Integrin-linked kinase activity modulates the pro-metastatic behavior of ovarian cancer cells

Abstract

Epithelial ovarian cancer (EOC) is the most fatal gynecologic cancer in the U.S., resulting in >14,000 deaths/year. Most women are diagnosed at late stage with widely disseminated intra-peritoneal metastatic disease, resulting in a 5-year survival rate of <30%. EOCs spread via direct extension and exfoliation into the peritoneal cavity, adhesion to peritoneal mesothelial cells, mesothelial cell retraction to expose sub-mseothelial matrix and anchoring in the type I collagen-rich matrix to generate secondary lesions. As a molecular-level understanding of EOC metastasis may identify novel therapeutic targets, the current study evaluated the expression and activity of integrin-linked kinase (ILK), a Ser/Thr protein kinase activated upon integrin-mediated adhesion. Results show that ILK is co-expressed in EOC with the pro-metastatic enzyme membrane type 1 matrix metalloproteinase (MT1-MMP) and catalyzed phosphorylation of the cytoplasmic tail of the proteinase. Downregulation of ILK expression or activity reduced adhesion to and invasion of collagen gels and organotypic meso-mimetic cultures. As an initial early event in EOC metastasis is integrin-mediated adhesion, these results suggest that further evaluation of ILK inhibitors as anti-metastatic agents in EOC is warranted.

Post-translational modification of the membrane type 1 matrix metalloproteinase (MT1-MMP) cytoplasmic tail impacts ovarian cancer multicellular aggregate dynamics

“…These data are consistent with previous results in which pharmacologic inhibition or genetic silencing of integrinlinked kinase (ILK) was used to prevent phosphorylation of Thr 567 in DOV13 cells, which endogenously express MT1-MMP (31). In this study, results observed were similar to those using cells transfected to exogenously express the phosphodefective mutant T567A in the current study.…”

“…Ala for Thr) (30). Using this approach, phosphorylation of MT1-MMP at Thr 567 of the cytoplasmic tail has been shown to promote expansive growth of invasive tumor cell colonies within constrained three-dimensional collagen gels (22,23,31,32). To investigate further the potential role of MT1-MMP Thr 567 in cellular behaviors correlated with metastasis, GFP-tagged MT1-MMP phosphomimetic (T567E (TE)) and phosphodefective (T567A (TA)) mutants as well as wild-type MT1-MMP (MT) were expressed in OVCA433 cells, which have very low levels of endogenous MT1-MMP ( Fig.…”

“…ILK is a serine/threonine kinase that is a cytoplasmic binding partner of ␤1and ␤3-integrins, is activated by cell-matrix adhesion, and is highly expressed in ovarian cancer (47)(48)(49). We recently reported that ILK is co-expressed with MT1-MMP in EOC cells and tissues and can catalyze phosphorylation of Thr 567 (31). Furthermore, silencing of ILK expression with siRNA or reduction of ILK activity with the small molecule inhibitor QLT0267 significantly inhibits adhesion to and invasion of both meso-mimetic cultures and collagen gels by EOC cells (31).…”

Emodin Inhibits the Epithelial to Mesenchymal Transition of Epithelial Ovarian Cancer Cells via ILK/GSK-3β/Slug Signaling Pathway

“…It has been shown that ILK is expressed in ovarian cancers and ILK expression increases with ovarian cancer progression [29–31]. ILK expression is an initial early event in EOC metastasis, which suggested that further evaluation of ILK inhibitors in EOC is warranted [32].…”

EMT: Present and future in clinical oncology

“…An example is the inhibition of ILK, an integrin‐linked kinase involved in AKT pathway activation leading to EMT (Jiang et al ., ). Treatment with emodin (1,3,8‐trihydroxy‐6‐methylanthraquinone) (Bruney et al ., ), promotes a MET process by targeting ILK in ovarian cancer (Lu et al ., ) and endometrial sarcoma cells (Zheng et al ., ), in addition to reducing EMT through the ILK/AKT/mTOR signaling pathway in breast cancer cells (Ma et al ., ) (Fig. ).…”