CD44 positive cancer stem cells express invasion and metastasis markers: Analysis of three tongue squamous cell carcinoma cell lines

Abstract

Objectives: This study aimed to analyze the expression of epithelial-mesenchymal transition (EMT) markers, E-cadherin, and alpha-smooth muscle actin (α-SMA) in CD44+ cancer stem cells (CSCs) compared to parental cells to shed light on the possible role of CSCs in the invasion and metastasis of tongue squamous cell carcinoma (TSCC).Materials and Methods: Three tongue squamous cell carcinoma cell lines were used in this study. Cells were cultured for cancer stem cell screening and isolation. Tumor cells underwent CD44-based fluorescence-activated cell sorting analysis. Subsequently the expression of E-cadherin and α-SMA in CSCs sub-population and parental cells was evaluated using quantitative real-time PCR. Results:The three cell lines displayed stable CD44 expression levels. Moreover, E-cadherin recorded a significantly higher value in parental cells compared to CSCs sub-population, whereas α-SMA recorded a significantly lower value in parental cells compared to CSCs sub-population. A very strong negative correlation was noted between E-cadherin and each of α-SMA and CD44, whereas a very strong positive correlation was noted between α-SMA and CD44. Conclusion:The findings of our study indicated that TSSC harbors a sub-population of CD44+ CSCs that exhibited enhanced EMT features compared to other cell populations. Our data provide new evidence in support of a potential link between α-SMA expression and CSC features which may have relevant implications for the development of cancer stem cell-based treatment options.