Telomerase activity detected in oral lichen planus by RNA in situ hybridisation: not a marker for malignant transformation

MALT1 Protease Regulates T-Cell Immunity via the mTOR Pathway in Oral Lichen Planus

Oral lichen planus (OLP) is a T cell-mediated immune mucosal disease of unknown pathogenesis. Whether mucosa-associated lymphoid tissue lymphoma translocation protein 1 (MALT1), an intracellular signaling protein, is involved in the T-cell immune dysfunction of OLP remains elusive. MALT1 expression in local and peripheral T cells of OLP and controls was analyzed using immunohistochemistry, multiplex immunohistochemistry, and flow cytometry. The expression of MALT1 in activated Jurkat T cells incubated with either OLP plasma or interleukin (IL)-7/IL-15 was determined by flow cytometry. The effects of MALT1 and mechanistic target of rapamycin (mTOR) on T-cell immunity were investigated through western blot, CCK8 assay, and flow cytometry. The expression of MALT1 protein was elevated in local OLP T cells and mucosal-associated invariant T (MAIT) cells, while reduced in peripheral OLP T cells, MAIT cells, and follicular helper-like MAIT (MAITfh) cells. Stimulation with OLP plasma and IL-7/ IL-15 had no effect on MALT1 expression in activated Jurkat T cells. MALT1 protease-specific inhibitor (MI-2) induced mTOR phosphorylation, increased B-cell lymphoma 10 (BCL10) expression, inhibited T-cell proliferation, and promoted T-cell apoptosis. The combination of MI-2 and rapamycin increased MALT1 expression, further suppressed T-cell proliferation, and facilitated T-cell apoptosis. MALT1 expression is aberrant in both local lesions and peripheral blood of OLP. Inhibition of the mTOR pathway further enhances the suppression of T-cell proliferation and the promotion of apoptosis induced by the MALT1 inhibitor MI-2.

Evaluation of Potential Risk Factors that contribute to Malignant Transformation of Oral Lichen Planus: A Literature Review

AIM

Many studies have suggested that a lesion originally diagnosed as oral lichen planus (OLP) has different possibilities of undergoing malignant transformation in time, although these findings remain a controversial issue; for example, some studies reported different values of potential malignancy of OLP.

INTRODUCTION

World Health Organization (WHO) classifies OLP as a "potentially malignant disorder" with unspecified malignant transformation risk, and suggests that OLP patients should be closely monitored. Numerous studies have attempted to confirm the malignant transformation potential of OLP.

REVIEW RESULTS

The Cochrane Controlled Trials Register, Medline and EMBASE databases, PubMed, Google Scholar, Ovid, Up To Date, BMJ Clinical Evidence, MD Consult, and Science Direct were searched for papers published between 1997 and 2015. The medical subject heading search terms were "lichen planus," "oral lichen planus," "erosive oral lichen planus," "dysplasia," "oral precancerous condition," "oral premalignant condition," oral cancer, oral squamous cell carcinoma (OSCC), and atrophic lichen planus. A total of 120 English language abstracts were reviewed, and 50 relevant articles identified. Because of the extensive literature on the association between OLP and SCC, we have divided the data into genetic and non-genetic factors for more accurate assessment.

CONCLUSION

In this evidence base, malignant transformation ranges from 0 to 37% with a mean of 4.59%. The highest rate of malignancy was noted in erythematosus and erosive lesions. In this way, follow-up of OLP patients could be carried out more efficiently and appropriately.

CLINICAL SIGNIFICANCE

Oral lichen planus is a premalignant lesion. All types of OLP in any site of oral mucosa must be monitored regularly.

Diagnosis of oral lichen planus: a position paper of the American Academy of Oral and Maxillofacial Pathology

Despite being one of the most common oral mucosal diseases and recognized as early as 1866, oral lichen planus (OLP) is still a disease without a clear etiology or pathogenesis, and with uncertain premalignant potential. More research is urgently needed; however, the research material must be based on an accurate diagnosis. Accurate identification of OLP is often challenging, mandating inclusion of clinico-pathological correlation in the diagnostic process. This article summarizes current knowledge regarding OLP, discusses the challenges of making an accurate diagnosis, and proposes a new set of diagnostic criteria upon which to base future research studies. A checklist is also recommended for clinicians to provide specific information to pathologists when submitting biopsy material. The diagnostic process of OLP requires continued clinical follow-up after initial biopsy, because OLP mimics can manifest, necessitating an additional biopsy for direct immunofluorescence study and/or histopathological evaluation in order to reach a final diagnosis.

Telomerase activity impacts on Epstein-Barr virus infection of AGS cells

The Epstein-Barr virus (EBV) is transmitted from host-to-host via saliva and is associated with epithelial malignancies including nasopharyngeal carcinoma (NPC) and some forms of gastric carcinoma (GC). Nevertheless, EBV does not transform epithelial cells in vitro where it is rapidly lost from infected primary epithelial cells or epithelial tumor cells. Long-term infection by EBV, however, can be established in hTERT-immortalized nasopharyngeal epithelial cells. Here, we hypothesized that increased telomerase activity in epithelial cells enhances their susceptibility to infection by EBV. Using HONE-1, AGS and HEK293 cells we generated epithelial model cell lines with increased or suppressed telomerase activity by stable ectopic expression of hTERT or of a catalytically inactive, dominant negative hTERT mutant. Infection experiments with recombinant prototypic EBV (rB95.8), recombinant NPC EBV (rM81) with increased epithelial cell tropism compared to B95.8, or recombinant B95.8 EBV with BZLF1-knockout that is not able to undergo lytic replication, revealed that infection frequencies positively correlate with telomerase activity in AGS cells but also partly depend on the cellular background. AGS cells with increased telomerase activity showed increased expression mainly of latent EBV genes, suggesting that increased telomerase activity directly acts on the EBV infection of epithelial cells by facilitating latent EBV gene expression early upon virus inoculation. Thus, our results indicate that infection of epithelial cells by EBV is a very selective process involving, among others, telomerase activity and cellular background to allow for optimized host-to-host transmission via saliva.

Expression of human DNA mismatch-repair protein, hMSH2, in patients with oral lichen planus

hMSH2 is one of the human DNA mismatch repair genes that plays an important role in reducing mutations and maintaining genomic stability. The aim of the present study was to detect the expression and significance of hMSH2 protein in patients with oral lichen planus (OLP). The expression levels of hMSH2 in the OLP group (n=51) and control group with normal oral mucosa (NM; n=40) were detected using an immunohistochemical method and subsequently assessed. The positive rate of hMSH2 expression in the OLP group was 52.94%, while the rate was 80% in the control group, exhibiting a statistically significant difference (χ²=7.1993; P<0.05). However, the expression of hMSH2 in the OLP tissues was not shown to significantly correlate with the patient gender, age and type of OLP (P>0.05). In conclusion, the protein expression levels of hMSH2 in the OLP tissues were significantly reduced as compared with that in the NM tissues, indicating that hMSH2 plays a role in the development of OLP. Therefore, hMSH2 may be used as a biomarker for evaluating the cancer risk of patients with OLP.

Gene expression based evidence of innate immune response activation in the epithelium with oral lichen planus

OBJECTIVE

Oral lichen planus (OLP) is a disease of the oral mucosa of unknown cause producing lesions with an intense band-like inflammatory infiltrate of T cells to the subepithelium and keratinocyte cell death. We performed gene expression analysis of the oral epithelium of lesions in subjects with OLP and its sister disease, oral lichenoid reaction (OLR), in order to better understand the role of the keratinocytes in these diseases.

DESIGN

Fourteen patients with OLP or OLR were included in the study, along with a control group of 23 subjects with a variety of oral diseases and a normal group of 17 subjects with no clinically visible mucosal abnormalities. Various proteins have been associated with OLP, based on detection of secreted proteins or changes in RNA levels in tissue samples consisting of epithelium, stroma, and immune cells. The mRNA level of twelve of these genes expressed in the epithelium was tested in the three groups.

RESULTS

Four genes showed increased expression in the epithelium of OLP patients: CD14, CXCL1, IL8, and TLR1, and at least two of these proteins, TLR1 and CXCL1, were expressed at substantial levels in oral keratinocytes.

CONCLUSIONS

Because of the large accumulation of T cells in lesions of OLP it has long been thought to be an adaptive immunity malfunction. We provide evidence that there is increased expression of innate immune genes in the epithelium with this illness, suggesting a role for this process in the disease and a possible target for treatment.

Salivary interleukin-6 and -8 in patients with oral cancer and patients with chronic oral inflammatory diseases

BACKGROUND

Previous research has indicated that salivary interleukin (IL)-6 and IL-8 are potential biomarkers for oral squamous cell carcinoma (OSCC). However, their levels have been found to be significantly elevated in patients with chronic periodontitis (CP) or oral lichen planus (OLP). The data also showed wide variations in levels among the different studies, and no standardization procedure was ever performed. Therefore, the objective of this study is to determine whether CP or OLP confounds the use of IL-6 or IL-8 for OSCC detection.

METHODS

Saliva samples were collected from five groups: OSCC before treatment (n = 18); CP (n = 21); disease-active OLP (n = 21); disease-inactive OLP (n = 20); and healthy controls (n = 21). IL-6 and IL-8 concentrations (determined by enzyme-linked immunosorbent assays) were compared, using total salivary protein-standardized levels to validate the data. The Kruskal-Wallis test (α = 0.05) followed by pairwise Mann-Whitney U (post hoc) tests with Bonferroni adjustments (α = 0.00625) were used for statistical analysis.

RESULTS

Salivary IL-6 levels were significantly higher in patients with OSCC than in patients with CP (P <0.001), disease-active OLP (P = 0.001), disease-inactive OLP (P <0.001), and healthy controls (P <0.001). Salivary IL-8 levels were significantly higher in patients with OSCC than in patients with CP (P <0.001), but only marginally significantly higher than in healthy controls (P = 0.014). Statistical results of standardized IL-6 and IL-8 levels were consistent with the non-standardized levels in all pairs except one.

CONCLUSION

Salivary IL-6 may be a useful biomarker in the detection of OSCC, unconfounded by CP or OLP.

Chromosomal Numerical Aberrations in Oral Lichen Planus

The malignant potential of oral lichen planus (OLP) has been a matter of serious controversy. We aimed to detect chromosomal numerical aberrations in cells of brush samples collected from affected mucosa. The samples were simultaneously analyzed for morphology and fluorescent in situ hybridization (FISH) with chromosomes 2 and 8 centromeric probes. We analyzed 57 persons with OLP and 33 control individuals. A cut-off value of aneuploid cells was determined as 1.1%. Aneuploid cells were found in 16 persons with OLP (28.1%); in 10 individuals (17.5%), over 5% of the cells were aneuploid. Aneuploid cells were also detected in normal-looking mucosa of seven persons with OLP. One person with OLP developed squamous cell carcinoma; 10% of the cells examined were aneuploid. OLP carries an increased risk for chromosomal instability. Identifying aneuploid cells in a brush sample and the combined morphological and FISH analysis can increase the specificity in predicting the malignant potential of OLP.

Molecular genetics of premalignant oral lesions

Oral squamous cell carcinoma (OSCC) is characterized by cellular and subcellular alterations that are associated with a progression towards dedifferentiation and growth. There are several histologically distinct lesions of the oral cavity which have malignant potential. These are leukoplakia, erythroplakia, lichen planus, and submucous fibrosis. These are characterized by a spectrum of chromosomal, genetic, and molecular alterations that they share with each other as well as with the malignant lesions that develop from them. In this review we summarize the investigation of the molecular genetics of each of these lesions and relate them to the alterations, which have been demonstrated in OSCC, to define their location on the continuum of changes, which lead to malignant transformation.

Telomerase: is it the future diagnostic and prognostic tool in human cancer?

A number of methods exist to detect levels of telomerase activity and the presence of telomerase subunits in a variety of tissues. As telomerase activation seems to be an important step in tumorigenesis, accurate detection of the presence and activity of the enzyme and its subunits is vital. The original method of detecting telomerase activity was developed by Kim and coworkers in 1994, and was termed the telomeric repeat amplification protocol. This assay led to a staggering increase in the number of telomerase-associated publications in scientific journals (85 publications from 1974-1994, 5063 publications from 1994-2004). A number of methods have been described to detect telomeres and to measure their length, with the standard measurement of telomere length performed using a modification of the Southern blot protocol. RNA in situ hybridization can be performed to detect levels of the RNA component of telomerase, and standard in situ hybridization and immunohistochemistry can be applied to examine expression levels and localization of the catalytic subunit of the enzyme. Reverse transcriptase PCR has also been applied to assess expression levels of the telomerase components in various tissues. This review provides a synopsis of telomeres, telomerase, telomerase and cancer, and finally, methods for the detection of telomerase in cancer.

The feasibility of monitoring NF-kappaB associated cytokines: TNF-alpha, IL-1alpha, IL-6, and IL-8 in whole saliva for the malignant transformation of oral lichen planus

Previous investigations have demonstrated that immune activation and chronic inflammation may be one of the causes of oncogenesis. A previous study from our lab has shown significant increases of NF-kappaB dependent cytokines, TNF-alpha, IL-1alpha, IL-6, and IL-8 in different oral fluids from oral lichen planus (OLP) patients. The aim of this analysis was to explore the potential of detecting these cytokines in whole unstimulated saliva (WUS) in monitoring the malignant transformation of OLP. Thirteen patients with OLP (with epithelial dysplasia), 13 cases with oral squamous cell carcinoma (OSCC), and 13 age-sex matched controls were enrolled in the study. The WUS samples were collected and the level of TNF-alpha, IL-1alpha, IL-6, and IL-8 in WUS was determined by ELISA. In moderate and severe dysplasia, the level of each cytokine was significantly higher than in control. In moderate dysplasia, TNF-alpha and IL-1alpha were significantly increased at a level without difference from OSCC, but IL-6 and IL-8 was detected at a concentration significantly lower than OSCC. In severe dysplasia, the level of TNF-alpha was also not significantly different from that of OSCC, and the level of IL-1alpha, IL-6, and IL-8 was still significantly lower than that of OSCC. The level of four cytokines between smokers and non-smokers in each group did not show a significant difference. These results indicate that the change of NF-kappaB dependent cytokines in WUS may in part reflect the malignant transformation of OLP and the analysis of these cytokines and may provide a useful, non-invasive surrogate endpoint for monitoring malignant transformation as well as the therapeutic response of OLP. This is the first in vivo study utilizing saliva to confirm preclinical data that NF-kappaB is upregulated in oral carcinogenesis.

Oral lichen planus part II: therapy and malignant transformation

Oral lichen planus lesions can cause discomfort, pain, and a burning sensation. Therefore, all professionals who deal with the oral cavity must be aware of all the therapeutic options for it. This article presents a review of the literature on oral lichen planus, focusing on its treatment, and also discusses the important and controversial potential for the evolution of oral lichen planus into epidermoid carcinoma.