背景:从头增强的脂肪生成对肝细胞癌(HCC)至关重要。异常高的cullin相关和neddylation解离1(CAND1)表达与HCC临床预后不良相关。SKP1-Cullin-1-F-box(SCF)复合物由SKP1,Cullin-1和F-box蛋白(FBP)组成,并执行多种功能,包括脂肪生成。SCF复合物受CAND1调节,但CAND1是否以及如何通过调节SCF复合物和脂肪生成促进HCC尚不清楚。
方法:肝癌样本用于分析CAND1表达与生存和预后等临床病理特征之间的相关性。通过细胞增殖测量CAND1,FBXO11和异质核核糖核蛋白A2/B1(hnRNPA2B1)的体外功能,集落形成和迁移测定。在多种小鼠肝癌模型中测试了体内功能,包括患者来源的异种移植物(PDX),细胞系来源的异种移植和AKT/NRASV12诱导的原发性肝癌模型。进行靶向CAND1(AAV-shCAND1)的腺相关病毒的注射以评估靶向CAND1的治疗功效。RNA-Seq和脂质组学测定,然后进行包括质谱在内的一系列生化实验,进行免疫沉淀和GST下拉以剖析潜在的机制。
结果:CAND1通过破坏SCF复合物组装和脂质积累来促进脂质合成基因的表达。此外,我们鉴定hnRNPA2B1为新的F-box蛋白11(FBXO11)结合伴侣。FBXO11直接结合hnRNPA2B1并促进hnRNPA2B1的泛素化和随后的降解。我们对AAV-shCAND1注射的治疗功效的评估证实靶向CAND1-SCFFBXO11-hnRNPA2B1A信号轴是治疗有效的。CAND1下调显著降低了原发性小鼠肝癌模型和PDX模型中的肿瘤负荷。
结论:我们的结果强调CAND1与HCC的不良预后相关,并通过解离SCF复合物调节脂质代谢重编程。靶向CAND1-SCFFBXO11-hnRNPA2B1轴可能是HCC治疗的新策略。
Enhanced de novo lipogenesis is essential for hepatocellular carcinoma (HCC). Abnormally high cullin-associated and neddylation-dissociated 1 (CAND1) expression is associated with poor clinical prognosis in HCC. The SKP1-Cullin-1-F-box (SCF) complex consists of the SKP1, Cullin-1 and F-box proteins (FBPs) and performs multiple functions including adipogenesis. SCF complex was modulated by CAND1, but Whether and how the CAND1 promotes HCC by regulating SCF complex and lipogenesis are unknown.
HCC samples were used to analyze the correlations between CAND1 expression and clinicopathological characteristics such as survival and prognosis. The in vitro functions of CAND1, FBXO11 and heterogeneous nuclear ribonucleoprotein A2/B1 (hnRNPA2B1) were measured by cell proliferation, colony formation and migration assays. The in vivo functions were tested in multiple mouse liver cancer models including patient-derived xenograft (PDX), cell line-derived xenograft and AKT/NRASV12-induced primary liver cancer models. Injections of adeno-associated virus targeting CAND1 (AAV-shCAND1) were performed to evaluate the therapeutic efficacy of targeting CAND1. RNA-Seq and lipidomic assays followed by serial biochemical experiments including mass spectrometry, immunoprecipitation and GST pull-down were performed to dissect the underlying mechanisms.
CAND1 promoted the expression of lipid synthesis genes by disrupting SCF complex assembly and lipid accumulation. Furthermore, we identified hnRNPA2B1 as a novel F-box protein 11 (FBXO11)-binding partner. FBXO11 directly bound to hnRNPA2B1 and promoted hnRNPA2B1 ubiquitination and subsequent degradation. Our evaluations of the therapeutic efficacy of AAV-shCAND1 injections confirmed that targeting the CAND1-SCFFBXO11 -hnRNPA2B1A signalling axis was therapeutically effective. CAND1 downregulation significantly reduced the tumour burden in a primary mouse liver cancer model and a PDX model.
Our results highlight that CAND1 is associated with poor prognosis in HCC and regulates lipid metabolic reprogramming by dissociating the SCF complex. Targeting the CAND1-SCFFBXO11 -hnRNPA2B1 axis may be a novel strategy for HCC treatment.