Cathepsin K expression is increased in oral lichen planus

Lichen Planus: What is New in Diagnosis and Treatment?

Lichen planus (LP), an idiopathic, multifaceted chronic inflammatory disease with a heterogeneous clinical presentation, affects approximately 0.5-1% of the population. The various clinical manifestations of LP fall into three broad categories, namely cutaneous, appendageal, and mucosal, with further subclassification depending on the morphology and distribution patterns of individual lesions. There is mounting evidence that LP has systemic associations, including autoimmune conditions, glucose intolerance, dyslipidemia, and cardiovascular disorders. Cutaneous hypertrophic and mucosal forms of LP are at a heightened risk for malignant transformation. Familiarity with these potential associations in conjunction with long-term follow-up and regular screening could lead to a timely diagnosis and management of concomitant conditions. In addition, the frequent quality of life (QoL) impairment in LP underscores the need for a comprehensive approach including psychological evaluation and support. Several treatment strategies have been attempted, though most of them have not been adopted in clinical practice because of suboptimal benefit-to-risk ratios or lack of evidence. More recent studies toward pathogenesis-driven treatments have identified Janus kinase inhibitors such as tofacitinib, phosphodiesterase-4 inhibitors such as apremilast, and biologics targeting the interleukin-23/interleukin-17 pathway as novel therapeutic options, resulting in a dramatic change of the treatment landscape of LP. This contemporary review focuses on the diagnosis and management of LP, and places emphasis on more recently described targeted treatment options.

Cathepsins in oral diseases: mechanisms and therapeutic implications

Cathepsins are a type of lysosomal globulin hydrolase and are crucial for many physiological processes, including the resorption of bone matrix, innate immunity, apoptosis, proliferation, metastasis, autophagy, and angiogenesis. Findings regarding their functions in human physiological processes and disorders have drawn extensive attention. In this review, we will focus on the relationship between cathepsins and oral diseases. We highlight the structural and functional properties of cathepsins related to oral diseases, as well as the regulatory mechanisms in tissue and cells and their therapeutic uses. Elucidating the associated mechanism between cathepsins and oral diseases is thought to be a promising strategy for the treatment of oral diseases and may be a starting point for further studies at the molecular level.

Lichen Planus

Lichen planus (LP) is a T cell-mediated disease affecting the stratified squamous epithelia of the skin and/or mucus membrane. Histologically, the disease is characterized by a lichenoid inflammatory infiltrate and vacuolar degeneration of the basal layer of the epidermis. LP has three major subtypes: Cutaneous, mucosal and appendageal LP. Rarely, it may affect the nails in the absence of skin and/or mucosal changes. LP may also be induced by several drugs, typically anti-hypertensive medication or be associated with infections, particularly viral hepatitis. The diagnosis is based on the clinical presentation and characteristic histological findings. Although the disease is often self-limiting, the intractable pruritus and painful mucosal erosions result in significant morbidity. The current first-line treatment are topical and/or systemic corticosteroids. In addition, immunosuppressants may be used as corticosteroid-sparing agents. These, however are often not sufficient to control disease. Janus kinase inhibitors and biologics (anti-IL-12/23, anti-IL17) have emerged as novel future treatment options. Thus, one may expect a dramatic change of the treatment landscape of LP in the near future.

Expression of Cathepsin B and Cystatin A in Oral Lichen Planus

Objective:

Cathepsin B (Cat-B), a cysteine protease, and cystatin A (Cys-A), a protease inhibitor, are involved in the immune response. This study determined Cat-B and Cys-A expression in oral lichen planus (OLP) by immunohistochemistry.

Materials and Methods:

Thirty specimens each of OLP and healthy gingiva (HG) were included. The expression pattern, the number of positive cells, the staining intensity, and the immunoreactive score (IRS) of Cat-B and Cys-A were investigated. The data were analyzed by using unpaired t-test, Chi-square, and Spearman’s rank correlation.

Results:

The Cat-B expression in OLP was observed as cytoplasmic staining in the epithelial cells, whereas Cys-A expression was exhibited in the nucleus and cytoplasm of the epithelium. An increase in Cat-B staining intensity was also observed in the basal cells. Conversely, the high staining intensity of Cys-A was observed in the stratum spinosum, but not the stratum basale. In HG, Cat-B expression demonstrated a relatively consistent intensity in the epithelial layer. The Cys-A expression in HG was similar to OLP with a lower staining intensity. The mean percentage of positive cells and the IRS score of Cat-B and Cys-A in OLP were significantly higher than HG (P < 0.05). There was no correlation between Cat-B and Cys-A levels in OLP. Interestingly, Cat-B expression in erosive OLP was greater than in non-erosive OLP (P < 0.05).

Conclusion:

The Cat-B and Cys-A expression in OLP was more outstanding than in HG, suggesting possible roles for the process of OLP pathogenesis. In addition, Cat-B expression may be an indicator of the disease severity.

Cathepsin K associates with lymph node metastasis and poor prognosis in oral squamous cell carcinoma

Background

Lymph node metastasis (LNM) is a major determinant of prognosis and treatment planning of oral squamous cell carcinoma (OSCC). Cysteine cathepsins constitute a family of proteolytic enzymes with known role in the degradation of the extracellular matrix. Involvement in pathological processes, such as inflammation and cancer progression, has been proved. The aim of the study was to discover the clinicopathological and prognostic implications of cathepsin K (CTSK) expression in oral squamous cell carcinoma.

Methods

Eighty-three patients with primary OSCC, treated surgically between 1996 and 2000, were included. Gene expression data were acquired from a previously reported study. Human papilloma virus (HPV) status was previously determined by an algorithm for HPV-16. CTSK Protein expression was semi-quantitatively determined by immunohistochemistry in tumor and stromal cells. Expression data were correlated with various clinicopathological variables.

Results

Elevated gene and protein expression of CTSK were strongly associated to LNM and perineural invasion (p < 0.01). Logistic regression analysis highlighted increased CTSK protein expression in tumor cells as the most significant independent factor of lymphatic metastasis (OR = 7.65, CI:2.31–23.31, p = 0.001). Survival analysis demonstrated CTSK protein expression in both stromal and tumor cells as significant indicators of poor 5-year disease specific survival (HR = 2.40, CI:1.05–5.50, p = 0.038 for stromal cells; HR = 2.79, CI:1.02–7.64, p = 0.045 for tumor cells).

Conclusion

Upregulation of CTSK seems to be associated with high incidence of lymphatic spread and poor survival in OSCC. CTSK could therefore serve as a predictive biomarker for OSCC.

Electronic supplementary material

The online version of this article (10.1186/s12885-018-4315-8) contains supplementary material, which is available to authorized users.

Cathepsin K modulates invasion, migration and adhesion of oral squamous cell carcinomas in vitro

OBJECTIVE

Cathepsin K was initially discovered as an osteoclast-specific cysteine proteinase, but the enzyme is also expressed in various cancers including oral squamous cell carcinomas. This study aimed to clarify the function of cathepsin K in oral squamous cell carcinomas.

MATERIALS AND METHODS

Expression levels of cathepsin K were examined in six types of cell carcinomas. Carcinomas overexpressing cathepsin K were constructed. Effects of cathepsin K overexpression and treatment with odanacatib, a specific cathepsin K inhibitor, on cell invasion, migration and adhesion were analysed.

RESULTS

Different levels of cathepsin K were expressed in carcinomas. Cathepsin K was predominantly localised in lysosomes. Cathepsin K overexpression impaired the proliferation of carcinomas. Invasion analysis showed that cathepsin K overexpression enhanced invasion and migration of carcinomas, whereas inhibition of cathepsin K by odanacatib caused the opposite effects in carcinomas. Cathepsin K overexpression also increased cell adhesion and slightly increased surface expression of the adhesion receptor CD29/integrin β₁ .

CONCLUSIONS

The enhanced invasion of carcinomas resulting from cathepsin K overexpression is probably due to the increased cell migration and adhesion. Thus, cathepsin K is implicated not only in protein degradation but also in invasion, migration and adhesion of oral squamous cell carcinomas.