PIN1C Antibody

What is PIN1 and why is it significant in research?

PIN1 is a peptidyl-prolyl cis-trans isomerase that specifically recognizes and isomerizes phosphorylated Ser/Thr-Pro motifs. It functions as a critical regulator of cell proliferation, differentiation, and survival pathways . PIN1's significance stems from its role as a molecular timer that controls the function of phosphoproteins by catalyzing conformational changes, thereby regulating numerous cellular processes.

Notably, PIN1 dysregulation has been linked to various pathological conditions, particularly cancer development and progression, making it a target of significant interest in oncology research . Studies have shown that PIN1 is highly expressed in cancer cells and cancer-associated fibroblasts (CAFs), suggesting its potential as a therapeutic target .

What applications are PIN1 antibodies validated for?

PIN1 antibodies are validated for multiple research applications, with the most common being:

For optimal results, validation should be performed in your specific experimental system as antibody performance can vary between applications and sample types .

How should I select the appropriate PIN1 antibody for my experimental needs?

Selection of the appropriate PIN1 antibody depends on multiple factors:

• Research Application: Ensure the antibody is validated for your specific application (WB, IHC, IF) .

• Species Reactivity: Verify the antibody's reactivity with your target species. Commercial PIN1 antibodies like A35515 show reactivity with human, mouse, and rat samples .

• Antibody Type: Consider whether a polyclonal or monoclonal antibody better suits your needs:

  • Polyclonal antibodies (like A35515 and CAB13665) recognize multiple epitopes, potentially offering higher sensitivity but less specificity .

  • Monoclonal antibodies recognize single epitopes, providing higher specificity but potentially lower sensitivity.

• Epitope Recognition: For specific research questions, consider antibodies that target specific domains or post-translational modifications of PIN1.

When studying PIN1 in cancer research, select antibodies validated in relevant cancer models, as demonstrated by the validation data showing PIN1 detection in human esophageal cancer samples .

What are the optimal protocols for using PIN1 antibodies in Western blotting?

Optimizing Western blot protocols for PIN1 detection requires attention to several critical factors:

• Sample Preparation:

  • Lyse cells in RIPA buffer supplemented with protease and phosphatase inhibitors

  • Typical protein load: 20-30 μg per lane

  • Include positive control (cell lines known to express PIN1 highly)

• Electrophoresis and Transfer:

  • PIN1 is approximately 18 kDa; use 12-15% polyacrylamide gels

  • Standard transfer conditions work well (100V for 60-90 minutes)

• Antibody Incubation:

  • Block membrane with 5% non-fat milk or BSA

  • Dilute primary antibody 1:1000-1:2000

  • Incubate overnight at 4°C for best results

  • Secondary antibody selection: anti-rabbit IgG HRP-conjugated antibody for PIN1 rabbit polyclonal antibodies

• Detection and Analysis:

  • Enhanced chemiluminescence (ECL) detection works well

  • Expected band size: 18 kDa

  • Validate specificity using PIN1 knockdown controls, as demonstrated in research using AG17724 (PIN1 inhibitor)

For quantitative analyses, normalize PIN1 expression to appropriate loading controls (β-actin, GAPDH) and use PIN1 knockdown cells as negative controls to confirm antibody specificity .

How can I optimize PIN1 antibody usage in immunohistochemistry studies?

For optimal IHC results with PIN1 antibodies:

• Tissue Processing and Antigen Retrieval:

  • Formalin-fixed, paraffin-embedded tissues are suitable

  • Recommended antigen retrieval: Citrate buffer (pH 6.0) for 15-20 minutes

  • Keep section thickness consistent (4-5 μm recommended)

• Antibody Incubation:

  • Dilution: Start with 1:100 for paraffin sections

  • Incubation time: 1-2 hours at room temperature or overnight at 4°C

  • Use a humidity chamber to prevent tissue drying

• Detection System:

  • DAB (3,3'-diaminobenzidine) works well for PIN1 visualization

  • Consider automated staining systems for consistency across samples

• Controls and Validation:

  • Include positive control tissues (e.g., human esophageal cancer sections)

  • Use isotype controls to assess non-specific binding

  • Include PIN1-low tissue sections as negative controls

• Quantification:

  • Score PIN1 expression using established systems (H-score, Allred score)

  • Consider digital image analysis for objective quantification

Studies have shown successful PIN1 detection in cancer tissues, particularly in esophageal cancer samples, demonstrating the utility of PIN1 antibodies for assessing expression in clinical specimens .

What approaches can I use to study PIN1 inhibition in cancer models?

Current approaches for studying PIN1 inhibition include:

• Antibody-Based Detection of Inhibition Effects:

  • Western blot analysis to measure PIN1 protein levels and downstream effectors (β-catenin, NF-κB, AKT) following inhibitor treatment

  • Immunofluorescence to visualize changes in PIN1 localization after inhibition

• Selective Inhibitor Delivery Systems:

  • DNA-barcoded micellular systems (DMS) for targeted delivery of PIN1 inhibitors to specific cell populations

  • Antibody-functionalized delivery systems (e.g., anti-FAP-α antibodies for targeting cancer-associated fibroblasts)

• Functional Assays:

  • PPIase enzymatic assays to measure PIN1 catalytic activity inhibition

  • Compare effects of different PIN1 inhibitors (AG17724, ATRA, Juglone) on PIN1 activity

  • Cell proliferation assays comparing wild-type and PIN1-knockdown cells treated with inhibitors

• Molecular Readouts:

  • RT-qPCR to examine changes in expression of PIN1-regulated genes following inhibition

  • Analysis of post-translational modifications of PIN1 substrates

Research has demonstrated that selective PIN1 inhibition in cancer-associated fibroblasts using targeted delivery systems can significantly slow tumor growth in pancreatic cancer models, highlighting the potential therapeutic value of PIN1 inhibition strategies .

What are common issues with PIN1 antibodies and how can they be resolved?

For antibody validation, compare results between different PIN1 antibodies and confirm specificity using PIN1 knockdown or knockout controls, as demonstrated in studies using PIN1 inhibitors .

How should PIN1 antibodies be stored and handled to maintain optimal activity?

For maximum antibody stability and performance:

• Storage Conditions:

  • Store concentrated antibody at -20°C as recommended

  • Avoid repeated freeze-thaw cycles by preparing single-use aliquots

  • Working dilutions can be stored at 4°C for up to one week

• Buffer Composition:

  • PIN1 antibodies are typically supplied in phosphate buffered saline (PBS) without Mg²⁺ and Ca²⁺, pH 7.4, with 150mM NaCl and 50% glycerol

  • 0.02% sodium azide is often included as a preservative

• Handling Precautions:

  • Allow frozen antibodies to thaw completely at 4°C before use

  • Mix gently by inversion; avoid vortexing to prevent antibody denaturation

  • Use sterile technique when preparing aliquots

• Working Dilution Preparation:

  • Dilute in fresh buffer containing 1-5% blocking agent

  • Prepare working dilutions just before use when possible

  • For longer storage of working dilutions, add protein carrier (0.1-1.0% BSA)

Following these guidelines will help maintain antibody performance and extend shelf life, ensuring consistent experimental results over time.

How can PIN1 antibodies be used to investigate PIN1's role in tumorigenesis?

PIN1 antibodies enable several approaches to studying PIN1's role in tumorigenesis:

• Expression Analysis in Clinical Samples:

  • IHC analysis of PIN1 expression in tumor versus normal tissues

  • Correlation of PIN1 levels with clinicopathological features and patient outcomes

  • Comparison of PIN1 expression across different cancer types and stages

• Mechanistic Studies:

  • Investigation of PIN1 interaction with oncogenic pathways

  • Analysis of PIN1's effects on key signaling molecules (β-catenin, NF-κB, AKT)

  • Study of PIN1-mediated post-translational modifications of cancer-related proteins

• Tumor Microenvironment Analysis:

  • Dual immunostaining to assess PIN1 expression in both cancer cells and cancer-associated fibroblasts (CAFs)

  • Analysis of PIN1's role in maintaining the immunosuppressive tumor microenvironment

• Therapeutic Target Validation:

  • Combining PIN1 antibodies with PIN1 inhibitors to validate target engagement

  • Assessment of phenotypic changes following PIN1 inhibition

  • Evaluation of PIN1 as a biomarker for response to specific cancer therapies

Recent research has demonstrated that PIN1 overexpression in CAFs contributes significantly to pancreatic cancer progression, highlighting PIN1 as a potential therapeutic target in the tumor microenvironment .

What methodologies are available for studying PIN1 interactions with other cancer-related proteins?

To investigate PIN1 interactions with cancer-related proteins:

• Co-Immunoprecipitation (Co-IP):

  • Use PIN1 antibodies to pull down PIN1 and associated proteins

  • Western blot analysis of precipitates for known PIN1 interactors

  • Recommended controls: PIN1 knockdown cells, IgG control

• Proximity Ligation Assay (PLA):

  • Visualize PIN1 interactions with target proteins at single-molecule resolution

  • Particularly useful for studying transient interactions

  • Requires specific antibodies for both PIN1 and interacting proteins

• FRET/BRET Analysis:

  • For studying dynamic interactions in living cells

  • Requires fusion proteins (PIN1-donor and interactor-acceptor)

  • Allows real-time monitoring of interaction dynamics

• Chromatin Immunoprecipitation (ChIP):

  • For studying PIN1's impact on transcription factors

  • Use PIN1 antibodies to pull down PIN1-associated chromatin

  • Analysis of target gene promoters by qPCR or sequencing

• Mass Spectrometry-Based Approaches:

  • Immunoprecipitate PIN1 from cancer cells before and after treatment

  • Identify novel interactors using mass spectrometry

  • Quantitative analysis to determine treatment-induced changes in the PIN1 interactome

Studies have shown that PIN1 interacts with and modulates the function of multiple cancer-related proteins, including β-catenin, NF-κB, and AKT, influencing tumor progression and treatment response .

How are PIN1 antibodies being used in developing targeted cancer therapies?

PIN1 antibodies are contributing to targeted cancer therapy development in several ways:

• Antibody-Drug Conjugate Development:

  • Exploration of PIN1 antibodies as targeting moieties for drug delivery

  • Potential for delivering cytotoxic payloads specifically to PIN1-overexpressing cells

• Targeted Drug Delivery Systems:

  • Development of antibody-functionalized DNA-barcoded micellular systems for selective delivery of PIN1 inhibitors

  • Creation of bispecific delivery systems that can simultaneously target CAFs and engage immune cells (e.g., antiCAFs-DMS-AptT)

• Biomarker Development:

  • Use of PIN1 antibodies for patient stratification

  • Correlation of PIN1 expression with response to specific therapies

• Immunotherapy Enhancement:

  • Study of PIN1 inhibition effects on the tumor immune microenvironment

  • Development of combination approaches with immune checkpoint inhibitors

Recent research has demonstrated that targeted delivery of PIN1 inhibitors to cancer-associated fibroblasts, combined with T-cell engaging aptamers, can significantly enhance antitumor responses in preclinical models of pancreatic cancer, highlighting the potential of PIN1-targeted therapeutic approaches .

What methods are available for studying PIN1 in the context of drug resistance mechanisms?

To investigate PIN1's role in drug resistance:

• Expression Analysis in Resistant vs. Sensitive Cells:

  • Western blot and IHC analysis of PIN1 expression levels

  • Correlation of PIN1 levels with resistance phenotypes

  • Time-course analysis during resistance development

• Functional Studies:

  • PIN1 overexpression or knockdown in sensitive cells followed by drug sensitivity testing

  • Analysis of PIN1 inhibition effects on resistant cell populations

  • Combined targeting of PIN1 and resistance-mediating pathways

• PIN1-Dependent Signaling Pathway Analysis:

  • Western blot analysis of PIN1-regulated proteins (β-catenin, NF-κB, AKT) in resistant vs. sensitive cells

  • RT-qPCR to examine expression changes in PIN1-regulated genes during resistance development

  • Analysis of post-translational modifications mediated by PIN1

• Combinatorial Approaches:

  • Testing PIN1 inhibitors in combination with standard therapies

  • Analysis of synergistic effects in resistant models

  • Investigation of molecular mechanisms underlying synergistic interactions

Research has shown that PIN1 can modulate multiple signaling pathways involved in drug resistance, suggesting that PIN1 inhibition strategies could potentially overcome resistance to standard therapies in various cancer types .