Cancer-associated mutations in the canonical cleavage site do not influence CD99 shedding by the metalloprotease meprin β but alter cell migration in vitro.
Cancer-associated mutations in the canonical cleavage site do not influence CD99 shedding by the metalloprotease meprin β but alter cell migration in vitro.
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DOI：
10.18632/oncotarget.18966
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发表时间：
2017-08-15
期刊：
影响因子：
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通讯作者：
Becker-Pauly C
中科院分区：
文献类型：
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作者：
Bedau T;Schumacher N;Peters F;Prox J;Arnold P;Koudelka T;Helm O;Schmidt F;Rabe B;Jentzsch M;Rosenstiel P;Sebens S;Tholey A;Rose-John S;Becker-Pauly C
跨内皮细胞迁移（TEM）是炎症和转移的关键。粘附分子CD 99被证明对于正确的免疫细胞外渗是重要的，并且在某些癌细胞上高度表达。最近，我们证明了由金属蛋白酶meprin β引起的CD 99的胞外域脱落在体外促进TEM。在这项研究中，我们采用了急性炎症模型（气囊/角叉菜胶），并发现在meprin β敲除动物中浸润细胞显著减少，验证了先前观察到的促炎活性。为了进一步分析meprin β在细胞粘附和增殖方面对CD 99脱落的影响，我们表征了两种肺癌相关的CD 99变体（D92 H，D92 Y），其在主要切割位点携带点突变。有趣的是，仍然可以检测到meprin β对这些变体的胞外域脱落。但是切割位点向相邻位置移动。然而，CD 99变体D92 H和D92 Y的表达揭示了部分错误折叠和蛋白酶体降解。先前观察到的CD 99对Src活化和增殖增加的影响在本研究中不能得到证实，与野生型CD 99或变体D92 H和D92 Y无关。然而，我们发现meprin β是Src磷酸化的有效诱导剂。重要的是，我们发现与野生型蛋白相比，表达癌症相关的CD 99变体D92 H时细胞迁移显著增加。
Transendothelial cell migration (TEM) is crucial for inflammation and metastasis. The adhesion molecule CD99 was shown to be important for correct immune cell extravasation and is highly expressed on certain cancer cells. Recently, we demonstrated that ectodomain shedding of CD99 by the metalloprotease meprin β promotes TEM in vitro. In this study, we employed an acute inflammation model (air pouch/carrageenan) and found significantly less infiltrated cells in meprin β knock-out animals validating the previously observed pro-inflammatory activity. To further analyze the impact of meprin β on CD99 shedding with regard to cell adhesion and proliferation we characterized two lung cancer associated CD99 variants (D92H, D92Y), carrying point mutations at the main cleavage site. Interestingly, ectodomain shedding of these variants by meprin β was still detectable. However the cleavage site shifted to adjacent positions. Nevertheless, expression of CD99 variants D92H and D92Y revealed partial misfolding and proteasomal degradation. A previously observed influence of CD99 on Src activation and increased proliferation could not be confirmed in this study, independent of wild-type CD99 or the variants D92H and D92Y. However, we identified meprin β as a potent inducer of Src phosphorylation. Importantly, we found significantly increased cell migration when expressing the cancer-associated CD99 variant D92H compared to the wild-type protein.