CDH20 Antibody

What is CDH20 and what is its primary function in normal tissues?

CDH20, also known as Cadherin-20, is a member of the cadherin superfamily of cell adhesion molecules. It functions primarily as a calcium-dependent cell-cell adhesion glycoprotein. In normal tissues, CDH20 contributes to maintaining tissue architecture and cellular organization by facilitating intercellular adhesion. Recent research has identified CDH20 as having tumor suppressor properties, particularly in cervical cancer where it is frequently downregulated . The protein has a calculated molecular weight of approximately 89 kDa, though it may be observed at 72 kDa in some experimental systems . CDH20 is expressed in multiple tissues and has been studied in human, mouse, and rat models .

What applications are CDH20 antibodies validated for?

CDH20 antibodies, such as the rabbit polyclonal A13390, have been validated for several research applications:

• Immunohistochemistry (IHC): Used for detecting CDH20 in paraffin-embedded tissues with recommended dilutions of 1:100-1:300

• Immunocytochemistry (ICC): For cellular localization studies

• Immunofluorescence (IF): With recommended dilutions of 1:200-1:1000

• Enzyme-linked immunosorbent assay (ELISA): With recommended dilutions of 1:10000

Each application requires specific optimization for the particular experimental system and antibody used. Validation methods typically include positive controls, negative controls, and blocking peptide controls to confirm specificity .

What are the recommended storage conditions for CDH20 antibodies?

For long-term storage, CDH20 antibodies should be kept at -20°C for up to one year. For frequent use and short-term storage (up to one month), keeping the antibody at 4°C is recommended . Most commercial CDH20 antibodies are provided in a stabilizing buffer containing PBS with 50% glycerol, 0.5% BSA, and 0.02% sodium azide . It's crucial to avoid repeated freeze-thaw cycles as these can compromise antibody activity and specificity. Aliquoting the antibody upon receipt is advisable for researchers who don't plan to use the entire volume at once .

How do I validate the specificity of a CDH20 antibody?

Validating CDH20 antibody specificity requires multiple approaches:

• Blocking peptide experiments: Compare staining patterns with and without pre-incubation with the immunogen peptide. Specific signals should be absent or significantly reduced in blocked samples .

• Positive and negative controls: Use tissues or cell lines known to express or not express CDH20.

• Multiple detection methods: Confirm results using different techniques (e.g., Western blot, IHC, and IF) to ensure consistent findings .

• Knockdown validation: In cell culture systems, compare antibody detection in wild-type cells versus cells where CDH20 has been knocked down using shRNA (as described in research using shRNA#1 and #2 against human CDH20) .

• Cross-reactivity assessment: If working across species, validate the antibody in each species separately, as cross-reactivity cannot be assumed without experimental confirmation .

How should I design experiments to study CDH20 interaction with β-catenin?

Designing experiments to study CDH20/β-catenin interactions requires multiple complementary approaches:

• Co-immunoprecipitation (Co-IP):

  • Use anti-CDH20 antibody to pull down CDH20 and probe for β-catenin in the precipitate

  • Perform the reverse experiment using anti-β-catenin antibody

  • Include appropriate negative controls (IgG or irrelevant antibody)

• Confocal microscopy co-localization:

  • Perform double immunofluorescence staining using anti-CDH20 (1:100) and anti-β-catenin (1:500) antibodies

  • Use appropriate fluorophore-conjugated secondary antibodies (Alexa Fluor 488/594)

  • Analyze co-localization using digital image analysis software

• Proximity ligation assay (PLA):

  • More sensitive than conventional co-localization for detecting protein-protein interactions

  • Provides quantitative data on interaction frequency

• Functional studies:

  • Overexpress CDH20 and examine β-catenin localization and expression

  • Perform CDH20 knockdown and assess effects on β-catenin signaling

  • Include TGF-β treatment (10 ng/ml) to examine EMT pathway modulation

• Domain mapping:

  • Use truncated CDH20 constructs to identify the specific domains interacting with β-catenin

These approaches should be accompanied by appropriate controls and quantification methods to ensure reliable and reproducible results .

What are the critical considerations when using CDH20 antibodies for studying cancer progression?

When studying cancer progression with CDH20 antibodies, researchers should consider:

• Antibody validation in specific cancer types: Different cancers may have altered post-translational modifications of CDH20 that affect antibody binding. Validate antibodies in each cancer type studied .

• Expression level interpretation:

  • Use standardized scoring systems for IHC (intensity scale 0-3, extent score 0-3)

  • Calculate final scores (0-9) to categorize samples (negative: 0-1, weak: 2-4, strong: 6-9)

  • Compare with normal adjacent tissues when assessing downregulation

• Correlation with clinical parameters:

  • Systematically record clinical features and correlate with CDH20 expression

  • Include data on metastatic status, as CDH20 levels correlate with metastatic potential

• Pathway analysis:

  • Examine TGF-β pathway components (Smad2/3, phosphorylated Smad2/3)

  • Assess EMT markers (E-cadherin, N-cadherin, Vimentin, Snail)

  • Use western blotting and immunofluorescence to evaluate protein levels and localization

• Functional validation: Complement expression studies with migration and invasion assays after CDH20 overexpression or knockdown .

These considerations ensure meaningful interpretation of CDH20's role in cancer progression and potential as a biomarker or therapeutic target.

How do I troubleshoot weak or absent CDH20 staining in IHC applications?

When encountering weak or absent CDH20 staining in IHC, consider these troubleshooting steps:

• Antigen retrieval optimization:

  • Test different antigen retrieval methods (heat-induced vs. enzymatic)

  • Adjust pH of retrieval buffer (citrate pH 6.0 vs. EDTA pH 9.0)

  • Optimize retrieval time (10-30 minutes)

• Antibody concentration:

  • Titrate antibody concentration beyond recommended range (1:50-1:500)

  • Increase antibody incubation time (overnight at 4°C may yield better results than 1-2 hours at room temperature)

• Detection system enhancement:

  • Switch to more sensitive detection systems (polymer-based vs. ABC method)

  • Consider tyramide signal amplification for very low-abundance targets

• Tissue processing assessment:

  • Check fixation conditions (overfixation can mask epitopes)

  • Evaluate tissue age (antigen degradation in older paraffin blocks)

  • Use positive control tissues processed identically to experimental samples

• Technical considerations:

  • Ensure sections aren't dried out during staining

  • Check all reagents are active and not expired

  • Consider using a different CDH20 antibody targeting a different epitope

• Biological factors:

  • Remember CDH20 is often downregulated in cervical cancer tissues (77.1% of cases)

  • Weak signals may represent actual biological downregulation rather than technical issues

Document all modifications to establish an optimized protocol for future experiments.

What methods should I use to quantitatively analyze CDH20 expression in tumor samples?

For quantitative analysis of CDH20 expression in tumor samples, employ these methodological approaches:

• Standardized IHC scoring:

  • Use a dual-parameter scoring system incorporating:

    • Staining intensity (0=none, 1=weak, 2=moderate, 3=strong)

    • Percentage of positive cells (0=none, 1=<10%, 2=10-50%, 3=>50%)

  • Calculate final score by multiplying these parameters (range: 0-9)

  • Have multiple independent pathologists score blindly to reduce bias

• Digital image analysis:

  • Use software like ImageJ, QuPath, or commercial platforms

  • Perform color deconvolution to separate DAB and hematoxylin staining

  • Set consistent thresholds for positive staining

  • Quantify by intensity, percentage area, or H-score methods

• mRNA quantification:

  • Use qRT-PCR for CDH20 mRNA with appropriate reference genes

  • Calculate relative expression using 2^-ΔΔCt method

  • Present data as Log2([T]/[N]) for tumor vs. normal comparisons

• Protein quantification by western blotting:

  • Use densitometry normalized to loading controls (GAPDH)

  • Include gradient standards to ensure measurements fall within linear range

• Statistical analysis:

  • Correlate CDH20 expression with clinical parameters

  • Use appropriate statistical tests based on data distribution

  • Present data with clear indication of statistical significance and effect size

This multi-modal approach provides robust quantitative assessment of CDH20 expression patterns in tumor samples .

How does CDH20 regulate the TGF-β/Smad/Snail signaling pathway?

CDH20 regulates the TGF-β/Smad/Snail signaling pathway through the following mechanisms:

• β-catenin interaction: CDH20 interacts with β-catenin, which affects downstream signaling. This interaction:

  • Increases β-catenin expression

  • Promotes cytoplasmic and membrane localization of β-catenin

  • Reduces nuclear translocation of β-catenin

• Regulation of Smad2/3 phosphorylation:

  • CDH20/β-catenin complex reduces phosphorylation of Smad2/3 in response to TGF-β stimulation

  • This decreased phosphorylation inhibits the nuclear translocation of Smad2/3

  • As a result, transcriptional activation of EMT-related genes is suppressed

• Snail downregulation:

  • The CDH20/β-catenin interaction leads to reduced Snail expression

  • Snail is a key transcription factor that promotes EMT

  • By downregulating Snail, CDH20 maintains epithelial characteristics and suppresses mesenchymal transition

• EMT marker modulation:

  • CDH20 expression maintains E-cadherin levels (epithelial marker)

  • CDH20 suppresses N-cadherin and Vimentin expression (mesenchymal markers)

  • This helps maintain the epithelial phenotype and prevents invasion and metastasis

This regulatory mechanism explains how CDH20 functions as a tumor suppressor in cervical cancer by inhibiting the TGF-β-induced EMT process that is critical for cancer invasion and metastasis .

What are the differences in CDH20 expression patterns between normal and cancerous tissues?

CDH20 expression patterns show notable differences between normal and cancerous tissues:

• Expression levels:

  • CDH20 mRNA is significantly downregulated in approximately 77.1% (37 out of 48) of cervical cancer tissues compared to adjacent normal tissues

  • Protein levels show concordant reduction in cancer samples as determined by IHC analysis

• Correlation with cancer progression:

  • CDH20 expression is inversely correlated with cervical cancer progression

  • Lower expression is observed in both nonmetastatic and lymphatic metastatic tumor samples compared to normal tissues

  • Metastatic samples often show even lower expression than nonmetastatic tumors

• Subcellular localization:

  • In normal tissues, CDH20 shows predominantly membrane localization with some cytoplasmic presence

  • In cancer cells, both the intensity and pattern of CDH20 staining may be altered

  • This change in localization may affect its interaction with binding partners like β-catenin

• Association with EMT markers:

  • Normal tissues with high CDH20 expression maintain epithelial marker expression

  • Cancer tissues with low CDH20 show increased mesenchymal markers

  • This pattern supports CDH20's role in suppressing EMT during cancer progression

These differential expression patterns suggest CDH20 downregulation may be an important event in cervical cancer development and could potentially serve as a biomarker for disease progression .

How can I design experiments to study the effect of CDH20 mutations on antibody binding and protein function?

To study the effects of CDH20 mutations on antibody binding and protein function, implement this experimental design approach:

• Mutation mapping and selection:

  • Identify naturally occurring mutations in CDH20 from cancer databases

  • Map mutations relative to the antibody epitope (amino acids 111-160 for A13390)

  • Select mutations within and outside the epitope region for comparison

  • Include known functional domains for studying effects on protein function

• Generation of mutant constructs:

  • Create expression vectors with wild-type and mutant CDH20

  • Use site-directed mutagenesis to introduce specific mutations

  • Include epitope tags (Flag, HA) distant from mutation sites for detection

• Antibody binding assessment:

  • Express wild-type and mutant proteins in appropriate cell lines

  • Perform western blotting with multiple CDH20 antibodies targeting different epitopes

  • Compare signal intensity to quantify binding efficiency

  • Conduct immunoprecipitation to evaluate antibody-antigen interactions in solution

• Functional assays:

  • β-catenin interaction: Co-IP and proximity ligation assays to assess interaction strength

  • Cell adhesion: Adhesion assays to evaluate cadherin functionality

  • EMT regulation: Examine TGF-β response in cells expressing mutant vs. wild-type CDH20

  • Migration/invasion: Transwell assays to assess functional outcomes

• Structural analysis:

  • Use computational modeling to predict how mutations affect protein structure

  • Consider validation with circular dichroism or other structural techniques

• Controls and validation:

  • Include multiple antibodies targeting different epitopes

  • Use epitope-tagged constructs for antibody-independent detection

  • Validate expression levels to ensure differences aren't due to expression variation

This comprehensive approach will distinguish between mutations affecting antibody recognition versus those altering protein function, providing insights into structure-function relationships of CDH20 .

What are the best practices for optimizing CDH20 antibody dilutions for different applications?

Optimizing CDH20 antibody dilutions requires systematic titration and application-specific considerations:

• General titration approach:

  • Begin with manufacturer's recommended dilution ranges:

    • IHC: 1:100-1:300

    • IF/ICC: 1:200-1:1000

    • ELISA: 1:10000

  • Test 3-5 dilutions spanning above and below this range

  • Include positive and negative controls for each dilution

• Immunohistochemistry optimization:

  • Start with 1:100, 1:200, and 1:300 dilutions

  • Evaluate signal-to-noise ratio, not just signal intensity

  • Optimize antigen retrieval in parallel with antibody dilution

  • Consider tissue-specific adjustments (cervical tissues may require different conditions than brain tissues)

• Immunofluorescence optimization:

  • Begin with higher dilutions (1:500) for fluorescence applications to minimize background

  • For co-localization studies with β-catenin, balance CDH20 antibody (1:200) with β-catenin antibody (1:500) for optimal dual detection

  • Adjust exposure settings to prevent signal saturation

• Western blot considerations:

  • Test gradient dilutions from 1:500 to 1:5000

  • Optimize blocking conditions alongside antibody concentration

  • Consider transfer efficiency for the high molecular weight CDH20 (89 kDa)

• Documentation and standardization:

  • Record lot numbers, as optimal dilutions may vary between lots

  • Standardize protocols once optimal conditions are established

  • Document incubation times and temperatures alongside dilutions

• Validation across samples:

  • Verify optimal dilutions across multiple sample types

  • Include gradient loading controls to ensure detection is within linear range

Following these best practices will yield reproducible and reliable results across different experimental applications .

What controls should I include when studying CDH20 expression in experimental models?

A robust experimental design for studying CDH20 expression requires comprehensive controls:

• Antibody validation controls:

  • Blocking peptide control: Pre-incubate CDH20 antibody with immunogen peptide to confirm specificity

  • Multiple antibody validation: Use antibodies targeting different CDH20 epitopes

  • Isotype control: Include appropriate isotype-matched control antibody (rabbit IgG for A13390)

• Expression controls:

  • Positive tissue controls: Include tissues known to express CDH20

  • Negative tissue controls: Include tissues with minimal CDH20 expression

  • Genetic controls:

    • CDH20 knockdown cells (using validated shRNAs)

    • CDH20 overexpression models using pGC-FU-CDH20

• Technical controls:

  • Loading controls: GAPDH for western blotting

  • Staining controls: Omit primary antibody to assess secondary antibody background

  • Counterstains: Use DAPI for nuclear visualization in fluorescence applications

• Experimental manipulation controls:

  • Vehicle controls: For TGF-β treatment experiments

  • Empty vector controls: For overexpression studies using pGC-FU vector

  • Non-targeting shRNA control (shCtrl): For knockdown experiments

• Biological replication:

  • Use multiple cell lines to ensure findings aren't cell-line specific

  • Include normal and cancer-derived cells to compare expression patterns

  • For animal models, include appropriate age and sex-matched controls

• Quantification controls:

  • Include standard curves where applicable

  • Use reference genes for qRT-PCR (document stability across experimental conditions)

Implementing these controls ensures experimental rigor and facilitates interpretation of results related to CDH20 expression and function .

How do post-translational modifications affect CDH20 antibody recognition?

Post-translational modifications (PTMs) can significantly impact CDH20 antibody recognition through several mechanisms:

• Epitope masking effects:

  • Phosphorylation, glycosylation, or other modifications within the antibody epitope region (amino acids 111-160 for A13390) may directly interfere with antibody binding

  • Modifications near but outside the epitope can alter protein conformation, indirectly affecting recognition

  • This may explain discrepancies between observed (72 kDa) and calculated (89 kDa) molecular weights

• Specific modification considerations:

  • Glycosylation: As a cadherin family member, CDH20 likely contains N-glycosylation sites that affect antibody recognition

  • Phosphorylation: May occur during signaling events, particularly in cancer contexts where kinase activity is altered

  • Proteolytic processing: Partial degradation or specific cleavage may remove the epitope region

• Experimental approaches to address PTM interference:

  • Sample preparation modifications:

    • Treat lysates with phosphatases to remove phosphorylation

    • Use PNGase F or other glycosidases to remove N-linked glycans

    • Compare reducing vs. non-reducing conditions

  • Detection strategies:

    • Use multiple antibodies targeting different epitopes

    • Compare with epitope-tagged CDH20 detection

  • PTM-specific studies:

    • Employ mass spectrometry to map actual modifications present

    • Use PTM-specific antibodies alongside total CDH20 antibodies

• Cancer-specific considerations:

  • Cancer cells often display altered glycosylation patterns

  • Hyperphosphorylation may occur in certain signaling contexts

  • Document any unexplained molecular weight shifts in western blots

Understanding these interactions improves interpretation of experimental results and explains potential discrepancies between different detection methods .

What are the recommended methods for extracting and preserving CDH20 protein for immunological applications?

Optimal extraction and preservation of CDH20 protein for immunological applications requires specialized techniques:

• Tissue sample preservation:

  • For IHC applications, fix tissues in 10% neutral buffered formalin for 24-48 hours

  • Alternatively, use fresh frozen sections for applications requiring native protein

  • For paraffin embedding, follow standard protocols but minimize processing time to prevent antigen loss

• Cell lysate preparation:

  • Use RIPA buffer supplemented with:

    • Protease inhibitor cocktail

    • Phosphatase inhibitors (sodium orthovanadate, sodium fluoride)

    • 1-2 mM EDTA to chelate calcium (important for cadherin stability)

  • Maintain cold temperature (4°C) throughout extraction

  • Consider gentler lysis buffers (NP-40 based) if native conformation is critical

• Membrane protein considerations:

  • As a cadherin, CDH20 is a membrane protein requiring special extraction attention

  • Include 0.1-0.5% SDS or 1% Triton X-100 in lysis buffer to solubilize membrane proteins

  • Consider membrane fractionation protocols for enriched preparations

• Protein stabilization:

  • Add 5-10% glycerol to lysates for cryopreservation

  • Store extracted proteins at -80°C in small aliquots to avoid freeze-thaw cycles

  • For long-term storage of antibodies, maintain at -20°C with 50% glycerol as stabilizer

• Sample handling for specific applications:

  • Western blotting: Denature samples in SDS buffer at 95°C for 5 minutes

  • Immunoprecipitation: Use gentler lysis conditions to preserve protein-protein interactions

  • Flow cytometry: Use non-permeabilizing conditions for surface CDH20 detection

• Quality control:

  • Assess protein integrity by SDS-PAGE and Coomassie staining

  • Verify protein concentration with Bradford or BCA assays

  • Document and standardize time from collection to preservation

These protocols help maintain CDH20 antigenicity and ensure consistent, reproducible results across immunological applications .

How can CDH20 antibodies be used to study epithelial-to-mesenchymal transition in cancer models?

CDH20 antibodies offer powerful tools for studying epithelial-to-mesenchymal transition (EMT) in cancer models through multiple experimental approaches:

• Monitoring CDH20 as an EMT regulator:

  • Track CDH20 expression changes during TGF-β-induced EMT (10 ng/ml treatment)

  • Correlate CDH20 levels with established EMT markers:

    • Epithelial: E-cadherin, ZO-1

    • Mesenchymal: N-cadherin, Vimentin

    • Transcription factors: Snail

• Mechanistic investigation techniques:

  • Co-immunoprecipitation: Use anti-CDH20 antibodies to pull down protein complexes and probe for β-catenin and other binding partners

  • Chromatin immunoprecipitation (ChIP): Study how CDH20/β-catenin affects Snail promoter regulation

  • Immunofluorescence co-localization: Visualize CDH20 and β-catenin redistribution during EMT using confocal microscopy

• Functional EMT assays:

  • Migration assays: Compare wound healing or Boyden chamber migration in cells with CDH20 overexpression or knockdown

  • Invasion assays: Quantify invasion through Matrigel-coated transwell membranes

  • Cell morphology analysis: Document epithelial-to-mesenchymal morphological changes with phase contrast microscopy

• Signaling pathway analysis:

  • Use phospho-specific antibodies alongside CDH20 detection to monitor:

    • Smad2/3 phosphorylation status

    • Nuclear translocation of Smad2/3 and β-catenin

    • TGF-β receptor activity

• In vivo applications:

  • Tissue analysis: Compare CDH20 expression in primary tumors and metastatic sites

  • Xenograft models: Assess how CDH20 manipulation affects tumor growth and metastasis

• Therapeutic implication studies:

  • Screen compounds that modulate CDH20 expression

  • Evaluate how restoring CDH20 affects EMT and cancer progression

These methodologies provide comprehensive insights into CDH20's role in EMT regulation and potential as a therapeutic target in cancer .

What emerging techniques are being developed for studying CDH20 expression and function?

Several cutting-edge techniques are enhancing our ability to study CDH20 expression and function:

• Advanced imaging approaches:

  • Super-resolution microscopy: Techniques like STORM or PALM enable visualization of CDH20 distribution at nanoscale resolution

  • Live-cell imaging: CRISPR-based tagging of endogenous CDH20 with fluorescent proteins for real-time tracking

  • Correlative light-electron microscopy (CLEM): Combines molecular specificity of fluorescence with ultrastructural context

• Single-cell analysis methods:

  • Single-cell RNA sequencing: Reveals heterogeneity in CDH20 expression across tumor cell populations

  • Mass cytometry (CyTOF): Allows multiplexed protein analysis including CDH20 and related signaling molecules

  • Spatial transcriptomics: Maps CDH20 expression patterns within the tumor microenvironment

• Protein interaction technologies:

  • BioID and TurboID: Proximity labeling to identify novel CDH20 interactors beyond β-catenin

  • FRET/BRET sensors: Detect dynamic CDH20 protein interactions in living cells

  • Protein complementation assays: Split fluorescent proteins to visualize CDH20 interactions

• Functional genomics approaches:

  • CRISPR activation/inhibition: CRISPRa/CRISPRi for precise modulation of CDH20 expression

  • Base editing: Introduction of specific mutations to study structure-function relationships

  • CRISPR screens: Identify synthetic lethal interactions with CDH20 loss in cancer

• Computational methods:

  • AI-based image analysis: Deep learning algorithms for automated quantification of CDH20 IHC/IF staining

  • Molecular dynamics simulations: Predict how mutations affect CDH20-β-catenin interactions

  • Network analysis: Place CDH20 in broader signaling networks using multi-omics data integration

• Translational applications:

  • Organoid models: Patient-derived organoids to study CDH20 function in personalized contexts

  • Antibody-drug conjugates: Targeting CDH20-expressing cells with therapeutic payloads

  • Liquid biopsy: Detection of CDH20 alterations in circulating tumor DNA

These emerging technologies offer unprecedented resolution and functional insights into CDH20 biology with implications for both basic research and clinical applications .

What are the practical considerations for using the same CDH20 antibody across multiple species?

Using the same CDH20 antibody across multiple species requires careful consideration of several factors:

This systematic approach to cross-species validation ensures reliable and comparable results when studying CDH20 across different experimental models .

How can I design experiments to investigate the impact of CDH20 on patient outcomes in cancer research?

Designing experiments to investigate CDH20's impact on patient outcomes requires a multidisciplinary approach combining molecular analyses with clinical data:

This comprehensive approach will establish whether CDH20 serves as a prognostic biomarker and potential therapeutic target in cancer, with implications for patient stratification and treatment selection .