Zhu XingWu, Mulcahy Lori A, Mohammed Rabab A A, Lee Andrew H S, Franks Hester A, Kilpatrick Laura, Yilmazer Acelya, Paish E Claire, Ellis Ian O, Patel Poulam M, Jackson Andrew M
Academic Unit of Clinical Oncology, University of Nottingham - City Hospital Campus, Nottingham NG5 1PB, UK.
Breast Cancer Res. 2008;10(6):R95. doi: 10.1186/bcr2195. Epub 2008 Nov 17.
IL-17 plays an important role in autoimmunity, promoting autoimmunity, inflammation and invasion in multiple sclerosis, rheumatoid arthritis and type I diabetes. The role of IL-17 in cancer is unclear, however, as there are few studies examining IL-17 protein expression in cancer. We therefore examined IL-17 protein expression in human breast cancer and modelled its potential biological significance in vitro.
Immunohistochemistry was used to determine IL-17 expression in breast cancers. Matrigel invasion assays were employed to examine the effect of IL-17 on cancer cell invasion by a panel of breast cancer cell lines. The role of matrix metalloproteinases (MMPs) was investigated with selective antagonists and immunoassays for MMP-2, MMP-3, MMP-9 and tissue inhibitor of MMP.
IL-17-expressing cells with macrophage morphology were identified in the peritumoural area of a proportion of patients (8/19 patients). Macrophages were confirmed by CD68 staining on serial sections. With the exception of occasional lymphocytes, one patient with rare multinucleate giant cells and one patient with occasional expression of IL-17 in tumour cells, no other IL-17-positive cells were detected. Addition of IL-17 to cell lines in vitro stimulated marked invasion of Matrigel. In contrast, IL-17 did not promote the invasion of MCF7 or T47D cell lines. Invasion was initially thought to be dependent on MMPs, as evidenced by the broad-spectrum MMP inhibitor GM6001 and selective antagonists of MMP-2/MMP-9 and MMP-3. Measurement of MMP-2, MMP-3 and MMP-9, and tissue inhibitor of MMP 1 secretion, failed to reveal any changes in expression following IL-17 exposure. In contrast, TNF promoted secretion of MMPs but IL-17 did not augment TNF, indicating that IL-17 acts via an independent mechanism.
The present study is the first to describe in situ expression of IL-17 protein in human breast tumours and to propose a direct association between IL-17 and breast cancer invasion. The precise effectors of IL-17-dependent invasion remain to be characterised but could include a range of proteases such as a disintegrin and metalloproteinase protein or astacins. Nevertheless, this work identifies a novel potential mechanism for breast cancer invasion and tumour progression, the prognostic implication of which is currently under investigation.
白细胞介素-17（IL-17）在自身免疫中发挥重要作用，可促进多发性硬化症、类风湿性关节炎和I型糖尿病中的自身免疫、炎症和侵袭。然而，IL-17在癌症中的作用尚不清楚，因为很少有研究检测癌症中IL-17蛋白的表达。因此，我们检测了人乳腺癌中IL-17蛋白的表达，并在体外模拟了其潜在的生物学意义。
采用免疫组织化学法测定乳腺癌中IL-17的表达。利用基质胶侵袭试验，通过一组乳腺癌细胞系检测IL-17对癌细胞侵袭的影响。使用选择性拮抗剂以及针对基质金属蛋白酶-2（MMP-2）、基质金属蛋白酶-3（MMP-3）、基质金属蛋白酶-9（MMP-9）和基质金属蛋白酶组织抑制剂的免疫测定法，研究基质金属蛋白酶（MMPs）的作用。
在部分患者（8/19例）的肿瘤周围区域发现了具有巨噬细胞形态的IL-17表达细胞。通过连续切片上的CD68染色证实为巨噬细胞。除偶尔出现的淋巴细胞、1例有罕见多核巨细胞的患者以及1例肿瘤细胞偶尔表达IL-17的患者外，未检测到其他IL-17阳性细胞。体外向细胞系中添加IL-17可刺激基质胶的显著侵袭。相比之下，IL-17并未促进MCF7或T47D细胞系的侵袭。侵袭最初被认为依赖于MMPs，广谱MMP抑制剂GM6001以及MMP-2/MMP-9和MMP-3的选择性拮抗剂可证明这一点。对MMP-2、MMP-3和MMP-9以及基质金属蛋白酶组织抑制剂1分泌的测量未能揭示IL-17暴露后表达的任何变化。相比之下，肿瘤坏死因子（TNF）促进MMPs的分泌，但IL-17并未增强TNF，这表明IL-17通过独立机制发挥作用。
本研究首次描述了人乳腺肿瘤中IL-17蛋白的原位表达，并提出IL-17与乳腺癌侵袭之间存在直接关联。IL-17依赖性侵袭的确切效应分子仍有待确定，但可能包括一系列蛋白酶，如去整合素和金属蛋白酶蛋白或虾红素。尽管如此，这项工作确定了一种乳腺癌侵袭和肿瘤进展的新潜在机制，其预后意义目前正在研究中。
