Wang Gang, Wu Yuanli, Su Yue, Qu Na, Chen Bo, Zhou Duanfang, Yuan Lie, Yin Manjialan, Liu Mingpu, Zhou Weiying
Department of Pharmacology, College of Pharmacy, Chongqing Medical University, Chongqing, 400016, China.
Chongqing Key Laboratory of Drug Metabolism, Chongqing Medical University, Chongqing, 400016, China.
J Transl Med. 2024 Aug 7;22(1):745. doi: 10.1186/s12967-024-05536-6.
Human epidermal growth factor receptor 2-positive (HER2+) breast cancer (BC), which accounts for approximately one-fifth of all BCs, are highly invasive with a high rate of recurrence and a poor prognosis. Several studies have shown that growth factor receptor-bound protein 7 (GRB7) might be a potential therapeutic target for tumor diagnosis and prognosis. Nevertheless, the role of GRB7 in HER2+ BC and its underlying mechanisms have not been fully elucidated. The aim of this study was to investigate the biological function and regulatory mechanism of GRB7 in HER2+ BC.
Bioinformatics analysis was performed using the TCGA, GEO and CancerSEA databases to evaluate the clinical significance of GRB7. RT quantitative PCR, western blot and immunofluorescence were conducted to assess the expression of GRB7 in BC cell lines and tissues. MTT, EdU, colony formation, wound healing, transwell, and xenograft assays were adopted to explore the biological function of GRB7 in HER2+ BC. RNA sequencing was performed to analyze the signaling pathways associated with GRB7 in SK-BR-3 cells after the cells were transfected with GRB7 siRNA. Chromatin immunoprecipitation analysis (ChIP) and luciferase reporter assay were employed to elucidate the potential molecular regulatory mechanisms of GRB7 in HER2+ BC.
GRB7 was markedly upregulated and associated with poor prognosis in BC, especially in HER2+ BC. Overexpression of GRB7 increased the proliferation, migration, invasion, and colony formation of HER2+ BC cells, while depletion of GRB7 had the opposite effects in HER2+ BC cells and inhibited xenograft growth. ChIP-PCR and luciferase reporter assay revealed that TCF12 directly bound to the promoter of the GRB7 gene to promote its transcription. GRB7 facilitated HER2+ BC epithelial-mesenchymal transition (EMT) progression by interacting with Notch1 to activate Wnt/β-catenin pathways and other signaling (i.e., AKT, ERK). Moreover, forced GRB7 overexpression activated Wnt/β-catenin to promote EMT progression, and partially rescued the inhibition of HER2+ BC proliferation, migration and invasion induced by TCF12 silencing.
Our work elucidates the oncogenic role of GRB7 in HER2+ BC, which could serve as a prognostic indicator and promising therapeutic target.
人表皮生长因子受体2阳性（HER2+）乳腺癌（BC）约占所有乳腺癌的五分之一，具有高度侵袭性，复发率高且预后较差。多项研究表明，生长因子受体结合蛋白7（GRB7）可能是肿瘤诊断和预后的潜在治疗靶点。然而，GRB7在HER2+ BC中的作用及其潜在机制尚未完全阐明。本研究旨在探讨GRB7在HER2+ BC中的生物学功能和调控机制。
使用TCGA、GEO和CancerSEA数据库进行生物信息学分析，以评估GRB7的临床意义。进行RT定量PCR、蛋白质免疫印迹和免疫荧光分析，以评估GRB7在BC细胞系和组织中的表达。采用MTT、EdU、集落形成、伤口愈合、Transwell和异种移植试验，探讨GRB7在HER2+ BC中的生物学功能。在SK-BR-3细胞中转染GRB7 siRNA后，进行RNA测序，以分析与GRB7相关的信号通路。采用染色质免疫沉淀分析（ChIP）和荧光素酶报告基因检测，阐明GRB7在HER2+ BC中的潜在分子调控机制。
GRB7在BC中显著上调，且与不良预后相关，尤其是在HER2+ BC中。GRB7的过表达增加了HER2+ BC细胞的增殖、迁移、侵袭和集落形成，而GRB7的缺失在HER2+ BC细胞中具有相反的作用，并抑制异种移植瘤的生长。ChIP-PCR和荧光素酶报告基因检测显示，TCF12直接与GRB7基因的启动子结合，促进其转录。GRB7通过与Notch1相互作用激活Wnt/β-连环蛋白通路和其他信号通路（即AKT、ERK），促进HER2+ BC上皮-间质转化（EMT）进程。此外，强制过表达GRB7激活Wnt/β-连环蛋白，促进EMT进程，并部分挽救了TCF12沉默诱导的HER2+ BC增殖、迁移和侵袭的抑制。
我们的研究阐明了GRB7在HER2+ BC中的致癌作用，其可作为预后指标和有前景的治疗靶点。
