Department of Otorhinolaryngology, Head and Neck Surgery, University Hospital Giessen and Marburg, Campus Marburg, Deutschhausstrasse 3, D-35037 Marburg, Germany.
Oral Oncol. 2010 Feb;46(2):116-22. doi: 10.1016/j.oraloncology.2009.11.011. Epub 2009 Dec 29.
Head and neck squamous cell carcinomas (HNSCCs) are the most frequent malignancies of the upper aerodigestive tract. The cancer stem cell (CSC) hypothesis concludes that CSCs constitute the dangerous tumor cell population due to their ability of self-renewal and being associated with relapse of tumor disease, invasiveness and resistance to chemo(radio)therapy. The aim of this study was to look for CSC candidates and expression of MMP-9 that previously was implicated in HNSCC invasiveness. Immunohistochemical, immunofluorescence and Western blot analysis were performed on HNSCC tumor specimens using antibodies specific for MMP-9, CD44, ALDH1 and CK14. Gelatinolytic activity was assessed by zymography. Pearson correlation analysis was used for statistical comparison. Immunohistochemical analysis found CD44 and MMP-9 to co-localize in tumor cells at the invasive front. Western blot analysis demonstrated a significant correlation (p=0.0047) between CD44 and MMP-9 in the tested tissues. In addition gelatinolytic activity of HNSCC tissues was found to significantly correlate (p=0.0010) with MMP-9 expression. The CD44(+) invasive front of the tumor was also positive for ALDH1 and CK14, all of them being typically expressed by cells in the basal cell layer of normal stratified squamous epithelia that also harbors the epithelial stem cells. The observations point to a role of a MMP-9 positive basal-cell-like cell layer in the process of HNSCC invasiveness. This compartment likely contains CSCs since it is expressing the putative CSC markers CD44, ALDH1 and CK14. This cell layer therefore should be considered a major therapeutic target in the treatment of head and neck cancer.
头颈部鳞状细胞癌（HNSCC）是上呼吸道最常见的恶性肿瘤。癌症干细胞（CSC）假说得出结论，CSC 构成了危险的肿瘤细胞群体，因为它们具有自我更新的能力，并与肿瘤疾病的复发、侵袭性和对化疗（放射）的耐药性有关。本研究旨在寻找 CSC 候选物和 MMP-9 的表达，MMP-9 先前被认为与 HNSCC 的侵袭性有关。使用针对 MMP-9、CD44、ALDH1 和 CK14 的特异性抗体，对头颈部鳞状细胞癌肿瘤标本进行免疫组织化学、免疫荧光和 Western blot 分析。通过明胶酶谱法评估凝胶酶活性。采用 Pearson 相关分析进行统计学比较。免疫组织化学分析发现 CD44 和 MMP-9 在肿瘤细胞的侵袭前沿处共同定位。Western blot 分析表明，在测试组织中 CD44 和 MMP-9 之间存在显著相关性（p=0.0047）。此外，HNSCC 组织的凝胶酶活性与 MMP-9 的表达呈显著相关（p=0.0010）。肿瘤的 CD44(+)侵袭前沿也对 ALDH1 和 CK14 呈阳性，所有这些标志物通常在正常分层鳞状上皮的基底细胞层中的细胞中表达，而基底细胞层也含有上皮干细胞。这些观察结果表明，MMP-9 阳性的基底样细胞层在 HNSCC 侵袭过程中起作用。这个隔室可能含有 CSC，因为它表达假定的 CSC 标志物 CD44、ALDH1 和 CK14。因此，这个细胞层应该被认为是治疗头颈部癌症的主要治疗靶点。
