CBR1 Antibody

What is CBR1 and why is it important to study with antibody-based techniques?

CBR1 (Carbonyl Reductase 1) is an NADPH-dependent oxidoreductase that belongs to the short-chain dehydrogenases/reductases (SDR) family. It catalyzes the reduction of various carbonyl compounds including quinones, prostaglandins, menadione, and xenobiotics . CBR1's significance lies in its role in several physiological processes:

• Lipid metabolism and hormone synthesis

• Detoxification of xenobiotics

• Reduction of antitumor anthracyclines (doxorubicin and daunorubicin) to cardiotoxic compounds

• Glucocorticoid metabolism by catalyzing NADPH-dependent cortisol/corticosterone conversion

• Potential involvement in glucose and lipid metabolism

Antibody-based techniques provide precise tools for studying CBR1's tissue distribution, expression levels, and functional roles in various pathological conditions, making them invaluable for understanding this enzyme's contribution to both normal physiology and disease states.

What are the key differences between polyclonal and monoclonal CBR1 antibodies in research applications?

The choice between polyclonal and monoclonal CBR1 antibodies significantly impacts experimental outcomes:

Methodological consideration: For initial screening of CBR1 expression in tissues, polyclonal antibodies offer broader detection. For highly specific detection or quantification experiments, monoclonal antibodies like EPR9660 (ab156590) or 4E12 provide more consistent results with less background.

How should CBR1 antibodies be stored and handled to maintain optimal reactivity?

Proper storage and handling are crucial for maintaining CBR1 antibody performance:

• Storage temperature: Store at -20°C for long-term preservation (stable for approximately 1 year)

• Short-term storage: Can be stored at 4°C for up to 3 months

• Reconstitution: For lyophilized antibodies, reconstitute with 0.2ml distilled water to yield 500μg/ml concentration

• Buffer conditions:

  • Most CBR1 antibodies are supplied in buffers containing:

    • TBS with 0.1% BSA and 0.09% sodium azide , or

    • Phosphate buffered solution (pH 7.4) with stabilizers and 50% glycerol

• Freeze-thaw cycles: Minimize repeated freezing and thawing. For maximum recovery, centrifuge the original vial after thawing and before removing the cap

• Aliquoting: For frequent use, prepare small aliquots to prevent freeze-thaw cycles

Methodological note: Always check specific manufacturer recommendations as formulations vary. For example, the Picoband® Antibody from Boster Bio (A02825-1) contains 4 mg Trehalose, 0.9 mg NaCl, and 0.2 mg Na2HPO4 per vial .

What are the optimal conditions for Western blot detection of CBR1 using specific antibodies?

Optimizing Western blot protocols for CBR1 detection requires careful consideration of several parameters:

Methodological considerations: When quantifying CBR1 expression, include recombinant CBR1 standards for calibration and assess β-actin expression as a loading control. The detection of CBR1 is linear in the range of 0.03–0.30 μg (r² > 0.96) .

How can immunohistochemistry (IHC) protocols be optimized for detecting CBR1 in different tissue types?

Successful IHC detection of CBR1 across diverse tissue types requires specific protocol adaptations:

• Antigen retrieval methods:

  • Heat-mediated retrieval in EDTA buffer (pH 8.0) is most effective for CBR1 in paraffin-embedded sections

  • For some tissues, enzymatic antigen retrieval using IHC enzyme antigen retrieval reagent may be more suitable

• Tissue-specific considerations:

  • Cancer tissues (breast, liver, lung, rectal): Block with 10% goat serum; incubate with 2 μg/ml anti-CBR1 antibody overnight at 4°C

  • Normal tissues (mouse/rat kidney): Same blocking and antibody concentration as cancer tissues, but may require longer incubation times

• Detection systems:

  • For bright-field microscopy: Use HRP-conjugated secondary antibodies with DAB as chromogen

  • For fluorescence imaging: Use fluorophore-conjugated secondary antibodies (e.g., DyLight488)

• Signal amplification considerations:

  • For tissues with low CBR1 expression, employ HRP-conjugated polymers or avidin-biotin complexes

  • Example: HRP Conjugated Rabbit IgG Super Vision Assay Kit (SV0002) with DAB as chromogen

• Controls:

  • Positive control: Include human liver tissue (known high CBR1 expression)

  • Negative control: Omit primary antibody or use isotype control

Methodological insight: CBR1 has been successfully detected in diverse cancer tissues (breast, liver, lung, rectal) and normal tissues (kidney), demonstrating the versatility of optimized IHC protocols across tissue types .

What are the key considerations for flow cytometry applications using CBR1 antibodies?

Flow cytometry with CBR1 antibodies requires specific technical considerations:

• Cell preparation protocol:

  • Fix cells with 4% paraformaldehyde

  • Permeabilize with appropriate permeabilization buffer to allow antibody access to intracellular CBR1

  • Block with 10% normal goat serum to reduce non-specific binding

• Antibody concentration and incubation:

  • Use 1 μg antibody per 1×10⁶ cells

  • Incubate for 30 minutes at 20°C

• Secondary antibody selection:

  • DyLight®488 conjugated anti-rabbit IgG (5-10 μg/1×10⁶ cells)

  • Incubate for 30 minutes at 20°C

• Critical controls:

  • Isotype control: Use rabbit IgG (1 μg/1×10⁶ cells) under identical conditions

  • Unlabeled control: Sample without primary and secondary antibody incubation

  • Single-stained controls: For compensation when multiplexing

• Gating strategy:

  • Use forward and side scatter to identify viable cells

  • Apply appropriate gating based on negative and isotype controls

  • Consider the need for viability dyes to exclude dead cells

Methodological note: Flow cytometry has been successfully used to detect CBR1 in U87 cells, demonstrating that proper permeabilization is critical for accessing this intracellular enzyme .

How can researchers effectively use CBR1 antibodies to study protein expression regulation by microRNAs?

Investigating microRNA regulation of CBR1 expression requires sophisticated experimental approaches:

• Identification of regulatory microRNAs:

  • microRNA-574-5p (hsa-miR-574-5p) has been identified as a regulator of CBR1

  • Use in silico prediction tools to identify potential miRNA binding sites in the CBR1 3'-UTR

• Experimental validation workflow:

  • Step 1: Generate CBR1 3'-UTR reporter constructs for luciferase assays

  • Step 2: Transfect cells with miRNA mimics or inhibitors

  • Step 3: Measure CBR1 protein levels by Western blot using specific antibodies

  • Step 4: Assess CBR1 enzymatic activity to confirm functional consequences

• CBR1 protein quantification after miRNA modulation:

  • Use validated anti-CBR1 antibodies (1:1,000 dilution)

  • Normalize to β-actin (1:1,000 dilution)

  • Calculate relative CBR1 levels compared to cells transfected with miRNA mimic negative control

• Analysis of CBR1 mRNA stability:

  • Treat cells with actinomycin D to block de novo RNA synthesis

  • Collect samples at 0, 2, 4, and 8 hours

  • Measure CBR1 mRNA levels by RT-qPCR

  • Use antibody-based methods to correlate mRNA changes with protein levels

• Genotype-specific miRNA effects:

  • Study CBR1 polymorphisms (e.g., rs9024) that may affect miRNA binding

  • Compare miRNA effects across cell lines with different CBR1 genotypes

Methodological consideration: To establish physiological relevance, assess the co-expression of identified miRNAs and CBR1 in human tissues (e.g., liver and heart) using antibody-based protein detection methods in parallel with miRNA quantification .

What strategies can be employed to study CBR1 induction in response to environmental toxicants?

Investigating CBR1 induction by environmental toxicants requires comprehensive experimental approaches:

• Cell culture model selection:

  • Human lung carcinoma A549 cells have been validated for studying CBR1 induction

  • Other cell types should be chosen based on toxicant target tissues

• Exposure conditions optimization:

  • Determine appropriate toxicant concentration (e.g., 2.5 μM B[a]P)

  • Establish optimal exposure duration (typically 24 hours)

  • Include appropriate vehicle controls (e.g., DMSO)

• Mechanistic studies using inhibitors:

  • Use translation inhibitors (e.g., 10 μM cyclohexamide) to distinguish between transcriptional and translational regulation

  • Include AhR inhibitors to assess receptor-mediated induction pathways

• Protein expression analysis:

  • Extract total protein from cell lysates using appropriate extraction kits

  • Quantify CBR1 protein by Western blot using specific antibodies

  • Include recombinant CBR1 standards (0.03-0.30 μg) for quantitative analysis

• Transcription factor analysis:

  • Assess AhR nuclear translocation in response to toxicant exposure

  • Investigate formation of specific DNA-protein complexes using antibody-based techniques

• Functional consequences assessment:

  • Measure CBR1 enzymatic activity using appropriate substrates

  • Correlate activity with protein levels determined by antibody-based methods

Methodological insight: Studies have demonstrated enhanced translocation of AhR into the nucleus of A549 cells exposed to B[a]P, coinciding with increased CBR1 expression, suggesting an AhR-dependent mechanism of CBR1 induction .

How can antibodies against CBR1 be used to investigate its role in anthracycline-induced cardiotoxicity?

Investigating CBR1's role in anthracycline-induced cardiotoxicity requires sophisticated experimental approaches:

• Tissue-specific expression analysis:

  • Quantify CBR1 levels in heart tissue versus tumor tissue using validated antibodies

  • Compare expression levels across different cardiac cell types (cardiomyocytes, fibroblasts, endothelial cells)

  • Assess induction of CBR1 after anthracycline treatment

• Subcellular localization studies:

  • Use immunofluorescence with anti-CBR1 antibodies to determine subcellular distribution

  • Co-stain with markers for various organelles to identify localization changes after anthracycline exposure

  • Employ cell fractionation followed by Western blot analysis with CBR1 antibodies

• Genetic variation impact assessment:

  • Compare CBR1 protein levels in samples with different CBR1 genotypes using quantitative immunoblotting

  • Calculate CBR1 levels relative to recombinant CBR1 standards (range 0.03–0.30 μg)

  • Correlate protein levels with cardiotoxicity outcomes

• In vitro functional studies:

  • Use CBR1 antibodies to confirm knockdown or overexpression in cellular models

  • Measure conversion of doxorubicin to cardiotoxic doxorubicinol

  • Correlate conversion rates with CBR1 protein levels determined by antibody-based methods

• Patient sample analysis:

  • Quantify CBR1 in peripheral blood mononuclear cells using flow cytometry

  • Assess CBR1 in cardiac tissue biopsies using IHC with specific antibodies

  • Correlate expression levels with clinical outcomes

Methodological consideration: CBR1 catalyzes the reduction of the antitumor anthracyclines doxorubicin and daunorubicin to the cardiotoxic compounds doxorubicinol and daunorubicinol . Antibody-based quantification of CBR1 in combination with functional assays can help identify patients at higher risk for developing cardiotoxicity.

What strategies can be employed to minimize cross-reactivity with other carbonyl reductases when using CBR1 antibodies?

Ensuring CBR1 antibody specificity requires systematic approaches to address potential cross-reactivity:

• Understanding potential cross-reactants:

  • CBR3 shares structural similarity with CBR1 and is a primary concern for cross-reactivity

  • Studies have shown that some polyclonal anti-human CBR1 antibodies do not cross-react with recombinant human CBR3

• Antibody selection criteria:

  • Choose antibodies raised against unique regions of CBR1

  • Select antibodies with documented validation against multiple carbonyl reductases

  • Consider monoclonal antibodies for higher specificity to a single epitope

• Validation experiments:

  • Positive control: Include recombinant CBR1 protein (≥96% purity)

  • Negative control: Test against recombinant CBR3 (≥90% purity)

  • Knockdown validation: Confirm antibody specificity using CBR1 siRNA or CRISPR knockout samples

• Optimizing detection conditions:

  • Adjust antibody concentration to minimize non-specific binding

  • Increase stringency of washing steps in immunoassays

  • Use appropriate blocking agents to reduce background

• Confirmatory approaches:

  • Perform mass spectrometry to confirm identity of detected proteins

  • Use multiple antibodies targeting different epitopes of CBR1

  • Combine protein detection with activity assays specific to CBR1

Methodological insight: Some validated anti-CBR1 antibodies show no immunoreactive bands when testing against recombinant human CBR3, confirming their specificity. For example, a polyclonal anti-human CBR1 antibody from Abcam has been validated to show no cross-reactivity with CBR3 .

How can researchers address variability in CBR1 detection across different tissue types?

Addressing tissue-specific variability in CBR1 detection requires systematic optimization:

• Tissue-specific expression levels:

  • CBR1 expression varies by 8-fold in samples from different populations

  • Expression range: 2.2–19.2 nmol/g cytosolic protein

  • Adjust antibody concentration and detection methods accordingly

• Optimizing tissue preparation:

  • Fresh frozen tissues: Immediate processing minimizes protein degradation

  • FFPE samples: Optimize antigen retrieval conditions based on tissue type

    • Cancer tissues: Heat-mediated retrieval in EDTA buffer (pH 8.0)

    • Normal tissues: May require longer retrieval times or enzymatic methods

• Application-specific considerations:

  • Western blot: Include recombinant CBR1 standards (0.03-0.30 μg) for calibration

  • IHC: Tissue-specific optimization of antibody concentration and incubation time

    • Human cancer tissues: 2 μg/ml, overnight at 4°C

    • Animal tissues: May require higher antibody concentrations

• Background reduction strategies:

  • High-background tissues: Increase blocking time and concentration (e.g., 10% goat serum)

  • Autofluorescent tissues: Use Sudan Black B treatment or spectral unmixing

  • Highly vascularized tissues: Block endogenous peroxidase activity thoroughly

• Quantification approaches:

  • Use digital image analysis software for objective quantification

  • Include internal standards within each experiment

  • Normalize to housekeeping proteins appropriate for the specific tissue type

Methodological consideration: Studies have shown that CBR1 protein levels do not significantly differ between populations (CBR1 in one population = 8.0 ± 3.4 nmol/g cytosolic protein versus another population = 9.0 ± 4.6 nmol/g cytosolic protein; p = 0.347) , but individual variation can be substantial.

What are the critical considerations for validating novel anti-CBR1 antibodies for research applications?

Comprehensive validation of novel anti-CBR1 antibodies requires a systematic approach:

• Fundamental characterization parameters:

  • Specificity: Test against recombinant CBR1 versus other carbonyl reductases

  • Sensitivity: Determine limit of detection (e.g., 0.01 μg) and quantification (e.g., 0.02 μg)

  • Affinity constant (Kaff): Measure binding strength (e.g., 7.85 × 10^8 M/L for high-affinity antibodies)

• Multi-platform validation:

  • ELISA: Confirm binding to CBR1 protein

  • Western blot: Verify correct molecular weight detection (~30 kDa)

  • IHC/IF: Demonstrate appropriate cellular/tissue localization

  • Flow cytometry: Confirm detection in permeabilized cells

• Cross-species reactivity assessment:

  • Test antibody against human, mouse, and rat samples

  • Verify species cross-reactivity claims with empirical data

  • Document species-specific optimization requirements

• Application-specific validation:

  • Establish linear detection range for quantitative applications (e.g., 0.05–0.30 μg; r² > 0.85)

  • Determine coefficient of variation for reproducibility assessment (e.g., 9.5%)

  • Optimize antibody concentration for each application:

    • WB: 1:1000-1:5000 dilution

    • IHC: 1:50-1:200 dilution

• Independent confirmation methods:

  • Correlation with mRNA expression

  • Comparison with enzymatic activity measurements

  • Validation in knockout/knockdown systems

Methodological insight: Development of a novel monoclonal antibody against CBR1 required systematic characterization through ELISA, spot-ELISA, Western blot, and immunohistochemistry to confirm specificity against recombinant human CBR1 protein .

How might advances in antibody engineering impact CBR1 research in cancer and metabolic disease studies?

Emerging antibody technologies offer new opportunities for CBR1 research:

• Recombinant antibody formats:

  • Single-chain variable fragments (scFvs) against CBR1 could penetrate tissues and cells more effectively

  • Bispecific antibodies targeting CBR1 and related enzymes could enable complex pathway studies

  • Nanobodies may provide access to previously inaccessible CBR1 epitopes

• Application in cancer research:

  • CBR1 antibodies coupled with cancer-specific markers for multiplexed IHC

  • Integration with spatial transcriptomics to correlate CBR1 protein and mRNA distribution

  • Development of antibody-drug conjugates targeting CBR1-overexpressing cancer cells

• Metabolic disease applications:

  • CBR1's role in glucose and lipid metabolism could be explored using:

    • In vivo imaging with fluorescently labeled CBR1 antibodies

    • Proximity ligation assays to study CBR1 interactions with metabolic enzymes

    • Single-cell analysis of CBR1 expression in metabolic tissues

• Therapeutic potential:

  • CBR1 is expressed in HL-7702 cells and lipid tissue

  • Antibodies could be engineered to modulate CBR1 activity in specific tissues

  • Imaging agents based on CBR1 antibodies could help monitor treatment response

• Integration with emerging technologies:

  • Mass cytometry (CyTOF) with CBR1 antibodies for high-dimensional analysis

  • Intrabodies to track and modulate CBR1 in living cells

  • CRISPR-based functional screening combined with antibody-based detection

Methodological consideration: The development of novel monoclonal antibodies against CBR1 has already revealed its expression in HL-7702 cells and lipid tissue, suggesting important roles in glucose and lipid metabolism that could be further explored with advanced antibody technologies .

What are the emerging methodologies for studying the interaction between CBR1 and drug resistance mechanisms using antibody-based approaches?

Innovative antibody-based approaches are advancing our understanding of CBR1's role in drug resistance:

• High-resolution imaging techniques:

  • Super-resolution microscopy with CBR1 antibodies to visualize subcellular localization

  • Correlative light and electron microscopy (CLEM) to study CBR1 in relation to drug metabolism organelles

  • Live-cell imaging with CBR1-GFP fusions validated by antibody staining

• Proximity-based interaction studies:

  • Proximity ligation assay (PLA) to detect CBR1 interactions with drug targets

  • BioID or APEX2 proximity labeling coupled with CBR1 antibody-based purification

  • FRET-based assays to study dynamic CBR1 interactions during drug metabolism

• Single-cell analysis platforms:

  • Mass cytometry with CBR1 antibodies to correlate expression with resistance markers

  • Single-cell Western blotting to capture cell-to-cell variability in CBR1 expression

  • Imaging mass cytometry for spatial distribution of CBR1 in resistant tumor regions

• Clinical sample assessment:

  • Multiplex immunofluorescence panels including CBR1 and resistance markers

  • Digital spatial profiling of tumor samples with CBR1 antibodies

  • Circulating tumor cell analysis for CBR1 expression in treatment-resistant disease

• Functional modulation approaches:

  • Antibody-directed enzyme prodrug therapy targeting CBR1

  • Intracellular delivery of CBR1 antibodies to modulate function

  • Conditional protein degradation systems validated with CBR1 antibodies

Methodological insight: CBR1 catalyzes the reduction of antitumor anthracyclines doxorubicin and daunorubicin to cardiotoxic compounds , suggesting its critical role in both drug efficacy and toxicity profiles. Advanced antibody-based approaches can help dissect these dual roles in treatment response.

How can researchers leverage CBR1 antibodies to understand tissue-specific enzyme regulation in normal physiology and disease states?

Advanced approaches for investigating tissue-specific CBR1 regulation include:

• Multi-omics integration strategies:

  • Correlate CBR1 protein levels (detected by antibodies) with:

    • Transcriptomics data to identify regulatory mechanisms

    • Metabolomics profiles to link to functional outcomes

    • Proteomics data to identify interacting partners

• Spatial biology approaches:

  • Multiplexed immunofluorescence to map CBR1 distribution within tissue architecture

  • Digital spatial profiling for quantitative assessment of CBR1 across tissue regions

  • 3D tissue reconstruction to understand CBR1 distribution in complex organs

• Developmental and disease progression studies:

  • Temporal analysis of CBR1 expression during:

    • Organ development and differentiation

    • Disease progression (e.g., cancer, metabolic disorders)

    • Response to therapeutic interventions

• Regulatory mechanism investigation:

  • Analysis of tissue-specific microRNA regulation of CBR1

  • Epigenetic profiling correlated with CBR1 protein levels

  • Investigation of tissue-specific transcription factors using ChIP-seq and antibody validation

• Physiological response assessment:

  • CBR1 expression changes in response to:

    • Environmental toxicants in lung tissue

    • Metabolic stress in adipose tissue

    • Xenobiotic exposure in liver tissue

Methodological consideration: Studies have already demonstrated tissue-specific CBR1 expression patterns across cancer tissues (breast, liver, lung, rectal) and normal tissues (kidney) . Advanced antibody-based methods can further elucidate how these patterns relate to tissue-specific functions and disease susceptibility.

Comparative analysis of commonly used CBR1 antibodies in research applications

Optimized protocol parameters for CBR1 antibody applications across different techniques