Internalization of cystatin C in human cell lines.
(2008) In The FEBS Journal Aug 9. p.4571-4582- Abstract
- Altered protease activity is considered important for tumour invasion and metastasis, processes in which the cysteine proteases cathepsin B and L are involved. Their natural inhibitor cystatin C is a secreted protein, suggesting that it functions to control extracellular protease activity. Because cystatins added to cell cultures can inhibit polio, herpes simplex and coronavirus replication, which are intracellular processes, the internalization and intracellular regulation of cysteine proteases by cystatin C should be considered. The extension, mechanism and biological importance of this hypothetical process are unknown. We investigated whether internalization of cystatin C occurs in a set of human cell lines. Demonstrated by flow... (More)
- Altered protease activity is considered important for tumour invasion and metastasis, processes in which the cysteine proteases cathepsin B and L are involved. Their natural inhibitor cystatin C is a secreted protein, suggesting that it functions to control extracellular protease activity. Because cystatins added to cell cultures can inhibit polio, herpes simplex and coronavirus replication, which are intracellular processes, the internalization and intracellular regulation of cysteine proteases by cystatin C should be considered. The extension, mechanism and biological importance of this hypothetical process are unknown. We investigated whether internalization of cystatin C occurs in a set of human cell lines. Demonstrated by flow cytometry and confocal microscopy, A-431, MCF-7, MDA-MB-453, MDA-MB-468 and Capan-1 cells internalized fluorophore-conjugated cystatin C when exposed to physiological concentrations (1 mum). During cystatin C incubation, intracellular cystatin C increased after 5 min and accumulated for at least 6 h, reaching four to six times the baseline level. Western blotting showed that the internalized inhibitor was not degraded. It was functionally intact and extracts of cells exposed to cystatin C showed a higher capacity to inhibit papain and cathepsin B than control cells (decrease in enzyme activity of 34% and 37%, respectively). The uptake of labelled cystatin C was inhibited by unlabelled inhibitor, suggesting a specific pathway for the internalization. We conclude that the cysteine protease inhibitor cystatin C is internalized in significant quantities in various cancer cell lines. This is a potentially important physiological phenomenon not previously described for this group of inhibitors. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/1223249
- author
- Ekström, Ulf LU ; Wallin, Hanna LU ; Lorenzo, Julia ; Holmqvist, Bo LU ; Abrahamson, Magnus LU and Avilés, Francesc X
- organization
- publishing date
- 2008
- type
- Contribution to journal
- publication status
- published
- subject
- in
- The FEBS Journal
- volume
- Aug 9
- pages
- 4571 - 4582
- publisher
- Wiley-Blackwell
- external identifiers
-
- wos:000258729100013
- pmid:18699780
- scopus:50849110155
- ISSN
- 1742-464X
- DOI
- 10.1111/j.1742-4658.2008.06600.x
- language
- English
- LU publication?
- yes
- additional info
- The information about affiliations in this record was updated in December 2015. The record was previously connected to the following departments: Division of Clinical Chemistry and Pharmacology (013250300), Pathology, (Lund) (013030000)
- id
- ae1fea72-2164-4be2-92bf-de56bab7e798 (old id 1223249)
- alternative location
- http://www.ncbi.nlm.nih.gov/pubmed/18699780?dopt=Abstract
- date added to LUP
- 2016-04-04 09:04:36
- date last changed
- 2022-03-15 17:32:34
@article{ae1fea72-2164-4be2-92bf-de56bab7e798,
abstract = {{Altered protease activity is considered important for tumour invasion and metastasis, processes in which the cysteine proteases cathepsin B and L are involved. Their natural inhibitor cystatin C is a secreted protein, suggesting that it functions to control extracellular protease activity. Because cystatins added to cell cultures can inhibit polio, herpes simplex and coronavirus replication, which are intracellular processes, the internalization and intracellular regulation of cysteine proteases by cystatin C should be considered. The extension, mechanism and biological importance of this hypothetical process are unknown. We investigated whether internalization of cystatin C occurs in a set of human cell lines. Demonstrated by flow cytometry and confocal microscopy, A-431, MCF-7, MDA-MB-453, MDA-MB-468 and Capan-1 cells internalized fluorophore-conjugated cystatin C when exposed to physiological concentrations (1 mum). During cystatin C incubation, intracellular cystatin C increased after 5 min and accumulated for at least 6 h, reaching four to six times the baseline level. Western blotting showed that the internalized inhibitor was not degraded. It was functionally intact and extracts of cells exposed to cystatin C showed a higher capacity to inhibit papain and cathepsin B than control cells (decrease in enzyme activity of 34% and 37%, respectively). The uptake of labelled cystatin C was inhibited by unlabelled inhibitor, suggesting a specific pathway for the internalization. We conclude that the cysteine protease inhibitor cystatin C is internalized in significant quantities in various cancer cell lines. This is a potentially important physiological phenomenon not previously described for this group of inhibitors.}},
author = {{Ekström, Ulf and Wallin, Hanna and Lorenzo, Julia and Holmqvist, Bo and Abrahamson, Magnus and Avilés, Francesc X}},
issn = {{1742-464X}},
language = {{eng}},
pages = {{4571--4582}},
publisher = {{Wiley-Blackwell}},
series = {{The FEBS Journal}},
title = {{Internalization of cystatin C in human cell lines.}},
url = {{http://dx.doi.org/10.1111/j.1742-4658.2008.06600.x}},
doi = {{10.1111/j.1742-4658.2008.06600.x}},
volume = {{Aug 9}},
year = {{2008}},
}