GAS5 Antibody

What is GAS5 and why is it significant in cancer research?

• Acting as a microRNA sponge to sequester oncogenic miRNAs

• Serving as a protein sponge for growth-related transcription factors like the glucocorticoid receptor

• Modulating TGFβ signaling pathways

• Regulating apoptosis-associated gene expression

The context-dependent expression patterns of GAS5 across different cancers make it an important research target for understanding tumor biology and developing potential therapeutic strategies.

How can GAS5 expression be detected and quantified in research samples?

Given that GAS5 is an RNA molecule rather than a protein, standard antibody-based protein detection methods are not directly applicable. Instead, researchers should employ RNA-based detection methods:

When designing experiments to detect GAS5, researchers should first assess its endogenous expression levels in their cell line of interest, as noted in commercial reagent guidelines . For example, RNA-FISH has been successfully used to detect decreased GAS5 expression in PDGF-BB-treated vascular smooth muscle cells (VSMCs) and increased expression in serum-starved VSMCs .

What are the key considerations when designing siRNA experiments targeting GAS5?

When designing siRNA experiments to knockdown GAS5:

• Target sequence selection: Choose sequences unique to GAS5 to avoid off-target effects. Commercial controls like Lincode GAS5 Control siRNA are available as effective positive controls .

• Chemical modifications: Use siRNAs with proprietary dual-strand modifications that prevent sense strand activity and reduce off-target effects. These modifications include:

  • Inactivation of passenger strand activity

  • Seed region modifications to disrupt microRNA-like off-targets

• Concentration optimization: A concentration of 25 nM has been shown effective in previous studies with HeLa and hNDF cells .

• Verification method: Plan to verify knockdown efficiency using appropriate methods such as RT-qPCR with specific primers for GAS5 .

• Cell viability assessment: Always measure cell viability (e.g., using resazurin assay) to ensure that observed effects are due to GAS5 knockdown rather than general cytotoxicity .

• Control selection: If GAS5 levels are not reliably detectable in your cell line, use alternative controls such as ON-TARGETplus GAPD siRNA Control Pool .

How does GAS5 regulate vascular smooth muscle cell cycle arrest, and what experimental approaches can verify this mechanism?

GAS5 regulates VSMC cycle arrest through complex molecular interactions. To investigate this mechanism:

• Expression correlation studies: Analyze the inverse correlation between GAS5 and proliferation markers like PCNA in VSMCs under different conditions (PDGF-BB treatment vs. serum starvation) .

• Gain/loss-of-function approaches: Use adenoviral vectors expressing GAS5 (AdGAS5) or short hairpin RNA against GAS5 (shGAS5) to manipulate GAS5 levels. The construction of these vectors involves:

  • Cloning rat GAS5 cDNA into the XhoI site of pShuttleIREShrGFP-1

  • Designing shRNA sequences (e.g., top strand: 5'-CGC GTC GGC CTT AGT CAC TAA CAA AGA GTT CAA GAG ACT CTT TGT TAG TGA CTA AGG CCT TTT TTC CAA A-3')

• Localization studies: Employ RNA-FISH to visualize GAS5 cellular distribution and how it changes under different proliferative conditions .

• Pathway analysis: Investigate downstream signaling pathways affected by GAS5, focusing on cell cycle regulators and proliferation-associated transcription factors.

• In vivo validation: Consider rodent models of vascular injury to validate the role of GAS5 in regulating VSMC proliferation in a physiological context.

What is the relationship between GAS5 expression, immune cell infiltration, and response to immunotherapy in cancer?

Recent research has uncovered fascinating connections between GAS5, immune responses, and potential immunotherapy applications:

• Immune cell infiltration correlation:

  • GAS5 positively coordinates with infiltration of macrophages and T cells in non-small cell lung cancer (NSCLC) .

  • Pan-cancer analysis reveals tissue-specific patterns: positive correlations with CD4+ T cells, CD8+ T cells, and macrophages in liver hepatocellular carcinoma (LIHC), but negative correlations with B cells and dendritic cells in kidney renal clear cell carcinoma (KIRC) .

• Mechanistic pathway:
  GAS5 impacts immune cell recruitment through the MYBBP1A-p53/IRF1 axis, by:

  • Stabilizing p53 through direct binding to MYBBP1A

  • Facilitating MYBBP1A-p53 interaction

  • Enhancing p53-mediated transcription of IRF1

  • Activating type I interferon signaling

  • Increasing production of chemokines CXCL10 and CCL5

• Immunotherapy relevance:

  • Type I interferon signaling activation correlates with better immunotherapy efficacy in NSCLC .

  • This suggests potential for GAS5 as a predictive biomarker for immunotherapy response.

• Experimental approaches:

  • Correlation studies between GAS5 expression and immune cell markers using immunohistochemistry

  • In vitro co-culture systems to assess immune cell recruitment

  • Analysis of chemokine production (CXCL10, CCL5) following GAS5 manipulation

  • Retrospective analysis of patient cohorts receiving immunotherapy, stratified by GAS5 expression levels

How does the epigenetic regulation of GAS5 impact its expression in different cancer types, and what methods can detect these modifications?

The epigenetic regulation of GAS5 varies across cancer types with significant implications for its expression:

• Promoter methylation status:

  • DNA hypermethylation of the CpG island in the GAS5 promoter region contributes to its downregulation in breast cancer .

  • Conversely, promoter hypomethylation serves as a key regulatory mechanism in cholangiocarcinoma, kidney renal clear cell carcinoma, and liver hepatocellular carcinoma .

• N4-acetylcytidine (ac4C) modification:

  • GAS5 stability is regulated by NAT10, the enzyme responsible for ac4C modification.

  • NAT10 binds to GAS5 and mediates its ac4C modification, affecting its stability .

• Methodological approaches for studying epigenetic regulation:

  Method	Application	Data Output
  Bisulfite sequencing	Methylation analysis of GAS5 promoter	Methylation percentage at individual CpG sites
  Methylation-specific PCR	Targeted analysis of methylated regions	Qualitative assessment of methylation status
  ChIP-seq for histone modifications	Chromatin state at GAS5 locus	Enrichment profiles of specific histone marks
  RNA immunoprecipitation	Detection of RNA modifications (e.g., ac4C)	Enrichment of modified RNA
  Pharmacological approaches	Effect of epigenetic modifiers on GAS5	Expression changes after treatment

• Experimental considerations:

  • Combine multiple approaches for comprehensive epigenetic profiling

  • Include appropriate controls for specificity validation

  • Consider tissue-specific epigenetic patterns when interpreting results

  • Correlate epigenetic changes with functional outcomes

What are the competing endogenous RNA (ceRNA) networks involving GAS5 and how can they be experimentally validated?

GAS5 functions as a ceRNA by competitively binding to microRNAs, thereby affecting the expression of their target mRNAs:

• Known ceRNA interactions:

  • GAS5 sequesters oncogenic miRNAs such as miR-21

  • Network analysis has established GAS5 as a ceRNA interacting with 36 miRNAs and 95 protein-coding genes

  • These interactions affect pathways including metabolism, MAPK signaling, and cytokine-cytokine receptor interactions in liver hepatocellular carcinoma

• Experimental validation approaches:

  Technique	Application	Considerations
  RNA immunoprecipitation (RIP)	Identify RNAs associated with RNA-binding proteins	Can be combined with AGO2 pulldown to identify miRNA-mediated interactions
  Luciferase reporter assays	Validate direct miRNA binding to GAS5	Requires cloning of predicted binding sites
  RNA pulldown assays	Identify proteins/RNAs bound to GAS5	Can use biotinylated GAS5 as bait
  CLIP-seq	Genome-wide identification of RNA-protein interactions	More comprehensive but technically challenging
  Expression correlation analysis	Assess relationships between GAS5, miRNAs, and targets	Requires multiple samples and careful statistical analysis

• Functional validation:

  • Overexpression/knockdown of GAS5 should result in predictable changes in miRNA target expression

  • Rescue experiments by modulating miRNA levels can confirm ceRNA relationships

  • Pathway analysis to identify biological processes affected by the GAS5 ceRNA network

• Tissue-specific considerations:

  • ceRNA networks may vary significantly between different tissues and cancer types

  • Context-specific validation is essential for accurate characterization

What are the optimal methods for detecting GAS5 in liquid biopsies and what is their clinical significance?

Detecting GAS5 in liquid biopsies offers potential for non-invasive monitoring of cancer patients:

• Extraction methods optimization:

  • Compare RNA isolation kits specifically designed for circulating RNA

  • Consider pre-analytical variables (collection tubes, processing time, storage conditions)

  • Optimize protocols for small RNA amounts typical in liquid biopsies

• Detection techniques:

  Technique	Sensitivity	Advantages	Limitations
  Digital droplet PCR (ddPCR)	Very high	Absolute quantification, high precision for low abundance targets	Requires specialized equipment
  RT-qPCR	High	Widely available, relatively simple	Less sensitive than ddPCR for rare targets
  Next-generation sequencing	Moderate-high	Comprehensive profiling, can detect variants	Expensive, complex bioinformatics
  Nanostring	Moderate	No amplification needed, multiplexing	Higher input requirements

• Clinical significance:

  • GAS5 has been investigated as a circulating biomarker in breast cancer with potential clinical importance

  • Changes in circulating GAS5 levels might indicate disease progression or treatment response

  • May complement tissue biopsy or imaging for longitudinal monitoring

• Standardization considerations:

  • Use appropriate endogenous controls for normalization

  • Establish reference ranges in healthy individuals

  • Account for potential confounding factors (age, comorbidities)

How can contradictory findings regarding GAS5 expression in different cancer types be reconciled in experimental design?

The contradictory findings regarding GAS5 expression (upregulated in some cancers, downregulated in others) present a research challenge:

• Experimental design considerations:

  • Include comprehensive tissue panels with matched normal controls

  • Perform subtype-specific analyses within each cancer type

  • Consider tumor microenvironment and stromal contribution to GAS5 expression

  • Analyze different disease stages to capture dynamic expression changes

• Technical factors to address:

  • Use multiple detection methods to confirm expression patterns

  • Consider splice variants and isoform-specific analysis

  • Standardize sample collection and processing protocols

  • Employ robust statistical methods accounting for heterogeneity

• Biological explanations to investigate:

  • Tissue-specific functions of GAS5 (potential dual role as tumor suppressor or oncogene)

  • Impact of genetic background and mutations on GAS5 function

  • Epigenetic regulation differences across tissues (promoter hypomethylation vs. hypermethylation)

  • Context-dependent interaction partners affecting GAS5 function

• Integration approaches:

  • Multi-omics analysis correlating GAS5 expression with genomic, epigenomic, and proteomic data

  • Pathway analysis to identify tissue-specific molecular networks

  • Meta-analysis of published studies with careful attention to methodological differences

What are the most effective ways to modulate GAS5 expression for potential therapeutic applications?

Modulating GAS5 expression has therapeutic potential, particularly in cancers where it acts as a tumor suppressor:

• Upregulation strategies:

  Approach	Mechanism	Development Stage	Considerations
  Epigenetic modifiers	Reverse promoter hypermethylation	Some in clinical trials for other targets	Non-specific effects on global methylation
  Small molecule enhancers	Increase transcription or stability	Early research	Target identification challenging
  mRNA/lncRNA delivery	Direct supplementation	Preclinical	Delivery systems needed for stability
  CRISPR activation	Targeted transcriptional activation	Preclinical	Delivery challenges, off-target effects

• Key considerations for therapeutic development:

  • Tissue-specific delivery systems to target affected organs

  • Understanding of dose-response relationships

  • Potential for combination with conventional therapies

  • Biomarkers to identify patients likely to respond

• Experimental approaches to evaluate efficacy:

  • In vitro functional assays (proliferation, apoptosis, migration)

  • 3D organoid models to better recapitulate in vivo conditions

  • Patient-derived xenograft models for preclinical validation

  • Combination studies with standard chemotherapeutics

• Potential clinical applications:

  • Research suggests that approaches to augment or restore GAS5 cellular levels may have important translational implications in breast cancer and other malignancies

  • Correlation with immunotherapy response suggests potential for combination therapy approaches