Quantitative phosphoproteomic analysis reveals γ‐bisabolene inducing p53‐mediated apoptosis of human oral squamous cell carcinoma via HDAC2 inhibition and ERK1/2 activation |
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Authors: | Yu‐Jen Jou Chao‐Jung Chen Yu‐Ching Liu Tzong‐Der Way Chih‐Ho Lai Chun‐Hung Hua Ching‐Ying Wang Su‐Hua Huang Jung‐Yie Kao Cheng‐Wen Lin |
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Institution: | 1. Department of Medical Laboratory Science and Biotechnology, China Medical University, Taichung, Taiwan;2. Department of biochemistry, College of life sciences, National Chung Hsing University, Taichung, Taiwan;3. Graduate Institute of Integrated Medicine, China Medical University, Taichung, Taiwan;4. Proteomics Core Laboratory, Department of Medical Research, China Medical University Hospital, Taichung, Taiwan;5. Department of Biological Science and Technology, China Medical University, Taichung, Taiwan;6. Department of Microbiology, School of Medicine, China Medical University, Taichung, Taiwan;7. Department of Otolaryngology, China Medical University Hospital, Taichung, Taiwan;8. School of Chinese Pharmaceutical Sciences and Chinese Medicine Resources, China Medical University, Taichung, Taiwan;9. Department of Biotechnology, College of Health Science, Asia University, Taichung, Taiwan |
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Abstract: | γ‐Bisabolene, one of main components in cardamom, showed potent in vitro and in vivo anti‐proliferative activities against human oral squamous cell carcinoma (OSCC). γ‐Bisabolene activated caspases‐3/9 and decreased mitochondrial memebrane potential, leading to apoptosis of OSCC cell lines (Ca9‐22 and SAS), but not normal oral fibroblast cells. Phosphoproteome profiling of OSCC cells treated with γ‐bisabolene was identified using TiO2‐PDMS plate and LC‐MS/MS, then confirmed using Western blotting and real‐time RT‐PCR assays. Phosphoproteome profiling revealed that γ‐bisabolene increased the phosphorylation of ERK1/2, protein phosphatases 1 (PP1), and p53, as well as decreased the phosphorylation of histone deacetylase 2 (HDAC2) in the process of apoptosis induction. Protein–protein interaction network analysis proposed the involvement of PP1‐HDAC2‐p53 and ERK1/2‐p53 pathways in γ‐bisabolene‐induced apoptosis. Subsequent assays indicated γ‐bisabolene eliciting p53 acetylation that enhanced the expression of p53‐regulated apoptotic genes. PP1 inhibitor‐2 restored the status of HDAC2 phosphorylation, reducing p53 acetylation and PUMA mRNA expression in γ‐bisabolene‐treated Ca9‐22 and SAS cells. Meanwhile, MEK and ERK inhibitors significantly decreased γ‐bisabolene‐induced PUMA expression in both cancer cell lines. Notably, the results ascertained the involvement of PP1‐HDAC2‐p53 and ERK1/2‐p53 pathways in mitochondria‐mediated apoptosis of γ‐bisabolene‐treated cells. This study demonstrated γ‐bisabolene displaying potent anti‐proliferative and apoptosis‐inducing activities against OSCC in vitro and in vivo, elucidating molecular mechanisms of γ‐bisabolene‐induced apoptosis. The novel insight could be useful for developing anti‐cancer drugs. |
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Keywords: | γ ‐Bisabolene Cell biology Histone deacetylase Oral squamous cell carcinoma Phosphoproteomics P53 acetylation |
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