Endothelins and their receptors as biological markers for oral cancer

Assessment of salivary endothelin-1 in patients with leukoplakia, submucous fibrosis, oral cancer and healthy individuals - a comparative study

BACKGROUND

Oral cancer is one of the highly prevalent cancers worldwide being. According to data of GLOBOCAN 2018, the estimated incidence, mortality and 5-year survival rates due to lip, oral cavity and salivary gland cancer in world is (2.0%), (0.5%) and (0.3%) respectively. (Bray, Ferlay and Soerjomataram, 2018). Endothelin-1 (ET-1) is a 21-amino acid peptide; its receptors have been implicated in the growth and progression of both primary and metastatic neoplasms throughout the human body. Studies have shown that ET-1 is expressed in tissue, serum and other body fluids.

AIM

To estimate the levels of salivary endothelin-1 in Oral potentially malignant disorders (oral leukoplakia and submucous fibrosis) and oral squamous cell carcinoma.

MATERIALS AND METHODS

The study population included 60 subjects and were divided into 4 groups. All patients included in the study are clinically and histopathological diagnosed cases of oral leukoplakia, submucous fibrosis and oral cancer and assessed for salivary ET-1 levels using human ELISA kit. Significant differences between the groups were determined using one-way analysis of variance, LSD and Post HOC, unpaired t test, biserial and spearson's correlation.

RESULTS

The mean levels of salivary Endothelin-1 level in study groups were: 82.78 ± 5.9 pg/mL (OSCC), 65.02 ± 1.8 pg/mL (SMF), 57.76 ± 4.1 pg/mL (LEUKOPLAKIA), 29.72 ± 14.1 pg/mL (CONTROLS). The mean Salivary ET-1 levels among these four groups was compared and the difference was statistically significant (P < 0.001). We also found a significant difference in the means of ET-1 levels among the clinical and histopathological staging of the study groups.

CONCLUSION

Our results demonstrate potential utility of salivary analysis for ET-1 levels to monitor patients at risk for OSCC. Although provides the basis for a larger prospective study to determine the critical levels of salivary ET-1 necessary to diagnose and monitor OPMD's and its potential to undergo malignant transformation.

Clinicopathological Significance of the ET Axis in Human Oral Squamous Cell Carcinoma

The interaction between cancer cells and the surrounding microenvironment in malignant tumor tissue is known to be closely associated with cancer cell invasion and proliferation. Endothelin (ET) present in the microenvironment surrounding tumors has been reported to play a role in cancer cell invasion and proliferation by binding to receptors on the cell membrane of cancer cells. Here, we immunohistologically detected the expression of ET-1 and its receptor ET_AR in oral squamous cell carcinoma (OSCC) and evaluated the association between the expression of each as well as their co-expression (ET-axis expression) and clinicopathological factors. A significant difference was observed between the invasion pattern as a parameter of cancer cell malignancy and the expressions of ET-1 and ET_AR. The survival rates were significantly lower among the patients who were strongly positive for ET-1 and the ET_AR-positive patients compared to negative patients. There was also a significant difference between ET-axis expression and the degree of histological differentiation and mode of invasion, and the survival rate of the positive cases was significantly lower than that of the negative cases. Our findings suggested that ET-axis assessments are important for assessing the malignancy of cancer cells and predicting the prognoses of OSCC patients.

ECE-1 overexpression in head and neck cancer is associated with poor tumor differentiation and patient outcome

BACKGROUND

Endothelin-converting enzyme-1 (ECE-1) primarily converts big endothelins (ETs) into active endothelin-1 (ET-1). However, the expression pattern and prognostication status of ECE-1 in head and neck cancer (HNC) are enigmatic. In this study, we investigated ECE-1 expression and assessed the roles of ECE-1 as a predictor for HNC differentiation and prognosis.

MATERIALS AND METHODS

ECE-1 expressions were evaluated by immunohistochemical analysis using a tissue microarray (TMA) composed of 100 cases of head and neck squamous cell carcinoma. The correlation of ECE-1 expression with clinicopathologic variables and patient outcomes was analyzed.

RESULTS

ECE-1 may be overexpressed in HNC carcinoma cells. Higher ECE-1 level was detected more frequently in moderately to poorly differentiated tumors and showed a lower differentiation category compared to the G1 cases (p = 0.015); this finding was further confirmed by an adjusted odds ratio (OR) of 4.071 (p = 0.042). Moreover, Kaplan-Meier survival analyses showed that a higher ECE-1 expression was associated with a poorer survival in patients with HNC (p < 0.0001). On multivariate Cox proportional hazards models analysis, ECE-1 of high expression proved to be an independent prognostic factor with a hazard ratio (HR) of 3.985 (p < 0.001).

CONCLUSION

Our data provide the first evidence that overexpression of ECE-1 in HNC is a predictor of poor tumor differentiation and prognosis.

Early detection and personalized treatment in oral cancer: the impact of omics approaches

BACKGROUND

Oral cancer is one of the most common malignant lesions of the head and neck. This cancer is an aggressive and lethal disease with no significant improvements in the overall survival in the last decades. Moreover, the incidence of oral HPV-positive tumors is rising, especially in young people. This oral neoplasm develops through numerous molecular imbalances that affect key genes and signaling pathways; however, the molecular mechanisms involved in the pathogenesis and progression of oral tumors are still to be fully determined. In order to improve the quality of life and long-term survival rate of these patients, it is vital to establish accurate biomarkers that help in the early diagnosis, prognosis and development of target treatments. Such biomarkers may possibly allow for selection of patients that will benefit from each therapy modality, helping in the optimization of intensity and sequence of the treatments in order to decrease side effects and improve survival.

CONCLUSION

In this review we discuss the current knowledge of oral cancer and the potential role of omics approaches to identify molecular biomarkers in the improvement of early diagnosis, treatment and prognosis. The pursuit to improve the quality of life and decrease mortality rates of the oral patients needs to be centralized on the identification of critical genes in oral carcinogenesis. Understanding the molecular biology of oral cancer is vital for search new therapies, being the molecular-targeted therapies the most promising treatment for these patients.

Role of endothelin receptor signalling in squamous cell carcinoma

Endothelin plays important roles in various physiological functions including vascular constriction. Recent studies reported that the endothelin receptors ETA and ETB are highly expressed in lung and skin tumor tissues. In contrast, there are few reports on endothelin signalling in the proliferation of head and neck cancer. We found that both ETA and ETB endothelin receptors were overexpressed in tumor cells of tongue cancer samples by immunohistochemistry. ETA and ETB were expressed in cultured lingual and esophageal squamous cell carcinoma (SCCs) cell lines. When both cultured cell lines were treated with an ETA selective antagonist (BQ123) or an ETB selective antagonist (BQ788), inhibition of cell growth was observed. Similar results were observed when SCCs were treated with specific siRNA for the suppression of ETA or ETB. Furthermore, inhibition of the mitogen-activated protein (MAP) kinase pathway by the treatments with ET receptor antagonists and siRNA was also observed. These results indicate that endothelin signalling may, in part, play important roles in cell growth in SCCs through the MAP kinase pathway.

Significance of serum butyrylcholinesterase levels in oral cancer

BACKGROUND

Oral squamous cell carcinoma (OSCC) is a relatively common epithelial malignancy, and thus represents a significant public health problem. Early detection improves quality of life for affected patients. Identification of molecular markers (or biomarkers) which can predict disease progression is necessary for better management of these disorders. A correlation of cholinesterase with tumourigenesis, cell proliferation and cell differentiation has been observed. Butyrylcholinesterase (BChE; pseudocholinesterase) has been shown to be a biochemical marker for cervical cancer which is also an epithelial malignancy. In this study, we sought to estimate and compare serum BChE levels in healthy controls and patients with biopsy-proven oral squamous cell cancer (also an epithelial malignancy) before definitive therapy as radiotherapy or chemotherapy may alter the levels of BChE and may act as a confounding variable.

METHOD

After obtaining consent from biopsy proven oral cancer patients (n= 39) (before onset of any definitive treatment), and from age- and sex-matched healthy controls (n = 20), 2ml of blood was collected. After clot formation samples were centrifuged, serum was collected for estimation of BChE.

RESULTS

Pre-treatment serum BChE levels were significantly elevated (p < 0.0001) in oral cancer patients compared to that of controls. BChE levels showed a significant increase (p = 0.005) with advancing stage in oral cancer patients.

CONCLUSION

Our results show there could be a role for serum BChE in determining the prognosis of oral cancer.