Targeting cell surface GRP78 enhances pancreatic cancer radiosensitivity through YAP/TAZ protein signaling
Targeting cell surface GRP78 enhances pancreatic cancer radiosensitivity through YAP/TAZ protein signaling
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DOI：
10.1074/jbc.ra119.009091
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发表时间：
2019-09-20
影响因子：
4.8
通讯作者：
Pizzo, Salvatore Vincent
中科院分区：
文献类型：
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作者：
Gopal, Udhayakumar;Mowery, Yvonne;Pizzo, Salvatore Vincent
电离辐射（IR）可以促进癌细胞的迁移和侵袭，但这种现象的基础尚未完全阐明。 IR 增加癌细胞 (CS-GRP78) 表面葡萄糖调节蛋白 78kDa (GRP78) 的表达，这种上调与癌症的侵袭性行为、放射抗性和复发相关。在这里，我们使用各种生化和免疫学方法，包括流式细胞术、细胞增殖和迁移测定、Rho 激活和定量 RT-PCR 测定，研究了 CS-GRP78 促进胰腺导管腺癌细胞 (PDAC) 放射抗性的机制。我们发现激活的 α(2)-巨球蛋白 (α M-2*) 是 CS-GRP78 受体的配体，可诱导 AKT 激酶 (AKT)/DLC1 Rho-GTPase 激活蛋白 (DLC1) 复合物的形成，从而增加 Rho 激活。此外，CS-GRP78以Rho依赖性方式激活转录共激活因子Yes相关蛋白（YAP）和tafazzin（TAZ），促进PDAC细胞的运动性和侵袭性。我们观察到辐射诱导的 CS-GRP78 刺激 YAP/TAZ 的核积累并增加 YAP/TAZ 靶基因的表达。值得注意的是，用 C38 单克隆抗体 (Mab) 靶向 CS-GRP78 可增强放射敏感性，并通过减少 PDAC 细胞运动和侵袭来提高放射治疗的疗效。这些发现表明，CS-GRP78 作用于 YAP/TAZ 信号传导的上游，促进 PDAC 细胞的迁移和辐射抗性。因此，我们得出的结论是，C38 Mab 是与放射疗法联合使用来管理 PDAC 的有前途的候选药物。
Ionizing radiation (IR) can promote migration and invasion of cancer cells, but the basis for this phenomenon has not been fully elucidated. IR increases expression of glucose-regulated protein 78kDa (GRP78) on the surface of cancer cells (CS-GRP78), and this up-regulation is associated with more aggressive behavior, radioresistance, and recurrence of cancer. Here, using various biochemical and immunological methods, including flow cytometry, cell proliferation and migration assays, Rho activation and quantitative RT-PCR assays, we investigated the mechanism by which CS-GRP78 contributes to radioresistance in pancreatic ductal adenocarcinoma (PDAC) cells. We found that activated alpha(2)-Macroglobulin (alpha M-2*) a ligand of the CS-GRP78 receptor, induces formation of the AKT kinase (AKT)/DLC1 Rho-GTPase-activating protein (DLC1) complex and thereby increases Rho activation. Further, CS-GRP78 activated the transcriptional coactivators Yes-associated protein (YAP) and tafazzin (TAZ) in a Rho-dependent manner, promoting motility and invasiveness of PDAC cells. We observed that radiation-induced CS-GRP78 stimulates the nuclear accumulation of YAP/TAZ and increases YAP/TAZ target gene expressions. Remarkably, targeting CS-GRP78 with C38 monoclonal antibody (Mab) enhanced radiosensitivity and increased the efficacy of radiation therapy by curtailing PDAC cell motility and invasion. These findings reveal that CS-GRP78 acts upstream of YAP/TAZ signaling and promote migration and radiation-resistance in PDAC cells. We therefore conclude that, C38 Mab is a promising candidate for use in combination with radiation therapy to manage PDAC.