Shikonin-induced necroptosis in nasopharyngeal carcinoma cells via ROS overproduction and upregulation of RIPK1/RIPK3/MLKL expression
Authors Liu TC, Sun X, Cao ZW
Received 7 January 2019
Accepted for publication 9 March 2019
Published 9 April 2019 Volume 2019:12 Pages 2605—2614
Checked for plagiarism Yes
Review by Single-blind
Peer reviewer comments 2
Editor who approved publication: Dr Sanjeev Srivastava
Tiancong Liu,1 Xun Sun,2 Zhiwei Cao1
1Department of Otorhinolaryngology – Head and Neck Surgery, Shengjing Hospital, China Medical University, Shenyang, Liaoning, People’s Republic of China; 2Department of Immunology, College of Basic Medicine, China Medical University, Shenyang, Liaoning, People’s Republic of China
Objective: Shikonin has inhibitory effects against nasopharyngeal carcinoma that are mediated through the apoptotic pathway. However, necroptosis signaling pathways may enable the elimination of apoptosis-resistant cancers when induced with targeted therapeutic agents. Thus, there is a need to clarify whether shikonin can cause necroptosis in nasopharyngeal carcinoma and to elucidate the underlying mechanisms.
Methods: In this study, we used the nasopharyngeal carcinoma cell line 5-8F and a 5-8F xenograft mouse model to evaluate the anticancer effects of shikonin. The viability and morphology of cells treated with shikonin were evaluated using CCK-8 assay and transmission electron microscopy, respectively. In addition, the expression levels of RIPK1, RIPK3, and MLKL were analyzed by western blotting, and the activities of caspase-3 and caspase-8 and levels of reactive oxygen species (ROS) were assessed.
Results: Shikonin exhibited a strong inhibitory effect on 5-8F cells in vitro and in vivo. The shikonin-treated 5-8F cells presented an electron-lucent cytoplasm, loss of plasma membrane integrity, and an intact nuclear membrane, indicating that shikonin induced necroptosis. Shikonin-induced cell death was inhibited by necrostatin-1. Moreover, RIPK1, RIPK3, and MLKL were upregulated by shikonin in a dose-dependent manner. Furthermore, shikonin significantly inhibited tumor growth in the 5-8F xenograft mouse model.
Conclusion: Shikonin induced 5-8F cell death via increased ROS production and the upregulation of RIPK1/RIPK3/MLKL expression, resulting in necroptosis. Thus, shikonin may represent a novel agent to treat nasopharyngeal carcinoma.
Keywords: nasopharyngeal carcinoma, necroptosis, reactive oxygen species, shikonin
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