Liu Run, Li Jin-Cheng, Li Shi-De, Li Jian-Di, He Rong-Quan, Chen Gang, Feng Zhen-Bo, Wei Jia-Liang
Department of Pathology, The First Affiliated Hospital of Guangxi Medical University, Nanning 530021, Guangxi Zhuang Autonomous Region, China.
Department of Gastroenterology, The First Affiliated Hospital of Guangxi Medical University, Nanning 530021, Guangxi Zhuang Autonomous Region, China.
World J Hepatol. 2025 Jul 27;17(7):106151. doi: 10.4254/wjh.v17.i7.106151.
Hepatocellular carcinoma (HCC) remains a lethal malignancy due to its molecular complexity and chemoresistance. Rac family small GTPase 3 (RAC3), a tumorigenic GTPase understudied in HCC, drives recurrence E2F transcription factor 1 (E2F1)-mediated transcriptional activation. This study integrates multiomics and clustered regularly interspaced short palindromic repeats (CRISPR) screening to delineate RAC3's roles. RAC3 overexpression correlates with advanced HCC and patient age, while its knockout suppresses proliferation. Mechanistically, RAC3 dysregulates cell-cycle checkpoints through E2F1 binding. Pharmacological RAC3 inhibition disrupts tumor growth and synergizes with chemotherapy to overcome resistance.
To explore RAC3's expression, clinical links, and HCC mechanisms multiomics and functional genomics.
Multiomic integration of The Cancer Genome Atlas (TCGA), Gene Expression Omnibus, and Genotype-Tissue Expression datasets was performed to analyze RAC3 mRNA expression. Immunohistochemistry quantified RAC3 protein in 108 HCC/adjacent tissue pairs. Kaplan-Meier/Cox regression assessed prognostic significance using TCGA data. CRISPR screening validated RAC3's necessity for HCC proliferation. Functional enrichment identified associated pathways; hTFtarget/JASPAR predicted transcription factors, validated chromatin immunoprecipitation sequencing (ChIP-seq).
RAC3 exhibited significant mRNA and protein overexpression in HCC tissues, which was correlated with advanced tumor stages and reduced overall survival rates (hazard ratio = 1.82, 95%CI: 1.31-2.53). Genetic ablation of RAC3 suppressed HCC cell proliferation across 16 cell lines. Pathway analysis revealed RAC3's predominant involvement in cell-cycle regulation, DNA replication, and nucleocytoplasmic transport. Mechanistic investigations identified E2F1 as a pivotal upstream transcriptional regulator, and ChIP-seq analysis validated its direct binding to the RAC3 promoter region. These findings suggest that RAC3 drives HCC progression through E2F1-mediated cell-cycle dysregulation.
This study identified RAC3 as a key HCC oncogenic driver; its overexpression links to poor prognosis/resistance. Targeting the RAC3/E2F1 axis offers a new therapy, which highlights RAC3 as a biomarker/target.
肝细胞癌（HCC）因其分子复杂性和化疗耐药性，仍然是一种致命的恶性肿瘤。Rac家族小GTP酶3（RAC3）是一种在HCC中研究较少的致癌GTP酶，它驱动由E2F转录因子1（E2F1）介导的转录激活。本研究整合多组学和规律成簇间隔短回文重复序列（CRISPR）筛选，以阐明RAC3的作用。RAC3过表达与晚期HCC及患者年龄相关，而其敲除可抑制细胞增殖。从机制上讲，RAC3通过与E2F1结合来失调细胞周期检查点。RAC3的药理学抑制可破坏肿瘤生长，并与化疗协同作用以克服耐药性。
通过多组学和功能基因组学探索RAC3的表达、临床关联及HCC机制。
对癌症基因组图谱（TCGA）、基因表达综合数据库和基因型-组织表达数据集进行多组学整合，以分析RAC3 mRNA表达。免疫组织化学对108对HCC/癌旁组织中的RAC3蛋白进行定量。使用TCGA数据通过Kaplan-Meier/Cox回归评估预后意义。CRISPR筛选验证RAC3对HCC增殖的必要性。功能富集确定相关途径；hTFtarget/JASPAR预测转录因子，并通过染色质免疫沉淀测序（ChIP-seq）进行验证。
RAC3在HCC组织中表现出显著的mRNA和蛋白过表达，这与肿瘤晚期和总生存率降低相关（风险比=1.82，95%置信区间：1.31-2.53）。RAC3的基因消融抑制了16种细胞系中的HCC细胞增殖。通路分析显示RAC3主要参与细胞周期调控、DNA复制和核质运输。机制研究确定E2F1是关键的上游转录调节因子，ChIP-seq分析验证了其与RAC3启动子区域的直接结合。这些发现表明，RAC3通过E2F1介导的细胞周期失调驱动HCC进展。
本研究确定RAC3是HCC的关键致癌驱动因子；其过表达与预后不良/耐药相关。靶向RAC3/E2F1轴提供了一种新的治疗方法，这突出了RAC3作为生物标志物/靶点的作用。
