Expression of COX-2 and bcl-2 in oral lichen planus lesions and lichenoid reactions

Erosive oral lichen planus inflicts higher cellular stress than reticular type

BACKGROUND

Lichen planus is a chronic inflammatory mucocutaneous disease which frequently involves the oral mucosa. The most common types of oral lichen planus (OLP) are reticular (asymptomatic) and erosive (ulcerative) with malignant potentiality. The aims of the present study are to assess the cellular stress level in both types of OLP lesions with respect to oxidative stress, DNA damage and inflammation.

MATERIALS AND METHODS

Freshly diagnosed untreated 25 OLP reticular type and 25 OLP erosive (OLP-E) type patients aged 35-55 years were enrolled in the study along with age and sex-matched 25 healthy subjects as control. Tissue antioxidant enzymes were measured biochemically, single-cell DNA damage was measured by comet assay and the molecular markers for inflammation were assessed by using semi-quantitative reverse transcriptase-polymerase chain reaction. Statistical analyses were performed using one-way ANOVA and Tukey's post hoc test.

RESULTS

Oxidative stress was significantly greater in OLP-E type compared to the reticular. mRNA expression of cyclooxygenase-2 was significantly elevated (P < 0.0001) in erosive form, but such expression of nuclear factor kappa beta, tumor necrosis factor-alpha, Interleukin-6 and inducible nitric oxide synthase did not significantly differ between the two disease groups. Comet assay revealed a higher degree of DNA strand breakage in erosive lesions.

CONCLUSIONS

The unhandled free radicals may imbalance the homeostatic network toward pro-inflammatory, DNA damaging responses, creating a vicious cell-damaging spree resulting in stress. Molecular analyses showed that erosive lichen planus is more under stress than the reticular form.

Synergistic Effects of Curcumin and 5-Fluorouracil on the Hepatocellular Carcinoma In vivo and vitro through regulating the expression of COX-2 and NF-κB

Curcumin (CU) has shown broad anti-cancer effects. 5-fluorouracil (5-FU) has been a conventional chemotherapeutic agent for hepatocellular carcinoma. Unfortunately, the nonspecific cytotoxicity and multidrug resistance caused by long-term use limited the clinical efficacy of 5-FU. This study was aimed to investigate whether the combination of CU and 5-FU could generate synergistic effect in inhibiting the human hepatocellular carcinoma. The results of cytotoxicity test showed that compared with applying single drugs, the combination of CU and 5-FU (1:1, 1:2, 1:4, 2:1 and 4:1, mol/mol) presented stronger cytotoxicity in SMMC-7721, Bel-7402, HepG-2 and MHCC97H cells, while the combination groups are relatively insensitive to normal hepatocytes (L02). Among them, the molar ratio of 2:1 combination group showed strong synergistic effect in SMMC-7721cells. Then, western blotting assay further verified that the mechanism of the synergistic effect may be related to the inhibition of the expression of NF-κB (overall) and COX-2 protein. In addition, the synergistic effect was also validated in the xenograft mice in vivo. This research not only provides a novel and effective combination strategy for the therapy of hepatocellular carcinoma but also provides an experimental basis for the development of CU and 5-FU compound preparation.

Expression of Ki-67, p53, α-SMA and COX-2 in lichen planus and related lesions: A pilot study

Background

Researchers have struggled to understand the natural history of lesions presenting with both lichenoid features and epithelial dysplasia. Thus the present study was designed to differentiate between OLP, OLP with dysplasia, epithelial dysplasia and epithelial dysplasia with lichenoid features based on the expressions of ki-67, p53, COX-2, and α-SMA.

Materials and methods

Formalin-fixed paraffin-embedded archival specimens of OLP, OLP with dysplasia, epithelial dysplasia and epithelial dysplasia with lichenoid features were subjected to immunohistochemical staining with ki-67, p53, COX-2, and α-SMA.

Results

Ki-67 exhibited strong positivity in 100% (6/6) of epithelial dysplasia cases, 71.4% (5/7) of lichenoid dysplasia cases, 57.1% (4/7) of OLP cases and 60% (3/5) of OLP with dysplasia cases. Strong p53 staining was evident in more cases of lichenoid dysplasia [42.8% (3/7)], while moderate staining was more frequent in OLP cases [42.8% (3/7)] and OLP with dysplasia cases [42.8% (3/7)] and mild intensity was more frequent in epithelial dysplasia cases [50% (3/6)] followed by lichenoid dysplasia cases [42.8% (3/7)], OLP cases [28.5 (2/7)] and OLP with dysplasia cases [40% (2/5)]. COX-2 strong positivity was more frequent in cases of epithelial dysplasia cases [57.1% (4/7)] and OLP [50% (3/6)]. Strong α- SMA staining was noted more frequently in lichenoid dysplasia cases [71.4 (5/7)], followed by OLP cases [42.8% (3/7)] and OLP with dysplasia cases [60% (3/5)].

Conclusions

Ki-67, p53, α-SMA and COX-2 expression do not differentiate between OLP, LP with dysplasia and epithelial dysplasia with lichenoid features.

Differential metallothionein expression in oral lichen planus and amalgam-associated oral lichenoid lesions

Background

Oral lichen planus (OLP) is a chronic inflammatory disease mediated by T cells, which manifests as reticular (white) or erosive (red) lesions, that are eventually painful. Oral lichenoid lesion (OLL) are distinguished from OLP by the presence of precipitating factors. The aim of this study was to evaluate whether the presence of metallothionein, which is involved in anti-apoptotic pathways and the anti-oxidative response, could serve as a differential diagnostic for OLP and OLL.

Material and Methods

We evaluated the expression of metallothionein in 40 cases of OLP and 20 cases of OLL using immunohistochemistry.

Results and Conclusions

White OLP has higher concentrations of metallothionein than red OLP in basal and parabasal layers. Moreover, metallothionein was more frequently observed in the cytoplasm and nuclei of basal cells in OLP patients compared to the same regions of OLL cases. Metallothionein levels are related to OLP severity and may contribute to a differential diagnosis between OLP and OLL.

Key words:Oral lichen planus, oral lichenoid lesions, autoimmune disorders, metallothionein, immunohistochemistry.

Increased cyclooxygenase 2 expression in association with oral lichen planus severity

Background/purpose

Although some studies have shown induction of cyclooxygenase 2 (COX-2) in oral lichen planus (OLP), an association between COX-2 upregulation and OLP clinical severity has not been investigated. Therefore, we aimed to compare COX-2 expression in OLP with that in normal oral tissues, and to determine correlations between COX-2 expression and both clinical criteria and visual analog scale (VAS) scores.

Materials and methods

COX-2 expression was studied in 25 OLP and 13 normal oral tissues by immunohistochemistry. Both clinical criteria and VAS scores were used to evaluate the clinical severity of OLP. The differences in COX-2 expression between OLP and normal tissues, and the correlations between COX-2 expression and clinical severity were determined by the nonparametric statistical tests.

Results

COX-2 expression was significantly increased in OLP epithelium when compared with normal epithelium (P < 0.001), and intense COX-2 staining in inflammatory infiltrates was observed in the OLP lamina propria. COX-2 expression in OLP epithelium and inflammatory infiltrates was significantly correlated with the clinical criteria score (r = 0.428, P = 0.007, and r = 0.681, P < 0.001, respectively), whereas a significant correlation with the VAS score was observed only in OLP inflammatory infiltrates (r = 0.605, P < 0.001).

Conclusion

Enhanced COX-2 expression in both OLP epithelium and inflammatory infiltrates correlates well with the clinical severity. An association between VAS score and COX-2 expression in OLP inflammatory infiltrates suggests an important role of additional COX-2 expression from inflammation in causing pain in OLP patients.