Mirković Bojana, Markelc Boštjan, Butinar Miha, Mitrović Ana, Sosič Izidor, Gobec Stanislav, Vasiljeva Olga, Turk Boris, Čemažar Maja, Serša Gregor, Kos Janko
Faculty of Pharmacy, University of Ljubljana, Ljubljana, Slovenia.
Department of Experimental Oncology, Institute of Oncology Ljubljana, Ljubljana, Slovenia.
Oncotarget. 2015 Aug 7;6(22):19027-42. doi: 10.18632/oncotarget.3699.
Cathepsin B is a ubiquitously expressed lysosomal cysteine protease that participates in protein turnover within lysosomes. However, its protein and activity levels have been shown to be increased in cancer. Cathepsin B endopeptidase activity is involved in the degradation of extracellular matrix, a process that promotes tumor invasion, metastasis and angiogenesis. Previously, we reported an established antibiotic nitroxoline as a potent and selective inhibitor of cathepsin B. In the present study, we elucidated its anti-tumor properties in in vitro and in vivo tumor models. Tumor and endothelial cell lines with high levels of active cathepsin B were selected for functional analysis of nitroxoline in vitro. Nitroxoline significantly reduced extracellular DQ-collagen IV degradation by all evaluated cancer cell lines using spectrofluorimetry. Nitroxoline also markedly decreased tumor cell invasion monitored in real time and reduced the invasive growth of multicellular tumor spheroids, used as a 3D in vitro model of tumor invasion. Additionally, endothelial tube formation was significantly reduced by nitroxoline in an in vitro angiogenesis assay. Finally, nitroxoline significantly abrogated tumor growth, angiogenesis and metastasis in vivo in LPB fibrosarcoma and MMTV-PyMT breast cancer mouse models. Overall, our results designate nitroxoline as a promising drug candidate for anti-cancer treatment.
组织蛋白酶B是一种广泛表达的溶酶体半胱氨酸蛋白酶，参与溶酶体内的蛋白质周转。然而，其蛋白质水平和活性在癌症中已显示出升高。组织蛋白酶B的内肽酶活性参与细胞外基质的降解，这一过程促进肿瘤侵袭、转移和血管生成。此前，我们报道了一种已确立的抗生素硝氧喹啉是组织蛋白酶B的有效且选择性抑制剂。在本研究中，我们阐明了其在体外和体内肿瘤模型中的抗肿瘤特性。选择具有高水平活性组织蛋白酶B的肿瘤和内皮细胞系用于硝氧喹啉的体外功能分析。使用荧光光谱法，硝氧喹啉显著降低了所有评估的癌细胞系对细胞外DQ-胶原蛋白IV的降解。硝氧喹啉还显著降低了实时监测的肿瘤细胞侵袭，并减少了用作肿瘤侵袭三维体外模型的多细胞肿瘤球体的侵袭性生长。此外，在体外血管生成试验中，硝氧喹啉显著减少了内皮管形成。最后，在LPB纤维肉瘤和MMTV-PyMT乳腺癌小鼠模型中，硝氧喹啉显著消除了体内肿瘤生长、血管生成和转移。总体而言，我们的结果表明硝氧喹啉是一种有前景的抗癌治疗候选药物。
