School of Clinical Medicine, Nanchang Medical College, Jiangxi Province, Nanchang, P.R.China.
Department of Organ Transplantation, Jiangxi Provincial People's Hospital, Nanchang, Jiangxi Province, P.R.China.
Bioengineered. 2022 Apr;13(4):10564-10577. doi: 10.1080/21655979.2022.2062990.
Endoplasmic reticulum stress (ER stress) is a double-edged sword in the occurrence and development of malignant cancer. The aim of this study was to explore the roles of ER stress in metastasis and epithelial-mesenchymal transitionin triple-negative breast cancer (TNBC) and potential mechanisms. In this study, 4-PBA was administrated to inhibit the ER stress. Cell viability was evaluated using a cell counting kit-8 assay. Cell migration and invasion were identified by wound healing and transwell assay, respectively. Levels of MMP2 and MMP9 were measured by enzyme-linked immunosorbent assay and immunohistochemical staining. Western blot assay was used to assess the levels of ER stress-related proteins, Syndecan-1 (SDC-1)/Syntenin-1 (SDCBP-1)/SRY-related HMG-box 4 (SOX4) signaling and Wnt/β-catenin signaling. Moreover, a xenograft mice model was conducted to confirm the role of ER stress in TNBC. The data indicate that the ability of viability and metastasis of breast cancer cells were stronger than normal mammary epithelial cells. More aggressiveness was manifested in TNBC cells than that in non-TNBC cells. 4-PBA significantly suppressed the viability, migration, and invasion in BC cells and inhibited the SDC/SDCBP/SOX4 axis and Wnt/β-catenin signaling. Furthermore, heat shock protein A4 (HSPA4) overexpression stimulated ER stress and activated the SDC-1/SDCBP-1/SOX4 pathway and Wnt/β-catenin signaling. Animal experiments showed similar results that 4-PBA repressed tumor growth and inactivated the two pathways, while HSPA4 overexpression reversed the effects of 4-PBA. In summary, inhibition of ER stress inhibited TNBC viability, migration, and invasion by Syntenin/SOX4/Wnt/β-catenin pathway via regulation of HSPA4 in vivo and in vitro.
内质网应激（ER 应激）在恶性肿瘤的发生和发展中是一把双刃剑。本研究旨在探讨 ER 应激在三阴性乳腺癌（TNBC）转移和上皮-间质转化中的作用及其潜在机制。在这项研究中，使用 4-PBA 抑制 ER 应激。通过细胞计数试剂盒-8 测定评估细胞活力。通过划痕愈合和 Transwell 测定分别鉴定细胞迁移和侵袭。通过酶联免疫吸附试验和免疫组织化学染色测定 MMP2 和 MMP9 的水平。Western blot 测定用于评估 ER 应激相关蛋白、Syndecan-1（SDC-1）/Syntenin-1（SDCBP-1）/SRY 相关 HMG 盒 4（SOX4）信号和 Wnt/β-连环蛋白信号的水平。此外，进行了异种移植小鼠模型以证实 ER 应激在 TNBC 中的作用。数据表明，乳腺癌细胞的活力和转移能力强于正常乳腺上皮细胞。TNBC 细胞比非 TNBC 细胞表现出更强的侵袭性。4-PBA 显著抑制 BC 细胞的活力、迁移和侵袭，并抑制 SDC/SDCBP/SOX4 轴和 Wnt/β-连环蛋白信号。此外，热休克蛋白 A4（HSPA4）过表达刺激 ER 应激并激活 SDC-1/SDCBP-1/SOX4 途径和 Wnt/β-连环蛋白信号。动物实验也得到了类似的结果，即 4-PBA 抑制肿瘤生长并使两条通路失活，而过表达 HSPA4 则逆转了 4-PBA 的作用。总之，抑制 ER 应激通过体内和体外调节 HSPA4 抑制 Syntenin/SOX4/Wnt/β-连环蛋白通路来抑制 TNBC 的活力、迁移和侵袭。
