State Key Laboratory of Cancer Biology and National Clinical Research Center for Digestive Diseases, Xijing Hospital of Digestive Diseases, Fourth Military Medical University (Air Force Medical University), Changle West Road 127, Xi'an, Shaanxi, 710032, China.
The Fifth Medical Center of Chinese PLA General Hospital, Beijing, 100071, China.
Cell Mol Life Sci. 2022 Feb 15;79(2):133. doi: 10.1007/s00018-022-04143-2.
Sec62 is a membrane protein of the endoplasmic reticulum that facilitates protein transport. Its role in cancer is increasingly recognised, but remains largely unknown. We investigated the functional role of Sec62 in gastric cancer (GC) and its underlying mechanism.
Bioinformatics, tissue microarray, immunohistochemistry (IHC), western blotting (WB), quantitative polymerase chain reaction (qPCR), and immunofluorescence were used to examine the expression of target genes. Transwell, scratch healing assays, and xenograft models were used to evaluate cell migration and invasion. Transmission electron microscopy and mRFP-GFP-LC3 double-labeled adenoviruses were used to monitor autophagy. Co-immunoprecipitation (CO-IP) was performed to evaluate the binding activity between the proteins.
Sec62 expression was upregulated in GC, and Sec62 upregulation was an independent predictor of poor prognosis. Sec62 overexpression promoted GC cell migration and invasion both in vitro and in vivo. Sec62 promoted migration and invasion by affecting TIMP-1 and MMP2/9 balance. Moreover, Sec62 could activate autophagy by upregulating PERK/ATF4 expression and binding to LC3II with concomitant FIP200/Beclin-1/Atg5 activation. Furthermore, autophagy blockage impaired the promotive effects of Sec62 on GC cell migration and invasion, whereas autophagy activation rescued the inhibitory effect of Sec62 knockdown on GC metastasis. Notably, Sec62 inhibition combined with autophagy blockage exerted a synergetic anti-metastatic effect in vitro and in vivo.
Sec62 promotes GC metastasis by activating autophagy and subsequently regulating TIMP-1 and MMP2/9 balance. The activation of autophagy by Sec62 may involve the unfolded protein response (UPR)-related PERK/ATF4 pathway and binding of LC3II during UPR recovery involving FIP200/Beclin-1/Atg5 upregulation. Specifically, the dual inhibition of Sec62 and autophagy may provide a promising therapeutic strategy for GC metastasis.
Sec62 是内质网膜上的一种蛋白，有助于蛋白质转运。它在癌症中的作用越来越受到重视，但仍知之甚少。我们研究了 Sec62 在胃癌（GC）中的功能作用及其潜在机制。
采用生物信息学、组织微阵列、免疫组织化学（IHC）、Western blot（WB）、定量聚合酶链反应（qPCR）和免疫荧光技术检测靶基因的表达。采用 Transwell、划痕愈合试验和异种移植模型评估细胞迁移和侵袭。采用透射电子显微镜和 mRFP-GFP-LC3 双标记腺病毒监测自噬。采用免疫共沉淀（CO-IP）评估蛋白间的结合活性。
Sec62 在 GC 中表达上调，Sec62 上调是预后不良的独立预测因子。Sec62 过表达在体外和体内均促进 GC 细胞迁移和侵袭。Sec62 通过影响 TIMP-1 和 MMP2/9 平衡来促进迁移和侵袭。此外，Sec62 通过上调 PERK/ATF4 表达并与 LC3II 结合，同时激活 FIP200/Beclin-1/Atg5，从而激活自噬。进一步研究表明，自噬阻断削弱了 Sec62 对 GC 细胞迁移和侵袭的促进作用，而 Sec62 敲低抑制 GC 转移的作用则可被自噬激活所挽救。值得注意的是，Sec62 抑制联合自噬阻断在体外和体内均发挥协同抗转移作用。
Sec62 通过激活自噬，继而调节 TIMP-1 和 MMP2/9 平衡，促进 GC 转移。Sec62 激活自噬可能涉及未折叠蛋白反应（UPR）相关 PERK/ATF4 途径和 UPR 恢复期间 LC3II 与 FIP200/Beclin-1/Atg5 上调的结合。具体而言，Sec62 和自噬的双重抑制可能为 GC 转移提供一种有前途的治疗策略。
