Evaluation Of Surrogate Serum Biomarker Of Sox9-expressing Hcc

Abstract

Introduction. Sex determining region Y-box 9 (Sox9) confers stemness properties in hepatocellular carcinoma (HCC). Its upregulation in HCC is markedly associated with clinicopathological features including poor tumor cell differentiation, advanced tumor stage, presence of venous invasion and poor overall survival. Recently, Sox9 is reported to regulate multiple matrix proteins and expression of Sox9 is correlated with severe liver fibrosis. This suggests that Sox9 regulates secretome during multi-step hepatocarcinogenesis. Thus, identification of surrogate serum biomarkers for Sox9-expressing HCC may further enhance the effectiveness to diagnose and sub-classify HCC. Aims. In view of a subset of HCC bearing aggressive phenotypes is driven by Sox9, we aimed to investigate and evaluate surrogate serum biomarker of Sox9-expressing HCC. Methods. Control (shCtrl) and stable Sox9 knockdown (shSox9) clones were established in human HCC cell lines (Huh7 and Hep3B) using lentiviral vectors. Conditioned media collected from shCtrl and shSox9 cells were characterized by liquid chromatography coupled with Orbitrap mass spectrometer (LC-MS). Serum Clusterin (CLU) level in our in-house cohort of HBV carriers (n=20) and HCC patients (n=60) was assessed by ELISA. Correlation between Sox9 and CLU in HCC (n=369) and normal liver (n=110) was analyzed using The Cancer Genome Atlas (TCGA) and GTEx databases. Results. MS data showed that CLU was the common deregulated target upon silencing of Sox9 in both Huh7 and Hep3B cell lines. A trend of positive correlation was observed between Sox9 and CLU in the normal liver and HCC tissues. CLU was significantly upregulated in HCC tissues when compared to normal liver tissues. Serum level of CLU was significantly higher in HCC patients than that of HBV carriers and it was capable of discriminating HCC from HBV carriers (AUC=0.824). Among the HCC patients, serum CLU was elevated in patients with advanced HCC. Discussion. We identified that CLU is deregulated upon alteration of Sox9 expression. Positive correlation between Sox9 and CLU in clinical samples suggested that serum CLU may be a surrogate biomarker of Sox9-expressing HCC. Leung CO et al (2016) Oncotarget 7:29371-86