Bjørnland Kristin, Flatmark Kjersti, Pettersen Solveig, Aaasen Ansgar O, Fodstad Oystein, Maelandsmo Gunhild M
Institute for Surgical Research, Rikshospitalet, 0027 Oslo, Norway.
J Surg Res. 2005 Aug;127(2):151-6. doi: 10.1016/j.jss.2004.12.016. Epub 2005 Apr 14.
Osteosarcoma (OS) is a highly malignant bone tumor and is the most frequent malignant bone tumor in children and adolescents. Metastases are the major cause of death, and patients with relapse have poor prognosis. Several solid tumors display enhanced expression of matrix metalloproteinases (MMPs), and recently MMP-inhibitors have entered clinical trials. A disturbance of the MMP system in favor of enhanced proteolytic activity may be suspected in OS because OS growth is accompanied by both enhanced local bone destruction and bone formation, two processes that are dependant on proteolytic enzymes. Thus, the aim of the present study was to evaluate the involvement of MMPs in a panel of human OS cell lines, xenografts and biopsies.
Expression of MMPs and their endogenous inhibitors were studied by zymography and Northern blot analyses. In vitro invasion of OS cell lines and effects of MMP-inhibitors (Marimastat and doxycycline) were assessed in the transwell chamber assay.
In vitro invasiveness was compared with gelatinase activity, and the most invasive cell line secreted the highest amounts of MMP-2 and MMP-9. Two different MMP-inhibitors significantly reduced OS cell invasion. The majority of the OS xenografts expressed both the inactive and active form of MMP-2 and in some cases also MMP-9. The biopsies from primary and metastatic OS also expressed MMP-2 mRNA. However, MMP-9 levels were higher in the biopsies than in the xenografts.
The obtained results support the hypothesis that MMPs and their endogenous inhibitors participate in the invasive process of human OS.
骨肉瘤（OS）是一种高度恶性的骨肿瘤，是儿童和青少年中最常见的恶性骨肿瘤。转移是主要的死亡原因，复发患者预后较差。几种实体瘤显示基质金属蛋白酶（MMPs）表达增强，最近MMP抑制剂已进入临床试验。由于骨肉瘤的生长伴随着局部骨破坏和骨形成的增强，这两个过程都依赖于蛋白水解酶，因此可能怀疑骨肉瘤中MMP系统紊乱有利于蛋白水解活性增强。因此，本研究的目的是评估MMPs在一组人骨肉瘤细胞系、异种移植瘤和活检组织中的作用。
通过酶谱分析和Northern印迹分析研究MMPs及其内源性抑制剂的表达。在Transwell小室试验中评估骨肉瘤细胞系的体外侵袭能力以及MMP抑制剂（马立马司他和强力霉素）的作用。
将体外侵袭能力与明胶酶活性进行比较，侵袭性最强的细胞系分泌的MMP-2和MMP-9量最高。两种不同的MMP抑制剂显著降低了骨肉瘤细胞的侵袭。大多数骨肉瘤异种移植瘤同时表达MMP-2的无活性和活性形式，在某些情况下还表达MMP-9。原发性和转移性骨肉瘤的活检组织也表达MMP-2 mRNA。然而，活检组织中MMP-9水平高于异种移植瘤。
所得结果支持MMPs及其内源性抑制剂参与人骨肉瘤侵袭过程这一假说。
