMT) and upregulation of cancer stem cell (CSC) -like properties. Besides, LX-2 cells synthesized and secreted hepatic growth factor (HGF) into the CM. HGF receptor tyrosine kinase mesenchymal–epithelial transition factor (Met) was activated in Hep3B cells after LX-2 CM exposure. The HGF level of LX-2 CM could be effectively reduced by using HGF neutralizing antibody. Furthermore, depletion of HGF in LX-2 CM abolished its effects on activation of Met as well as promotion of the EMT, CSC-like features and cisplatin resistance in Hep3B cells. Collectively, secreting HGF into tumor milieu, HSCs may decrease hepatoma cells sensitization to chemotherapeutic agents by promoting EMT and CSC-like features via HGF/Met signaling.

Highlights

Hepatocellular carcinoma (HCC) which accounting for 70% to 85% of the total primary liver cancer, is one of the most common primary malignant tumors with a fairly high and increasing incidence, frequently relapse and dismal prognosis [1]
Tumor stroma is involved in mediating epithelial to mesenchymal transition (EMT) and maintaining the cancer stem cell (CSC) like characteristics of epithelial tumor cells, both of which are responsible for cancer chemoresistance [9,10]
In response to cisplatin treatment, Hep3B cells with HGFdepleted LX-2 Cultured media (CM) exposure showed lower cell viability and higher active caspase 8 and 3 than that of LX-2 CM exposure(Figure 5E and F). These data indicated that the hepatic growth factor (HGF) that we identified was the key molecule in LX-2 CM to promote the EMT, CSC phenotypes and cisplatin resistance in Hep3B cells

Summary

Introduction

Hepatocellular carcinoma (HCC) which accounting for 70% to 85% of the total primary liver cancer, is one of the most common primary malignant tumors with a fairly high and increasing incidence, frequently relapse and dismal prognosis [1]. The intimate cross-talk between tumor cells and their surrounding microenvironment plays an extremely important role in modulating the biological behaviors of tumor, and eventually affects clinical outcome [4]. In HCC, HSCs secrete soluble cytokines, chemokines, chemotaxis to create the complexity of tumor milieu [6]. Tumor microenvironment heterogeneity and plasticity may lead to the diversities of cell proliferation rate, significant regional gradient of hypoxia and acidic zone, all of which would influence the sensitivity of tumor cells to chemotherapy [8]. Tumor stroma is involved in mediating epithelial to mesenchymal transition (EMT) and maintaining the cancer stem cell (CSC) like characteristics of epithelial tumor cells, both of which are responsible for cancer chemoresistance [9,10]

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