Identification of Integrin β1 as a Novel PAG1-Interacting Protein Involved in the Inherent Radioresistance of Human Laryngeal Carcinoma
Identification of Integrin β1 as a Novel PAG1-Interacting Protein Involved in the Inherent Radioresistance of Human Laryngeal Carcinoma
复制标题
整合素 β1 的鉴定作为一种新型 PAG1 相互作用蛋白，参与人喉癌固有的放射抗性
DOI：
10.7150/jca.26885
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发表时间：
2018-01-01
影响因子：
3.9
通讯作者：
Shen, Li
中科院分区：
文献类型：
--
作者：
Dong, Xiaoxia;Luo, Zhiguo;Shen, Li
固有放射抗性在放射治疗失败中起着至关重要的作用。使用从亲代细胞系 Hep-2 建立的固有放射抗性 (Hep-2max) 和放射敏感 (Hep-2min) 细胞系，我们之前报道了与喉癌细胞中富含糖鞘脂的微结构域 1 (PAG1) 过表达相关的磷蛋白与固有放射抗性表型相关。然而，这种效应的潜在机制仍然未知。在本研究中，我们进行了蛋白质组筛选来研究 Hep-2max 细胞中 PAG1 的相互作用组，从而鉴定了几种相互作用伙伴。生物信息分析和免疫荧光实验表明整合素β1是PAG1的重要相互作用伙伴。 PAG1 在喉癌放射抗性组织中也高表达，并与整合素 β1 共定位。此外，我们证明整合素 β1 与 PAG1 的结合可以被脂筏形成抑制剂 MβCD 中断。此外，通过 RNA 干扰敲低整合素 β1 可以使抗辐射细胞对辐射敏感。重要的是，我们使用高通量肽阵列在 PAG1 的细胞质结构域中鉴定了 2 个潜在的相互作用位点（Pro216-Arg232 和 Asn356-Gly377）。综上所述，这些结果表明，PAG1 与脂筏中整合素 β1 的结合对于人喉癌固有的放射抗性至关重要。
Inherent radioresistance plays a crucial role in the failure of radiotherapy. Using the inherent radioresistant (Hep-2max) and radiosensitive (Hep-2min) cell lines established from the parental cell line Hep-2, we previously reported that phosphoprotein associated with glycosphingolipid-enriched microdomains 1(PAG1) overexpression in laryngeal carcinoma cells was correlated with inherent radioresistant phenotypes. However, the underlying mechanisms of this effect remain unknown. In the present study, we performed a proteomic screen to investigate the interactome of PAG1 in Hep-2max cells resulting in the identification of several interaction partners. Bioinformatic analysis and immunofluorescence experiments indicated the integrin β1 to be a crucial interaction partner of PAG1. PAG1 was also highly expressed in laryngeal carcinoma radioresistant tissues and showed co-localization with integrin β1. In addition, we demonstrated that integrin β1's binding to PAG1 could be interrupted by MβCD, an inhibitor of lipid rafts formation. Moreover, knockdown of integrin β1 by RNA interference sensitized radioresistant cells to irradiation. Importantly, we identified 2 potential interaction sites (Pro216-Arg232 and Asn356-Gly377) in the cytoplasmic domain of PAG1 using high throughput peptide arrays. Taken together, these results suggest that the binding of PAG1 to integrin β1 in lipid rafts is essential for inherent radioresistance of human laryngeal carcinoma.