FOXQ1 Antibody

What is FOXQ1 and what are its molecular characteristics?

Forkhead box Q1 (FOXQ1, also known as HFH1) is a member of the FOX gene family of transcription factors. It contains a core DNA binding domain, with flanking wings that contribute to its sequence specificity . The protein has a calculated molecular weight of 41 kDa (403 amino acids), though it typically appears at approximately 42 kDa in Western blot applications . FOXQ1 plays critical roles in multiple biological processes, including hair follicle differentiation , and has been implicated in cancer progression through its ability to repress the promoter activity of smooth muscle-specific genes such as telokin and SM22α .

What applications can FOXQ1 antibodies be used for in research?

FOXQ1 antibodies have been validated for multiple experimental applications:

When designing experiments, it is recommended to titrate the antibody for optimal results in each specific testing system .

What species reactivity do commercial FOXQ1 antibodies demonstrate?

Most commercial FOXQ1 antibodies show reactivity with human, mouse, and rat samples . The high level of homology in FOXQ1 across mammalian species often permits cross-reactivity, though validation is necessary for each specific application. For example, the Proteintech antibody (23718-1-AP) has been tested and confirmed to react with human, mouse, and rat samples , while the Abcam recombinant monoclonal antibody [BLR230K] (ab314093) has validated reactivity with human and mouse samples .

How should FOXQ1 antibodies be stored and handled in the laboratory?

For optimal antibody performance and longevity, FOXQ1 antibodies should be stored at -20°C, where they remain stable for approximately one year after shipment . Most commercial preparations are supplied in a storage buffer containing PBS with 0.02% sodium azide and 50% glycerol at pH 7.3 . Importantly, for small volume antibodies (20μl), aliquoting is generally unnecessary for -20°C storage, and some formulations contain 0.1% BSA as a stabilizer . Repeated freeze-thaw cycles should be avoided to prevent degradation of the antibody.

How can FOXQ1 antibodies be used to study cancer progression and metastasis?

FOXQ1 has emerged as a promising prognostic biomarker and potential therapeutic target in cancer research, particularly in colorectal cancer (CRC) . Methodologically, researchers can employ FOXQ1 antibodies to:

• Evaluate FOXQ1 expression levels in patient samples through IHC, correlating expression with clinical outcomes

• Perform Western blot analysis to compare FOXQ1 protein levels between normal and cancerous tissues

• Conduct immunofluorescence studies to examine subcellular localization changes during cancer progression

In functional studies, FOXQ1 knockdown has been shown to inhibit cell proliferation and suppress migration and invasion in CRC cells . This suggests that quantifying FOXQ1 expression using validated antibodies can provide valuable prognostic information. When designing such experiments, it is essential to include appropriate controls and carefully standardize antibody dilutions (typically 1:1000 for Western blot applications in cancer studies) .

What is the role of FOXQ1 in epithelial-mesenchymal transition (EMT)?

FOXQ1 promotes epithelial-mesenchymal transition, a critical process in cancer metastasis . Mechanistically, FOXQ1 directly represses E-cadherin expression by binding to the E-box in its promoter region . To investigate this process:

• Use FOXQ1 antibodies in chromatin immunoprecipitation (ChIP) assays to demonstrate direct binding to the E-cadherin promoter

• Employ Western blot analysis to monitor changes in EMT markers following FOXQ1 modulation

• Implement immunofluorescence to visualize cytoskeletal reorganization during EMT

Research has shown that FOXQ1 overexpression increases cell migration (by 2.5-fold) and invasion (by 4-fold) in HMLE cells, while knockdown of FOXQ1 in 4T1 cells decreases migration by 48% and invasion by 53% . When designing experiments to study FOXQ1's role in EMT, researchers should consider both gain-of-function and loss-of-function approaches to comprehensively characterize its effects.

How is FOXQ1 expression regulated, and how can this be studied using antibodies?

FOXQ1 expression is regulated by TGF-β1 signaling, a key pathway in many developmental and pathological processes . To investigate this regulatory relationship:

• Treat cells with TGF-β1 and monitor FOXQ1 protein levels via Western blot at various time points

• Perform immunofluorescence to observe changes in FOXQ1 subcellular localization following TGF-β1 treatment

• Use co-immunoprecipitation with FOXQ1 antibodies to identify interaction partners in the TGF-β signaling cascade

In experimental designs, it is important to include TGF-β pathway inhibitors as controls to confirm specificity. The relationship between TGF-β1 and FOXQ1 has significant implications for cancer research, as FOXQ1 knockdown has been shown to block TGF-β1-induced EMT at both morphological and molecular levels .

What are the optimal conditions for FOXQ1 detection by immunohistochemistry?

For successful immunohistochemical detection of FOXQ1 in tissue samples:

For FFPE sections of human colon carcinoma and mouse bladder, rabbit anti-FOXQ1 recombinant monoclonal antibodies have shown reliable and specific staining patterns . Optimization of antigen retrieval methods is particularly important, as epitope accessibility can vary between tissue types and fixation methods.

How should Western blot protocols be optimized for FOXQ1 detection?

For optimal Western blot detection of FOXQ1:

• Load approximately 30μg of total protein extract per sample on 10% polyacrylamide-SDS gels

• Block membranes in 5% fat-free milk to reduce background

• Incubate with primary FOXQ1 antibody at 1:1000 dilution overnight at 4°C

• Use HRP-conjugated goat anti-rabbit secondary antibody (1:3000 dilution) for detection

When troubleshooting Western blot issues, verify that the observed molecular weight matches the expected 42 kDa for FOXQ1 . If detecting multiple bands, consider the possibility of isoforms, post-translational modifications, or degradation products. Including positive control samples (such as mouse or rat kidney tissue, which express FOXQ1 ) can help validate the specificity of the antibody.

What in vivo models are appropriate for studying FOXQ1's role in metastasis?

Several in vivo models have been validated for studying FOXQ1's role in metastasis:

• Mammary fat pad injection model: EpRas cells overexpressing FOXQ1 show significantly enhanced lung metastasis (2-15% tumor area in lung sections) compared to control cells

• Orthotopic injection of 4T1 cells: FOXQ1 knockdown reduces metastatic burden in BALB/C mice, with an average of 8.3% metastatic foci in lung sections compared to 37% in control cells

• Rescue experiments: Re-expression of human FOXQ1 in mouse 4T1 cells with endogenous FOXQ1 knockdown partially restores metastatic capability to 20.5%

These models allow for quantitative assessment of FOXQ1's metastatic effects while controlling for primary tumor growth, which has not shown significant differences between FOXQ1-modulated and control groups .

Why might Western blot results with FOXQ1 antibodies show variability between experiments?

Variability in FOXQ1 Western blot results can stem from several factors:

• Sample preparation: FOXQ1 is a transcription factor primarily located in the nucleus, so inefficient nuclear protein extraction can reduce detection

• Antibody specificity: Different antibodies target distinct epitopes within FOXQ1, potentially yielding different banding patterns

• Protein modification: Post-translational modifications may alter apparent molecular weight or epitope availability

• Expression levels: FOXQ1 expression varies significantly between tissue types and disease states

To address these issues, standardize protein extraction protocols (particularly nuclear extraction methods), include positive control samples known to express FOXQ1 (such as kidney tissue ), and validate antibody specificity using FOXQ1 knockout or knockdown samples .

How can discrepancies between FOXQ1 expression at mRNA and protein levels be interpreted?

Discrepancies between FOXQ1 mRNA and protein levels may reflect:

• Post-transcriptional regulation: miRNAs, such as miR-342, have been identified as regulators of FOXQ1 expression

• Protein stability: Variations in FOXQ1 protein half-life across different cellular contexts

• Methodological differences: Limitations in antibody sensitivity compared to PCR-based detection

• Temporal dynamics: Time lags between transcriptional and translational responses

When encountering such discrepancies, researchers should consider complementary approaches, such as using multiple antibodies targeting different epitopes, implementing pulse-chase experiments to assess protein stability, and evaluating potential regulatory factors like miR-342, which has been shown to modulate FOXQ1 expression in colorectal cancer cells .

How can researchers verify that phenotypic changes are specifically attributable to FOXQ1 modulation?

To confirm that observed phenotypic changes are specifically due to FOXQ1:

• Implement rescue experiments: Re-expression of FOXQ1 in knockdown models should restore the original phenotype, as demonstrated in metastasis studies

• Use multiple knockdown approaches: Combining siRNA, shRNA, and CRISPR-Cas9 methods targeting different regions of FOXQ1 helps rule out off-target effects

• Employ domain-specific mutations: Introduce mutations in specific functional domains of FOXQ1 to identify which domains are essential for particular phenotypes

• Monitor downstream targets: Assess known FOXQ1 targets (such as E-cadherin ) to confirm pathway engagement

In published research, rescue experiments have successfully demonstrated FOXQ1 specificity, showing that human FOXQ1 expression can partially restore metastatic capability in mouse cells with endogenous FOXQ1 knockdown .

How can FOXQ1 antibodies be used to explore the relationship between FOXQ1 and other FOX family members?

The FOX family contains numerous members with diverse functions, and understanding the interplay between FOXQ1 and other family members requires careful experimental design:

• Use highly specific antibodies to distinguish between closely related FOX proteins

• Implement co-immunoprecipitation with FOXQ1 antibodies followed by mass spectrometry to identify interactions with other FOX proteins

• Employ chromatin immunoprecipitation sequencing (ChIP-seq) to compare genome-wide binding sites of FOXQ1 versus other FOX proteins

• Conduct sequential ChIP (re-ChIP) to identify genomic regions co-occupied by FOXQ1 and other FOX proteins

Recent research has begun to reveal functional relationships between FOXQ1 and other FOX proteins, such as FOXM1, which has been identified alongside FOXQ1 as a promising prognostic biomarker in colorectal cancer .

What are the therapeutic implications of targeting FOXQ1 in cancer, and how can antibodies facilitate this research?

The identification of FOXQ1 as a prognostic biomarker suggests potential therapeutic applications:

• Use FOXQ1 antibodies to screen patient samples and stratify for potential targeted therapies

• Develop therapeutic antibodies or small molecules targeting FOXQ1 or its downstream effectors

• Monitor FOXQ1 expression as a biomarker of treatment response

• Investigate combination therapies targeting both FOXQ1 and TGF-β1 signaling pathways

Research has indicated that FOXQ1, alongside FOXM1, represents a promising therapeutic target in colorectal cancer . The development of effective targeting strategies requires thorough validation using well-characterized antibodies to confirm target engagement and monitor therapeutic effects in both preclinical models and clinical samples.