Expression of prostasin and its inhibitors during colorectal cancer carcinogenesis
Research output: Contribution to journal › Journal article › Research › peer-review
ABSTRACT: BACKGROUND: Clinical trials where cancer patients were treated with protease inhibitors have suggested that the serine protease, prostasin, may act as a tumour suppressor. Prostasin is proteolytically activated by the serine protease, matriptase, which has a very high oncogenic potential. Prostasin is inhibited by protease nexin-1 (PN-1) and the two isoforms encoded by the mRNA splice variants of hepatocyte growth factor activator inhibitor-1 (HAI-1), HAI-1A, and HAI-1B. METHODS: Using quantitative RT-PCR, we have determined the mRNA levels for prostasin and PN-1 in colorectal cancer tissue (n=116), severe dysplasia (n=13), mild/moderate dysplasia (n=93), and in normal tissue from the same individuals. In addition, corresponding tissues were examined from healthy volunteers (n=23). A part of the cohort was further analysed for the mRNA levels of the two variants of HAI-1, here denoted HAI-1A and HAI-1B. mRNA levels were normalised to beta-actin. Immunohistochemical analysis of prostasin and HAI-1 was performed on normal and cancer tissue. RESULTS: The mRNA level of prostasin was slightly but significantly decreased in both mild/moderate dysplasia (p<0.001) and severe dysplasia (p<0.01) and in carcinomas (p<0.05) compared to normal tissue from the same individual. The mRNA level of PN-1 was more that two-fold elevated in colorectal cancer tissue as compared to healthy individuals (p<0.001) and elevated in both mild/moderate dysplasia (p<0.01), severe dysplasia (p<0.05) and in colorectal cancer tissue (p<0.001) as compared to normal tissue from the same individual. The mRNA levels of HAI-1A and HAI-1B mRNAs showed the same patterns of expression. Immunohistochemistry showed that prostasin is located mainly on the apical plasma membrane in normal colorectal tissue. A large variation was found in the degree of polarization of prostasin in colorectal cancer tissue. CONCLUSIONS: These results show that the mRNA level of PN-1 is significantly elevated in colorectal cancer tissue. Future studies are required to clarify whether down-regulation of prostasin activity via up regulation of PN-1 is causing the malignant progression or if it is a consequence of it.
Original language | English |
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Journal | BMC Cancer |
Volume | 9 |
Issue number | 1 |
Pages (from-to) | 201 |
Number of pages | 1 |
ISSN | 1471-2407 |
DOIs | |
Publication status | Published - 2009 |
ID: 12921231