Nrf2 signaling promotes cancer stemness, migration, and expression of ABC transporter genes in sorafenib-resistant hepatocellular carcinoma cells.

Luping Gao,Katsuki Miyazaki,Yu Saito,Kazunori Tokuda,Yuji Morine,Mitsuo Shimada,Chie Takasu,Tetsuya Ikemoto,Shinichiro Yamada,Olorunseun Ogunwobi

doi:10.1371/journal.pone.0256755

Abstract

As a multiple tyrosine kinase inhibitor, sorafenib is widely used to treat hepatocellular carcinoma (HCC), but patients frequently face resistance problems. Because the mechanism controlling sorafenib-resistance is not well understood, this study focused on the connection between tumor characteristics and the Nrf2 signaling pathway in a sorafenib-resistant HCC cell line. A sorafenib-resistant HCC cell line (Huh7) was developed by increasing the dose of sorafenib in the culture medium until the target concentration was reached. Cell morphology, migration/invasion rates, and expression of stemness-related and ATP-binding cassette (ABC) transporter genes were compared between sorafenib-resistant Huh7 cells and parental Huh7 cells. Next, a small interfering RNA was used to knock down Nrf2 expression in sorafenib-resistant Huh7 cells, after which cell viability, stemness, migration, and ABC transporter gene expression were examined again. Proliferation, migration, and invasion rates of sorafenib-resistant Huh7 cells were significantly increased relative to the parental cells with or without sorafenib added to the medium. The expression levels of stemness markers and ABC transporter genes were up-regulated in sorafenib-resistant cells. After Nrf2 was knocked down in sorafenib-resistant cells, cell migration and invasion rates were reduced, and expression levels of stemness markers and ABC transporter genes were reduced. Nrf2 signaling promotes cancer stemness, migration, and expression of ABC transporter genes in sorafenib-resistant HCC cells.

Highlights

Hepatocellular carcinoma (HCC) is the most common primary liver cancer and is a serious medical problem, as its incidence is continuing to grow
Because the mechanism controlling sorafenib-resistance is not well understood, this study focused on the connection between tumor characteristics and the Nuclear factor erythroid-derived 2-like 2 (Nrf2) signaling pathway in a sorafenib-resistant HCC cell line
A small interfering RNA was used to knock down Nrf2 expression in sorafenib-resistant Huh7 cells, after which cell viability, stemness, migration, and ATP-binding cassette (ABC) transporter gene expression were examined again

Summary

Introduction

Hepatocellular carcinoma (HCC) is the most common primary liver cancer and is a serious medical problem, as its incidence is continuing to grow. There are limitations to chemotherapy treatment of HCC. Previous studies have reported potential mechanisms that lead to sorafenib-resistant HCC [3]. Nuclear receptor binding protein 2 (NRBP2) may increase HCC cell chemotherapy resistance by affecting expression of survival proteins in the Bcl and Akt pathways [4]. KRAS pathway accelerates RAF/ERK and PI3K/AKT signaling, which results in increased cell proliferation and suppressed apoptosis in sorafenib-resistant HCC cells [6]. As a multiple tyrosine kinase inhibitor, sorafenib is widely used to treat hepatocellular carcinoma (HCC), but patients frequently face resistance problems. Because the mechanism controlling sorafenib-resistance is not well understood, this study focused on the connection between tumor characteristics and the Nrf signaling pathway in a sorafenib-resistant HCC cell line

Methods

Results

Conclusion