OncoTargets and Therapy (Jul 2017)
Targeted TPX2 increases chromosome missegregation and suppresses tumor cell growth in human prostate cancer
Abstract
Hung-Wei Pan,1,2,* Hsing-Hao Su,3,4,* Chao-Wen Hsu,5,6 Guan-Jin Huang,7 Tony Tong-Lin Wu6,8 1Department of Medical Education and Research, Kaohsiung Veterans General Hospital, Kaohsiung, 2Department of Applied Chemistry, National Pingtung University, Pingtung, 3Department of Otorhinolaryngology-Head and Neck Surgery, 4Department of Pharmacy and Graduate Institute of Pharmaceutical Technology, Tajen University, Pingtung, 5Division of Colorectal Surgery, Department of Surgery, Kaohsiung Veterans General Hospital, Kaohsiung, 6Faculty of Medicine, School of Medicine, National Yang-Ming University, Taipei, 7Department of Pathology, National Chung Kung University Hospital, Tainan, 8Department of Surgery, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan *These authors contributed equally to this work Abstract: Prostate cancer is a complex disease that can be relatively harmless or extremely aggressive. Although androgen-deprivation therapy is a commonly used treatment for men with prostate cancer, the adverse effects can be detrimental to patient health and quality of life. Therefore, identifying new target genes for tumor growth will enable the development of novel therapeutic intervention. TPX2 plays a critical role in chromosome segregation machinery during mitosis. Low rates of chromosome missegregation can promote tumor development, whereas higher levels might promote cell death and suppress tumorigenesis. Hence, the strategy of promoting cell death by inducing massive chromosome missegregation has been a therapeutic application for selectively eliminating highly proliferating tumor cells. RNAi was used for TPX2 protein expression knockdown, and a clonogenic assay, immunostaining, double thymidine block, image-cytometry analysis, and tumor spheroid assay were used to analyze the role of TPX2 in tumor cell growth, cell cycle progression, multinuclearity, ploidy, and tumorigenicity, respectively; finally, Western blotting was used to analyze anticancer mechanisms in TPX2 targeting. We demonstrated that targeting TPX2 reduced cell cycle regulators and chromosome segregation genes, resulting in increased cell micronucleation. Moreover, TPX2 depletion led to prostate cancer cell growth inhibition, increased apoptosis, and reduced tumorigenesis. These results confirmed the therapeutic potential of targeting TPX2 in prostate cancer treatment. Moreover, we found that TPX2 silencing led to deregulation of CDK1, cyclin B, securin, separase, and aurora A proteins; by contrast, p21 mRNA was upregulated. We also determined the molecular mechanisms for TPX2 targeting in prostate cancer cells. In conclusion, our study illustrates the power of TPX2 as a potential novel target gene for prostate cancer treatment. Keywords: TPX2, prostate cancer, micronucleation
