Jin Sun Kim1, Gwang Hyeon Choi1, Yusun Jung1, Kang Mo Kim2, Se-Jin Jang3, Eun Sil Yu3, Han Chu Lee1. 1. Department of Gastroenterology, Asan Liver Center, Asan Medical Center, University of Ulsan College of Medicine, 88 Olympic-ro 43-gil, Songpa-gu, Seoul, 05505, South Korea. 2. Department of Gastroenterology, Asan Liver Center, Asan Medical Center, University of Ulsan College of Medicine, 88 Olympic-ro 43-gil, Songpa-gu, Seoul, 05505, South Korea. kimkm70@amc.seoul.kr. 3. Department of Pathology, Asan Liver Center, Asan Medical Center, University of Ulsan College of Medicine, 88 Olympic-ro 43-gil, Songpa-gu, Seoul, South Korea.
Abstract
PURPOSE: Although sorafenib enhances overall survival, sorafenib resistance has been reported to be a significant limiting factor for improved prognosis in patients with hepatocellular carcinoma (HCC). Therefore, it is important to identify the mechanism of sorafenib resistance. This study aimed to identify the causative factor of sorafenib resistance and suggest methods for overcoming it. METHODS: The sensitivity to sorafenib was compared in human HCC cell lines and patient-derived HCC primary cells. Based on its cytotoxicity, signaling pathways altered by sorafenib and the causative factors were examined through assays. The mechanism by which sorafenib modified the sorafenib-resistance inducer through gene or protein expression or stability was also investigated. We also designed a treatment option to overcome sorafenib resistance. RESULTS: Sorafenib activated the Raf/MEK/ERK pathway and caused sorafenib resistance in HCC cell lines and patient-derived HCC primary cells. Sorafenib reactivated the MAPK pathway by down-regulating RKIP at the post-translational level. Knockdown of RKIP increased phosphorylated ERK and thus suppressed sorafenib-mediated cell death. We also found that sorafenib-reactivated ERK maybe an attractive target for second-line therapy for patients with sorafenib resistance. Sequential combination treatment with sorafenib and PD98059 significantly reduced the viability and proliferation of sorafenib-resistant cells, while their increasing apoptosis efficacy. CONCLUSION: Reactivation of the Raf/MEK/ERK pathway through aberrant expression of RKIP is one of the mechanisms behind sorafenib resistance in HCC. Sequential combination treatment with sorafenib and PD98059 could provide a new strategy to overcome sorafenib resistance in future clinical studies.
PURPOSE: Although sorafenib enhances overall survival, sorafenib resistance has been reported to be a significant limiting factor for improved prognosis in patients with hepatocellular carcinoma (HCC). Therefore, it is important to identify the mechanism of sorafenib resistance. This study aimed to identify the causative factor of sorafenib resistance and suggest methods for overcoming it. METHODS: The sensitivity to sorafenib was compared in human HCC cell lines and patient-derived HCC primary cells. Based on its cytotoxicity, signaling pathways altered by sorafenib and the causative factors were examined through assays. The mechanism by which sorafenib modified the sorafenib-resistance inducer through gene or protein expression or stability was also investigated. We also designed a treatment option to overcome sorafenib resistance. RESULTS:Sorafenib activated the Raf/MEK/ERK pathway and caused sorafenib resistance in HCC cell lines and patient-derived HCC primary cells. Sorafenib reactivated the MAPK pathway by down-regulating RKIP at the post-translational level. Knockdown of RKIP increased phosphorylated ERK and thus suppressed sorafenib-mediated cell death. We also found that sorafenib-reactivated ERK maybe an attractive target for second-line therapy for patients with sorafenib resistance. Sequential combination treatment with sorafenib and PD98059 significantly reduced the viability and proliferation of sorafenib-resistant cells, while their increasing apoptosis efficacy. CONCLUSION: Reactivation of the Raf/MEK/ERK pathway through aberrant expression of RKIP is one of the mechanisms behind sorafenib resistance in HCC. Sequential combination treatment with sorafenib and PD98059 could provide a new strategy to overcome sorafenib resistance in future clinical studies.
Authors: Josep M Llovet; Sergio Ricci; Vincenzo Mazzaferro; Philip Hilgard; Edward Gane; Jean-Frédéric Blanc; Andre Cosme de Oliveira; Armando Santoro; Jean-Luc Raoul; Alejandro Forner; Myron Schwartz; Camillo Porta; Stefan Zeuzem; Luigi Bolondi; Tim F Greten; Peter R Galle; Jean-François Seitz; Ivan Borbath; Dieter Häussinger; Tom Giannaris; Minghua Shan; Marius Moscovici; Dimitris Voliotis; Jordi Bruix Journal: N Engl J Med Date: 2008-07-24 Impact factor: 91.245