Biological characteristics of a cell subpopulation in tongue squamous cell carcinoma

Molecular signaling in cancer stem cells of tongue squamous cell carcinoma: Therapeutic implications and challenges

Head and neck squamous cell carcinoma is the seventh most common cancer worldwide with high mortality rates. Amongst oral cavity cancers, tongue carcinoma is a very common and aggressive oral cavity carcinoma. Despite the implementation of a multimodality treatment regime including surgical intervention, chemo-radiation as well as targeted therapy, tongue carcinoma shows a poor overall 5-year survival pattern, which is attributed to therapy resistance and recurrence of the disease. The presence of a rare population, i.e., cancer stem cells (CSCs) within the tumor, are involved in therapy resistance, recurrence, and distant metastasis that results in poor survival patterns. Therapeutic agents targeting CSCs have been in clinical trials, although they are unable to reach into therapy stage which is due to their failure in trials. A more detailed understanding of the CSCs is essential for identifying efficient targets. Molecular signaling pathways, which are differentially regulated in the CSCs, are one of the promising targets to manipulate the CSCs that would provide an improved outcome. In this review, we summarize the current understanding of molecular signaling associated with the maintenance and regulation of CSCs in tongue squamous cell carcinoma in order to emphasize the need of the hour to get a deeper understanding to unravel novel targets.

Characterisation of a subpopulation of CD133+ cancer stem cells from Chinese patients with oral squamous cell carcinoma

Cancer stem cells (CSCs) play a critical role in cancer development and growth. The aim of this study was to identify and isolate CSCs from populations of primary oral squamous cell carcinoma (OSCC) cells, which were obtained from OSCC specimens and identified by cell morphology and immunohistochemical staining for keratin. CD133⁺ cells detected by flow cytometry comprised 0.41 ± 0.06% of primary OSCC cells and were isolated from primary OSCC cell populations using magnetic-activated cell sorting, revealing that 93.39% of high-purity CD133⁺ cells were in the G0/G1 phase of the cell cycle. Additionally, the growth rate of CD133⁺ cells was higher than that of CD133⁻ cells, and in vivo tumourigenesis experiments showed that the tumourigenic ability of CD133⁺ cells was markedly stronger than that of CD133⁻ cells. Moreover, CD133⁺ cells showed increased chemotherapeutic resistance to cisplatin and higher self-renewal ability according to sphere-formation assay, as well as higher mRNA levels of stemness-associated genes, including NANOG, SOX2, ALDH1A1, and OCT4. These results indicated that OSCC cells, which share certain characteristics of CSCs, harbour CD133⁺ cells potentially responsible for OSCC aggressiveness, suggesting CD133 as a potential prognostic marker and therapeutic target.

The current markers of cancer stem cell in oral cancers

Head and neck cancer (HNC) constitute 5% of all reported cancers. Among all, the oral cavity cancer is the most frequent type of HNC which accounts for over half of HNC cases. Mouth cancer ranks the sixth leading cause of cancer-related mortality. Generally, conventional chemotherapy has shown success at decreasing relapse and metastasis rates and improves the overall prognosis. Recently, target therapy and targeted drug delivery systems have been introduced as promising treatments. The elimination of efficiency of current therapeutic strategies due to the spared cancer stem cells that cause chemotherapy resistance, relapse and metastasis. Inefficiency methodologies in the elimination of all cancer cells in the body are a major problem that remained to be resolved before to confront the new cancer therapies. Many studies imply to cancer stem cell markers as important agents for targeted anti-cancer as well as improving chemotherapy efficiencies. The potentials of targeted cancer therapy led us to search for novel markers in the mouth cancer stem cells especially in rare cancers. The aimed of this research was, first a comprehensive critical review of the previous studies on the markers of cancer stem cells in oral cancers including oral squamous cell carcinoma, salivary gland cancers, and to highlight the most common cancer stem cell markers which have potential to be exploited as indicators for the preneoplastic lesion malignancy, oral cancer progression, and/or treatment prognosis.

Head and neck cancer management and cancer stem cells implication

Head and neck squamous cell carcinomas (HNSCCs) arise in the mucosal linings of the upper aerodigestive tract and are heterogeneous in nature. Risk factors for HNSCCs are smoking, excessive alcohol consumption, and the human papilloma virus. Conventional treatments are surgery, radiotherapy, chemotherapy, or a combined modality; however, no international standard mode of therapy exists. In contrast to the conventional model of clonal evolution in tumor development, there is a newly proposed theory based on the activity of cancer stem cells (CSCs) as the model for carcinogenesis. This “CSC hypothesis” may explain the high mortality rate, low response to treatments, and tendency to develop multiple tumors for HNSCC patients. We review current knowledge on HNSCC etiology and treatment, with a focus on CSCs, including their origins, identifications, and effects on therapeutic options.

The promise of stem cell markers in the diagnosis and therapy of epithelial dysplasia and oral squamous cell carcinoma

Oral squamous cell carcinoma (OSCC) is the most common type of head and neck cancer. Epithelial dysplasia is often initiated in the cells and cell nuclei adjacent to the epithelial cell membrane. Reduced cell-cell adhesions enable cancer cells to detach from the tumor and disseminate to other organs. The mutations in epithelial dysplasia markers such as E-cadherin and epithelial cell adhesion molecules (CD326) can lead to proliferation, growth and survival of the tumor cells and persistence of numerous malignancies that play a key role in epithelial dysplasia of OSCC. Accordingly, these genes can be considered prognostic markers or potential therapeutic targets for the tailored management of patients with OSCC. The gene expression profile of OSCC stem cells indicates a differential pattern that facilitates establishing a cell signature. Owing to the highly tumorigenic behavior of cancer stem cells and the role of these cells in tumor differentiation, treatment resistance, relapse, and metastasis, we reviewed the role of stem cell markers in epithelial dysplasia and OSCC.

[Clinical significance of CD44 and CD133 expression in oral potentially malignant disorder and oral squamous cell carcinoma]

OBJECTIVE

This study aims to investigate the expression and relationship of CD44 and CD133 in normal oral mucosa, oral potentially malignant disorder (OPMD), and oral squamous cell carcinoma (OSCC). This work also analyzes the relationship between such expression and clinical factors. This study intends to evaluate the clinical value of using CD44 and CD133 as indices to evaluate the carcinogenic potential of OPMD.

METHODS

Clinical data from 60 patients with OPMD, 60 patients with OSCC, and 10 cases of normal oral mucosa were analyzed. Double immunohistochemical analysis was applied to investigate the expression of CD44 and CD133 in paraffin sections of normal oral mucosa, OPMD, and OSCC tissues. Subsequently, the relationships between such expression and clinical factors were analyzed.

RESULTS

The positive rates of CD44 expression in the normal oral mucosa, OPMD, and OSCC tissues were 100.00%, 96.67%, and 71.67% (P<0.05), respectively. Meanwhile, the positive rates of CD133 expression in the normal oral mucosa, OPMD, and OSCC tissues were 0.00%, 35.00%, and 63.33% (P<0.05), respectively. The expression of CD44 and CD133 was found to be correlated (P<0.05). Such expression was related to the clinical stages and lymphatic metastasis of OSCC (P<0.05).

CONCLUSIONS

CD44 and CD133 can be used individually as clinical indices to evaluate the carcinogenic potential of OPMD.
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MicroRNA-27a-3p Modulates the Wnt/β-Catenin Signaling Pathway to Promote Epithelial-Mesenchymal Transition in Oral Squamous Carcinoma Stem Cells by Targeting SFRP1

This study aimed to elucidate how microRNA27a-3p (miR-27a-3p) modulates the Wnt/β-catenin signaling pathway to promote the epithelial-mesenchymal transition (EMT) in oral squamous carcinoma stem cells (OSCSCs) by targeting secreted frizzled-related protein 1 (SFRP1). Flow cytometry was used to sort OSCSCs from the SCC-9 and Tca8113 cell lines. The OSCSCs were randomly assigned into the miR-27a-3p inhibitors group, the miR-27a-3p inhibitors-NC group, the si-SFRP1 group, the si-SFRP1 + miR-27a-3p inhibitors group and the blank group. A luciferase reporter, immunofluorescence and Transwell assays were performed to detect luciferase activity, SFRP1, and cell migration and invasion, respectively. The mRNA expression of miR-27a-3p, SFRP1 and EMT markers (E-cadherin, N-cadherin, vimentin and ZEB1) were detected using qRT-PCR. The protein expression of SFRP1, EMT markers and the proteins of the Wnt/β-catenin signaling pathway was detected by Western blotting. OSCSCs showed up-regulated miR-27a-3p, Wnt/β-catenin signaling pathway-related proteins, vimentin, N-cadherin and ZEB1 and down-regulated SFRP1 and E-cadherin. MiR-27a-3p targeted SFRP1. Down-regulated miR-27a-3p resulted in increased E-cadherin and SFRP1 but decreased vimentin, N-cadherin, ZEB1, the Wnt/β-catenin signaling pathway-related proteins, and invasive and migratory cells. Silenced SFRP1 reversed this effect. We found that miR-27a-3p modulated the Wnt/β-catenin signaling pathway to promote EMT in OSCSCs by down-regulating SFRP1.

Expression of SOX2 in oral squamous cell carcinoma and the association with lymph node metastasis

Oral squamous cell carcinomas (OSCCs) are a growing problem in the world. The various existing treatments have not markedly improved the survival rate of patients with OSCC during the past three decades. Novel treatment strategies are required. Sex determining region Y-box 2 (SOX2) is a transcription factor that is involved in the maintenance of embryonic stem cell pluripotency and in multiple developmental processes. SOX2 expression was indicated to act as a prognostic factor in various types of tumors, including breast, colorectal, gastric and lung cancer and glioblastoma, and as a link between malignancy and stemness. Cancer stem cells (CSCs) may be responsible for the genesis, growth and metastatic spread of tumors. The poor survival outcomes for OSCC patients may be attributable to a poor selection of target cells for treatment, as current oral cancer therapies are generally aimed at the global mass of tumor. Therefore, the consideration that novel approaches to oral cancer may be targeted using SOX2 and CSCs appears reasonable. In order to better understand the oncogenic roles and the corresponding signal transduction pathways of the SOX2 protein, the present study emphasizes the role of SOX2 in OSCC, including the proteins associated with OSCC, and reviews the literature regarding the role of SOX2 in lymph node metastasis. The aim of the present study is to provide a reference for future studies that engage in research on the aforementioned subject.

Cancer stem cells and stemness markers in oral squamous cell carcinomas

Head and neck squamous cell carcinoma (HNSCC) is one of the world top ten most common cancers with its highest occurrence in the Indian subcontinent and different aggressive and etiological behavioural patterns. The scenario is only getting worst with the 5 year survival rates dropping to 50%, persistent treatment failures and frequent cases of relapse/recurrence. One of the major reasons for these failures is the presence of cancer stem cells (CSCs), a small population of cancer cells that are highly tumourigenic, capable of self-renewal and have the ability to differentiate into cells that constitute the bulk of tumours. Notably, recent evidence suggests that cancer stem cells are especially resistant to conventional therapy and are the "drivers" of local recurrence and metastatic spread. Specific markers for this population have been investigated in HNSCC in the hope of developing a deeper understanding of their role in oral cancer pathogenesis, elucidating novel biomarkers for early diagnosis and newer therapeutic strategies. This review covers the fundamental relevance of almost all the CSC biomarkers established to date with a special emphasis on their impact in the process of oral tumourigenesis and their potential role in improving the diagnosis, prognosis and treatment of OSCC patients.

Co-expression of CD133, CD44v6 and human tissue factor is associated with metastasis and poor prognosis in pancreatic carcinoma

The metastasis-related molecules CD133, CD44v6 and human tissue factor (TF) have been shown to be associated with tumor invasion and metastasis. This study aimed to determine whether co-expression of these three molecules was associated with metastasis and overall prognosis in pancreatic carcinoma. We analyzed the expression profiles of these three molecules by immunohistochemistry and evaluated the relationship of their expression profiles with metastasis and prognosis in 109 pancreatic carcinomas. The results showed that the expression levels of CD133, CD44v6 and TF were increased in pancreatic carcinoma. Co-expression of CD133, CD44v6 and TF (tri-expression) was also detected in pancreatic carcinoma. Clinical analysis showed that individual expression of CD133, CD44v6 or TF was associated with vessel invasion, lymph node metastasis and liver metastasis, while tri-expression was associated with lymph node metastasis. Survival analysis showed that patients with co-expression of CD133 and TF or tri-expression had lower and the lowest overall survival rates, respectively. Univariate analysis showed that T-factor, lymph node metastasis, TNM stage, and individual levels or tri-expression of CD133, CD44v6 and TF were survival risk factors. Multivariate analysis showed that tri-expression of CD133, CD44v6 and TF was an independent predictor of survival. These results suggest that overexpression of CD133, CD44v6 and TF is associated with pancreatic carcinoma metastasis. Tri-expression of these three molecules may be a useful predictor for pancreatic carcinoma prognosis.

CD44+/CD133+ immunophenotype and matrix metalloproteinase-9: Influence on prognosis in early-stage oral squamous cell carcinoma

BACKGROUND

The purpose of this study was to investigate the expression of CD44 and/or CD133 immunophenotypes and the associated effects of matrix metalloproteinase-9 (MMP-9) in early-stage oral squamous cell carcinomas (SCC) to assess their influence on tumor prognosis.

METHODS

The following data were derived from 150 patients: age, sex, primary anatomic site, smoking status, alcohol intake, recurrence, metastases, histological classification, treatment, disease-free survival (DFS), and overall survival (OS). Immunohistochemical study of CD44, CD133, and MMP-9 expression was performed on a tissue microarray of 150 paraffin blocks of oral SCCs.

RESULTS

The predominant immunophenotype identified to exhibit a significant correlation with MMP-9 was the CD44+/CD133+. Multivariate analyses identified a significant correlation of OS with surgical treatment and with CD44+/CD133+ immunophenotype.

CONCLUSION

This investigation demonstrated the prognostic importance of CD44/CD133 expression, which can help improve the prognostic value of surgical treatment for oral SCCs when diagnosed in early stages.

CD133 expression in oral lichen planus correlated with the risk for progression to oral squamous cell carcinoma

Oral lichen planus (OLP) is a potentially malignant disorder associated with an increased risk for progression to oral squamous cell carcinoma (OSCC). The objective of this study to determine protein expression of cancer stem cell marker CD133 in tissue samples of patients with OLP and evaluate the correlation between CD133 expression and the risk of progression to OSCC. In this longitudinal case-control study, a total of 110 patients with OLP who received a mean follow-up of 56 months were enrolled, including 100 patients who did not progress to OSCC and 10 patients who had progressed to OSCC. CD133 expression was determined using immunohistochemistry in samples from these patients. Analysis of 10 cases of normal oral mucosa and 6 cases of postmalignant OSCC form previously diagnosed OLP was also performed. The results showed that CD133 expression was observed in 29% cases of nonprogressing OLP and in 80% cases of progressing OLP (P = .002). CD133 was not expressed in normal oral mucosa, but it positively expressed in the 100% cases of OSCC. Logistic regression analysis revealed that the risk of malignant progression in the patients with CD133-positive expression was significantly higher than those with CD133 negativity (odds ratio, 9.79; 95% confidence interval, 1.96-48.92; P = .005). Collectively, CD133 expression was significantly associated with malignant progression in a longitudinal series of patients with OLP. Our findings suggested that CD133 may serve as a novel candidate biomarker for risk assessment of malignant potential of OLP.

Relevance of cancer initiating/stem cells in carcinogenesis and therapy resistance in oral cancer

Oral squamous cell carcinoma (OSCC) acquires the top most position among the other malignancies and patients die with this disease complication within 5years. One of the causes behind this scenario is the identified sub-population in heterogeneous tumor mass that are purported as cancer stem cells (CSCs) or tumor-initiating cells (TICs). Oral CSCs populations show upregulation of the stem cell related genes Oct-4, Nanog, Nestin, CK19, BMI-1, CD117 (c-kit), CD44 and CD133 with sunken expression of involucrin and CK13. This small proportion of tumor cells can sustain tumor growth, proliferation, invasion and distant metastasis playing a pivotal role in relapse of oral cancer. Unanimous risk factors include prevalent use of cigarette smoking, tobacco chewing with less explored HPV infection play an important role in origin of CSCs. Moreover, highly apoptotic resistant oral CSCs show enhanced protective autophagy for survival. Several studies report them to be more chemo and radiation resistant than non-stem cell population implicating the failure of the present cancer therapy. This resistance associated with normal stem cell protective mechanisms including increased expression of drug efflux pumps, alteration in program cell death, cell cycle, and DNA repair mechanisms. Notably, CSCs appear to play a major role in tumor recurrence and metastatic spread, common causes of the high morbidity and ultimately the death of the majority of patients with oral cancer. In this review we would like to highlight the intricate crosstalk of the cancer initiating/stem cells involved in carcinogenesis and potential hurdle to oral cancer therapy.

Cancer stem cell markers in head and neck squamous cell carcinoma

Head and neck squamous cell carcinoma (HNSCC) is one of the world's top ten most common cancers. Current survival rates are poor with only 50% of patients expected to survive five years after diagnosis. The poor survival rate of HNSCC is partly attributable to the tendency for diagnosis at the late stage of the disease. One of the reasons for treatment failure is thought to be related to the presence of a subpopulation of cells within the tumour called cancer stem cells (CSCs). CSCs display stem cell-like characteristics that impart resistance to conventional treatment modalities and promote tumour initiation, progression, and metastasis. Specific markers for this population have been investigated in the hope of developing a deeper understanding of their role in the pathogenesis of HNSCC and elucidating novel therapeutic strategies.