Suppression of granzyme B activity and caspase-3 activation in leukaemia cells constitutively expressing the protease inhibitor 9

• Verfasst von: Fritsch, Kristina [VerfasserIn]
• Verfasst von: Finke, Jürgen [VerfasserIn]
• Verfasst von: Grüllich, Carsten [VerfasserIn]
• Titel: Suppression of granzyme B activity and caspase-3 activation in leukaemia cells constitutively expressing the protease inhibitor 9
• Verf.angabe: Kristina Fritsch, Jürgen Finke, Carsten Grüllich
• E-Jahr: 2013
• Jahr: 28 July 2013
• Umfang: 7 S.
• Teil: volume:92
• Teil: year:2013
• Teil: number:12
• Teil: pages:1603-1609
• Teil: extent:7
• Fussnoten: Gesehen am 07.06.2021
• Titel Quelle: Enthalten in: Annals of hematology
• Ort Quelle: Berlin : Springer, 1955
• Jahr Quelle: 2013
• Band/Heft Quelle: 92(2013), 12, Seite 1603-1609
• ISSN Quelle: 1432-0584
• DOI: doi:10.1007/s00277-013-1846-6
• Datenträger: Online-Ressource
• Sprache: eng
• K10plus-PPN: 1759939560

Abstract

Immune surveillance against malignant cells is mediated by cytotoxic T-lymphocytes and NK-cells (CTL/NK) that induce apoptosis through the granzyme-B-dependent pathway. The serine protease inhibitor serpinB9/protease inhibitor-9 (PI-9) is a known inhibitor of granzyme B. Ectopic expression of PI-9 in tumour cells has been reported. However, the impact of PI-9 on granzyme-B-induced apoptosis in tumour cells remains unclear. The aim of this study was to investigate the influence of constitutive PI-9 expression in leukaemia cell lines on the activity of granzyme B and apoptosis induction. PI-9 negative (lymphoblastic Jurkat cells; myeloblastic U937 cells) and PI-9-expressing cell lines (myeloblastic K562 cells, EBV-transformed LCL-1 and LCL-2 B-cells, lymphoblastic Daudi cells, AML-R cells f leukaemia and the U937 subclone U937PI-9+). For accurate granzyme B activity determination a quantitative substrate (Ac-IEPD-pNA) cleavage assay was established and caspase-3 activation measured for apoptosis assessment. Cells were treated with a cytotoxic granule isolate that has previously been shown to induce apoptosis through granzyme B signalling. We found a robust correlation between constitutive PI-9 expression levels and the suppression of granzyme B activity. Further, inhibition of granzyme B translated into reduced caspase-3 activation. We conclude, suppression of granzyme B initiated apoptosis in PI-9-expressing cells could contribute to immune evasion and the measurement of granzyme B activity with our assay might be a useful predictive marker in immune-therapeutic approaches against cancer.