Cell Polarity and Cancer Pr Jean-Paul Borg Email: jean-paul.borg@inserm.fr
Features of malignant cells
Steps in Malignant Progression
Cell polarity, cell adhesion, morphogenesis and tumorigenesis pathways Feigen and Muthuswamy, Curr. Op. Cell. Biol. 2009
E-cadherin mediated junctions MDCK Stable cell adhesion E-cadherin based
Cell adhesion molecules
Epithelial-mesenchymal transition (EMT) 1. Loss of cell-cell contacts 2. Acquisition of a mesenchymal morphology 3. Manifest a migratory phenotype 4. Increase of extracellular proteolytic activity 5. Proliferation
Colon Cancer (E-cadherin in brown)
Cellular changes during EMT Lost or decreased 1. Epithelial adhesion receptors - E-cadherin, Occludin, Claudins 2. α-catenin, β-catenin frequently translocates to nucleus (Wnt) 3. Circumferential F-actin fibers 4. Epithelial cytokeratins 5. Apico-basal polarity Acquired 1. Intermediate filament protein - Vimentin 2. Matrix metalloproteinases secreted, produced 3. Fibronectin secretion 4. N-cadherin 5. α-smooth muscle actin (myofibroblasts) 6. αvβ6 integrin 7. Motility, Invasiveness
EMT during embryonic development Neural Crest Delamination Epithelial Mesenchymal
EMT in the Adult - epithelia wound healing (skin) - tissue fibrosis in response to injury (lung, kidney, liver) - epithelial cancer metastasis Skin wound healing Slug expression
The Snail family of transcriptional repressors SNAG Domain Zinc Fingers Snail Slug Smuc Scratch
E-cadherin Loss/Downregulation 1. Mutation - Seen in gastric carcinoma and lobular breast cancer 2. Post-transcriptional down-regulation 3. Promoter methylation 4. Transcriptional Repression
E-cadherin transcriptional repression Wnt BMP Notch
E-cadherin transcriptional repression + Snail
Epithelial cell polarity complexes Borg and Margolis, J Cell Sci 2005
Epithelial cell polarity complexes Feigen and Muthuswamy, Curr Op. Cell, Biol. 2009
Protein interaction domains from Pawson et al.
Binding specificities of PDZ domains PSD-95 Discs Large ZO-1 Class I S/TxV Class II ΨxΨ Class III DxV
The tumor suppressor Scribble is conserved during evolution dpatj Scribble Patj Scrib LRR PDZ
Studies on the Scribble tumor suppressor gene in Drosophila and humans WT scrib Scrib -/- RasV12 Scrib -/- Ras12 tumors +++ +/- +++ metastasis - - +++ Bilder and Perrimon, Nature 2000
Studies on the Scribble tumor suppressor gene in humans Breast carcinoma Ductal Lobular Scribble Scribble localization E-cadherin Navarro et al., Oncogene 2005
Purification and identification of proteins bound to Scribble in epithelial cells IP: control Scrib1 Scrib2 Lano 175 * * Cdc42 GTP Cdc42 GDP 80 62 βpix GIT1 Scrib 47.5 ARF6 GTP ARF6 GDP Audebert et al., Curr. Biol 2004
LRR PDZ localization signaling
Human BC Xenografted mice
Prostatic intraepithelial neoplasia (PIN)
Scribble is a bona fide tumor suppressor
Scribble is a sensor of extracellular cues Scribble actin Primary astrocytes -HRG + HRG T47D cells Osmani et al., Curr Biol 2006 Nola et al., Hum.Mol.Genet. 2008
Scribble-deficient cells have a defect of cell migration Nola et al., Hum. Molec. Genet 2008
The mammalian Scribble complex LRR PDZ Cdc42 GTP Cdc42 GDP PAK βpix GIT1 Scribble ARF6 GTP ARF6 GDP Audebert et al., Current Biology 2004 Lahuna et al., EMBO J. 2005 Osmani et al., Curr. Biol. 2006 Nola, et al., Hum. Mol. Genet. 2008
Compartimentalization of signals
Compartimentalization of EGFR signaling
Compartimentalization of EGFR signaling EGFR ErbB2 ErbB3 ErbB4
Compartimentalization of EGFR signaling
Compartimentalization of TGFβ signaling
Compartimentalization of TGFβ signaling Barios-Rodiles et al., 2005
Deregulated cell signaling drives cell polarity defects
Compartimentalization of PTEN signaling
Compartimentalization of PTEN signaling
3D models MDCK cells
Compartimentalization of PTEN signaling
Roles of β-catenin
Adenomatous Polyposis Coli
Primary cilium
Cell signaling in the primary cilium
Peutz-Jeghers Syndrome ~70% of PJS patients have LKB1 mutation Autosomal dominant Benign harmatomatous polyps Mucocutaneous hyperpigmentation on lips and hands Increased risk of cancer
Structure of LKB1 http://www.nature.com/nrc/journal/v2/n7/fig_tab/nrc843_f3.html
LKB1 mutations in Cancer Germ line mutations in PJS Somatic mutations in LKB1 Pancreatic Pulmonary Biliary Melanomas
Animal Model LKB1-/- mutation in mice is lethal Midgestation Neural-tube defects Severely impaired vascular development LKB1+/- mice: gastrointestinal polyposis, similar to PJS patients Different distribution of polyps in GI tract Similar histology of polyps Mouse model for PJS
Cell Polarity and pathogens
Human Papilloma Virus (HPV) Over 100 Different Subtypes High risk of cervical cancer associated with types 16, 18, 31, 33
Human Papilloma Virus (HPV) Early Genes: E1: Viral replication; maintains episome E2: Transcriptional regulation, co-factor for viral replication E4: Disrupts cytokeratins E5: Interacts with growth factor receptors E6: Transforming protein; p53 and PDZ proteins degradation E7: Transforming protein; Rb binding Late Genes: L1: major capsid protein L2: minor capsid protein
The HPV-16 E6 oncoprotein
E6 E6 TQL MUPP1 Scrib Dlg1 CASK LIN-7 Thomas et al., 2008 Audebert, S.
PDZ proteins Human Fly Worm Yeast 253 (148 proteins) 214 93 3 Class I S/TxV Class II ΨxΨ Class III DxV
PDZ-containing targets of papillomavirus oncoproteins Thomas et al., 2008
Thomas et al., 2008
Helicobacter pylori