Laminin-332 cleavage by matriptase alters motility parameters of prostate cancer cells.
BACKGROUND
Matriptase, a type II transmembrane serine protease, has been linked to initiation and promotion of epidermal carcinogenesis in a murine model, suggesting that deregulation of its role in epithelia contributes to transformation. In human prostate cancer, matriptase expression correlates with progression. It is therefore of interest to determine how matriptase may contribute to epithelial neoplastic progression. One approach for studying this is to identify potential matriptase substrates involved in epithelial integrity and/or transformation like the extracellular matrix macromolecule, laminin-332 (Ln-332), which is found in the basement membrane of many epithelia, including prostate. Proteolytic processing of Ln-332 regulates cell motility of both normal and transformed cells, which has implications in cancer progression.


METHODS
In vitro cleavage experiments were performed with purified Ln-332 protein and matriptase. Western blotting, enzyme inhibition assays, and mass spectrometry were used to confirm cleavage events. Matriptase overexpressing LNCaP prostate cancer cells were generated and included in Transwell migration assays and single cell motility assays, along with other prostate cells.


RESULTS
We report that matriptase proteolytically cleaves Ln-332 in the β3 chain. Substrate specificity was confirmed by blocking cleavage with the matriptase inhibitor, Kunitz domain-1. Transwell migration assays showed that DU145 cell motility was significantly enhanced when plated on matriptase-cleaved Ln-332. Similarly, Transwell migration of matriptase-overexpressing LNCaP cells was significantly increased on Ln-332 and, as determined by live single-cell microscopy, two motility parameters of this cell line, speed and directional persistence, were also higher.


CONCLUSIONS
Proteolytic processing of Ln-332 by matriptase enhances speed and directional persistence of prostate cancer cells.
Tripathi
Manisha
M
Department of Cancer Biology, Vanderbilt University Medical Center, Nashville, Tennessee, USA.
Potdar
Alka A
AA
Yamashita
Hironobu
H
Weidow
Brandy
B
Cummings
Peter T
PT
Kirchhofer
Daniel
D
Quaranta
Vito
V
D045744:Cell Line, Tumor; D002465:Cell Movement / Q000502:physiology*; D006801:Humans; D007797:Laminin / Q000378:metabolism*; D008297:Male; D008858:Microscopy, Phase-Contrast; D011471:Prostatic Neoplasms / Q000201:enzymology / Q000378:metabolism* / Q000473:pathology; D053491:Proteinase Inhibitory Proteins, Secretory / Q000494:pharmacology; D012697:Serine Endopeptidases / Q000378:metabolism*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
D007797:Laminin; D053491:Proteinase Inhibitory Proteins, Secretory; C109149:SPINT1 protein, human; D012697:Serine Endopeptidases; C485595:matriptase