A cell motility screen reveals role for MARCKS-related protein in adherens junction formation and tumorigenesis

• Published in: PloS one 2009-11, Vol.4 (11), p.e7833
• Main Authors: Finlayson, Alexander E, Freeman, Kevin W
• Format: Article
• Language: English
• Subjects: Adenomatous polyposis coli; Adherens junctions; Adherens Junctions - metabolism; Antisense RNA; beta Catenin - metabolism; Cadherins - metabolism; Cancer metastasis; Cell adhesion; Cell adhesion & migration; Cell Biology/Cell Signaling; Cell Biology/Extra-Cellular Matrix; Cell Communication; Cell Line, Tumor; Cell migration; Cell Movement; Cell Transformation, Neoplastic; Colorectal cancer; E-cadherin; Epidermal growth factor; Epithelial cells; Extracellular matrix; Humans; Immunology; Invasiveness; Kinases; Mammary gland; MARCKS protein; MARCKS-related protein; Material requirements planning; Membrane Proteins - metabolism; Metastases; Metastasis; MicroRNAs - metabolism; Microscopy, Fluorescence - methods; miRNA; Motility; Neoplasm Metastasis; Oncology; Oncology/Breast Cancer; Oncology/Prostate Cancer; Phosphorylation; Plasma; Prostate cancer; Proteins; Ribonucleic acid; RNA; Signal Transduction; Signaling; Trends; Trifluoperazine; Tumorigenesis; Wound Healing; β-Catenin
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0007833

Invasion through the extracellular matrix (ECM) is important for wound healing, immunological responses and metastasis. We established an invasion-based cell motility screen using Boyden chambers overlaid with Matrigel to select for pro-invasive genes. By this method we identified antisense to MARCKS related protein (MRP), whose family member MARCKS is a target of miR-21, a microRNA involved in tumor growth, invasion and metastasis in multiple human cancers. We confirmed that targeted knockdown of MRP, in both EpRas mammary epithelial cells and PC3 prostate cancer cells, promoted in vitro cell migration that was blocked by trifluoperazine. Additionally, we observed increased immunofluoresence of E-cadherin, beta-catenin and APC at sites of cell-cell contact in EpRas cells with MRP knockdown suggesting formation of adherens junctions. By wound healing assay we observed that reduced MRP supported collective cell migration, a type of cell movement where adherens junctions are maintained. However, destabilized adherens junctions, like those seen in EpRas cells, are frequently important for oncogenic signaling. Consequently, knockdown of MRP in EpRas caused loss of tumorigenesis in vivo, and reduced Wnt3a induced TCF reporter signaling in vitro. Together our data suggest that reducing MRP expression promotes formation of adherens junctions in EpRas cells, allowing collective cell migration, but interferes with oncogenic beta-catenin signaling and tumorigenesis.