Structural and functional characterization of β2-glycoprotein I domain 1 in anti-melanoma cell migration

Shr Jeng Jim Leu, Tzong Yi Lee, Shu Wei Cheng, Meng Ying Tsai, Yu Shan Lin, Tzeon Jye Chiou, Kai Yao Huang, An Na Chiang

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)


We previously found that circulating β2-glycoprotein I inhibits human endothelial cell migration, proliferation, and angiogenesis by diverse mechanisms. In the present study, we investigated the antitumor activities of β2-glycoprotein I using structure-function analysis and mapped the critical region within the β2-glycoprotein I peptide sequence that mediates anticancer effects. We constructed recombinant cDNA and purified different β2-glycoprotein I polypeptide domains using a baculovirus expression system. We found that purified β2-glycoprotein I, as well as recombinant β2-glycoprotein I full-length (D12345), polypeptide domains I-IV (D1234), and polypeptide domain I (D1) significantly inhibited melanoma cell migration, proliferation and invasion. Western blot analyses were used to determine the dysregulated expression of proteins essential for intracellular signaling pathways in B16-F10 treated with β2-glycoprotein I and variant recombinant polypeptides. Using a melanoma mouse model, we found that D1 polypeptide showed stronger potency in suppressing tumor growth. Structural analysis showed that fragments A and B within domain I would be the critical regions responsible for antitumor activity. Annexin A2 was identified as the counterpart molecule for β2-glycoprotein I by immunofluorescence and coimmunoprecipitation assays. Interaction between specific amino acids of β2-glycoprotein I D1 and annexin A2 was later evaluated by the molecular docking approach. Moreover, five amino acid residues were selected from fragments A and B for functional evaluation using site-directed mutagenesis, and P11A, M42A, and I55P mutations were shown to disrupt the anti-melanoma cell migration ability of β2-glycoprotein I. This is the first study to show the therapeutic potential of β2-glycoprotein I D1 in the treatment of melanoma progression.

Original languageEnglish
Pages (from-to)1974-1986
Number of pages13
JournalCancer Science
Issue number6
Publication statusPublished - Jun 2019
Externally publishedYes


  • anti-melanoma cell migration
  • melanoma growth
  • protein structure analysis
  • recombinant β-glycoprotein I polypeptide domain
  • site-directed mutagenesis

ASJC Scopus subject areas

  • Oncology
  • Cancer Research


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