PTGS2 Antibody
Description
Introduction
The PTGS2 antibody is a research tool used to detect and study the enzyme prostaglandin-endoperoxide synthase 2 (PTGS2), also known as cyclooxygenase-2 (COX-2). This enzyme is a key mediator of inflammation and is implicated in various pathological conditions, including cancer and cardiovascular diseases. PTGS2 antibodies enable researchers to quantify the enzyme's expression in tissues, fluids, or cell cultures, providing insights into its role in disease mechanisms and therapeutic targets.
Structure and Function of PTGS2
PTGS2 is a 604-amino-acid protein encoded by the PTGS2 gene in humans. It exists as a sequence homodimer, with each monomer containing a peroxidase and a cyclooxygenase active site . The enzyme catalyzes the conversion of arachidonic acid to prostaglandin H2 (PGH2), a precursor for pro-inflammatory prostaglandins such as PGE2 and PGF2α . PTGS2 is inducible under inflammatory stimuli and is absent or minimally expressed in most normal tissues, except in the kidneys, brain, and endothelium .
Key Post-Translational Modifications
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Glycosylation: A 72 kDa glycosylated isoform is detected in colorectal cancer (CRC) tissues, associated with tumor progression .
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Acetylation: Aspirin treatment modifies PTGS2 to produce anti-inflammatory 15(R)-HETE and epi-lipoxins .
Applications of PTGS2 Antibodies
PTGS2 antibodies are widely used in molecular biology techniques to study enzyme expression and localization.
Common Applications
Inflammation and Disease
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Cancer: PTGS2 overexpression promotes tumor angiogenesis, metastasis, and resistance to apoptosis, particularly in colorectal cancer (CRC) . Stromal PTGS2 expression in CRC correlates with improved survival .
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Cardiovascular Disease: Selective COX-2 inhibitors increase cardiovascular risks by disrupting prostacyclin production, which inhibits platelet aggregation .
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Arthritis: PTGS2 inhibitors reduce joint inflammation but may exacerbate gastrointestinal bleeding .
Biomarker Potential
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AVF Failure: Elevated PTGS2 levels correlate with oxidative stress and lumen stenosis in arteriovenous fistula (AVF) failure; inhibition reduces stenosis .
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CRC Prognosis: Stromal PTGS2 expression in CRC is associated with favorable outcomes, possibly via anti-tumor immune responses .
Regulatory Mechanisms
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ROBO4 Signaling: In endothelial cells, ROBO4 suppresses PTGS2 expression by inhibiting RAC1 activation, mitigating inflammation .
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RUNX1 Transcription Factor: RUNX1 directly activates the PTGS2 promoter in CRC cells, promoting tumor growth and metastasis .
Therapeutic Implications
Product Specs
Constituents: 50% Glycerol, 0.01M PBS, pH 7.4
Target Background
- SND1 may serve as a potential biomarker for therapeutic strategies involving COX-2 inhibitors. PMID: 30365124
- Studies indicate upregulation of COX-2 and HER2 mRNA and protein levels in colorectal cancer (CRC) compared to adjacent tissues. COX-2 protein levels and nuclear COX-2 expression correlated with poor prognosis, and COX-2 expression showed a positive association with HER2 expression. PMID: 29873317
- PTGS2 polymorphisms were associated with advanced liver fibrosis in patients with HCV mono-infection and HCV/HIV co-infection. PMID: 30139224
- Research suggests an interaction between follicular dendritic cells and B cells leading to COX-2 expression during immune inflammatory responses. PMID: 29241029
- Neuronal SphK1 acetylates COX-2, contributing to Alzheimer's disease pathogenesis. PMID: 29662056
- miR-137 suppresses retinoblastoma cell proliferation and invasion by targeting the COX-2/PGE2 signaling pathway. PMID: 29945115
- The dual regulation of YAP and COX-2 may offer promising therapeutic targets for hepatocellular carcinoma (HCC). PMID: 29505957
- COX-2 expression was positively associated with recurrence and poor prognosis in nasopharyngeal carcinoma. PMID: 29956730
- COX-2 is implicated as an important factor in dengue virus replication. PMID: 28317866
- Lysophosphatidylcholine induces COX-2-mediated IL-6 expression, with NADPH oxidase/reactive oxygen species involvement. PMID: 30229288
- Findings suggest a critical role for ATF6alpha in cellular senescence via upregulation of a COX-2/PGE2 intracrine pathway. PMID: 28803844
- High PTGS2 expression is associated with breast carcinoma. PMID: 30051683
- The COX-2 gene rs5275 variant contributes to nasopharyngeal carcinoma risk in a Chinese population. PMID: 30087034
- COX-2 and YAP1 signaling pathways interact to induce SOX2 expression, cancer stem cell enrichment, and acquired chemotherapy resistance in urothelial bladder carcinoma. PMID: 29180467
- No significant association was found between the COX-2 8473 T>C polymorphism and cancer risk. PMID: 30143023
- TLR4 and COX-2 were upregulated in prostate cancer (PCa) tissues; silencing either inhibited PCa cell proliferation, migration, and invasion. PMID: 30098292
- Cyclooxygenase-2 (COX-2) mediates TGF-beta effects on breast cancer stem cell (BCSC) properties, suggesting COX-2 pathway targeting as a potential triple-negative breast cancer treatment strategy. PMID: 28054666
- The effects of miR-101 inhibition on tumor growth were suppressed by COX-2 inhibition. PMID: 29404887
- Low PTGS2 expression is associated with invasive breast carcinoma. PMID: 28808873
- rs2243250 (IL4) and rs5275 (PTGS2) were associated with shorter renal cell cancer-specific survival. PMID: 28117391
- Meta-analysis showed that COX-2 rs5275 and rs689466 polymorphisms significantly decrease lung cancer risk in Asians, suggesting COX-2 as a potential diagnostic marker. PMID: 30170377
- Meta-analysis investigated the association between the 765G/C polymorphism and periodontitis in a Chinese population. PMID: 29514641
- Downregulation of COX-2 expression in SGC-7901 and MGC-803 cells was observed. PMID: 29901169
- High baseline COX-2 expression in tumor biopsies correlated with reduced treatment response. PMID: 29893307
- A study investigated the association between integrin subunit alpha 2 (GPIa) and prostaglandin-endoperoxide synthase 2 (COX-2) genetic polymorphisms in Chinese ischemic stroke patients with or without aspirin resistance. PMID: 28948649
- COX-2 was significantly associated with a lower 5-year disease-free survival (DFS) rate. PMID: 29559247
- The COX-2 gene polymorphism is associated with increased susceptibility to colorectal cancer, particularly rectosigmoid tumors. PMID: 29257846
- Unregulated expression of ANXA1 and COX-2 was demonstrated in precursor lesions of esophageal and stomach cancers. PMID: 29254791
- EB1 gene knockdown-induced cytotoxicity resulted from reactive oxygen species activation via p38 MAPK, inducing cyclooxygenase-2 expression and apoptosis. PMID: 29484424
- High COX-2 expression is associated with Ras and BRAF mutations in hepatocellular carcinoma. PMID: 28188432
- High COX-2 expression is associated with ovarian cancer cell migration and invasion. PMID: 28677781
- Lower PTGS2 transcript levels in cumulus cells may impair oocyte quality, potentially contributing to infertility. PMID: 28734688
- A correlation exists between the COX-2 1195 G-carrier genotype and intestinal metaplasia in H. pylori-infected gastric mucosa. PMID: 28946145
- Activated Ras, protumorigenic COX-2, and Notch1 are implicated in papillary mucinous neoplasm development. PMID: 27381829
- TGF-beta1 increased COX-2 and PGE2 levels in cultured pulp cells via ALK5/Smad2/3 and MEK/ERK pathways. PMID: 28779848
- Culinary herbs and spices inhibit HCA-7 colorectal adenocarcinoma cell growth and COX-2 expression. PMID: 28934138
- The limited clinical use of COX inhibitors in glioblastoma is attributed to vascular toxicity and inconsistent outcomes; PGE2 is a key mediator in COX-2 driven gliomagenesis. PMID: 28718447
- COX-2 inversely regulates Notch1 in gastric cancer, partially dependent on the Notch1 signaling pathway in altering Snail expression. PMID: 28586004
- Both the benzenesulfonyl group and the central five-membered ring contribute to selective COX-2 inhibition. PMID: 27145042
- COX-2 and p-Akt1 play a combined role in melanoma progression and are associated with metastasis and survival rates. PMID: 28604419
- Higher COX-2 expression may be a negative prognostic factor in conjunctival melanoma, suggesting potential for anti-COX-2 drugs as adjuvant therapy. PMID: 29297092
- ERK1/2 signaling is required for hCG-induced SPRY2 upregulation; SPRY2 knockdown attenuates AREG-induced COX-2 expression and PGE2 production by inhibiting ERK1/2 signaling. PMID: 27539669
- COX-2 is elevated in glioma tissues, and its expression is negatively correlated with miR-128 levels, suggesting miR-128 as a potential therapeutic target. PMID: 29524580
- Post-transcriptional regulation of COX-2 mRNA translation by stress granules indicates a role in IL-1beta-mediated catabolic response in osteoarthritis. PMID: 27271770
- In influenza A virus (IAV)-infected cells, COX-2 expression is initially induced by RIG-I recognition of IAV vRNA but later reduced by IAV-induced TTP-mediated mRNA destabilization. PMID: 27265729
- COX-2 contributes to constitutive IDO1 expression by human tumors, suggesting COX-2 inhibitors could improve cancer immunotherapy efficacy. PMID: 28765120
- The COX-2 gene polymorphism rs689466 GG genotype is associated with increased post-traumatic osteomyelitis risk in a Chinese population. PMID: 28682162
- 4-Hydroxy-2-nonenal is a natural inducer of COX-2 in atherosclerosis (Review). PMID: 28192229
- RhoA and COX-2 upregulation in early gastric cancer facilitated cancer cell proliferation and migration. PMID: 28624843
- LXR gene expression was increased in obese children with obstructive sleep apnea-hypopnea syndrome (OSAHS), positively correlating with COX-2 levels. PMID: 28676625
Q&A
Basic Research Questions
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What is the optimal fixation method for PTGS2 immunohistochemistry?
For optimal PTGS2 detection in tissue samples, 10% neutral buffered formalin fixation for 24-48 hours is recommended. Overfixation can mask epitopes and reduce staining intensity, while underfixation may lead to inconsistent results. For paraffin-embedded sections, antigen retrieval is crucial - heat-induced epitope retrieval (HIER) using citrate buffer (pH 6.0) or EDTA buffer (pH 9.0) for 20 minutes typically yields optimal results. When evaluating fixation protocols, it's advisable to include positive control tissues with known PTGS2 expression patterns such as colon cancer specimens with inflammatory regions . Alternative fixatives like Bouin's solution should be avoided as they can interfere with PTGS2 epitope recognition.
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How do I determine the specificity of a PTGS2 antibody?
Antibody specificity should be verified through multiple validation approaches. First, perform Western blotting using positive control samples (e.g., macrophages stimulated with LPS) and negative controls (PTGS2 knockout cells if available). A specific PTGS2 antibody should detect a single band at approximately 69-72 kDa . Second, conduct immunohistochemistry on tissues with known PTGS2 expression patterns, such as colon cancer specimens, comparing results with published literature. Third, perform peptide competition assays where pre-incubation of the antibody with its immunogenic peptide should eliminate specific staining. Finally, for monoclonal antibodies, verify the exact epitope recognition region (e.g., C-terminal, amino acids 501-604) to ensure appropriate detection of your target . Cross-reactivity with PTGS1 (COX-1) should be excluded, particularly when studying tissues that express both isozymes.
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What controls should be included in PTGS2 Western blot experiments?
Comprehensive controls for PTGS2 Western blotting should include: (1) Positive controls: cell lines with documented PTGS2 expression (e.g., HeLa cells treated with TNF-α or IL-1β for 24 hours); (2) Negative controls: unstimulated cells or PTGS2 knockout cells; (3) Loading control: β-actin, GAPDH, or α-tubulin to normalize protein loading; (4) Molecular weight marker: to confirm the expected 69 kDa band for PTGS2 . Additionally, include a specificity control by pre-incubating the antibody with its immunogenic peptide. For experiments comparing PTGS2 expression across conditions, consider including a standard curve using recombinant PTGS2 protein to ensure detection falls within the linear range. When troubleshooting, remember that PTGS2 can appear as multiple bands due to post-translational modifications, particularly glycosylation, resulting in bands between 70-74 kDa.
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What are the key differences between polyclonal and monoclonal PTGS2 antibodies?
Polyclonal PTGS2 antibodies recognize multiple epitopes on the PTGS2 protein, providing stronger signals but potentially higher background and batch-to-batch variability. They are ideal for applications like immunoprecipitation and can detect denatured PTGS2 in Western blots effectively. Monoclonal antibodies target a single epitope, offering high specificity and consistency between experiments but potentially lower sensitivity. They excel in applications requiring precise epitope recognition, such as distinguishing between PTGS1 and PTGS2 . For immunohistochemistry, rabbit monoclonal antibodies against PTGS2 generally provide optimal results with minimal background. When selecting between polyclonal and monoclonal antibodies, consider: (1) the application requirements, (2) whether conformational epitopes need to be recognized, (3) the host species to avoid cross-reactivity with secondary antibodies, and (4) whether the specific epitope region (e.g., C-terminal vs. N-terminal) affects detection in your experimental context.
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How should PTGS2 expression be quantified in immunohistochemistry studies?
Quantification of PTGS2 expression in immunohistochemistry should employ standardized scoring systems to ensure reproducibility. The H-score method is widely accepted, calculated as: 3 × % of strongly staining cytoplasm + 2 × % of moderately staining cytoplasm + 1 × % of weakly staining cytoplasm, yielding a range of 0-300 . Alternatively, use the categorical scoring system described by Chan et al., classifying expression as absent, weak, moderate, or strong, with weak/absent classified as PTGS2-low and moderate/strong as PTGS2-high . Digital image analysis software like QuPath can enhance objectivity and reproducibility. For clinical studies, establish cutoff values (e.g., H-score of 145.5) based on receiver-operating characteristic analysis to differentiate high from low expression . Always include positive controls (e.g., colon cancer with known PTGS2 overexpression) and negative controls (primary antibody omitted) in each staining batch, and have at least two independent observers score a subset of samples to assess inter-observer agreement (κ value).
