Kallikrein-related peptidase 4: a new activator of the aberrantly expressed protease-activated receptor 1 in colon cancer cells.
Publication year
2010Source
American Journal of Pathology, 176, 3, (2010), pp. 1452-61ISSN
Annotation
01 maart 2010
Publication type
Article / Letter to editor
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Organization
Laboratory of Genetic, Endocrine and Metabolic Diseases
Journal title
American Journal of Pathology
Volume
vol. 176
Issue
iss. 3
Page start
p. 1452
Page end
p. 61
Subject
IGMD 6: Hormonal regulation; ONCOL 5: Aetiology, screening and detection; Laboratory Medicine Radboud University Medical CenterAbstract
Certain serine proteases are considered to be signaling molecules that act through protease-activated receptors (PARs). Our recent studies have implicated PAR1 and PAR4 (thrombin receptors) and PAR2 (trypsin receptor) in human colon cancer growth. Here we analyzed the expression of KLK4, a member of the kallikrein-related peptidase (KLK) family of serine proteases and explored whether this member can activate PAR1 and PAR2 in human colon cancer cells. Immunohistochemistry showed KLK4 expression in human colon adenocarcinomas and its absence in normal epithelia. KLK4 (1 micromol/L) initiated loss of PAR1 and PAR2 from the HT29 cell surface as well as increased intracellular calcium transients in HT29 cells. This KLK4-induced Ca2+ flux was abrogated after an initial challenge of the cells with TRAP (SFLLR-NH2; 100 micromol/L), which is known to desensitize PAR1 and PAR2. Interestingly, PAR1 blocking antibody, which inhibits cleavage and activation by thrombin, dramatically reduced KLK4-induced Ca2+ influx, but blocking cleavage of PAR2 failed to attenuate the KLK4-induced Ca2+ flux. Consistently, desensitization with AP1 (TFFLR-NH2), targeting PAR1, attenuated most of the Ca2+ flux induced by KLK4. KLK4 also induced a rapid and significant ERK1/2 phosphorylation in HT29 cells. Our results demonstrate, for the first time, that KLK4 is aberrantly expressed in colon cancer and capable of inducing PAR1 signaling in cancer cells. These data suggest that KLK4 signaling via PAR1 may represent a novel pathway in colon tumorigenesis.
This item appears in the following Collection(s)
- Academic publications [246764]
- Electronic publications [134215]
- Faculty of Medical Sciences [93461]
- Open Access publications [107745]
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