An overview on the expression of cyclooxygenase-2 in tumors of the head and neck

Biomarker Profiles and Clinicopathological Features in Head and Neck Squamous Cell Carcinoma Patients

Background and Objectives: Head and neck squamous cell carcinomas (HNSCCs) vary significantly in terms of invasiveness, growth rate, and metastatic potential. This study aimed to investigate the expression of several prognostic biomarkers (Ki67, p53, EGFR, COX-2, Cx43, and p16) in HNSCC from various anatomical regions and to correlate these expressions with clinicopathological parameters. Materials and Methods: We performed immunohistochemistry on 91 histologically verified HNSCC cases from the County Emergency Hospital, Targu Mures. Biomarker expression for Ki67, COX-2, and Cx43 was assessed using a standard immunoexpression scoring system: S1: 0-10%, S2: 11-25%, S3: 26-50%, S4 > 50%; EGFR was scored based on membrane staining intensity: 0, 1+, 2+, 3+; we classified p16 as positive or negative; p53 was grouped into mutant and wild-type; and we compared these across histopathological types, tumor grades, anatomical locations, gender, and different age groups. We performed a comparative analysis of Cx43 expression levels in relation to the expression of the rest of the markers. Statistical analysis was conducted using GraphPad InStat 3 software, version 3.06 (GraphPad Software Inc., San Diego, USA). Results: The majority of tumors were in males (95.6%) aged 51-60 years. Mutant p53 expression was prevalent in most cases. Elevated Ki67 and EGFR expression were associated with more aggressive tumors. COX-2 levels varied, with a higher proportion of moderate and high immunoexpression (S3 + S4) observed in patients under 70 years old. Cx43 expression was generally low, especially in extralaryngeal tumors. Conclusions: HNSCC primarily affects older males, with the larynx being the most common site. High levels of Ki-67 and EGFR suggest more aggressive tumors, while low COX-2 levels reflect varying prognoses. Women may develop more aggressive tumors, and extralaryngeal tumors often present with more challenging prognoses. Low Cx43 expression may be more likely to coincide with higher Ki67 and COX-2 levels, possibly indicating a link with more aggressive tumor behavior.

Differential Expression of Immunohistochemical Markers in Ameloblastoma & Ameloblastic Carcinoma: A Systematic Review and Meta-analysis of observational studies

BACKGROUND

Differentiating between ameloblastoma (AB) and ameloblastic carcinoma (AC) is difficult, especially when AB has atypical cytological characteristics or an uncommon clinical history. This systematic review and meta-analysis aimed to elucidate the differential expression of immunohistochemical markers between AB and AC.

METHODS

We conducted a thorough search of PUBMED and SCOPUS according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines to identify cross-sectional studies that compared the expression of immunohistochemical markers in AB and AC. We used a random-effects model to analyze the risk ratios and their corresponding 95% confidence intervals (CIs). The quality of the included studies was assessed using the Newcastle-Ottawa scale. The Egger's test was used to assess publication bias.

RESULTS

In total, 301 articles were identified. After excluding irrelevant titles and abstracts, 86 articles were selected for full-text review. We categorized the 41 markers into proliferative and non-proliferative markers. Among non-proliferative markers, nuclear markers were differentially expressed in AB and AC. SOX2 was the only marker that significantly differentiated AB and AC, with an RR of -0.19 (CI 0.10-0.36, I2=0).

CONCLUSION

The current evidence suggests the significance of SOX2 in differentiating between AB and AC, warranting prospective confirmation in well-defined extensive studies. We highlight the paucity of high-quality replicated studies of other markers in this field. Collaborative efforts with standardized techniques are necessary to generate clinically useful immunohistochemical markers.

The Role of Inflammation-Associated Factors in Head and Neck Squamous Cell Carcinoma

Head and neck squamous cell carcinoma (HNSCC), which originates in the head or neck tissues, is characterized by high rates of recurrence and metastasis. Inflammation is important in HNSCC prognosis. Inflammatory cells and their secreted factors contribute to the various stages of HNSCC development through multiple mechanisms. In this review, the mechanisms through which inflammatory factors, signaling pathways, and cells contribute to the initiation and progression of HNSCC have been discussed in detail. Furthermore, the diagnostic and therapeutic potential of targeting inflammation in HNSCC has been discussed to gain new insights into improving patient prognosis.

Targeted therapy for head and neck squamous cell carcinoma microenvironment

Head and neck squamous cell carcinoma (HNSCC) originates from the squamous epithelium of the oral cavity, oropharynx, larynx, and hypopharynx. HNSCC in the oral cavity and larynx is strongly associated with tobacco smoking and alcohol consumption, while oropharyngeal cancer is increasingly attributed to infection by human papillomavirus (HPV), particularly HPV-16. The tumor microenvironment (TME) is a complex network of cancer cells, immune cells, stromal cells, surrounding blood vessels, and signaling molecules, and plays a critical role in tumor cell survival, invasion, and recurrence. Therefore, it is critical to elucidate the molecular basis of the interaction between tumor cells and the TME in order to develop innovative anti-cancer therapeutic strategies.

Fluorine-18 Labelled Radioligands for PET Imaging of Cyclooxygenase-2

Molecular imaging probes enable the early and accurate detection of disease-specific biomarkers and facilitate personalized treatment of many chronic diseases, including cancer. Among current clinically used functional imaging modalities, positron emission tomography (PET) plays a significant role in cancer detection and in monitoring the response to therapeutic interventions. Several preclinical and clinical studies have demonstrated the crucial involvement of cyclooxygenase-2 (COX-2) isozyme in cancer development and progression, making COX-2 a promising cancer biomarker. A variety of COX-2-targeting PET radioligands has been developed based on anti-inflammatory drugs and selective COX-2 inhibitors. However, many of those suffer from non-specific binding and insufficient metabolic stability. This article highlights examples of COX-2-targeting PET radioligands labelled with the short-lived positron emitter ¹⁸F, including radiosynthesis and PET imaging studies published in the last decade (2012–2021).

Cyclooxygenase-2 expression is associated with chemoresistance through cancer stemness property in hypopharyngeal carcinoma

Cyclooxygenase-2 (COX-2) is one of the two isoforms of COX, an enzyme that catalyzes the conversion of arachidonic acid to prostaglandins. COX-2 is associated with the progression in various types of cancer, and its expression has been associated with a poor prognosis in head and neck squamous cell carcinoma (HNSCC). Furthermore, COX-2 expression has been associated with resistance to anticancer drugs. However, the precise mechanism of COX-2 for chemoresistance in HNSCC has not been fully elucidated. The present study aimed to investigate the effect of COX-2 on cancer stem cell (CSC) property and to reveal its effect on chemoresistance using in vitro and clinicopathological assays in HNSCC cells and tissues. The current study analyzed the immunohistochemical expression levels of COX-2 and clinicopathological factors using matched samples of pretreatment biopsy and surgical specimens from patients with hypopharyngeal carcinoma who underwent tumor resection with preoperative chemotherapy, including docetaxel. Additionally, the chemoresistance to docetaxel with or without a COX-2 inhibitor (celecoxib) was examined in HNSCC cell lines by MTS assays. To evaluate the association of COX-2 expression with stemness property, the expression levels of CSC-associated genes after exposure to celecoxib were assessed by reverse transcription-quantitative PCR. A sphere formation assay was also performed using ultra-low attachment dishes and microscopic imaging. The immunohistochemical analysis of biopsy specimens revealed a negative association between COX-2 expression in biopsy specimens and the pathological effect of induction chemotherapy in surgical specimens. The cell survival rate under exposure to docetaxel was decreased by the addition of celecoxib. COX-2 inhibition led to downregulation of CSC-associated gene expression and sphere formation. The present findings suggested that COX-2 expression may be associated with chemoresistance through the cancer stemness property, and inhibition of COX-2 may enhance chemo-sensitivity in HNSCC. Therefore, COX-2 may be an attractive target for the treatment of HNSCC.

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.

Molecular targeted therapy: novel therapeutic approach for head and neck cancer

Cancer is a major public health burden worldwide, affecting millions of people each year. One of the major hallmarks of cancer is rapid growth and progression by evasion of host immune responses. Tumor resistance to conventional anticancer drugs by several mechanisms, such as drug inactivation, efflux pumps and enhanced toxicity to normal cells decreases their clinical efficacy. These limitations resulted in the development of new targeted agents, such as monoclonal antibodies and small molecule inhibitors that have high tumor specificity. This paper discusses the therapeutic applications of novel molecular targeted agents and immunotherapy as an alternative treatment option for head and neck cancers, as well as provides insight into future therapeutic approaches for advanced head and neck cancers.

Comparison of fatty acid synthase and cyclooxygenase-2 immunoexpression in embryonal, benign, and malignant odontogenic tissues

OBJECTIVES

The aim of this study was to analyze the immunohistochemical expression of fatty acid synthase (FASN) and cyclooxygenase-2 (COX-2) in tooth germ (TG), ameloblastoma (AM), ameloblastic carcinoma (AC), ameloblastic fibroma (AF), and ameloblastic fibrosarcoma (AFS).

STUDY DESIGN

Immunohistochemistry for FASN and COX-2 was performed in 10 TG, 44 AM, 10 AC, 9 AF, and 5 AFS specimens. The results were analyzed by using the immunoreactive score (IRS) and Kruskal-Wallis test followed by Dunn's post-test.

RESULTS

Most TG specimens were strongly positive for FASN, whereas COX-2 was weak or negative. All AM and AC specimens expressed both proteins. In AF specimens, FASN and COX-2 were variably expressed in the epithelium and negative in the mesenchyme. In AFS specimens, FASN was strongly positive in the malignant mesenchyme and variable in the epithelium; COX-2 was focal or weak in both components. FASN expression showed significant differences in the following comparisons: TG vs AC, AM vs AC, and AF vs AFS. Differences in COX-2 were significant when comparing TG specimens with AM, AC, and AF specimens.

CONCLUSIONS

The results suggest that FASN and COX-2 overexpression may have a role in the pathogenesis of AM and AC, whereas in AFS, FASN seems to be mainly involved. Further studies are necessary to clarify these mechanisms and their clinical implications.

Protein 53, B-Cell Lymphoma-2, Cyclooxygenase-2, and CD105 Reactivity in Keratocystic Odontogenic Tumors: An Immunohistochemical Analysis

OBJECTIVE

The objective is to evaluate and compare immunohistochemically, the biological behavior of keratocystic odontogenic tumor (KCOT) with normal oral mucosa by analyzing cell proliferation, angiogenesis, and antiapoptosis using cyclooxygenase-2 (COX-2), protein 53 (p53), B-cell lymphoma-2 (Bcl-2), and CD105 (endoglin).

MATERIALS AND METHODS

The present study comprised 30 cases of KCOT in the study group, in which the expression of COX-2, p53, Bcl-2, and CD105 were analyzed and compared with that of control group consisting of 30 normal oral mucosae.

RESULTS

The results were evaluated based on a number of positively stained cells; among 30 samples of KCOT, 22 samples were p53 positive, 23 samples were Bcl-2 positive, 18 samples were COX-2 positive, whereas all the above markers were negative in all the 30 samples of the normal oral mucosa and CD105 mean vascular density in KCOT 13.8 in normal oral mucosa.

CONCLUSION

The present study suggests that angiogenesis, cell proliferation, and antiapoptosis may be the possible factors contributing for the unique biological behavior of KCOT.

Substrate-inactivated cyclooxygenase-2 is disposed of by exosomes through the ER-Golgi pathway

Catalysis of arachidonic acid (AA) by cyclooxygenase-2 (COX-2) gives rise to a single product that serves as a precursor for all prostaglandins, which are central mediators of inflammation. Rapid up-regulation of COX-2 expression in response to pro-inflammatory stimuli is a well-characterized means of generating the large pool of prostaglandins necessary for inflammation. However, an efficient inflammatory process must also terminate rapidly and thus requires cessation of COX-2 enzymatic activity and removal of excess protein from the cell. Previous studies showed that COX-2 that has not been exposed to AA ('naive') degrades in the cellular proteasome. However, continuous exposure to AA induces suicide inactivation of COX-2 and its elimination no longer occurs in neither the proteasomal nor lysosomal machineries. In the present study, we show that either overexpressed or endogenously induced COX-2 is secreted via exosomes through the endoplasmic reticulum-Golgi pathway. We further find that excretion of COX-2 is significantly enhanced by prolonged exposure to AA. Genetic or chemical inhibition of COX-2 enzymatic activity has no effect on its secretion in the absence of substrate, but prevents the additional activity-dependent secretion. Finally, transfer of COX-2 to target cells only occurs in the absence of AA stimulation. Together, these results suggest that exosomal secretion of AA-activated COX-2 constitutes a means to remove damaged inactive COX-2 from the cell.

Cyclooxygenase-1 (COX-1) and COX-1 Inhibitors in Cancer: A Review of Oncology and Medicinal Chemistry Literature

Prostaglandins and thromboxane are lipid signaling molecules deriving from arachidonic acid by the action of the cyclooxygenase isoenzymes COX-1 and COX-2. The role of cyclooxygenases (particularly COX-2) and prostaglandins (particularly PGE₂) in cancer-related inflammation has been extensively investigated. In contrast, COX-1 has received less attention, although its expression increases in several human cancers and a pathogenetic role emerges from experimental models. COX-1 and COX-2 isoforms seem to operate in a coordinate manner in cancer pathophysiology, especially in the tumorigenesis process. However, in some cases, exemplified by the serous ovarian carcinoma, COX-1 plays a pivotal role, suggesting that other histopathological and molecular subtypes of cancer disease could share this feature. Importantly, the analysis of functional implications of COX-1-signaling, as well as of pharmacological action of COX-1-selective inhibitors, should not be restricted to the COX pathway and to the effects of prostaglandins already known for their ability of affecting the tumor phenotype. A knowledge-based choice of the most appropriate tumor cell models, and a major effort in investigating the COX-1 issue in the more general context of arachidonic acid metabolic network by using the systems biology approaches, should be strongly encouraged.

Calcifying odontogenic cyst: A 26-year retrospective clinicopathological analysis and immunohistochemical study

Background

To identify the prevalence and clinicopathological profile of calcifying odontogenic cysts (COC) stored at an oral pathology service, and to analyze the immunoexpression of cyclooxygenase 2 (COX-2) and cyclin D1 (CD1) in these cysts.

Material and Methods

After a retrospective analysis (1990-2016) carried out to identify cases of COC, a sample of 12 cases was selected for immunohistochemical analysis of COX-2 and CD1 by the immunoperoxidase technique. Protein expression was evaluated semiquantitatively by attributing a score of 0 to 3 (0 = no staining; 1 = 1-25%; 2 = 26-50%, and 3 = >51% immunopositive cells).

Results

Twenty cases of COC were diagnosed over the study period. These cysts were more common in the posterior mandible and in men (male-to-female ratio of 1.2:1), with a mean age of 29.9 years. Among the 12 cases analyzed, immunoexpression of COX-2 was observed only in the inflammatory infiltrate in 50% of the cysts (n = 6). Protein CD1 was detected (score 1) in 66.6% of cases (n = 8), and COX-2 was negative in 50% (n = 6).

Conclusions

The prevalence of COC among all odontogenic cysts was 3.5%, representing an uncommon lesion. Immunohistochemical analysis suggested that COX-2 does not participate in lesion progression. The cell proliferation index of COC was low, as demonstrated by the expression of CD1, suggesting a proliferative profile compatible with more indolent lesions.

Key words:Odontogenic cysts, odontogenic tumors, epidemiology, immunohistochemistry, cell proliferation.

COX-2 as a determinant of lower disease-free survival for patients affected by ameloblastoma

Ameloblastoma is a locally aggressive neoplasm with a poorly understood pathogenesis. Therefore, the aim of this study is to investigate whether COX-2 expression is associated with ameloblastoma microvascular density (MVD) and with tumor aggressiveness. Sixty-three cases of primary ameloblastomas arranged in tissue microarray were submitted to immunohistochemistry against cyclooxigenase-2 (COX-2) and CD34. Clinicopathological parameters regarding sex, age, tumour size, tumour duration, tumour location, treatment, recurrences, radiographic features, vestibular/lingual and basal cortical disruption and follow-up data were obtained from patients' medical records and correlated with the proteins expression. The results on BRAF-V600E expression were obtained from our previous study and correlated with COX-2 and CD34 expressions. Log-rank univariate analysis and multivariate Cox regression model were done to investigate the prognostic potential of the molecular markers. Twenty-eight cases (44.4%) exhibited cytoplasmic positivity for COX-2, predominantly in the columnar peripheral cells, with a mean MVD of 2.2 vessels/mm². COX-2 was significantly associated with recurrences (p < 0.001) and BRAF-V600E expression (p < 0.001), whereas lower MVD was associated with the use of conservative therapy (p = 0.004). Using univariate and multivariate analyses, COX-2 was significantly associated with a lower 5-year disease-free survival (DFS) rate (p < 0.001 and p = 0.012, respectively), but not with a higher MVD (p = 0.68). In conclusion, COX-2 expression in ameloblastomas is not associated with MVD, but it is significantly associated with recurrences and with a lower DFS.

Investigation of clinicopathological parameters and expression of COX-2, bcl-2, PCNA, and p53 in primary and recurrent sporadic odontogenic keratocysts

Objectives

Odontogenic keratocyst (OKC) presents considerable variation in aggressiveness and propensity for recurrence, yet hitherto, no explicit clinicopathological features have been determined to clearly demonstrate the potential for relapse. This retrospective study aims to investigate the prognostic relevance of various clinicopathological features as well as immunoexpression of COX-2, bcl-2, PCNA, and p53 in sporadic OKC.

Materials and methods

Among 41 patients with OKC treated by enucleation, the frequency of recurrence for various clinicopathological features as well as immunoexpression for COX-2, bcl-2, PCNA, and p53 was evaluated.

Results

The mean follow-up was 8.49 years, and recurrences were ascertained in 29.27% of cases. We found significant differences between recurrent and non-recurrent cysts in terms of multilocularity (P = 0.029), cortical perforation (P = 0.001), and lesion size (P < 0.001). Hazard risk for the recurrence was 3.362 (95% CI 1.066–10.598) for multilocular cysts, 7.801 (95% CI 2.1–28.985) for evidence of cortical perforation, and 1.004 (1.002–1.006) for 1 mm² of lesion size on panoramic radiographs. We also found that immunoexpression of PCNA significantly correlates with the radiographic evidence of cortical perforation (P = 0.048) and that there is significant positive correlation between expression of COX-2 and bcl-2 (P = 0.001) as well as significant negative correlation between immunoexpression of COX-2 and age (P = 0.002). None of the other analyzed factors were associated with the recurrence.

Conclusions

Larger size, multilocularity, and cortical perforation in sporadic OKC may be correlated with the relapse.

Clinical relevance

Immunohistochemical analyses of COX-2, bcl-2, PCNA, and p53 lack prognostic utility in sporadic OKC.

Inflammation and cancer: role of annexin A1 and FPR2/ALX in proliferation and metastasis in human laryngeal squamous cell carcinoma

The anti-inflammatory protein annexin A1 (ANXA1) has been associated with cancer progression and metastasis, suggesting its role in regulating tumor cell proliferation. We investigated the mechanism of ANXA1 interaction with formylated peptide receptor 2 (FPR2/ALX) in control, peritumoral and tumor larynx tissue samples from 20 patients, to quantitate the neutrophils and mast cells, and to evaluate the protein expression and co-localization of ANXA1/FPR2 in these inflammatory cells and laryngeal squamous cells by immunocytochemistry. In addition, we performed in vitro experiments to further investigate the functional role of ANXA1/FPR2 in the proliferation and metastasis of Hep-2 cells, a cell line from larynx epidermoid carcinoma, after treatment with ANXA1_2–26 (annexin A1 N-terminal-derived peptide), Boc2 (antagonist of FPR) and/or dexamethasone. Under these treatments, the level of Hep-2 cell proliferation, pro-inflammatory cytokines, ANXA1/FPR2 co-localization, and the prostaglandin signalling were analyzed using ELISA, immunocytochemistry and real-time PCR. An influx of neutrophils and degranulated mast cells was detected in tumor samples. In these inflammatory cells of peritumoral and tumor samples, ANXA1/FPR2 expression was markedly exacerbated, however, in laryngeal carcinoma cells, this expression was down-regulated. ANXA1_2–26 treatment reduced the proliferation of the Hep-2 cells, an effect that was blocked by Boc2, and up-regulated ANXA1/FPR2 expression. ANXA1_2–26 treatment also reduced the levels of pro-inflammatory cytokines and affected the expression of metalloproteinases and EP receptors, which are involved in the prostaglandin signalling. Overall, this study identified potential roles for the molecular mechanism of the ANXA1/FPR2 interaction in laryngeal cancer, including its relationship with the prostaglandin pathway, providing promising starting points for future research. ANXA1 may contribute to the regulation of tumor growth and metastasis through paracrine mechanisms that are mediated by FPR2/ALX. These data may lead to new biological targets for therapeutic intervention in human laryngeal cancer.

Regulation of COX-2 expression by miR-146a in lung cancer cells

Prostaglandins are a class of molecules that mediate cellular inflammatory responses and control cell growth. The oxidative conversion of arachidonic acid to prostaglandin H2 is carried out by two isozymes of cyclooxygenase, COX-1 and COX-2. COX-1 is constitutively expressed, while COX-2 can be transiently induced by external stimuli, such as pro-inflammatory cytokines. Interestingly, COX-2 is overexpressed in numerous cancers, including lung cancer. MicroRNAs (miRNAs) are small RNA molecules that function to regulate gene expression. Previous studies have implicated an important role for miRNAs in human cancer. We demonstrate here that miR-146a expression levels are significantly lower in lung cancer cells as compared with normal lung cells. Conversely, lung cancer cells have higher levels of COX-2 protein and mRNA expression. Introduction of miR-146a can specifically ablate COX-2 protein and the biological activity of COX-2 as measured by prostaglandin production. The regulation of COX-2 by miR-146a is mediated through a single miRNA-binding site present in the 3' UTR. Therefore, we propose that decreased miR-146a expression contributes to the up-regulation and overexpression of COX-2 in lung cancer cells. Since potential miRNA-mediated regulation is a functional consequence of alternative polyadenylation site choice, understanding the molecular mechanisms that regulate COX-2 mRNA alternative polyadenylation and miRNA targeting will give us key insights into how COX-2 expression is involved in the development of a metastatic condition.

Expression of human papillomavirus is correlated with Ki-67 and COX-2 expressions in keratocystic odontogenic tumor

The aim of the current study was to investigate the presence of human papillomavirus (HPV) and evaluate its association with Ki-67 and cyclooxygenase-2 (COX-2) expressions in keratocystic odontogenic tumor (KCOT). Nineteen cases were included in the present study. Conventional PCR method and immunohistochemical analysis were performed for the detection of HPV-DNA and HPV-L1 capsid protein. Moreover, the expressions of Ki-67 and COX-2 proteins were analyzed immunohistochemically. HPV-DNA was detected in 36.8% (7/19) of tumor samples, whilst HPV-L1 protein was identified in 68.4% (13/19) of them. The Kappa coefficient statistical test showed a moderate agreement (κ 0.424) between PCR and IHC assays for HPV detection. Expression of HPV-DNA was positively correlated with Ki-67 and COX-2 expressions (p < 0.05), whereas HPV-L1 positive staining was positively correlated with COX-2 (p < 0.05) and highly associated with those of Ki-67 (p < 0.01). There was no significant correlation between the presence of HPV and the recurrence of the studied lesions. The results of the current study showed that active HPV infection was present in the odontogenic epithelium of KCOT, and it was associated with increased proliferation rate and COX-2 expression. These findings suggest that HPV may have a role in the pathogenesis and aggressiveness of KCOT. Based on these conclusions, we recommend further investigations of HPV vaccine or antiviral therapy and COX-2 inhibitors as nonsurgical options in the prevention and management of KCOT.

Mechanisms of oral carcinogenesis induced by dibenzo[a,l]pyrene: an environmental pollutant and a tobacco smoke constituent

We previously reported that dibenzo[a,l]pyrene (DB[a,l]P), the most potent known environmental carcinogen among polycyclic aromatic hydrocarbons (PAH) congeners, is carcinogenic in the oral tissues of mice. We have now developed a new mouse model which employs the oral application of the fjord region diol epoxide, (±)-anti-11,12-dihydroxy-13,14-epoxy-11,12,13,14-tetrahydrodibenzo[a,l]pyrene (DB[a,l]PDE), a metabolite of the tobacco smoke constituent DB[a,l]P, and we show its specific induction of oral squamous cell carcinoma (OSCC) in both tongue and other oral tissues. Groups of B6C3F1 mice (20/group) received 6 or 3 nmol of (±)-anti-DB[a,l]PDE administered into the oral cavity; 3 times per week for 38 weeks. Additional groups received the vehicle alone or were left untreated. Mice were sacrificed 42 weeks after the first carcinogen administration. The high dose induced 74 and 100% OSCC in the tongue and other oral tissues, respectively; the corresponding values at the lower dose were 45 and 89%. Using immunohistochemistry, we showed that DB[a,l]PDE resulted in overexpression of p53 and COX-2 proteins in malignant tissues when compared to normal oral tissues and tongues. Consistent with the carcinogenicity, we demonstrated powerful mutagenicity in cII gene in B6C3F1 (Big Blue) mouse tongue. The mutational profile in lacI reporter gene is similar to those detected in human head and neck cancer, and p53 mutations were observed in mouse oral tumor tissues. Taken together, we conclude that the formation of diol epoxides plays a major role among the mechanisms by which DB[a,l]P exerts its oral mutagenicity and tumorigenicity.

Cyclooxygenase-2 expression in keratocystic odontogenic tumour decreased following decompression

Marsupialisation or decompression is frequently performed as a conservative therapy for keratocystic odontogenic tumours (KCOTs). Positive cyclooxygenase-2 (COX-2) expression in the epithelium of KCOTs was recently reported and may be associated with neoplastic invasion and progression. The aim of the present study was to investigate the change in COX-2 expression in the KCOT epithelium following decompression. In this study, 16 pairs of KCOT biopsy specimens obtained during decompression or enucleation were collected and analysed. Formalin-fixed, paraffin-embedded blocks were sectioned and immunohistochemically investigated using anti-COX-2 antibody. The molecular expression was semi-quantitatively evaluated as follows: 0, negative; 1, weakly to moderately positive; and 2, strongly positive. In the samples obtained prior to decompression, the positive staining for COX-2 was immunolocalised to the cell membrane and the cytoplasm, it involved the full thickness of the epithelium and 15 of the 16 specimens (93.8%) exhibited mild to strong positivity. As regards the samples obtained following decompression, only 3 of the 16 specimens (18.8%) exhibited a mild positivity. The expression levels of COX-2 were significantly decreased following decompression (P<0.05). It may be concluded that loss or a significant reduction of COX-2 expression is associated with decompression in KCOTs. However, large-scale studies are required to verify these results and improve our knowledge of the possible involvement of COX-2 in the pathogenic mechanism underlying the development of KCOTs.

Up-regulation of cyclooxygenase 2 and matrix metalloproteinases-2 and -9 in cutaneous squamous cell carcinoma: active role of inflammation and tissue remodeling in carcinogenesis

Background

Tissue inflammation and remodeling have been extensively studied in various tumors in relation with their invasiveness and metastasis.

Objective

The purpose of this study was to investigate the change in tissue inflammation and remodeling markers in cutaneous squamous cell carcinoma (SCC).

Methods

Expression levels of cyclooxygenase-2 (COX-2) as an inflammatory marker and matrix metalloproteinases-2 and -9 (MMPs 2/9) as remodeling markers were studied in mouse and human SCCs. Western blot analysis and RT-PCR for COX-2 and MMPs 2/9 were performed with skin samples from SCC patients and chronic ultraviolet B (UVB)-induced SCC from hairless mice.

Results

mRNA and protein levels of COX-2 and MMPs 2/9 were up-regulated with the higher sensitivity for MMP-9 in mouse SCCs, which were induced by chronic UVB irradiation. Consistently, COX-2 and MMPs 2/9 were up-regulated with the higher sensitivity for MMP-9 in human SCCs.

Conclusion

COX-2 and MMPs 2/9 are up-regulated in well-differentiated cutanous SCC. Our findings indicate that inflammatory and tissue remodeling processes are actively induced during carcinogenesis of cutaneous SCC.

Anastrozole and celecoxib for endometriosis treatment, good to keep them apart?

Endometriosis is a benign gynecological disease. Cyclooxygenase-2 (COX-2) and aromatase proteins have been shown to be overexpressed in eutopic endometrium from women suffering from this disease compared to disease-free women. Furthermore, inhibition of these molecules individually was demonstrated to have antiproliferative and proapoptotic effects both in vitro and in vivo in several models. In this study, the effect of combining celecoxib, a selective COX-2 inhibitor, and anastrozole, an aromatase inhibitor, on the implantation and growth of endometriotic like lesions in a murine model of endometriosis was evaluated. Endometriosis was surgically induced in female BALB/c mice. After 28 days of treatment with celecoxib, anastrozole, or their combination, animals were killed and lesions were counted, measured, excised, and fixed. Immunohistochemistry for proliferating cell nuclear antigen and CD34 was performed for assessment of cell proliferation and vascularization. TUNEL technique was performed for apoptosis evaluation. Celecoxib was the only treatment to significantly reduce the number of lesions established per mouse, their size and vascularized area. In addition, cell proliferation was significantly diminished and apoptosis was significantly enhanced by both individual treatments. When the therapies were combined, they reversed their effects. These results confirm that celecoxib and anastrozole separately decrease endometriotic growth, but when combined they might have antagonizing effects.

Proapoptotic, anti-cell proliferative, anti-inflammatory and anti-angiogenic potential of carnosic acid during 7,12 dimethylbenz[a]anthracene-induced hamster buccal pouch carcinogenesis

The present study has investigated the modulating effect of carnosic acid on the expression pattern of cell proliferative (proliferating cell nuclear antigen (PCNA) cyclin D1 and a transcription factor c-fos), apoptotic (p53, Bcl-2, Bax caspase -3 and 9), inflammatory (Nuclear factor kappa B (NFκB) and cyclooxygenase-2 (COX- 2) and angiogenic (vascular endothelial growth factor (VEGF) markers during 7,12-dimethylbenz[a]anthracene (DMBA)-induced hamster buccal pouch carcinogenesis. Oral tumors were developed in the hamsters buccal pouches by painting with 0.5% DMBA in liquid paraffin three times a week for 14 weeks. Hundred per cent tumour formation (well-differentiated squamous cell carcinoma) accompanied by deregulation in the above mentioned molecular markers was noticed in hamsters treated with DMBA alone (tumour bearing hamsters). Oral administration of carnosic acid at dose of 10mg/kg bw to hamsters treated with DMBA not only completely prevented the tumour formation, but also corrected the abnormalities in the expression pattern of molecular markers. The present study suggests that carnosic acid might have inhibited the tumour formation by exerting anti-cell-proliferative, anti-inflammatory, anti-angiogenic and apoptotic potential during DMBA-induced hamster buccal pouch carcinogenesis.

Multifaceted link between cancer and inflammation

Increasing evidence from epidemiological, preclinical and clinical studies suggests that dysregulated inflammatory response plays a pivotal role in a multitude of chronic ailments including cancer. The molecular mechanism(s) by which chronic inflammation drives cancer initiation and promotion include increased production of pro-inflammatory mediators, such as cytokines, chemokines, reactive oxygen intermediates, increased expression of oncogenes, COX-2 (cyclo-oxygenase-2), 5-LOX (5-lipoxygenase) and MMPs (matrix metalloproteinases), and pro-inflammatory transcription factors such as NF-κB (nuclear factor κB), STAT3 (signal transducer and activator of transcription 3), AP-1 (activator protein 1) and HIF-1α (hypoxia-inducible factor 1α) that mediate tumour cell proliferation, transformation, metastasis, survival, invasion, angiogenesis, chemoresistance and radioresistance. These inflammation-associated molecules are activated by a number of environmental and lifestyle-related factors including infectious agents, tobacco, stress, diet, obesity and alcohol, which together are thought to drive as much as 90% of all cancers. The present review will focus primarily on the role of various inflammatory intermediates responsible for tumour initiation and progression, and discuss in detail the critical link between inflammation and cancer.

Multiple roles of dihomo-γ-linolenic acid against proliferation diseases

Considerable arguments remain regarding the diverse biological activities of polyunsaturated fatty acids (PUFA). One of the most interesting but controversial dietary approaches focused on the diverse function of dihomo-dietary γ-linolenic acid (DGLA) in anti-inflammation and anti-proliferation diseases, especially for cancers. This strategy is based on the ability of DGLA to interfere in cellular lipid metabolism and eicosanoid (cyclooxygenase and lipoxygenase) biosynthesis. Subsequently, DGLA can be further converted by inflammatory cells to 15-(S)-hydroxy-8,11,13-eicosatrienoic acid and prostaglandin E₁ (PGE₁). This is noteworthy because these compounds possess both anti-inflammatory and anti-proliferative properties. PGE1 could also induce growth inhibition and differentiation of cancer cells. Although the mechanism of DGLA has not yet been elucidated, it is significant to anticipate the antitumor potential benefits from DGLA.

Epidemiology of basal cell carcinoma

Basal cell carcinoma is the most common malignant neoplasm in humans and its incidence has increased over the last decades. Its high frequency significantly burdens the health system, making the disease a public health issue. Despite the low mortality rates and the rare occurrence of metastases, the tumor may be locally invasive and relapse after treatment, causing significant morbidity. Exposure to ultraviolet radiation is the main environmental risk factor associated with its cause. However, other elements of risk are described, such as light skin phototypes, advanced age, family history of skin carcinoma, light eyes and blond hair, freckles in childhood and immunosuppression. Behavioral aspects such as occupational sun exposure, rural labor and sunburns at a young age also play a role. Between 30% and 75% of the sporadic cases are associated with patched hedgehog gene mutation, but other genetic changes are also described. The tumor is commonly found in concomitance with skin lesions related to chronic sun exposure, such as actinic keratoses, solar lentigines and facial telangiectasia. The prevention of basal cell carcinoma is based on the knowledge of risk factors, early diagnosis and treatment, as well as on the adoption of specific measures, particularly in susceptible populations. The authors present a review of the epidemiology of basal cell carcinoma.