TNF receptor superfamily member 10 d is a novel diagnostic and therapeutic target in hepatocellular carcinoma progression and sorafenib-resistance

Introduction:

Hepatocellular carcinoma (HCC) is hallmarked by resistance to Tumor necrosis factor related apoptosis inducing ligand (TRAIL)-induced apoptosis which is poorly understood. TRAIL mediates apoptosis via activation of Death cell receptor 4 and 5 (DR4, DR5). Moreover, TRAIL can bind to decoy receptors 1 (TNFRSF10C) and 2 (TNFRSF10D). TNFRSF10C does not contain a cytoplasmic domain and functions as an anti-apoptotic, TRAIL-neutralizing decoy-receptor. In contrast, TNFRSF10D has a truncated, but functional intracellular domain which can activate different signaling pathways such as NFkappaB. However, the possible contribution and function of TNFRSF10D to HCC development and progression is completely unexplored. The aim of this study was to elucidate the expression, regulation, function and prognostic and therapeutic role of TNFRSF10D in HCC.

Methods:

RNA expression array analysis was performed in HCC cells that were transfected with different tumorsuppressive microRNAs. The human HCC cell lines PLC, Huh-7, Hep3B and HepG2 were used for functional and expression analysis. Microscopy, qRT-PCR and Western blot analysis were used to analyze changes in cell morphology and gene expression. TNFRSF10D was inhibited by si-RNA-Pool-mediated gene knockdown. Boyden chamber assays were used to quantify migration. Fluorescence-activated cell sorting (FACS) analysis was used to quantify apoptosis.

Results:

Treatment with several tumorsuppressive microRNAs strongly induced TNFRSF10D upregulation in HCC cells. Quantitative RT-PCR analysis showed that TNFRSF10D expression was strongly enhanced in HCC cell lines as compared to primary human hepatocytes. Moreover, TNFRSF10D was significantly overexpressed in HCC tissue samples from patients as compared to corresponding non-tumorous liver tissues. TNFRSF10D inhibition caused marked reduction of proliferation, migration, clonogenicity, AKT- and JNK-activation in HCC cells. Si-RNA-mediated knockdown of TNFRSF10D re-sensitized HCC cells for TRAIL-mediated apoptosis-induction. Analysis of patient datasets derived from The Cancer Genome Atlas (TCGA) revealed that high TNFRSF10D expression correlated with a poor patient survival in HCC. Moreover, TNFRSF10D was even further upregulated in sorafenib-resistant HCC cells. Functional analysis revealed that acquired resistance to sorafenib can partly be mediated by TNFRSF10D.

Conclusions:

The current study reveals that the TRAIL decoy receptor TNFRDF10D which is unknown in liver cancer is a novel diagnostic and therapeutic target in HCC. Moreover, TNFRSF10D is overexpressed and functional in acquired resistance to sorafenib.