FBP1 Antibody

What is FBP1 and why is it relevant in research applications?

FBP1 (Fructose-1,6-bisphosphatase 1) is a key enzyme in gluconeogenesis that has been associated with tumor initiation in several cancers . Beyond its enzymatic function, FBP1 has been identified as an independent biomarker associated with favorable prognosis in esophageal adenocarcinoma (EAC) . The protein has dual significance - first as a metabolic regulator and second as a potential prognostic indicator in cancer research. FBP1 deficiency is also recognized as a rare inborn metabolic error (OMIM:229700) that causes severe hypoglycemia, lactic acidosis, seizures, and other metabolic complications .

What tissue types express FBP1 and can be targeted with FBP1 antibodies?

FBP1 antibodies have demonstrated successful detection in multiple tissue types. Western blot analysis has confirmed positive detection in mouse, rat, and pig liver tissues, as well as in human cancer cell lines including MCF-7 and T-47D . Immunohistochemical (IHC) applications have shown positive results in mouse kidney tissue . The wide range of detectable tissues makes FBP1 antibodies versatile tools for comparative studies across different model organisms and human samples.

What are the primary applications for FBP1 antibodies in research?

FBP1 antibodies have been validated for several key applications in molecular and cellular biology research:

These applications enable researchers to investigate FBP1 expression, localization, and interactions in various experimental contexts .

How does FBP1 antibody staining correlate with clinical outcomes in cancer research?

Immunohistochemical analysis of FBP1 expression using specific antibodies has revealed significant associations with prognosis in cancer patients. In a study of 571 esophageal adenocarcinoma (EAC) patients, varying intensities of FBP1 expression were categorized into four scores: score 0 (no expression), score 1 (weak expression), score 2 (moderate expression), and score 3 (strong expression) .

The median survival times observed were:

• Score 0: 15.1 months (95% CI 8.26–21.84)

• Score 1: 24.3 months (95% CI 19.19–29.31)

• Score 2: 32.7 months (95% CI 18.47–46.85)

• Score 3: 30.1 months (95% CI 14.1–46.03)

This demonstrates that FBP1 antibody staining intensity can provide valuable prognostic information, particularly in patients who undergo primary surgery without neoadjuvant treatment .

How can researchers distinguish between enzymatic and non-enzymatic functions of FBP1 using antibodies?

Recent research has uncovered that FBP1 possesses functions independent of its catalytic activity. FBP1 serves as an endogenous "safety valve" that prevents insulin hyperresponsiveness and balances glucose and lipid metabolism . To investigate these dual roles, researchers can employ co-immunoprecipitation (co-IP) with FBP1 antibodies followed by mass spectrometry to identify binding partners.

This approach has revealed that FBP1 nucleates a stable multiprotein complex containing Aldolase B (ALDOB), the catalytic subunit of protein phosphatase 2A (PP2A-C), and AKT1 . By comparing results between wild-type and catalytically inactive FBP1 mutants, researchers can differentiate between protein interactions dependent on enzymatic activity versus structural roles of the protein.

What are the challenges in interpreting FBP1 antibody signals in tissues that have undergone treatment?

Interpreting FBP1 antibody signals in tissues from patients who have received treatments like neoadjuvant therapy requires careful consideration. Research has shown that the prognostic relevance of FBP1 was highest in cohorts of patients who underwent surgery without any pre-treatment . The pronounced survival difference observed in untreated patients suggests that neoadjuvant therapy may influence FBP1 protein expression as measured by immunohistochemistry .

Researchers should design studies that account for treatment history, potentially including pre- and post-treatment samples to track changes in FBP1 expression. Additionally, multivariate analysis should be employed to control for confounding factors when assessing the prognostic value of FBP1 in treated tissues .

What are the optimal conditions for antigen retrieval when using FBP1 antibodies in immunohistochemistry?

For optimal immunohistochemical detection of FBP1, the recommended antigen retrieval method involves TE buffer at pH 9.0 . Alternatively, citrate buffer at pH 6.0 may be used, though comparative studies suggest the alkaline TE buffer provides superior epitope unmasking for FBP1 detection . Researchers should note that optimization of antigen retrieval conditions may be necessary depending on tissue type, fixation method, and duration of fixation.

How should researchers validate FBP1 antibody specificity for their particular experimental system?

Validating antibody specificity is essential for reliable research results. For FBP1 antibodies, a multi-faceted validation approach is recommended:

• Positive and negative controls: Include tissues/cells known to express (liver, kidney) or lack FBP1.

• Knockdown/knockout verification: Use siRNA/CRISPR to create FBP1-deficient samples and confirm loss of signal.

• Multiple antibody comparison: Use antibodies targeting different epitopes of FBP1 to verify consistent patterns.

• Western blot correlation: Confirm that band intensity in Western blots correlates with immunohistochemistry or immunofluorescence signal intensity.

• Recombinant protein competition: Pre-incubate antibody with purified FBP1 protein to demonstrate signal abolishment.

These validation steps ensure that observed signals truly represent FBP1 rather than non-specific binding .

What dilution optimization strategies should be employed when using FBP1 antibodies across different applications?

Dilution optimization is critical for achieving optimal signal-to-noise ratios. For FBP1 antibodies, application-specific recommendations provide starting points, but systematic titration is necessary:

• Western Blot: Begin with a midrange dilution (1:10000) and test serial dilutions (1:5000, 1:20000, 1:40000) to identify optimal concentration .

• Immunohistochemistry: Start with 1:2000 dilution and adjust based on tissue type and fixation method .

• Immunofluorescence: Initial testing at 1:800 dilution followed by refinement is advised .

Each new lot of antibody should undergo verification testing, as lot-to-lot variability can significantly impact optimal dilutions. Additionally, sample-dependent optimization may be necessary as FBP1 expression levels vary across tissues and disease states .

How can FBP1 antibodies be used to investigate the relationship between FBP1 and other molecular markers in cancer?

FBP1 antibodies enable correlation studies between FBP1 expression and other cancer-relevant biomarkers. Research has demonstrated significant correlations between FBP1 and several important markers:

• HER2: High FBP1 expression correlates with increased levels of HER2 (p = 0.007), a tyrosine kinase regulating intracellular signal pathways that affect proliferation .

• IDO: FBP1 expression positively correlates with IDO levels (p = 0.004), an immunomodulatory enzyme .

• CD3+ T cells: Higher FBP1 levels connect to increased CD3-positive T cell infiltration (p = 0.039), which has been associated with survival benefits in esophageal adenocarcinoma .

Researchers can employ multiplex immunohistochemistry or sequential staining approaches with FBP1 antibodies to investigate these relationships further, potentially uncovering mechanistic connections between metabolic regulation and immune response in the tumor microenvironment.

What insights can FBP1 antibodies provide regarding the complex between FBP1, ALDOB, PP2A-C, and AKT1?

FBP1 antibodies are instrumental in elucidating the components and dynamics of the multiprotein complex formed by FBP1. Mass spectrometry analysis of immunoprecipitates using FBP1 antibodies has identified ALDOB, AKT1, and PP2A-C as top FBP1 interacting partners . Notably, no PP2A regulatory subunits co-immunoprecipitate with FBP1, suggesting a unique interaction pattern .

Researchers can employ co-immunoprecipitation with FBP1 antibodies followed by Western blotting for interaction partners to:

• Map interaction domains through truncation mutants

• Assess complex formation under various metabolic conditions

• Investigate how complex assembly/disassembly relates to insulin signaling dynamics

• Determine how post-translational modifications affect complex stability

These approaches can reveal how FBP1 functions beyond its enzymatic role to regulate insulin signaling and metabolic homeostasis .

How can FBP1 antibodies be used to explore the potential therapeutic relevance of FBP1 in individualized cancer treatment?

FBP1 antibodies can facilitate research into personalized cancer treatment strategies based on FBP1 status. Evidence suggests that FBP1 expression may predict response to specific therapies:

• BET inhibitors: In pancreatic cancer, FBP1 presence increases sensitivity to bromodomain and extraterminal domain (BET) inhibitors like JQ1 . FBP1 antibodies can help stratify tumors for potential BET inhibitor trials.

• Platinum-based chemotherapy: In ovarian cancer, increased FBP1 expression sensitizes cells to cisplatin-induced apoptosis . Immunohistochemical analysis using FBP1 antibodies could help identify patients likely to benefit from platin-containing regimens.

• Radiotherapy response: FBP1 enhances radiosensitivity in nasopharyngeal carcinoma cells . Researchers can use FBP1 antibodies to investigate whether this relationship holds in other cancer types.

By combining FBP1 expression profiling with treatment response data, researchers can develop predictive biomarkers for therapy selection, potentially improving outcomes through personalized treatment approaches .