Paracrine SLPI secretion upregulates MMP-9 transcription and secretion in ovarian cancer cells

Abstract

Objectives Secretory leukocyte protease inhibitor (SLPI) is amplified in serous ovarian cancer. We have dissected its function, showing it is a survival factor for ovarian cancer and promotes tumorigenesis and paclitaxel-resistance. We hypothesized that the protease inhibitory function was responsible for modulating SLPI’s invasive capacity. Methods Stable HEYA8 ovarian cancer transfectants expressing vector, wild type SLPI, and protease inhibitor null (F-)SLPI were examined in vitro and in xenografts. Invasion, enzyme activity, and MMP production and function assays were applied. SLPI and MMP immunoexpression were graded on tissue microarray and clinical samples. Statistical comparisons used unpaired T test and ANOVA, where appropriate. Results SLPI and F-SLPI cells caused greater parenchymal and peritoneal dissemination over control cells in xenografts and invasion assays (p<0.001). MMP-9 protease activity was increased in SLPI and F-SLPI cells over control. SLPI, but not F-SLPI, inhibited plasmin activity, necessary for MMP-9 activation and release, and inhibited activation of MMP-9. However, paradoxically, both induced quantitative MMP-9 transcription (p<0.05) and protein (p<0.008), yielding an increased net MMP-9 activity in the face of plasmin inhibition. SLPI and MMP-9 expression were strongly correlated in serous ovarian cancers (r2=0.986) and a set of ovarian cancers (p<0.02). SLPI expression was greater in serous than endometrioid ovarian cancers (p=0.04). Conclusions SLPI stimulates ovarian cancer invasion, modulated in part by its serine protease inhibitory activity attenuating MMP-9 release. However, SLPI induction of MMP-9, independent of protease inhibition activity, is greater yielding a net pro-invasive behavior. These findings further support SLPI as a molecular target for ovarian cancer.

A lack of secretory leukocyte protease inhibitor (SLPI) causes defects in granulocytic differentiation

“…SLPI modulates intracellular signaling pathways, such as NF-kB, ERK, and TGF-b, 32,33,43 and prevents synthesis of TNF-a and matrix metalloproteinases. 29,44,45 In line with published data, we detected diminished expression of IkBa and elevation of NFkB p65 after inhibition of SLPI (Figure 7). However, we did not detect any differences in TNF-a synthesis by hematopoietic cells deficient in SLPI.…”

Promotive role of recombinant HE4 protein in proliferation and carboplatin resistance in ovarian cancer cells

“…There is a growing body of evidence demonstrating the tumorpromoting roles of WAP domain family members (6,7). Among these WAP genes is secretory leukocyte protease inhibitor (SLPI), which is also overexpressed in ovarian cancer (6,8).…”

“…Hoskins et al (8) reported that SLPI stimulated ovarian cancer invasion, modulated in part by its serine protease inhibitory activity. Significantly, comparative genomic hybridization studies have shown that 20q13 is among the most frequently amplified chromosomal regions in ovarian cancers (9)(10)(11).…”

Targeting secretory leukocyte protease inhibitor (SLPI) inhibits colorectal cancer cell growth, migration and invasion via downregulation of AKT

“…Targeting SLPI by siRNA induced apoptosis, and inhibited the migration and invasion of PDAC cells ( Zhang et al, 2015 ). SLPI was increased in ovarian cancer and enhances the invasiveness of ovarian cancer cells via modulating MMP-9 release ( Hoskins et al, 2011 ; Tsukishiro et al, 2005 ). In the previous study, SLPI was found overexpressed in colorectal cancer tissues of 296 CRC patients ( Liu et al, 2014 ).…”