Novel Combination of Sorafenib and Celecoxib Provides Synergistic Anti-Proliferative and Pro-Apoptotic Effects in Human Liver Cancer Cells

Melchiorre Cervello,Dimcho Bachvarov,Nadia Lampiasi,Giuseppe Montalto,Antonina Azzolina,James A Mccubrey,Antonella Cusimano,Manlio Vinciguerra

doi:10.1371/journal.pone.0065569

Abstract

Molecular targeted therapy has shown promise as a treatment for advanced hepatocellular carcinoma (HCC). Sorafenib, a multikinase inhibitor, recently received FDA approval for the treatment of advanced HCC. However, although sorafenib is well tolerated, concern for its safety has been expressed. Celecoxib (Celebrex®) is a selective cyclooxygenase-2 (COX-2) inhibitor which exhibits antitumor effects in human HCC cells. The present study examined the interaction between celecoxib and sorafenib in two human liver tumor cell lines HepG2 and Huh7. Our data showed that each inhibitor alone reduced cell growth and the combination of celecoxib with sorafenib synergistically inhibited cell growth and increased apoptosis. To better understand the molecular mechanisms underlying the synergistic antitumor activity of the combination, we investigated the expression profile of the combination-treated liver cancer cell lines using microarray analysis. Combination treatment significantly altered expression levels of 1,986 and 2,483 transcripts in HepG2 and Huh7 cells, respectively. Genes functionally involved in cell death, signal transduction and regulation of transcription were predominantly up-regulated, while genes implicated in metabolism, cell-cycle control and DNA replication and repair were mainly down-regulated upon treatment. However, combination-treated HCC cell lines displayed specificity in the expression and activity of crucial factors involved in hepatocarcinogenesis. The altered expression of some of these genes was confirmed by semi-quantitative and quantitative RT-PCR and by Western blotting. Many novel genes emerged from our transcriptomic analyses, and further functional analyses may determine whether these genes can serve as potential molecular targets for more effective anti-HCC strategies.

Highlights

Hepatocellular carcinoma (HCC) represents the fifth most frequent cancer and the third most common cause of death from cancer [1,2]
We demonstrated that treatment of human HCC cells with a COX-2 inhibitor is associated with the activation of ERK1/2, and that the inhibition of the MEK/ERK signaling pathway by a MEK inhibitor potentiates the antitumor activity of the inhibitor
Our results suggest that the MEK/ERK pathway does not mediate cytotoxicity induced by COX-2 inhibitors but may protect cells from death, which indirectly supports the role of the MEK/ERK pathway in the survival signaling of HCC cells [12]

Summary

Introduction

Hepatocellular carcinoma (HCC) represents the fifth most frequent cancer and the third most common cause of death from cancer [1,2]. The clinical diagnosis and management of early-stage HCC has improved significantly, HCC prognosis is still extremely poor. Advanced HCC is a highly aggressive tumor with a low or no response to common therapies. New effective and well-tolerated therapy strategies are urgently needed. A multikinase inhibitor which targets Raf kinases as well as VEGFR-2/-3, PDGFR-b, Flt-3 and c-Kit, recently received FDA and EMEA approval for the treatment of patients with advanced HCC.

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Conclusion