High Mannose Binding Lectin (PFL) from Pseudomonas fluorescens Down-Regulates Cancer-Associated Integrins and Immune Checkpoint Ligand B7-H4
High Mannose Binding Lectin (PFL) from Pseudomonas fluorescens Down-Regulates Cancer-Associated Integrins and Immune Checkpoint Ligand B7-H4
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DOI：
10.3390/cancers11050604
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发表时间：
2019-04
期刊：
影响因子：
5.2
通讯作者：
Yuichiro Sato;K. Matsubara;T. Kubo;Hirobumi Sunayama;Yuta Hatori;K. Morimoto;T. Seyama
中科院分区：
文献类型：
--
作者：
Yuichiro Sato;K. Matsubara;T. Kubo;Hirobumi Sunayama;Yuta Hatori;K. Morimoto;T. Seyama
荧光假单胞菌凝集素（PFL）属于高甘露糖（HM）结合的OAAH （agardhii振荡菌凝集素同源物）凝集素家族，可诱导癌细胞死亡。然而，这一过程背后的详细机制尚未阐明。我们发现PFL通过促进这些分子的内化和自噬降解，从而诱导依赖caspase-8的细胞凋亡，从而降低癌细胞中的各种整合素和EGFR。利用大鼠主动脉模型进行的体外血管生成实验显示，PFL以剂量依赖的方式抑制新生血管形成，这可能是通过下调内皮整合素介导的。有趣的是，PFL还下调了癌细胞中的B7-H4，这被认为是T细胞介导的免疫的负调节因子。我们发现B7-H4在MKN28胃癌细胞中与β3整合素共定位。siRNA沉默B7-H4在MKN28细胞中降低β3整合素的表达，提示这些分子之间存在物理和功能关联。通过表面等离子体共振分析检测PFL与整合素αvβ3或B7-H4的直接相互作用，发现PFL具有高亲和力的甘聚糖依赖性结合。这些研究表明，PFL与细胞表面整合素的相互作用是PFL具有抗癌活性的关键过程。
Pseudomonas fluorescens lectin (PFL), which belongs to the high mannose (HM)-binding OAAH (Oscillatoria agardhii agglutinin homologue) lectin family, induces cancer cell death. However, the detailed mechanisms underlying this process have not yet been elucidated. We found that PFL decreased various integrins as well as EGFR in cancer cells by promoting internalization and autophagic degradation of these molecules, subsequently inducing caspase-8 dependent cell apoptosis. As revealed by an ex vivo angiogenesis assay using the rat aortic model, PFL inhibited neovascularization in a dose-dependent manner, which was potentially mediated by down-regulation of endothelium integrins. Interestingly, PFL also down-regulated B7-H4 in cancer cells, which has been implicated as a negative regulator of T cell-mediated immunity. We found that B7-H4 co-localized with β3 integrin in MKN28 gastric cancer cells. siRNA silencing of B7-H4 in MKN28 cells decreased expression of β3 integrin, suggesting physical and functional association between these molecules. Direct interaction of PFL with integrin αvβ3 or B7-H4 was examined by surface plasmon resonance analysis, which detected high affinity glycan-dependent binding to PFL. These investigations suggest that PFL interaction with cell surface integrins is a key process for the anti-cancer activities of PFL.