Department of Neurosurgery, Changhai Hospital, Second Military Medical University, Shanghai 200433, China.
Tongji University Cancer Center, Shanghai Tenth People's Hospital of Tongji University, School of Medicine, Tongji University, Shanghai 200092, China.
J Zhejiang Univ Sci B. 2023 Aug 15;24(8):698-710. doi: 10.1631/jzus.B2200503.
To explore the role of forkhead box protein O1 (FOXO1) in the progression of glioblastoma multiforme (GBM) and related drug resistance, we deciphered the roles of FOXO1 and miR-506 in proliferation, apoptosis, migration, invasion, autophagy, and temozolomide (TMZ) sensitivity in the U251 cell line using in vitro and in vivo experiments. Cell viability was tested by a cell counting kit-8 (CCK8) kit; migration and invasion were checked by the scratching assay; apoptosis was evaluated by terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) staining and flow cytometry. The construction of plasmids and dual-luciferase reporter experiment were carried out to find the interaction site between FOXO1 and miR-506. Immunohistochemistry was done to check the protein level in tumors after the in vivo experiment. We found that the FOXO1-miR-506 axis suppresses GBM cell invasion and migration and promotes GBM chemosensitivity to TMZ, which was mediated by autophagy. FOXO1 upregulates miR-506 by binding to its promoter to enhance transcriptional activation. MiR-506 could downregulate E26 transformation-specific 1 (ETS1) expression by targeting its 3'-untranslated region (UTR). Interestingly, ETS1 promoted FOXO1 translocation from the nucleus to the cytosol and further suppressed the FOXO1-miR-506 axis in GBM cells. Consistently, both miR-506 inhibition and ETS1 overexpression could rescue FOXO1 overactivation-mediated TMZ chemosensitivity in mouse models. Our study demonstrated a negative feedback loop of FOXO1/miR-506/ETS1/FOXO1 in GBM in regulating invasiveness and chemosensitivity. Thus, the above axis might be a promising therapeutic target for GBM.
为了探索叉头框蛋白 O1（FOXO1）在多形性胶质母细胞瘤（GBM）进展和相关耐药性中的作用，我们通过体外和体内实验，阐明了 FOXO1 和 miR-506 在 U251 细胞系中的增殖、凋亡、迁移、侵袭、自噬和替莫唑胺（TMZ）敏感性中的作用。通过细胞计数试剂盒-8（CCK8）试剂盒检测细胞活力；通过划痕实验检测迁移和侵袭；通过末端脱氧核苷酸转移酶 dUTP 缺口末端标记（TUNEL）染色和流式细胞术评估凋亡。构建质粒和双荧光素酶报告实验，以找到 FOXO1 和 miR-506 之间的相互作用位点。免疫组织化学用于检查体内实验后肿瘤中的蛋白水平。我们发现，FOXO1-miR-506 轴抑制 GBM 细胞侵袭和迁移，并通过自噬促进 GBM 对 TMZ 的化学敏感性，这是由自噬介导的。FOXO1 通过结合其启动子上调 miR-506，增强转录激活。miR-506 可以通过靶向其 3'-非翻译区（UTR）下调 E26 转化特异性 1（ETS1）的表达。有趣的是，ETS1 促进 FOXO1 从细胞核到细胞质的易位，并进一步抑制 GBM 细胞中的 FOXO1-miR-506 轴。一致地，miR-506 抑制和 ETS1 过表达都可以挽救 FOXO1 过激活介导的 TMZ 化学敏感性在小鼠模型中。我们的研究表明，在调节侵袭性和化学敏感性方面，FOXO1/miR-506/ETS1/FOXO1 之间存在负反馈环。因此，该轴可能是 GBM 的一个有前途的治疗靶点。
