Effects of cancer-testis antigen, TFDP3, on cell cycle regulation and its mechanism in L-02 and HepG2 cell lines in vitro

PLoS One. 2017 Aug 10;12(8):e0182781. doi: 10.1371/journal.pone.0182781. eCollection 2017.

Abstract

TFDP3, also be known as HCA661, was one of the cancer-testis antigens, which only expressed in human tissues. The recent researches about TFDP3 mostly focused on its ability to control the drug resistance and apoptosis of tumor cells. However, the role of TFDP3 in the progress of the cell cycle is rarely involved. In this study, we examined the expression of TFDP3 in human liver tissues firstly. After that, we detect the expression of TFDP3 at the RNA level and protein level in L-02 cell line and HepG2 cell line, and the location of TFDP3 was defined by immunofluorescence technique. Furthermore, we synchronized the cells to G1 phase, S phase and G2 phase, and arrested cell mitosis. The localization of TFDP3 and co-localization with E2F1 molecules in different phases of hepatocyte lines. Finally, TFDP3 gene knockout was performed on L-02 and HepG2 cell lines, and detected the new cell cycles by flow cytometry. The result showed that the expression of TFDP3 molecule is negative in normal liver tissue, but positive in immortalized human hepatocyte cell line, and the expression level is lower than in hepatocellular carcinoma cell line. The expression level of TFDP3 was in the dynamic change of L-02 and HepG2 cell lines, and was related to the phase transition. TFDP3 can bind to E2F1 molecule to form E2F/TFDP3 complex; and the localizations of TFDP3 and E2F1 molecules and the co-localization were different in different phases of cell cycle in the nucleus and cytoplasm, which indicated that the E2F/TFDP3 complex involved in the process of regulating the cell cycle. By knocking down the TFDP3 expression level in L-02 and HepG2 cell lines, the cell cycle would be arrested in S phase, which confirmed that TFDP3 can be a potential target for tumor therapy.

MeSH terms

  • Carcinoma, Hepatocellular / metabolism
  • E2F1 Transcription Factor / metabolism
  • Hep G2 Cells
  • Humans
  • Liver / metabolism
  • Liver Neoplasms / metabolism
  • Male
  • S Phase Cell Cycle Checkpoints*
  • Testis / metabolism
  • Transcription Factor DP1 / physiology*

Substances

  • E2F1 Transcription Factor
  • E2F1 protein, human
  • TFDP3 protein, human
  • Transcription Factor DP1

Grants and funding

This work was supported by Natural Science Foundation of Beijing Municipality (7162099, 7174316)(http://www.bjnsf.org/), Science and Technology Program of Shenzhen (JCYJ20150403110829615)(http://www.szsti.gov.cn), National Natural Science Foundation of China (81603119)(http://www.nsfc.gov.cn/), Leading Academic Discipline Project of Beijing Education Bureau (BMU20110254)(http://www.bjedu.gov.cn/)and Fostering Talents in Basic Science of the National Natural Science Foundation of China (J1030831/J0108)(http://www.nsfc.gov.cn/). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.