Research Paper|Volume 11, Issue 15|pp 5483—5497

CBX3/HP1γ promotes tumor proliferation and predicts poor survival in hepatocellular carcinoma

Xiaoping Zhong^1,², Anna Kan², Wancong Zhang¹, Jianda Zhou³, Huayong Zhang^2,⁴, Jiasheng Chen¹, Shijie Tang¹

¹Department of Burns and Plastic Surgery, The Second Affiliated Hospital of Shantou University Medical College, Shantou, Guangdong 515041, P.R. China
²The Department of Hepatobiliary Oncology of Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Guangzhou, Guangdong 510060, P.R. China
³Department of Plastic Surgery, The Third Xiangya Hospital of Central South University, Changsha, Hunan 410013, P.R. China
⁴Department of Thyroid and Breast Surgery, The Fifth Affiliated Hospital of Sun Yat sen University, Zhuhai, Guangdong 519000, P.R. China

Received: April 24, 2019Accepted: July 26, 2019Published: August 2, 2019

Copyright © 2019 Zhong et al. This is an open-access article distributed under the terms of the Creative Commons Attribution (CC BY) 3.0 License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Abstract

HP1γ, encoded by CBX3, is associated with cancer progression and patient prognosis. However, the prognostic value and functions of CBX3/HP1γ in hepatocellular carcinoma (HCC) remain unclear. Here, we performed a bioinformatics analysis using the Oncomine, TCGA and Human Protein Atlas databases, the Kaplan-Meier plotter, and the UALCAN web-portal to explore the expression and prognostic significance of CBX3/HP1γ in patients with different cancers, including liver cancer. HCC tissues and microarrays containing 354 samples were examined using immunohistochemical staining, quantitative real-time polymerase chain reaction, and Western blotting. CBX3-overexpression HCC cell lines were tested in proliferation assays to determine the function of CBX3/HP1γ. We found that CBX3/HP1γ was upregulated in many cancers and was associated with poor prognosis. Our results also revealed that CBX3/HP1γ is elevated in HCC tissues and is associated with malignant clinicopathological characteristics. Kaplan-Meier and Cox regression analyses verified that high CBX3/HP1γ expression is an independent and significant prognostic factor for reduced overall survival in HCC patients. Moreover, in vitro functional assays showed that CBX3/HP1γ overexpression promotes HCC cell proliferation. These findings suggest that CBX3/HP1γ is an important oncogene in HCC that might act as a useful biomarker for prognosis and targeted therapy.