Functional Polymorphisms in COX-2 Gene Are Correlated with the Risk of Oral Cancer

Association between the variations in metabolic pathways and oral cancer risk: results from a Pakistani case-control study

BACKGROUND

Oral cancer (OC) is a significant global health concern, with Pakistan ranking 5th worldwide in OC incidence. Given the poor prognosis, early detection of at-risk individuals is crucial. Genetic factors, particularly single nucleotide polymorphisms (SNPs) in metabolic genes, may influence OC susceptibility. This study investigated the association between SNPs in CYP1A1, COX2, SOD2, and HIF1a genes and OC risk in the Pakistani population.

METHODS

A prospective study was conducted from October 2019 to March 2022, enrolling 215 newly diagnosed OC patients and 410 controls. Genetic variations were analyzed using High-Resolution Melting (HRM) analysis and Sanger sequencing, with protein expression evaluated by ELISA.

RESULTS

No significant associations were found between the studied SNPs and OC risk. However, a non-significant trend was observed for the SOD2 variant (rs4880), where the G allele was associated with a higher OC risk than the A allele (p = 0.20). Elevated COX2 and HIF1α levels (p-values of 0.014 and < 0.001, respectively) and reduced SOD2 levels (p < 0.0001) were observed in OC patients, while CYP1A1 levels remained similar in both controls and cases.

CONCLUSION

Although SNPs in CYP1A1, COX2, SOD2, and HIF1α were not significantly associated with OC risk in the Pakistani population, altered protein expression levels of COX2, HIF1α and SOD2 suggest additional regulatory mechanisms. Further investigation into post-transcriptional modifications and epigenetic factors could lead to novel biomarkers and therapeutic targets for OC in Pakistan.

A double-blind, randomized controlled study of the effects of celecoxib on clinical symptoms and cognitive impairment in patients with drug-naïve first episode schizophrenia: pharmacogenetic impact of cyclooxygenase-2 functional polymorphisms

Chronic low-grade peripheral and central nervous system inflammation may have a role in the pathogenesis of schizophrenia (SCZ). Inhibition of cyclooxygenase-2 (COX2), the arachidonic acid pathway, may inhibit cytokine responses and minimize inflammation. In this study, we added the COX2 inhibitor celecoxib to risperidone monotherapy to examine its efficacy on clinical symptoms and cognitive deficits in drug-naïve first episode (DNFE) SCZ patients. First, we genotyped two polymorphisms (rs5275 and rs689466) in the COX-2 gene in a case-control study of 353 SCZ patients and 422 healthy controls. Ninety patients participated in a 12-week, double-blind, randomized, placebo-controlled trial of celecoxib 400 mg/day. We used the Positive and Negative Syndrome Scale (PANSS) and the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) to assess clinical symptoms and cognition. Our results show that the COX2 rs5275 polymorphism was significantly correlated with SCZ and positive symptoms. After 12-week treatment, celecoxib significantly improved the PANSS total and three subscale scores of SCZ patients. Furthermore, patients with the rs5275 TT genotype had greater improvement in PANSS total score than patients carrying the C allele. However, no significant difference in RBANS total and subscale scores existed between the celecoxib and placebo groups at week 12. Our findings suggest that COX2 inhibitors may be promising therapeutics for clinical symptoms rather than cognitive impairment in first episode SCZ patients. COX2 rs5275 gene polymorphism may be implicated in the development and the efficacy of treating clinical symptoms in SCZ.Trial Registration Number: The trial was registered with www.clinicaltrials.gov (NCT00686140).

Genetic polymorphism of tumor necrosis factor alpha (TNF-α) and tumor necrosis factor beta (TNF-β) genes and risk of oral pre-cancer and cancer in North Indian population

OBJECTIVE

There are inconclusive data connecting single-nucleotide polymorphisms (SNPs) of TNF-α (rs361525) and TNF-β (rs909253) to potential malignant oral disorder (PMOD) such as lichen planus and oral fibrosis. Here, we have investigated the risk of oral squamous cell carcinoma as well as oral pre-cancerous lesions in North Indian population with the polymorphism of the TNFα/ β genes.

MATERIAL AND METHODS

A total 500 patients with oral pre-cancer and OSCC and 500 healthy volunteers were genotypes for the TNF-α (-238) G/A (rs361525) and TNF-β (252) A/G (rs909253) gene polymorphism. Genotypes were identified by polymerase chain reaction (PCR) restriction fragment length polymorphism (RFLP). Genotype frequencies were evaluated by Chi-square test.

RESULTS

Compared to the GG genotype, the GA genotype of TNF-α (G238A) polymorphism (rs361525) has been found to significantly increase the risk of oral disease (OR = 1.99) and especially the risk of lichen planus and OSCC (OR = 2.805 and 5.790, respectively). Similarly, the risk of oral disease was also more in the heterozygote (AG) than the common allele homozygote (AA) of TNF-β (A252G) polymorphism (rs909253) (OR = 1.483).

CONCLUSION

We conclude that the SNPs rs361525 and rs909253 were significantly associated with oral pre-cancer and OSCC.

New Insights Into Oral Squamous Cell Carcinoma: From Clinical Aspects to Molecular Tumorigenesis

Oral squamous cell carcinoma (SCC) is a prevalent malignant disease worldwide, especially so in Taiwan. Early- or even preclinical-stage detection is critical for reducing morbidity and mortality from oral SCC. Epidemiological and genome association studies are useful for identifying clinicopathological risk factors for preventive, diagnostic, and therapeutic approaches of oral SCC. For advanced oral SCC, effective treatments are critical to prolonging survival and enhancing quality of life. As oral SCC is characteristic of regional invasion with lymph node metastases, understanding the aggressive features of oral SCC, particularly in lymphangiogenesis, is essential for determining effective treatments. Emerging evidence has demonstrated that the tumor microenvironment (TME) plays a pivotal role in tumor growth, invasion, and metastases. Recent clinical successes in immune checkpoint inhibitors either alone or combined with chemotherapy have also supported the therapeutic value of immunotherapy in oral SCC. This review summarizes critical advances in basic knowledge of oral SCC from the perspective of clinicopathological risk factors, molecular tumorigenesis, and the TME. We also highlight our recent investigations on the microbiome, genome association studies, lymphangiogenesis, and immunomodulation in oral SCC. This review may provide new insights for oral SCC treatment by systematically interpreting emerging evidence from various preclinical and clinical studies.

Role of Cyclooxygenase-2 in Head and Neck Tumorigenesis

The cyclooxygenase-2 (COX-2) is a potent enzyme that converts arachidonic acid to prostaglandins (PG), including PGE2, a key mediator of inflammation and angiogenesis. Importantly, COX-2 is activated in response to inflammatory stimuli, where it is also believed to promote the development and progression of head and neck cancers (HNC). COX-2 can mediate its protumorigenic effect through various mechanisms, such as inducing cell proliferation, inhibition of apoptosis, and suppressing the host’s immune response. Furthermore, COX-2 can induce the production of vascular endothelial growth factors, hence, promoting angiogenesis. Indeed, the ability of COX-2 inhibitors to selectively restrict the proliferation of tumor cells and mediating apoptosis provides promising therapeutic targets for cancer patients. Thus, in this comprehensive review, we summarized the reported differential expression patterns of COX-2 in different stages of head and neck carcinogenesis—from potentially premalignant lesions to invasive carcinomas. Furthermore, we examined the available meta-analysis evidence for COX-2 role in the carcinogenesis of HNC. Finally, further understanding of the biological processes of COX-2 and its role in orchestrating cell proliferation, apoptosis, and angiogenesis may give therapeutically beneficial insight to develop the management plan of HNC patients and improve their clinical outcomes.

Isoform-Specific Role of Akt in Oral Squamous Cell Carcinoma

Protein kinase B (Akt) plays a very significant role in various cancers including oral cancer. However, it has three isoforms (Akt1, Akt2, and Akt3) and they perform distinct functions and even play contrasting roles in different cancers. Therefore, it becomes essential to evaluate the isoform-specific role of Akt in oral cancer. In the present study, an attempt has been made to elucidate the isoform-specific role of Akt in oral cancer. The immunohistochemical analysis of oral cancer tissues showed an overexpression of Akt1 and 2 isoforms but not Akt3. Moreover, the dataset of "The Cancer Genome Atlas" for head and neck cancer has suggested the genetic alterations of Akt1 and 2 tend to be associated with the utmost poor clinical outcome in oral cancer. Further, treatment of oral cancer cells with tobacco and its components such as benzo(a)pyrene and nicotine caused increased mRNA levels of Akt1 and 2 isoforms and also enhanced the aggressiveness of oral cancer cells in terms of proliferation, and clonogenic and migration potential. Finally, silencing of Akt1 and 2 isoforms caused decreased cell survival and induced cell cycle arrest at the G2/M phase. Akt1/2 silencing also reduced tobacco-induced aggressiveness by decreasing the clonogenic and migration potential of oral cancer cells. Moreover, silencing of Akt1 and 2 isoforms was found to decrease the expression of proteins regulating cancer cell survival and proliferation such as cyclooxygenase-2, B-cell lymphoma 2 (Bcl-2), cyclin D1, and survivin. Thus, the important role of Akt1 and 2 isoforms have been elucidated in oral cancer with in-depth mechanistic analysis.

Functional analysis of polymorphisms in the COX-2 gene and risk of lung cancer

The enzyme cyclooxygenase 2 (COX-2) is known to be involved in tumorigenesis and metastasis in certain types of cancer. Nevertheless, the prognostic value of COX-2 overexpression and its polymorphisms in patients with non-small cell lung cancer (NSCLC) have yet to be fully elucidated. The aim of the present study was to investigate the association between the three most commonly studied COX-2 gene polymorphisms (-1195 G/A, -765 G/C and 8473 T/C) with COX-2 expression and lung cancer risk in a Brazilian cohort. In the present hospital based, case-control retrospective study, 104 patients with NSCLC and 202 cancer free control subjects were genotyped for -1195 G/A, -765 G/C and 8473 T/C polymorphisms using allelic discrimination with a reverse transcription quantitative polymerase chain reaction method. COX-2 mRNA expression was analyzed in surgically resected tumors from 34 patients with NSCLC. The results revealed that COX-2 expression levels were higher in tumor tissue compared with normal lung tissue. However, this overexpression of COX-2 was not associated with the patient outcome, and furthermore, none of the analyzed polymorphisms were associated with the risk of developing lung cancer, COX-2 overexpression, or the overall survival of the patients with NSCLC. Taken together, the findings described in the present study do not support a major role for COX-2 polymorphisms and COX-2 overexpression in lung carcinogenesis within the Brazilian population.

Studies on the Contribution of Cox-2 Expression in the Progression of Oral Squamous Cell Carcinoma and H-Ras Activation

The aim of this study was to investigate the relationship between the H-ras and Cox-2 gene expression in tumors from Iranian Oral Squamous Cell Carcinoma (OSCC) patients. Fresh tumor biopsies removed from oral cavity were collected from 67 new cases. Total RNA was extracted from biopsies and processed for quantification of H-ras and Cox-2 specific RNA expression using real-time PCR (QPCR). In addition, 59 gingival biopsies from apparently normal individuals were processed for QPCR assays. The results showed that Cox-2 expression at mRNA levels was at minimal levels in normal gingival biopsies. However, there was a surge in Cox-2 expression in tumor tissues (11.5 fold, p < 0.0001). Cox-2 expression was elevated depending on the tumor grade and there was a 1.7 fold increase (p = 0.003) in tumors diagnosed as MD/PD compared to that pathologically diagnosed as WD. This inflammatory marker was increased more significantly in smoker patients compared to non-smoker matching group. The H-ras expression at mRNA levels was significantly higher in OSCC samples compared to normal gingival (3 fold; p = 0.044). This expression was significantly higher in tumors diagnosed as MD/PD compared to WD (1.59 fold, p = 0.033). In conclusion, we found a correlation between H-ras expression and Cox-2 induction in OSCC tissue, suggesting that together these genes are contributing to cancer progression. Cox-2 is an early event in cancers of mucosal epithelial cells and a surge in Cox-2 expression in OSCC could be partly due to pro-inflammatory factors such as smoking.