Trichonomas vaginalis metalloproteinase induces apoptosis of SiHa cells through disrupting the Mcl-1/Bim and Bcl-xL/Bim complexes

PLoS One. 2014 Oct 24;9(10):e110659. doi: 10.1371/journal.pone.0110659. eCollection 2014.

Abstract

To elucidate the roles of metalloproteinases and the Bcl-2 family of proteins in Trichovaginalis. vaginalis-induced apoptosis in human cervical cancer cells (SiHa cells) and vaginal epithelial cells (MS74 cells), SiHa cells and MS74 cells were incubated with live T. vaginalis, T. vaginalis excretory and secretory products (ESP), and T. vaginalis lysates, either with or without the specific metalloproteinase inhibitor 1,10-phenanthroline (1,10-PT), and examined apoptotic events and Bcl-2 signaling. The live T. vaginalis and the T. vaginalis ESP induced the release of cytochrome c into the cytosol, the activation of caspase-3 and caspase-9, and the cleavage of PARP. Additionally, the live T. vaginalis, but not the T. vaginalis lysate, induced the cleavage of the proapoptotic Bim protein. The live T. vaginalis and the T. vaginalis ESP, but not the T. vaginalis lysate, induced the dose-dependent cleavage of the antiapoptotic Bcl-xL and Mcl-1 proteins and decreased the association levels of Bcl-xL/Bim and Mcl-1/Bim complexes. We performed gelatin zymography and casein-hydrolysis assays on the live T. vaginalis and the T. vaginalis ESP to identify the apoptosis-inducing factor. Both the live T. vaginalis and the ESP contained high levels of metalloproteinases, of which activities were significantly inhibited by 1,10-PT treatment. Furthermore, the 1,10-PT blocked the cleavage of Bcl-xL, Mcl-1, PARP, caspase-3, and caspase-9, as well as the release of cytochrome c into the cytosol, and it significantly increased the association levels of the Bcl-xL/Bim and Mcl-1/Bim protein complexes, returning them to normal levels. Our results demonstrate that T. vaginalis induces mitochondria-dependent apoptosis in SiHa cells through the dissociation of Bcl-xL/Bim and Mcl-1/Bim complexes and that the apoptosis is blocked by the metalloproteinase inhibitor 1,10-PT. These results expand our understanding of the role of metalloproteinases in T. vaginalis-induced apoptosis and the signaling pathway in trichomoniasis of the cervicovaginal epithelial cells.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antigens, Protozoan / immunology
  • Apoptosis Regulatory Proteins / metabolism*
  • Apoptosis* / drug effects
  • Bcl-2-Like Protein 11
  • Blotting, Western
  • Cell Line, Tumor
  • Female
  • Humans
  • Membrane Proteins / metabolism*
  • Metalloproteases / metabolism*
  • Mitochondria / drug effects
  • Mitochondria / metabolism
  • Multiprotein Complexes / metabolism*
  • Myeloid Cell Leukemia Sequence 1 Protein / metabolism*
  • Parasites / drug effects
  • Parasites / physiology
  • Phenanthrolines / pharmacology
  • Protein Binding / drug effects
  • Proto-Oncogene Proteins / metabolism*
  • Trichomonas vaginalis / drug effects
  • Trichomonas vaginalis / enzymology*
  • Trichomonas vaginalis / immunology
  • bcl-X Protein / metabolism*

Substances

  • Antigens, Protozoan
  • Apoptosis Regulatory Proteins
  • BCL2L11 protein, human
  • Bcl-2-Like Protein 11
  • Membrane Proteins
  • Multiprotein Complexes
  • Myeloid Cell Leukemia Sequence 1 Protein
  • Phenanthrolines
  • Proto-Oncogene Proteins
  • bcl-X Protein
  • Metalloproteases
  • 1,10-phenanthroline

Grants and funding

This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIP) (No. 2007-0054932), and National Natural Science Foundation of China (Grant No. 81300368 to Juan-Hua Quan). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.