Abnormal COX2 protein expression may be correlated with poor prognosis in oral cancer: a meta-analysis

Molecular Markers in Oral Lichen Planus - Insight into Pathogenesis

PURPOSE

Oral lichen planus (OLP) is a chronic inflammatory disease, characterized by immune-mediated basal keratinocyte apoptosis. In recent years the importance of programmed cell death for the tissue destruction in OLP has been disputed, while at the same time an increased proliferative index has been reported in the epithelium of these lesions. OLP is considered as a precancerous condition. This study investigated the expression of pro-apoptotic, anti-apoptotic and proliferative markers in OLP lesions in an attempt to understand more about the pathogenesis and malignant potential of the disease.

METHODS

Twenty patients with histologically confirmed OLP were compared to ten healthy controls through immunohistochemical analysis of the levels of p53, p63, bcl-2, Ki-67 and COX-2.

RESULTS

The results demonstrated significantly decreased expression of p63 in OLP lesions compared to normal oral mucosa. The levels of p53, bcl-2, Ki-67, and COX-2 were not significantly different from those in the control group. A significant association was found between p63 and Ki-67 (p = 0.001), as well as between p63 and p53 (p = 0.016). Expression of the inflammatory COX-2 and the apoptotic p53 appeared to be independent of each other (p = 0.44). The intensity of expression of any of the five analyzed markers was not related to the severity of the clinical manifestation.

CONCLUSIONS

The obtained results suggest that apoptosis may not be the dominant mechanism in the disease's pathogenesis. Decreased expression of p63 on the other hand appears to play an important role. Among the possible effects of this protein deficiency are activation of programmed cell death, cell cycle arrest, cellular senescence, or anoikis; suppression of cell proliferation or changes in cell differentiation. The observed reduction in p63, Ki67 and bcl-2 levels predisposes to epithelial thinning, erosions and/or ulcers. For the presented OLP cohort, there was no molecular evidence of increased malignant potential of the lesions.

COX-2 Silencing in Canine Malignant Melanoma Inhibits Malignant Behaviour

Metastatic melanoma is a very aggressive form of cancer in both humans and dogs. Dogs primarily develop oral melanoma of mucosal origin. Although oral melanoma in humans is rare, both diseases are highly aggressive with frequent metastases. This disease represents a “One Health” opportunity to improve molecular and mechanistic understanding of melanoma progression. Accumulating evidence suggests that cyclooxygenase-2 (COX-2) may play a critical role in the malignant behaviour of melanoma. In this study we analysed 85 histologically confirmed melanomas from canine patients and showed that COX-2 is overexpressed in both oral and cutaneous melanomas and that COX-2 expression correlates with established markers of poor prognosis. To determine the role of COX-2 in melanoma we developed two melanoma cell lines with stable integration of an inducible doxycycline-regulated expression vector containing a COX-2 targeted micro-RNA (miRNA). Using this system, we showed that cellular proliferation, migration and invasion are COX-2 dependent, establishing a direct relationship between COX-2 expression and malignant behaviour in canine melanoma. We have also developed a powerful molecular tool to aid further dissection of the mechanisms by which COX-2 regulates melanoma progression.

ARG1 mRNA Level Is a Promising Prognostic Marker in Head and Neck Squamous Cell Carcinomas

Head and neck squamous cell carcinomas (HNSCC) can be induced by smoking or alcohol consumption, but a growing part of cases relate to a persistent high-risk papillomavirus (HPV) infection. Viral etiology has a beneficial impact on the prognosis, which may be explained by a specific immune response. Tumor associated macrophages (TAMs) represent the main immune population of the tumor microenvironment with a controversial influence on the prognosis. In this study, the level, phenotype, and spatial distribution of TAMs were evaluated, and the expression of TAM-associated markers was compared in HPV positive (HPV+) and HPV negative (HPV−) tumors. Seventy-three formalin and embedded in paraffin (FFPE) tumor specimens were examined using multispectral immunohistochemistry for the detection of TAM subpopulations in the tumor parenchyma and stroma. Moreover, the mRNA expression of TAM markers was evaluated using RT-qPCR. Results were compared with respect to tumor etiology, and the prognostic significance was evaluated. In HPV− tumors, we observed more pro-tumorigenic M2 in the stroma and a non-macrophage arginase 1 (ARG1)-expressing population in both compartments. Moreover, higher mRNA expression of M2 markers—cluster of differentiation 163 (CD163), ARG1, and prostaglandin-endoperoxide synthase 2 (PTGS2)—was detected in HPV− patients, and of M1 marker nitric oxide synthase 2 (NOS2) in HPV+ group. The expression of ARG1 mRNA was revealed as a negative prognostic factor for overall survival of HNSCC patients.

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.

miR-146a-5p impairs melanoma resistance to kinase inhibitors by targeting COX2 and regulating NFkB-mediated inflammatory mediators

Background

Targeted therapy with BRAF and MEK inhibitors has improved the survival of patients with BRAF-mutated metastatic melanoma, but most patients relapse upon the onset of drug resistance induced by mechanisms including genetic and epigenetic events. Among the epigenetic alterations, microRNA perturbation is associated with the development of kinase inhibitor resistance. Here, we identified and studied the role of miR-146a-5p dysregulation in melanoma drug resistance.

Methods

The miR-146a-5p-regulated NFkB signaling network was identified in drug-resistant cell lines and melanoma tumor samples by expression profiling and knock-in and knock-out studies. A bioinformatic data analysis identified COX2 as a central gene regulated by miR-146a-5p and NFkB. The effects of miR-146a-5p/COX2 manipulation were studied in vitro in cell lines and with 3D cultures of treatment-resistant tumor explants from patients progressing during therapy.

Results

miR-146a-5p expression was inversely correlated with drug sensitivity and COX2 expression and was reduced in BRAF and MEK inhibitor-resistant melanoma cells and tissues. Forced miR-146a-5p expression reduced COX2 activity and significantly increased drug sensitivity by hampering prosurvival NFkB signaling, leading to reduced proliferation and enhanced apoptosis. Similar effects were obtained by inhibiting COX2 by celecoxib, a clinically approved COX2 inhibitor.

Conclusions

Deregulation of the miR-146a-5p/COX2 axis occurs in the development of melanoma resistance to targeted drugs in melanoma patients. This finding reveals novel targets for more effective combination treatment.

Diclofenac sodium gel therapy as an alternative to actinic cheilitis

OBJECTIVE

Actinic cheilitis (AC) is a potentially malignant lesion caused by prolonged exposure to ultraviolet light. The aim of this research was to analyze the efficacy of diclofenac sodium 3% gel in the treatment of this condition, through clinical follow-up.

METHODS

Thirty-one patients diagnosed with AC were instructed to perform a topical application of the gel three times a day for a period of 90 days. In each visit, a digital photography was obtained for verified progress and response to treatment. Two researchers evaluated all images after treatment was completed and assigned the following scores regarding clinical aspect of the lip: 1, complete improvement; 2, partial improvement; 3, no changes; 4, worsening of the clinical condition. In addition, the patients' tolerability to the drug and their satisfaction after treatment were evaluated.

RESULTS

Twelve cases abandoned the treatment for reasons unrelated to the study. Ten participants showed total remission of all clinical features of the lesion and three had partial improvement of the characteristics. One participant presented worsening of clinical condition, and in five cases, treatment was discontinued due to development of mild adverse effects at the site of gel application. Regarding satisfaction analyses and tolerability to the drug, from 14 patients who completed treatment without adverse effects or complications, most agreed fully that they were satisfied with the therapy (n = 11) and that the drug was not irritating to the mouth (n = 9). Patients are being monitored without clinical signs of recurrence and/or progression of the lesions.

CONCLUSION

Topical application of the drug has provided a convenient and well tolerated in most cases.

CLINICAL RELEVANCE

Diclofenac sodium gel (3%) may be a promising alternative for treatment of actinic cheilitis.

Cats, Cancer and Comparative Oncology

Naturally occurring tumors in dogs are well-established models for several human cancers. Domestic cats share many of the benefits of dogs as a model (spontaneous cancers developing in an immunocompetent animal sharing the same environment as humans, shorter lifespan allowing more rapid trial completion and data collection, lack of standard of care for many cancers allowing evaluation of therapies in treatment-naïve populations), but have not been utilized to the same degree in the One Medicine approach to cancer. There are both challenges and opportunities in feline compared to canine models. This review will discuss three specific tumor types where cats may offer insights into human cancers. Feline oral squamous cell carcinoma is common, shares both clinical and molecular features with human head and neck cancer and is an attractive model for evaluating new therapies. Feline mammary tumors are usually malignant and aggressive, with the ‘triple-negative’ phenotype being more common than in humans, offering an enriched population in which to examine potential targets and treatments. Finally, although there is not an exact corollary in humans, feline injection site sarcoma may be a model for inflammation-driven tumorigenesis, offering opportunities for studying variations in individual susceptibility as well as preventative and therapeutic strategies.

Fenofibrate in cancer: mechanisms involved in anticancer activity

Objective: To review the mechanisms of anti-cancer activity of fenofibrate (FF) and other Peroxisome Proliferator Activator Receptor α (PPARα) agonists based on evidences reported in the published literature.Methods: We extensively reviewed the literature concerning FF as an off target anti-cancer drug. Controversies regarding conflicting findings were also addressed.Results: The main mechanism involved in anti-cancer activity is anti-angiogenesis through down-regulation of  Vascular Endothelial Growth Factor (VEGF), Vascular Endothelial Growth Factor Receptor (VEGFR) and Hypoxia Inducible factor-1 α (HIF-1α), inhibition of endothelial cell migration, up-regulation of endostatin and thrombospondin-1, but there are many other contributing mechanisms like apoptosis and cell cycle arrest, down-regulation of Nuclear Factor Kappa B (NF-kB) and Protein kinase B (Akt) and decrease of cellular energy by impairing mitochondrial function. Growth impairment is related to down-regulation of Phospho-Inositol 3 Kinase (PI3K)/Akt axis and down-regulation of the p38 map kinase (MAPK) cascade. A possible role should be assigned to FF stimulated over-expression of Tribbles Homolog-3 (TRIB3) which inhibits Akt phosphorylation. Important anti-cancer and anti-metastatic activities are due to down-regulation of MCP-1 (monocyte chemotactic protein-1), decreased Metalloprotease-9 (MMP-9) production, weak down-regulation of adhesion molecules like E selectin, intercellular adhesion molecules (ICAM) and Vascular Endothelial Adhesion Molecules (VCAM), and decreased secretion of chemokines like Interleukin-6 (IL-6), and down-regulation of cyclin D-1. There is no direct link between FF activity in lipid metabolism and anticancer activity, except for the fact that many anticancer actions are dependent from PPARα agonism. FF exhibits also PPARα independent anti-cancer activities.Conclusions: There are strong evidences indicating that FF can disrupt growth-related activities in many different cancers, due to anti-angiogenesis and anti-inflammatory effects. Therefore FF may be useful as a complementary adjunct treatment of cancer, particularly included in anti-angiogenic protocols like those currently increasingly used in glioblastoma. There are sound reasons to initiate well planned phase II clinical trials for FF as a complementary adjunct treatment of cancer.

COX-2 overexpression and -8473 T/C polymorphism in 3' UTR in non-small cell lung cancer

A new class of compounds targeting cyclooxygenase 2 (COX-2) together with other different clinically used therapeutic strategies has recently shown a promise for the chemoprevention of several solid tumors including lung cancer. The aim was to study the possible role of COX-2 -8473 T/C NP and its expression in the pathogenesis of non-small cell lung cancer. One hundred ninety non-small cell lung cancer (NSCLC) patients and 200 healthy age-, sex-, and smoking-matched controls were used for polymorphic analysis, and 48 histopathologically confirmed NSCLC patients were analyzed for COX-2 messenger RNA (mRNA) and protein expression. Our results showed that the frequencies of variant genotypes 8473 CT/CC were significantly less common in the cases (30.0%) than in the controls (36%), suggesting that the 8473 C variant allele is related with lower susceptibility in NSCLC (OR = 0.79, 95% CI 0.54-1.4). However, the frequency of COX-2 -8473 TC and CC genotypes were significantly associated with age in NSCLC (P = 0.02). Quantitative real-time expression analysis showed a significant increase in the COX-2 mRNA in tumor tissues as compared to their adjacent normal tissues [delta cycle threshold (ΔCT) = 9.25 ± 4.67 vs 5.63 ± 3.85, P = 0.0001]. Multivariate logistic regression analyses revealed that the COX-2 expression was associated significantly with age (P = 0.044). Also, an increasing trend was observed in stages I and II and in female patients compared to stages III and IV and male patients, respectively, but no statistical significance was observed. However, COX-2 mRNA expression shown no association with the -8473 C variant allele. Our findings indicate that the COX-2 T8473C polymorphism may contribute to NSCLC cancer susceptibility in the Kashmiri population, while our expression analysis revealed a significant increase of COX-2 in tumor tissues as compared to their adjacent normal tissues, suggesting that it could become an important therapeutic marker in NSCLC in the future.