Editorial: sorafenib toxicity, a biomarker of effect?

Inhibition of EPS8L3 suppresses liver cancer progression and enhances efficacy of sorafenib treatment

BACKGROUND

Liver cancer is a devastating disease that has second highest cancer mortality rate worldwide. Although surgical resection or liver transplantation sometimes cures early stage liver cancer, few therapeutic options are available for advanced-stage liver cancer, highlighting the importance of a better understanding of the disease to find novel therapeutic targets.

METHODS

Firstly, clinical features of EPS8L3 on liver cancer RNA-seq dataset of The Cancer Genome Atlas (TCGA) database was analyzed, including gene expression levels in tumor tissues in comparison with the normal tissues as well as the patients' OS. To confirm the candidate genes, we used short hairpin RNA (shRNA) to knock down the gene and quantify the cell proliferation, apoptosis, and migration. Then micro-array analysis was did to investigate the intracellular mechanisms of EPS8L3. Moreover, to gain further insights into the translational value of the findings, we treated the liver cancer cells with Sorafenib after knocking down the candidate gene, in order to interrogate the combinatorial inhibitory effects on cell metabolism.

RESULTS

As a result, by comparing gene expression profiles of normal liver and cancerous tissues, we find that epidermal growth factor receptor kinase substrate 8-like protein 3 (EPS8L3), a gene with unknown function, is upregulated in liver cancer, and is associated with poor prognosis. Further gene set analyses on liver cancer cells revealed that EPS8L3 is pertinent to cell division and proliferation. Indeed, knocking down EPS8L3 inhibits cell proliferation and migration, and triggers apoptosis in vitro. Additionally, when inoculated into mice, EPS8L3 knocked down cells exhibit slower growth rate. Moreover, EPS8L3 expression can substantially increase the efficacy of low dosage of Sorafenib treatment. Furthermore, the results of immunohistochemical staining of 90 paired liver cancer and adjacent normal samples demonstrated high expression of EPS8L3 yields poor prognosis in Chinese liver cancer patients.

CONCLUSIONS

Collectively, our results suggest that EPS8L3 has pivotal oncogenic functions in liver cancer and we propose that EPS8L3 could be a potential therapeutic target to treat liver cancer.

Systemic treatments for hepatocellular carcinoma: challenges and future perspectives

Sorafenib has been the only approved systemic treatment of hepatocellular carcinoma (HCC) for almost a decade. Recently, two new drugs showed positive results in two Phase III studies. The RESORCE trial identified regorafenib as a valid second-line treatment for patients progressing to sorafenib, the REFLECT trial showed that lenvatinib is noninferior to sorafenib as front-line treatment. Following these trials, the therapeutic scenario will be dominated by anti-VEGFR drugs, with three different molecules showing a proven anticancer activity. Some open problems still remain and different immunotherapy trials are underway, following promising preliminary results. In this review we analyze: the most recent advancements about patients treated with sorafenib; the results of RESORCE and REFLECT trials; and the ongoing Phase III clinical trials. Finally, we discuss how they could address the current problems and possibly reshape the future of the systemic treatments for HCC.