FGFR1OP Human

What is the genomic location and basic structure of FGFR1OP?

FGFR1OP is located on chromosome 6q27 and encodes a largely hydrophilic centrosomal protein . The gene product contains functional domains including a leucine-rich region at the N-terminus that becomes part of fusion proteins in chromosomal translocations . When studying FGFR1OP, researchers should consider both the wild-type protein structure and the chimeric variants that arise from gene fusion events. The most common fusion involves the N-terminal leucine-rich region of FGFR1OP joined to the catalytic domain of FGFR1, creating an oncogenic protein with constitutive tyrosine kinase activity.

How is FGFR1OP expression measured in experimental settings?

FGFR1OP expression can be evaluated through multiple complementary techniques:

• Northern blot analysis: Can be performed using 32P-labeled PCR products of FGFR1OP as probes, with primers such as 5′-TAATAGTACCAGCCATCGCTCAG-3′ and 5′-ATCCTACGGCTTTATTGACACCT-3′ .

• Immunohistochemistry: Requires specific antibodies such as rabbit polyclonal anti-human FGFR1OP antibodies. Tissue microarrays are particularly effective for analyzing multiple samples simultaneously .

• Western blot analysis: Can be performed using antibodies raised against histidine-tagged human FGFR1OP protein (codons 7–173; accession No. NM_007045) .
  For reliable quantification, it's advisable to compare expression levels across multiple normal tissues and cancer samples, as was done in studies examining 23 normal tissues and 372 non-small cell lung cancer specimens .

What cellular functions does FGFR1OP regulate in normal physiology?

FGFR1OP functions primarily as a centrosomal protein required for anchoring microtubules to subcellular structures . Its role in cellular physiology includes:

• Cell cycle regulation: FGFR1OP shows cell cycle-dependent localization, which can be studied by synchronizing cells at the G1–S boundary using aphidicolin block (1 μg/mL for 24 hours) .

• Microtubule organization: As a centrosomal protein, it participates in maintaining cellular architecture and facilitating cellular division.

• Protein-protein interactions: FGFR1OP interacts with proteins such as ABL1 and WRNIP1, which are involved in DNA replication and cell cycle progression .
  To study these functions, researchers typically use confocal microscopy at wavelengths of 488 and 594 nm to visualize the protein's cellular localization throughout the cell cycle .

How does FGFR1OP contribute to lung cancer pathogenesis and what are the molecular mechanisms involved?

FGFR1OP contributes to lung carcinogenesis through multiple mechanisms:

• Cell growth promotion: Overexpression of FGFR1OP increases cellular growth, while its suppression using siRNA inhibits growth of lung cancer cells .

• Enhanced cellular motility: Induction of FGFR1OP increases cell motility, potentially contributing to metastatic capacity .

• Modulation of ABL1-dependent signaling: FGFR1OP significantly reduces ABL1-dependent phosphorylation of WRNIP1, resulting in promotion of cell cycle progression .
  Experimental approaches to investigate these mechanisms include:

• RNA interference assays using vector-based RNAi systems such as psiH1BX3.0

• Cell proliferation assays following FGFR1OP knockdown or overexpression

• Cell cycle analysis using flow cytometry after synchronization with aphidicolin

• Co-immunoprecipitation studies to identify and validate protein interaction partners
  Immunohistochemical analysis has revealed positive FGFR1OP staining in 334 (89.8%) of 372 NSCLC specimens, with high expression levels significantly associated with shorter tumor-specific survival times (P < 0.0001) .

What is the prognostic value of FGFR1OP expression in lung cancer patients?

FGFR1OP has significant prognostic implications for lung cancer patients:

• Survival correlation: High levels of FGFR1OP expression are significantly associated with shorter tumor-specific survival times (P < 0.0001 by log-rank test) .

• Independent prognostic factor: Multivariate Cox analysis has determined that FGFR1OP is an independent prognostic factor for surgically treated NSCLC patients (P < 0.0001) .
  Methodologically, researchers should:

• Utilize tissue microarrays for high-throughput analysis

• Apply multivariate Cox analysis on backward (stepwise) procedures

• Include variables that satisfy an entry level of P < 0.05

• Establish exit criteria of P < 0.05 for independent factors

• Perform Kaplan-Meier survival analysis with log-rank tests for statistical validation
  When designing prognostic studies, it's crucial to include adequate sample sizes and appropriate clinical follow-up periods to ensure robust statistical power for survival analyses.

What are the characteristics and oncogenic potential of FGFR1OP fusion proteins in hematological malignancies?

FGFR1OP participates in oncogenic fusion events in hematological malignancies:

• FGFR1OP-FGFR1 fusion: Resulting from t(6;8)(q27;p11) chromosomal translocation, found in myeloproliferative disorders .

• FGFR1OP-RET fusion: A novel fusion identified in chronic myelomonocytic leukemia (CMML) and primary myelofibrosis (PMF) with secondary acute myeloid leukemia (AML) .
  The FGFR1OP-RET fusion protein demonstrates:

• Constitutive tyrosine kinase activity

• Transforming potential in NIH3T3 fibroblasts

• Ability to induce IL3-independent growth in hematopoietic Ba/F3 cells

• Activation of PI3K/STAT signaling pathways

• Support of cytokine-independent growth and enhanced self-renewal of hematopoietic progenitor cells
  In vivo studies have shown that FGFR1OP-RET causes a spectrum of disease phenotypes, with >50% of mice developing fatal myeloproliferative disorder (MPD) . Other observed phenotypes include transplantable leukemia, expansion of the mast cell lineage, and reduced repopulating activity following lethal irradiation .

What experimental approaches are most effective for studying FGFR1OP function in cancer models?

Several experimental approaches have proven effective for investigating FGFR1OP functions:

• RNA interference:

  • Vector-based RNAi systems like psiH1BX3.0 for targeted gene silencing

  • Assessment of phenotypic changes following FGFR1OP knockdown

• Protein interaction studies:

  • Co-immunoprecipitation to identify binding partners such as ABL1 and WRNIP1

  • Analysis of phosphorylation status of interaction partners

• Cell cycle analysis:

  • Synchronization with aphidicolin (1 μg/mL for 24h)

  • Release from cell cycle arrest and harvesting at specific timepoints (1.5, 4.0 and 9.0 hours)

  • Confocal microscopy at wavelengths of 488 and 594 nm

• In vivo models:

  • Expression of FGFR1OP or fusion proteins in murine hematopoietic progenitor cells

  • Transplantation into irradiated recipients to assess oncogenic potential

  • Serial transplantation to evaluate leukemogenic capacity

• Clinical correlation:

  • Tissue microarrays for high-throughput analysis of clinical specimens

  • Multivariate survival analysis to establish prognostic significance

How can FGFR1OP be targeted therapeutically in cancer treatment?

Based on current research, several therapeutic approaches could target FGFR1OP:

• RNA interference strategies:

  • siRNA or shRNA targeting FGFR1OP has been shown to suppress expression and inhibit cell growth in lung cancer models

  • Delivery methods include liposomal formulations or viral vectors

• Inhibition of downstream signaling pathways:

  • PI3K/STAT pathway inhibitors could counteract the signaling activated by FGFR1OP and its fusion proteins

  • ABL1 inhibitors might modulate FGFR1OP's effect on WRNIP1 phosphorylation

• Targeting FGFR1OP fusion proteins:

  • For FGFR1OP-RET fusions, RET tyrosine kinase inhibitors might prove effective

  • For FGFR1OP-FGFR1 fusions, FGFR inhibitors could potentially block constitutive signaling
    When designing therapeutic targeting studies, researchers should consider:

• Cell line models with varying FGFR1OP expression levels

• Patient-derived xenografts to better recapitulate the tumor microenvironment

• Combination approaches targeting multiple nodes in FGFR1OP-related pathways

• Biomarker development to identify patients most likely to respond to FGFR1OP-targeted therapies

What are the optimal conditions for immunohistochemical detection of FGFR1OP in tissue samples?

For optimal immunohistochemical detection of FGFR1OP:

• Antibody preparation:

  • Use rabbit polyclonal antibodies raised against histidine-tagged human FGFR1OP protein (codons 7–173; accession No. NM_007045)

  • Purify antibodies using affinity columns (e.g., Affi-gel 10) conjugated with histidine-tagged protein

• Sample preparation:

  • Create tissue microarrays containing multiple cores (diameter 0.6 mm; height 3–4 mm) from donor tumor blocks

  • Include normal tissue cores as controls

  • Use 5-μm sections for immunohistochemical analysis

• Staining protocol:

  • Block endogenous peroxidase and proteins

  • Apply rabbit polyclonal anti-human FGFR1OP antibody

  • Incubate with HRP-labeled anti-rabbit IgG as secondary antibody

  • Add substrate-chromogen

  • Counterstain with hematoxylin

• Evaluation criteria:

  • Assess staining intensity (negative, weak, moderate, strong)

  • Determine percentage of positive cells

  • Consider both cytoplasmic and nuclear staining patterns
    Validation of antibody specificity should be performed using Western blot analysis with lysates from NSCLC tissues and cell lines as well as normal lung tissues .

How can researchers effectively study FGFR1OP-protein interactions and their functional consequences?

To study FGFR1OP protein interactions and functional consequences:

• Identification of interaction partners:

  • Yeast two-hybrid screening

  • Co-immunoprecipitation followed by mass spectrometry

  • Protein array approaches

• Validation of interactions:

  • Reciprocal co-immunoprecipitation experiments

  • GST pull-down assays

  • Proximity ligation assays for in situ detection

• Functional analysis:

  • Phosphorylation status assessment using phospho-specific antibodies

  • Domain mapping through truncation or deletion constructs

  • Site-directed mutagenesis to identify critical interaction residues

• Cellular consequences:

  • Cell cycle analysis following disruption of specific interactions

  • Assessment of localization changes during cell cycle progression

  • Evaluation of effects on cell growth, motility, and survival
    For studying FGFR1OP's interaction with ABL1 and WRNIP1 specifically, researchers should examine how FGFR1OP influences ABL1-dependent phosphorylation of WRNIP1 and the subsequent effects on cell cycle progression .

What is the role of FGFR1OP in cancer drug resistance mechanisms?

While direct evidence linking FGFR1OP to drug resistance is limited in the provided search results, several avenues warrant investigation:

• Cell survival pathways: Given FGFR1OP's role in promoting cell growth and its interaction with signaling proteins like ABL1, it may contribute to resistance by activating survival pathways.

• Cell cycle regulation: FGFR1OP's influence on cell cycle progression through WRNIP1 could potentially affect the efficacy of cell cycle-targeting therapies.

• Fusion proteins and resistance: FGFR1OP-containing fusion proteins (like FGFR1OP-RET) activate multiple signaling pathways including PI3K/STAT , which are known to contribute to therapy resistance in various cancers.
  Methodological approaches to study FGFR1OP in drug resistance:

• Generate resistant cell lines through chronic drug exposure

• Compare FGFR1OP expression and function between sensitive and resistant populations

• Assess whether FGFR1OP knockdown resensitizes resistant cells to therapy

• Investigate combinations of FGFR1OP targeting with standard therapies

How do FGFR1OP expression patterns vary across different cancer types and subtypes?

While the search results primarily focus on FGFR1OP in lung cancer and hematological malignancies, researchers should consider:

• Multi-cancer analysis:

  • Comprehensive immunohistochemical analysis across tumor tissue microarrays representing diverse cancer types

  • Mining of cancer genomics databases (TCGA, ICGC) for FGFR1OP expression patterns

  • Correlation with clinical outcomes across different malignancies

• Cancer subtype specificity:

  • Comparison between NSCLC subtypes (adenocarcinoma vs. squamous cell carcinoma)

  • Analysis in different molecular subtypes of lung adenocarcinoma (EGFR-mutant, ALK-rearranged, KRAS-mutant, etc.)

  • Assessment in various subtypes of hematological malignancies beyond CMML and PMF/AML

• Correlation with other biomarkers:

  • Integration with established prognostic and predictive biomarkers

  • Potential for creating composite biomarker panels including FGFR1OP
    Current data shows that FGFR1OP is overexpressed in 89.8% (334/372) of NSCLC specimens , suggesting its widespread relevance in lung cancer. Similar comprehensive analyses across other tumor types would be valuable for expanding the therapeutic potential of FGFR1OP targeting.