1. Academic Validation
  2. FBXO22 promotes the development of hepatocellular carcinoma by regulating the ubiquitination and degradation of p21

FBXO22 promotes the development of hepatocellular carcinoma by regulating the ubiquitination and degradation of p21

  • J Exp Clin Cancer Res. 2019 Feb 26;38(1):101. doi: 10.1186/s13046-019-1058-6.
Long Zhang 1 2 Jin Chen 1 Deng Ning 3 Qiumeng Liu 1 Chao Wang 1 Zhaoqi Zhang 1 Liang Chu 1 Chengpeng Yu 1 Hui-Fang Liang 4 Bixiang Zhang 5 Xiaoping Chen 6
Affiliations

Affiliations

  • 1 Hepatic Surgery Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Clinical Medicine Research Center for Hepatic Surgery of Hubei Province, Key Laboratory of Organ Transplantation, Ministry of Education, NHC Key Laboratory of Organ Transplantation, Key Laboratory of Organ Transplantation, Chinese Academy of Medical Sciences, Wuhan, Hubei, 430030, People's Republic of China.
  • 2 Department of Hepatobiliary Surgery, The First Affiliated Hospital, College of Medicine, Shihezi University, Shihezi, Xinjiang, 832008, People's Republic of China.
  • 3 Department of Biliary and Pancreatic Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, 430030, People's Republic of China.
  • 4 Hepatic Surgery Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Clinical Medicine Research Center for Hepatic Surgery of Hubei Province, Key Laboratory of Organ Transplantation, Ministry of Education, NHC Key Laboratory of Organ Transplantation, Key Laboratory of Organ Transplantation, Chinese Academy of Medical Sciences, Wuhan, Hubei, 430030, People's Republic of China. lianghuifang1997@126.com.
  • 5 Hepatic Surgery Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Clinical Medicine Research Center for Hepatic Surgery of Hubei Province, Key Laboratory of Organ Transplantation, Ministry of Education, NHC Key Laboratory of Organ Transplantation, Key Laboratory of Organ Transplantation, Chinese Academy of Medical Sciences, Wuhan, Hubei, 430030, People's Republic of China. bixiangzhang@163.com.
  • 6 Hepatic Surgery Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Clinical Medicine Research Center for Hepatic Surgery of Hubei Province, Key Laboratory of Organ Transplantation, Ministry of Education, NHC Key Laboratory of Organ Transplantation, Key Laboratory of Organ Transplantation, Chinese Academy of Medical Sciences, Wuhan, Hubei, 430030, People's Republic of China. chenxpchenxp@163.com.
Abstract

Background: Deregulation of ubiquitin ligases is related to the malignant progression of human cancers. F-box only protein 22 (FBXO22), an F-box E3 Ligase, is a member of the F-box protein family. However, the biological function of FBXO22 in HCC and the underlying molecular mechanisms are still unclear. In this study, we explored the role of FBXO22 in HCC and its mechanism of promoting tumor development.

Methods: We examined the expression of FBXO22 in normal liver cell lines, HCC cell lines, HCC tissue microarrays and fresh specimens. The correlation between FBXO22 and clinical features was analyzed in a retrospective study of 110 pairs of HCC tissue microarrays. Univariate and multivariate survival analyses were used to explore the prognostic value of FBXO22 in HCC. At the same time, the correlation between the FBXO22 and p21 was also studied in HCC samples. Knock-down and overexpression experiments, CHX and Mg132 intervention experiments, ubiquitination experiments, rescue experiments and nude mouse xenograft models were used to determine the potential mechanism by which FBXO22 promotes tumorigenesis in vitro and in vivo.

Results: The expression of FBXO22 in HCC tissues was significantly higher than in normal liver tissues. The overall survival rate and disease-free survival time of patients with high expression of FBXO22 were significantly shorter than those of patients with low expression of FBXO22. The high expression of FBXO22 in HCC tissues were significantly correlated with serum AFP (p = 0. 003, Pearson's chi-squared test), tumor size (p = 0. 019, Pearson's chi-squared test) and vascular invasion (p = 0. 031, Pearson's chi-squared test). Especially, Multivariate analysis showed that tumor size and the expression of FBXO22 were independent prognostic indicator of OS (95% CI: 1.077-5.157, P<0.05). Correlation analysis also showed that FBXO22 was negatively correlated with p21 in tissue microarrays (r = - 0.3788, P<0.001, Pearson correlation) and fresh specimens (r = - 0.4037, P<0.01, Pearson correlation). Moreover, both in vitro and in vivo experiments showed that knocking down FBXO22 expression could inhibit cell proliferation, while overexpression of FBXO22 promoted tumor formation. Furthermore, we identified that FBXO22 interacts with p21 by regulating protein stability and by influencing the ubiquitination process. A knockdown of FBXO22 decreased the ubiquitylation of p21, while overexpression enhanced it.

Conclusions: This study uncovered a new mechanism by which FBXO22 functions as an oncogene in HCC pathogenesis and progression by mediating the ubiquitination and degradation of p21. It was also found that tumor size and the expression of FBXO22 were independent prognostic indicator of OS and the expression of FBXO22 and p21 was negatively correlated in clinical samples. Our findings present a new perspective for understanding the development of HCC, which may provide a new target for the treatment and management of this challenging Cancer.

Keywords

FBXO22; HCC; Ubiquitination; p21.

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