Division of Oto-Rhino-Laryngology and Head & Neck Surgery, Department of Clinical and Experimental Medicine, Faculty of Health Sciences, Linköping University, Linköping, Sweden.
PLoS One. 2012;7(9):e44071. doi: 10.1371/journal.pone.0044071. Epub 2012 Sep 25.
Mortality in head and neck squamous cell carcinoma (HNSCC) is high due to emergence of therapy resistance which results in local and regional recurrences that may have their origin in resistant cancer stem cells (CSCs) or cells with an epithelial-mesenchymal transition (EMT) phenotype. In the present study, we investigate the possibility of using the cell surface expression of CD44 and epidermal growth factor receptor (EGFR), both of which have been used as stem cell markers, to identify subpopulations within HNSCC cell lines that differ with respect to phenotype and treatment sensitivity. Three subpopulations, consisting of CD44(high)/EGFR(low), CD44(high)/EGFR(high) and CD44(low) cells, respectively, were collected by fluorescence-activated cell sorting. The CD44(high)/EGFR(low) population showed a spindle-shaped EMT-like morphology, while the CD44(low) population was dominated by cobblestone-shaped cells. The CD44(high)/EGFR(low) population was enriched with cells in G0/G1 and showed a relatively low proliferation rate and a high plating efficiency. Using a real time PCR array, 27 genes, of which 14 were related to an EMT phenotype and two with stemness, were found to be differentially expressed in CD44(high)/EGFR(low) cells in comparison to CD44(low) cells. Moreover, CD44(high)/EGFR(low) cells showed a low sensitivity to radiation, cisplatin, cetuximab and gefitinib, and a high sensitivity to dasatinib relative to its CD44(high)/EGFR(high) and CD44(low) counterparts. In conclusion, our results show that the combination of CD44 (high) and EGFR (low) cell surface expression can be used to identify a treatment resistant subpopulation with an EMT phenotype in HNSCC cell lines.
头颈部鳞状细胞癌(HNSCC)的死亡率很高,这是由于出现了治疗耐药性,导致局部和区域复发,这些复发可能起源于耐药性癌症干细胞(CSCs)或具有上皮-间充质转化(EMT)表型的细胞。在本研究中,我们研究了使用细胞表面表达的 CD44 和表皮生长因子受体(EGFR)的可能性,这两者都被用作干细胞标记物,以鉴定 HNSCC 细胞系中表型和治疗敏感性不同的亚群。通过荧光激活细胞分选,收集了三个亚群,分别是 CD44(high)/EGFR(low)、CD44(high)/EGFR(high)和 CD44(low)细胞。CD44(high)/EGFR(low)群体表现出纺锤形 EMT 样形态,而 CD44(low)群体则以鹅卵石形细胞为主。CD44(high)/EGFR(low)群体富含处于 G0/G1 期的细胞,增殖率相对较低,种植效率较高。使用实时 PCR 阵列,发现 27 个基因在 CD44(high)/EGFR(low)细胞中与 EMT 表型相关的 14 个基因和与干性相关的 2 个基因的表达存在差异,与 CD44(low)细胞相比。此外,与 CD44(high)/EGFR(high)和 CD44(low)细胞相比,CD44(high)/EGFR(low)细胞对辐射、顺铂、西妥昔单抗和吉非替尼的敏感性较低,对达沙替尼的敏感性较高。总之,我们的结果表明,CD44(高)和 EGFR(低)细胞表面表达的组合可用于鉴定 HNSCC 细胞系中具有 EMT 表型的治疗耐药亚群。