E cadherin and MetastasisE cadherin and MetastasisBy Andy CiesielskiBy Andy Ciesielski

Genomic organization of the human E-cadherin gene. Positions of exons are shown in color boxes with the base pair number of each exon. The connecting lines are introns.

CDH1 geneCDH1 gene

Encodes E Cadherin Encodes E Cadherin

16q22.116q22.1

Ca2+ Dependent Cell-Cell Adhesion MoleculeCa2+ Dependent Cell-Cell Adhesion Molecule

16 exons16 exons

Shematic illustration of E-cadherin in adherens junction. E-cadherin homodimer on the cytoplasmic membranes of adjacentcells is shown. The juxtamembrane region with the interacting molecules is also shown. CM – cytoplasmic membrane; AJ –adherens junction; ED – extracellular domain; ID – intracellular domain; AC – actin cytoskeleton; 1-beta-catenin; 2-alpha-catenin;3-p120.

5 Extracellular Domains containing conserved repeated Amino Acid 5 Extracellular Domains containing conserved repeated Amino Acid sequences (cadherin repeats),1 Transmembrane Domain, 1 sequences (cadherin repeats),1 Transmembrane Domain, 1 Intracellular DomainIntracellular Domain

Forms Homophilic Interactions with Adjacent E cadherins in Lateral Forms Homophilic Interactions with Adjacent E cadherins in Lateral DimerizationDimerization

Dynamically Associates with Alpha, Beta, and Gamma Catenins and Dynamically Associates with Alpha, Beta, and Gamma Catenins and p120p120

120 kDa120 kDa

Cellular RolesCellular Roles

Adhesion Between Epithelial Adhesion Between Epithelial Cells- Adherens JunctionsCells- Adherens Junctions

Development- Gastrulation, Development- Gastrulation, Neurulation, OrganogenesisNeurulation, Organogenesis

Adhesion of blastomeres and Adhesion of blastomeres and embryo compactionembryo compaction

Controlled epithelial Controlled epithelial mesenchymal conversion mesenchymal conversion (loss of epithelial adhesion (loss of epithelial adhesion and polarity)and polarity)

-/- mutations lethal at -/- mutations lethal at blastocyst stage in miceblastocyst stage in mice

Cellular RolesCellular Roles

Signaling PathwaysSignaling Pathways EGFR and MAPKEGFR and MAPK WntWnt Snail, Slug, Twist- Snail, Slug, Twist-

RepressorsRepressors

of E cadherinof E cadherin

Tumor SuppressorTumor Suppressor

MetastasisMetastasisTumor cells lose adhesion for surrounding cells, undergoing EMTTumor cells lose adhesion for surrounding cells, undergoing EMT

Spread into blood vessels and other tissues forming new tumors at Spread into blood vessels and other tissues forming new tumors at new sitesnew sites

Loss of E cadherin Leads to Metastatic Loss of E cadherin Leads to Metastatic TumorsTumors

E cadherin functions as a Tumor E cadherin functions as a Tumor SuppressorSuppressor

E cadherin loss enables E cadherin loss enables disaggregation of cancer cells disaggregation of cancer cells from one anotherfrom one another

LOH in CDH1 Correlates with LOH in CDH1 Correlates with metastasizing malignanciesmetastasizing malignancies

Over 75% of Metastatic Cancers Over 75% of Metastatic Cancers Exhibit CDH1 AbnormalitiesExhibit CDH1 Abnormalities

CDH1 mutations involved with CDH1 mutations involved with several cancers: Breast, Liver, several cancers: Breast, Liver, Prostate, Stomach, Endometrium, Prostate, Stomach, Endometrium, Ovary, and LungOvary, and Lung

Loss of E cadherin Function Loss of E cadherin Function Correlates with Poor PrognosisCorrelates with Poor Prognosis

E Cadherin Expression in CancerE Cadherin Expression in Cancer

Type 1- Preserved Type, Tumor Cells Retain Cadherin Type 1- Preserved Type, Tumor Cells Retain Cadherin ExpressionExpression

Type 2- Reduced Type, Tumor Cells Show Reduced Type 2- Reduced Type, Tumor Cells Show Reduced Cadherin Expression, Cadherin Expression,

Type 3- Complete Loss of Cadherin FunctionType 3- Complete Loss of Cadherin Function

Type 4- Aggregate FailureType 4- Aggregate Failure

E Cadherin Mutations E Cadherin Mutations

HypermethylationHypermethylation

Somatic Mutations- Insertions, Deletions, Non-sense MutationsSomatic Mutations- Insertions, Deletions, Non-sense Mutations

Diffuse Gastric Tumor Showed In-Frame MutationsDiffuse Gastric Tumor Showed In-Frame Mutations

Infiltrative Breast Cancers Showed Out-of-frame Mutations Leading Infiltrative Breast Cancers Showed Out-of-frame Mutations Leading to Truncated E Cadherinsto Truncated E Cadherins

Hereditary PredispositionsHereditary Predispositions Early onset cancers, high penetranceEarly onset cancers, high penetrance

Silencing or Over Activation of Various Influential FactorsSilencing or Over Activation of Various Influential Factors CDH1 promoterCDH1 promoter Snail, Slug, Twist – trigger EMT, repress E cadherinSnail, Slug, Twist – trigger EMT, repress E cadherin Tyrosine Phosphorylation of accessory proteins, Alpha, Beta, Gamma Tyrosine Phosphorylation of accessory proteins, Alpha, Beta, Gamma

Catenins interfering with Cadherin ActionCatenins interfering with Cadherin Action

Down Regulation of E cadherin and Dominant Down Regulation of E cadherin and Dominant Negative E cadherin Proteins Results in Loss of Negative E cadherin Proteins Results in Loss of Typical Morphology- Loss of Cellular AdhesionTypical Morphology- Loss of Cellular Adhesion

The adoption of fibroblastic morphology by shEcad cells typifies a EMT

shEcad cells also showed increases in Mesenchymal proteins N-Cadherin and Vimentin compared to control cells

shCntrl

shEcad

DN-Ecad

Orthotopic and Tail Vein Assays Reveal Metastases in Orthotopic and Tail Vein Assays Reveal Metastases in Lungs of Nude MiceLungs of Nude Mice

Motility and Apoptosis of Cells Upon Loss of Cell Motility and Apoptosis of Cells Upon Loss of Cell AdhesionAdhesion

shEcad cells showed increased motility and invasiveness in Boyden Chamber Assays

shEcad cells showed high levels of cells indicating decreased apoptosis in the absence of substrate attachment

shEcad cells showed decreased amounts of annexinV indicatinglower rates of apoptosis

SummarySummaryE cadherin normally functions to maintain cell adherens E cadherin normally functions to maintain cell adherens junctions in epithelial tissuesjunctions in epithelial tissuesE cadherin can be appropriately regulated to trigger EMT E cadherin can be appropriately regulated to trigger EMT during developmentduring developmentInappropriate regulation or mutations is strongly Inappropriate regulation or mutations is strongly correlated with a variety of metastatic cancers correlated with a variety of metastatic cancers E cadherin loss appears sufficient to give metastatic E cadherin loss appears sufficient to give metastatic ability HMLER cells.ability HMLER cells.Loss of extracellular and intracellular domains is Loss of extracellular and intracellular domains is necessary for gaining metastatic abilitynecessary for gaining metastatic abilityLoss of E cadherin with additional oncogenic lesions Loss of E cadherin with additional oncogenic lesions quickens the transition to invasive metastasesquickens the transition to invasive metastases

ReferencesReferences

Takeichi, Masatoshi, Cadherins in Cancer: Implications for Invasion Takeichi, Masatoshi, Cadherins in Cancer: Implications for Invasion and Metastasis. Cell Biology 5 (1993) 806-811.and Metastasis. Cell Biology 5 (1993) 806-811.

T. Onder, P. Gupta, S. Mani, J. Yang, E. Lander, R. Weinberg. Loss T. Onder, P. Gupta, S. Mani, J. Yang, E. Lander, R. Weinberg. Loss of E-Cadherin Promotes Metastasis via Multiple Downstream of E-Cadherin Promotes Metastasis via Multiple Downstream Transcriptional Pathways. Cancer Research 68 (2008) 3645-3654.Transcriptional Pathways. Cancer Research 68 (2008) 3645-3654.

Pecina-Slaus, Nives. Tumor Repressor Gene E-Cadherin and its Pecina-Slaus, Nives. Tumor Repressor Gene E-Cadherin and its Role in Normal and Malignant Cells. Cancer Cell International 3 Role in Normal and Malignant Cells. Cancer Cell International 3 (2003) 1-7.(2003) 1-7.