ZEB1 通过转录激活 PFKM 增强了肝癌的瓦博格效应,促进了肿瘤的发生和转移。
ZEB1 enhances Warburg effect to facilitate tumorigenesis and metastasis of HCC by transcriptionally activating PFKM.
机构信息
Department of Hepatobiliary & Pancreatovascular Surgery, The First Affiliated Hospital of Xiamen University, Xiamen, Fujian 361003, China.
The State Key Laboratory of Cellular Stress Biology, Innovation Center for Cell Signaling Network, School of Life Sciences, Xiamen University, Xiamen, Fujian 361102, China.
出版信息
Theranostics. 2021 Apr 3;11(12):5926-5938. doi: 10.7150/thno.56490. eCollection 2021.
Metabolic reprogramming, especially Warburg effect, is a key event in tumor initiation and progression. ZEB1 plays a vital role in metastasis of various cancers. We previously found that ZEB1 was excessively expressed in hepatocellular carcinoma (HCC) and its high expression was closely correlated with metastasis and recurrence of HCC. We want to know whether glycolytic enzymes are regulated by ZEB1 and contribute to carcinogenesis and metastasis of HCC. To explore whether ZEB1 could enhance glycolysis in HCC, we knocked down ZEB1 by short hairpin RNA (shRNA) in MHCC-97H and HCC-LM3 cells and performed glucose uptake, lactate production, ECAR and OCR assays. To investigate how ZEB1 enhances glycolysis, the protein levels of glycolytic enzymes were detected in the same cell lines using Western blot. The regulatory effect of ZEB1 on PFKM mRNA level was confirmed by RT-qPCR, luciferase report assay and ChIP assay. In order to assess the role of ZEB1-PFKM axis in cell proliferation, cell counting and CCK-8 assays were performed in MHCC-97H and HCC-LM3 cell lines knocked down for ZEB1 and further re-expressed for either ZEB1 or PFKM or not. To explored whether the ZEB1-PFKM axis also functions in HCC cell migration, invasion and metastasis, the same MHCC-97H and HCC-LM3 cell lines were performed for wound healing assays, transwell assays and colony formation assays, meanwhile, MHCC-97H cell lines were performed for orthotopic liver transplantation assays. Finally, the expression of ZEB1 and PFKM were examined in human liver cancer specimens and non-tumorous liver tissues using immunohistochemical and Western blot. We found that ZEB1 transcriptionally upregulates the expression of the muscle isoform of phosphofructokinase-1 (PFKM), a rate-limiting enzyme in glycolysis. Intriguingly, a non-classic ZEB1-binding sequence in the promoter region of PFKM was identified through which ZEB1 directly activates the transcription of PFKM. Silencing of ZEB1 in MHCC-97H and HCC-LM3 cell leads to impaired PFKM expression, glycolysis, proliferation and invasion, and such impairments are rescued by exogenous expression of PFKM. Importantly, HCC xenograft assays and studies from TCGA database demonstrate that ZEB1-PFKM axis is crucial for carcinogenesis and metastasis of HCC. Our study reveals a novel mechanism of ZEB1 in promoting HCC by activating the transcription of PFKM, establishing the direct link of ZEB1 to the promotion of glycolysis and Warburg effect and suggesting that inhibition of ZEB1 transcriptional activity toward PFKM may be a potential therapeutic strategy for HCC.
代谢重编程,尤其是瓦博格效应,是肿瘤发生和进展的关键事件。ZEB1 在各种癌症的转移中起着至关重要的作用。我们之前发现,ZEB1 在肝细胞癌(HCC)中过度表达,其高表达与 HCC 的转移和复发密切相关。我们想知道糖酵解酶是否受 ZEB1 调控,是否有助于 HCC 的癌变和转移。为了探讨 ZEB1 是否能增强 HCC 的糖酵解,我们通过短发夹 RNA(shRNA)在 MHCC-97H 和 HCC-LM3 细胞中敲低 ZEB1,并进行葡萄糖摄取、乳酸生成、ECAR 和 OCR 测定。为了研究 ZEB1 如何增强糖酵解,我们使用 Western blot 在相同的细胞系中检测糖酵解酶的蛋白水平。通过 RT-qPCR、荧光素酶报告测定和 ChIP 测定证实了 ZEB1 对 PFKM mRNA 水平的调节作用。为了评估 ZEB1-PFKM 轴在细胞增殖中的作用,我们在 MHCC-97H 和 HCC-LM3 细胞系中敲低 ZEB1,并进一步过表达 ZEB1 或 PFKM 或不表达,进行细胞计数和 CCK-8 测定。为了探讨 ZEB1-PFKM 轴是否也能影响 HCC 细胞的迁移、侵袭和转移,我们对相同的 MHCC-97H 和 HCC-LM3 细胞系进行了划痕愈合试验、Transwell 试验和集落形成试验,同时对 MHCC-97H 细胞系进行了原位肝移植试验。最后,使用免疫组化和 Western blot 检测人肝癌标本和非肿瘤性肝组织中 ZEB1 和 PFKM 的表达。我们发现,ZEB1 转录上调了糖酵解限速酶肌肉型磷酸果糖激酶-1(PFKM)的表达。有趣的是,通过鉴定 PFKM 启动子区域的非经典 ZEB1 结合序列,ZEB1 直接激活了 PFKM 的转录。在 MHCC-97H 和 HCC-LM3 细胞中敲低 ZEB1 导致 PFKM 表达、糖酵解、增殖和侵袭受损,而过表达 PFKM 可挽救这种损伤。重要的是,HCC 异种移植试验和 TCGA 数据库的研究表明,ZEB1-PFKM 轴对 HCC 的发生和转移至关重要。我们的研究揭示了 ZEB1 通过激活 PFKM 的转录促进 HCC 的一种新机制,建立了 ZEB1 与促进糖酵解和瓦博格效应的直接联系,并表明抑制 ZEB1 对 PFKM 的转录活性可能是 HCC 的一种潜在治疗策略。