Abstract
Human proteinase inhibitor-9 (PI-9)/serpinB9 is an intracellular ovalbumin-family serpin with nucleocytoplasmic distribution which is expressed in certain normal cell types and cancer cells of different origin. Due to binding and inactivating of granzyme B (GrB), PI-9 can protect the cells from GrB-mediated apoptosis. High levels of PI-9 expression in certain cancer cells may contribute to their resistance against the immune mediated killing. So far, it is not known whether non-small cell lung cardinomas (NSCLCs) express PI-9 mRNA and a functional PI-9 protein. Herein we report for the first time that NSCLC cells express both PI-9 mRNA and protein and that there is a subset of NSCLC cells with upregulated PI-9 mRNA and protein expression. Futhermore, our work revealed that the PI-9 protein expressed in NSCLC cells can inhibit the active GrB. Finally, analysis of PI-9 mRNA expression in NSCLC tumours from surgically treated patients showed that the expression of this transcript is upregulated in the less-differentiated lung adenocarcinomas. We suggest, that the upregulated expression of PI-9 in NSCLC cells may serve to protect them from apoptosis induced by GrB.
Original language | English (US) |
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Pages (from-to) | 275-283 |
Number of pages | 9 |
Journal | International Journal of Oncology |
Volume | 36 |
Issue number | 1 |
DOIs | |
State | Published - Jan 1 2010 |
Keywords
- Apoptosis
- Caspase
- Expression
- Granzyme B
- Non-small cell lung carcinoma
- Proteinase inhibitor-9
- SerpinB9