Identification of the critical site of calponin 1 for suppression of ovarian cancer properties

Background: Although several studies have demonstrated the tumor suppressive function of CNN1 (calponin 1), no studies have performed a site-specific analysis of CNN1 on tumor cell activities. Materials and Methods: We herein studied the site-specific effects of CNN1 in ovarian cancer cells using full-length CNN1 (fCNN1), three CNN1 repeats (3CNRs), or the first CNN1 repeat (CNR1) expression vectors. Ovarian cancer cells stably expressing each construct were analyzed for in vitro proliferation, cell motility, invasion, and soft agar assays. An in vitro model of pleural dissemination was also established. Results: Cell proliferation, anchorageindependent colony formation, cell motility, and cell invasion were all suppressed in fCNN1, 3CNRs, and CNR1-stably-expressing cells. CNN1 expression in mesothelial cells suppressed cancer cell invasion into a monolayer of mesothelial cells. Conclusion: CNR1 showed similar suppressive effects as fCNN1. Results suggest CNR1 as a potential small synthetic peptide candidate for therapeutic strategies against ovarian cancer.