Selective localization of matrix metalloproteinase 9, β1 integrins, and human lymphocyte antigen class I molecules on membrane vesicles shed by 8701-BC breast carcinoma cells

Vincenza Dolo, Angela Ginestra, Donata Cassarà, Stefania Violini, Giuseppe Lucania, Maria Rosaria Torrisi, Hideaki Nagase, Silvana Canevari, Antonio Pavan, Maria Letizia Vittorelli

Research output: Contribution to journalArticlepeer-review

Abstract

The shedding of membrane vesicles from the cell surface is a vital process considered to be involved in cell-cell and cell-matrix interactions and in tumor progression. By immunoelectron microscopic analysis of surface replicas of 8701-BC human breast carcinoma cells, we observed that membrane vesicles shed from plasma membranes contained densely clustered gelatinase B [matrix metalloproteinase 9 (MMP-9)], β1 integrins, and human lymphocyte antigen class I molecules. By contrast, α-folate receptor was uniformly distributed on the smooth cell membrane and shedding areas. Both cell surface clustering of selected molecules and membrane vesicle release were evident only when cells were cultured in the presence of serum. Vesicle shedding occurred preferentially at the edge or along narrow protrusions of the cell. Specific accumulation of proMMP-9 and active forms of MMP-9 in shed vesicles was also demonstrated by gelatin zymography. In addition, Western blotting analysis showed the presence of a large amount of proMMP-9/tissue inhibitor of metalloproteinase I complex. The release of selected areas of plasma membranes enriched with MMP-9 and β1 integrins indicates that membrane vesicle shedding from tumor cells plays an important role in the directional proteolysis of the extracellular matrix during cellular migration. The presence of human lymphocyte antigen class I antigens suggests a mechanism for tumor cells to escape from immune surveillance.

Original languageEnglish
Pages (from-to)4468-4474
Number of pages7
JournalCancer Research
Volume58
Issue number19
Publication statusPublished - Oct 1 1998

ASJC Scopus subject areas

  • Cancer Research
  • Oncology

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