Expression of cyclooxygenase-2 (COX-2) in colorectal adenocarcinoma: an immunohistochemical and histopathological study

Loss of CDX2 and high COX2 (PTGS2) expression in metastatic colorectal cancer

Lack of expression of the tumour suppressor gene caudal-type homeobox 2 (CDX2) associates with poor outcomes in early stage colorectal cancer (CRC). Yet its prognostic value in the context of other prognostic biomarkers in metastatic CRC (mCRC) is unknown. Overexpressed cyclooxygenase-2 (COX2) has been reported in advanced CRC. However, CDX2 and COX2 relationship in mCRC remains undetermined. We aimed to assess their expression in mCRC tumours from a clinically characterised cohort and their influence on overall survival (OS) and progression-free survival (PFS) in first line. Among 720 consecutive mCRC patients, 346 had tumour samples appropriate for tissue microarray assembly and immunohistochemistry analyses. Clinical and survival data were retrospectively assessed. Loss of CDX2 expression was detected in 27 (7.8%) samples, enriched in poorly differentiated tumours (20%; p < 0.01) and in those with the BRAF p.V600E variant (40%; p < 0.01). Most tumours (93.4%) expressed COX2. COX2-negative samples were enriched in poorly differentiated mCRC. In unadjusted analyses, median OS (p < 0.001) and median PFS (p < 0.05) were inferior for patients with CDX2-negative versus CDX2-positive tumours. In conclusion, loss of CDX2 was significantly associated with poorly differentiated mCRC and BRAF p.V600E allele and a prognostic marker of worse OS.

Colonic mucosal eosinophilia and immunohistochemical expression of COX-2 and NF-kB in patients with irritable bowel syndrome

BACKGROUND

There is growing evidence that eosinophilic infiltration can release mediators which are harmful to the intestinal epithelium in patients with irritable bowel syndrome (IBS). Although cyclooxygenase 2 (COX-2) and nuclear factor-kappa beta (NF-kB) expression had been previously reported to increase in many inflammatory conditions, there is a paucity in data investigating their expressions in IBS. Our aim was to evaluate colonic mucosal eosinophilia and immunohistochemical expression of COX-2 and NF-kB in patients with irritable bowel syndrome.

METHODS

A total of 80 patients who met the inclusion criteria of IBS based on Rome IV symptoms questionnaire were subjected to abdominal ultrasound, laboratory investigations, serum immunoglobulin E (IgE) level assessment and colonoscopic examination. Immunohistochemistry was performed to detect COX-2 and NF-kB expression in colonic biopsies obtained from IBS patients.

RESULTS

Histopathological examination showed that 60 colonic biopsy specimens (75%) showed few mixed inflammatory cells ≤3 cells/ HPF, 12 biopsy specimens (15%) showed eosinophilic infiltration ≥25 eosinophils/HPF and 8 biopsy specimens (10%) showed severe lymphocytic infiltration and aggregation. Colonic eosinophilic infiltrate was significantly higher among patients presented with IBS-D subtype. Serum IgE was significantly higher among patients with colonic eosinophilic infiltrate than the others. In IBS-D patients, colonic mucosa showed positive expression of COX-2 and NF-kB in 52.1% and 81.25% of cases, respectively.

CONCLUSION

Patients with IBS -particularly IBS-D subtype- should undergo colonoscopy and biopsy to exclude underlying inflammatory pathology. Moreover, patients with positive COX-2 and NF-kB need further evaluation and follow-up.

Immunohistochemical expression and significance of SATB2 protein in colorectal cancer

In this study we evaluated the expression of SATB2 protein in colorectal cancer (CRC) and its association with microsatellite instability (MSI) status, inflammation and hypoxia. Immunohistochemical SATB2 expression was observed in 111 CRC samples. We assessed the correlation between SATB2 expression and clinico-morphological parameters, MSI, COX-2 and HIF-1α expression. SATB2 was noticed in 92.8% CRC. We observed nuclear staining with predominantly strong immunoreaction intensity (67.6%) and percentage of SATB-2 positive cells in more than 50% of cells (87.4%). The statistically significant associations were recorded between high SATB2 expression and low grade, negative lymph nodes and negative vascular invasion. Statistical analysis confirmed a significant correlation between SATB2 expression and microsatellite stability, tendency to correlate with COX-2 and no significant correlation with HIF-1α. SATB2 is overexpressed in CRC and its high expression is a marker of good prognosis. Moreover, SATB2 expression is significantly associated with microsatellite stability, there is tendency to correlate with pro-inflammatory COX-2 and there is no association with hypoxia.

Understanding the Interplay between COX-2 and hTERT in Colorectal Cancer Using a Multi-Omics Analysis

Background: Cyclooxygenase 2 (COX-2) is involved in the initial steps of colorectal cancer (CRC) formation, playing a key role in the catalysis of arachidonic acid to prostaglandin E2 (PGE₂). The human telomerase reverse transcriptase (hTERT or TERT) also plays an important role in colorectal cancer growth, conferring sustained cell proliferation and survival. Although hTERT induces COX-2 expression in gastric and cervical cancer, their interaction has not been investigated in the context of CRC. Methods: COX-2, PGE₂ levels, and telomerase activity were evaluated by immunohistochemistry, ELISA, and TRAP assay in 49 colorectal cancer samples. PTGS1, PTGS2, PTGES3, TERT mRNA, and protein levels were investigated using RNA-seq and antibody-based protein profiling data from the TCGA and HPA projects. A multi-omics comparison was performed between PTGS2 and TERT, using RNAseq, DNA methylation, copy number variations (CNVs), single nucleotide polymorphisms (SNPs), and insertions/deletions (Indels) data. Results: COX-2 expression was positive in 40/49 CRCs, bearing cytoplasmic and heterogeneous staining, from moderate to high intensity. COX-2 staining was mainly detected in the stroma of the tumor cells and the adjacent normal tissues. PGE₂ expression was lower in CRC compared to the adjacent normal tissue, and inversely correlated to telomerase activity in right colon cancers. COX-1 and COX-2 were anticorrelated with TERT. Isoform structural analysis revealed the most prevalent transcripts driving the differential expression of PTGS1, PTGS2, PTGES3, and TERT in CRC. COX-2 expression was significantly higher among B-Raf proto-oncogene, serine/threonine kinase, mutant (BRAF^mut) tumors. Kirsten ras oncogene (KRAS) mutations did not affect COX-2 or TERT expression. The promoter regions of COX-2 and TERT were reversely methylated. Conclusions: Our data support that COX-2 is involved in the early stages of colorectal cancer development, initially affecting the tumor’s stromal microenvironment, and, subsequently, the epithelial cells. They also highlight an inverse correlation between COX-2 expression and telomerase activity in CRC, as well as differentially methylated patterns within the promoter regions of COX-2 and TERT.

Over-Expression of Cyclooxygenase-2 in Colorectal Cancer Patients

Background:

Colorectal carcinoma (CRC) is the most common neoplasm of the gastrointestinal tract. COX-2 plays an important role in CRC development and is a key target for the regression of colorectal tumorigenesis by non-steroidal anti-inflammatory drugs. The present study was conducted to examine the relationship of the levels of COX-2 in CRC patients with the clinico-pathological parameters and also to assess its usefulness as a potential biomarker for diagnosis of CRC.

Methods:

Prior to surgery, 30 CRC patients were enrolled and the samples from colon tumors and surrounding tissues were taken after they underwent surgical intervention at PGIMER, Chandigarh. mRNA expression levels of COX-2 were examined in 30 CRC and adjacent normal colonic mucosa by quantitative polymerase chain reaction (qPCR). The expression of COX-2 was assessed by immunohistochemical method using rabbit polyclonal antibodies against human COX-2 protein.

Results:

The quantitative relative expression of COX-2 mRNA was observed to be significantly higher (p<0.05) in colorectal cancer tissues as compared to adjacent normal colon tissues. Also, female CRC patients showed significantly higher (p<0.009) expression of COX-2 mRNA vis-a-vis male colorectal cancer patients. This is the first study which has reported a direct relationship between COX-2 mRNA expressions in male colorectal cancer patients versus females. Further, immunohistochemistry of COX-2 confirmed the quantitative real time-PCR findings.

Conclusion:

Our study shows that COX-2 over expression in colorectal carcinoma patients is closely associated with clinico-pathological parameters and is more pronounced in males versus females. Further, COX-2 mRNA expression can serve as a potential biomarker for the diagnosis of CRC.

IL-1β/IL-6 network in the tumor microenvironment of human colorectal cancer

OBJECTIVES

Recent studies suggest that the interaction between interleukin (IL)-1β and IL-6 in the microenvironment might be involved in the development and progression of human colorectal cancer (CRC). However, the expression of IL-1β/IL-6 network within the CRC microenvironment is not fully understood.

MATERIALS AND METHODS

The level of IL-1β/IL-6 network expression in 40 biopsies of sporadic CRC and 15 biopsies of controls was assessed using quantitative real-time polymerase chain reaction (PCR) assay, immunohistochemistry (IHC) and double immunofluorescence staining.

RESULTS

Quantitative results obtained by real-time PCR revealed that both IL-1β and IL-6 mRNA expressions were increased in CRC tissues compared with expressions in controls. In which, IL-6 mRNA expression in primary CRC tissues showed a statistically significant relationship with tumor invasion depth. IHC observations confirmed that increased expression of IL-1β and IL-6 immunoreactivities was located in both the CRC epithelium and stroma. Furthermore, IHC results also revealed that increased expression of IL-1β receptor type 1 (IL-1R1) and IL-6 receptor (IL-6R) were observed in both CRC epithelial and stromal cells. IHCs in serial CRC sections and double immunofluorescence staining revealed a highly co-expression of IL-1R1 immunoreactivity with IL-6 immunoreactivity in the same cells, which confirmed a histological fundament of IL-1β/IL-6 network.

CONCLUSION

The IL-1β/IL-6 network is highly expressed in the CRC microenvironment, indicating that this network is important in the progression of CRC.

Correlated non-nuclear COX2 and low HER2 expression confers a good prognosis in colorectal cancer

BACKGROUND/AIMS

COX2 and HER2 are shown to be critical in the regulation of cancer progression. However, the prognostic value of nuclear COX2 in colorectal cancer (CRC) and its relationship with HER2 still remains unknown. In this study, the expression and biological significance of COX2 and HER2 were evaluated in CRC at mRNA and protein levels.

MATERIALS AND METHODS

RNA-Seq data of CRC were downloaded from TCGA, and 229 CRC and 50 non-cancerous subjects were enrolled in this study. Bioinformatics and immunohistochemistry analysis was performed based on the obtained data. Survival analysis was conducted to identify factors associated with overall survival of CRC patients.

RESULTS

We showed that mRNA and protein levels of COX2 and HER2 were upregulated in CRC compared with the adjacent tissues. COX2 protein levels and nuclear COX2 expression were correlated with a poor prognosis of CRC patients. In addition, we also revealed that nuclear COX2 expression was positively associated with HER2 expression. Non-nuclear COX2 combined with low HER2 expression, was negatively correlated with Duke's stage and lymph node metastasis, predicting the best outcomes for CRC patients. In addition, our data indicated that non-nuclear COX2 combined with low HER2 expression is an independent prognostic factor for CRC after surgical resection.

CONCLUSION

The study suggests that nuclear COX2 in combination with HER2 can serve as potential biomarkers for the clinical diagnosis and prognosis of CRC, and targeted inhibition of COX2 and HER2 might be an alternative strategy for the management of CRC.

Targeted therapies for colorectal cancer: Current status and future perspectives

Colorectal cancer (CRC) is a common malignant tumor of the digestive system. At present, traditional chemotherapy is often combined with targeted drugs to treat patients with metastatic colon cancer, in order to increase the response rate, prolong the progression free survival and overall survival, and improve the quality of life of patients. In this paper, we describe the molecular targets for targeted therapy of CRC and their distribution in CRC, which include vascular endothelial growth factor, epidermal growth factor receptor, cyclooxygenase-2, matrix metalloproteinase, receptor tyrosine kinase, PD-1/PD-L1, RAS, BRAF and so on. In addition, we review current targeted therapies for CRC, including antibody drugs, small molecule targeted drugs, fusion proteins, immune therapy and so on. This paper will provide a reference for individualized treatment of CRC.

Seminal cyclooxygenase relationship with oxidative stress in infertile oligoasthenoteratozoospermic men with varicocele

This study aimed to assess the relation of seminal cyclooxygenase COX-1, COX-2 with oxidative stress in infertile oligoasthenoteratozoospermic (OAT) men with varicocele (Vx). In all, 128 men were allocated into fertile men, fertile men with Vx, infertile OAT men without Vx and infertile OAT men with Vx. They were subjected to history taking, clinical examination and semen analysis. Also, seminal COX-1, COX-2, malondialdehyde (MDA) and glutathione peroxidase (GPx) were estimated. Mean levels of seminal COX-1, COX-2 were over-expressed, the mean level of seminal MDA was significantly increased, and the mean level of seminal GPx was significantly decreased in infertile OAT men with Vx compared with other groups. Seminal COX-1 and COX-2 were over-expressed in cases with Vx grade III compared with Vx grades I, II cases and in cases with bilateral Vx compared with unilateral Vx. There was significant negative correlation between seminal COX-1 and COX-2 with sperm concentration, sperm motility, sperm normal morphology, seminal GPx and significant positive correlation with seminal MDA. It is concluded that seminal COX-1 and COX-2 are over-expressed in infertile OAT men with Vx compared with fertile men with/without and infertile OAT men without Vx being associated with oxidative stress, Vx grade and Vx laterality.

Tissue Specific Promoters in Colorectal Cancer

Colorectal carcinoma is the third most prevalent cancer in the world. In the most advanced stages, the use of chemotherapy induces a poor response and is usually accompanied by other tissue damage. Significant progress based on suicide gene therapy has demonstrated that it may potentiate the classical cytotoxic effects in colorectal cancer. The inconvenience still rests with the targeting and the specificity efficiency. The main target of gene therapy is to achieve an effective vehicle to hand over therapeutic genes safely into specific cells. One possibility is the use of tumor-specific promoters overexpressed in cancers. They could induce a specific expression of therapeutic genes in a given tumor, increasing their localized activity. Several promoters have been assayed into direct suicide genes to cancer cells. This review discusses the current status of specific tumor-promoters and their great potential in colorectal carcinoma treatment.

In vivo regulation of colonic cell proliferation, differentiation, apoptosis, and P27Kip1 by dietary fish oil and butyrate in rats

We have shown that dietary fish oil is protective against experimentally induced colon cancer, and the protective effect is enhanced by coadministration of pectin. However, the underlying mechanisms have not been fully elucidated. We hypothesized that fish oil with butyrate, a pectin fermentation product, protects against colon cancer initiation by decreasing cell proliferation and increasing differentiation and apoptosis through a p27(Kip1)-mediated mechanism. Rats were provided diets of corn or fish oil, with/without butyrate, and terminated 12, 24, or 48 hours after azoxymethane (AOM) injection. Proliferation (Ki-67), differentiation (Dolichos Biflorus Agglutinin), apoptosis (TUNEL), and p27(Kip1) (cell-cycle mediator) were measured in the same cell within crypts in order to examine the coordination of cell cycle as a function of diet. DNA damage (N(7)-methylguanine) was determined by quantitative IHC analysis. Dietary fish oil decreased DNA damage by 19% (P = 0.001) and proliferation by 50% (P = 0.003) and increased differentiation by 56% (P = 0.039) compared with corn oil. When combined with butyrate, fish oil enhanced apoptosis 24 hours after AOM injection compared with a corn oil/butyrate diet (P = 0.039). There was an inverse relationship between crypt height and apoptosis in the fish oil/butyrate group (r = -0.53, P = 0.040). The corn oil/butyrate group showed a positive correlation between p27(Kip1) expression and proliferation (r = 0.61, P = 0.035). These results indicate the in vivo effect of butyrate on apoptosis and proliferation is dependent on dietary lipid source. These results demonstrate the presence of an early coordinated colonocyte response by which fish oil and butyrate protects against colon tumorigenesis.