Department of General Surgery, Tangdu Hospital, Air Force Military Medical University, Xi'an, 710032, China.
Department of General Surgery, The First Affiliated Hospital, Zhengzhou University, Zhengzhou, 450052, China.
Br J Cancer. 2023 Oct;129(9):1477-1489. doi: 10.1038/s41416-023-02418-4. Epub 2023 Sep 15.
Hepatoblastoma (HB) is a highly aggressive paediatric malignancy that exhibits a high presence of cancer stem cells (CSCs), which related to tumour recurrence and chemotherapy resistance. Brain expressed X-linked protein 1 (BEX1) plays a pivotal role in ciliogenesis, axon regeneration and differentiation of neural stem cells. However, the role of BEX1 in metabolic and stemness programs in HB remains unclear.
BEX1 expression in human and mouse HB was analyzed using gene expression profile data from NCBI GEO and immunohistochemical validation. Seahorse extracellular flux analyzer, ultra-high-performance liquid-chromatography mass spectrometry (LC-MS), flow cytometry, qRT-PCR, Western Blot, sphere formation assay, and diluted xenograft tumour formation assay were used to analyze metabolic and stemness features.
Our results indicated that overexpression of BEX1 significantly enhanced the Warburg effect in HB cells. Furthermore, glycolysis inhibition largely attenuated the effects of BEX1 on HB cell growth and self-renewal, suggesting that BEX1 promotes stemness maintenance of HB cells by regulating the Warburg effect. Mechanistically, BEX1 enhances Warburg effect through the downregulation of peroxisome proliferator-activated receptor-gamma (PPARγ). Furthermore, pyruvate dehydrogenase kinase isozyme 1 (PDK1) is required for PPARγ-induced inhibition of Warburg effect in HB. In addition, BEX1 supports the stemness of HB by enhancing Warburg effect in a PPARγ/PDK1 dependent manner.
HB patients with high BEX1 and PDK1 expression had a poor prognosis. BEX1 promotes the stemness maintenance of HB cells via modulating the Warburg effect, which depends on PPARγ/PDK1 axis. Pioglitazone could be used to target BEX1-mediated stemness properties in HB by upregulating PPARγ.
肝母细胞瘤（HB）是一种高度侵袭性的儿科恶性肿瘤，其存在大量的癌症干细胞（CSCs），这与肿瘤复发和化疗耐药有关。脑表达 X 连锁蛋白 1（BEX1）在纤毛发生、轴突再生和神经干细胞分化中发挥关键作用。然而，BEX1 在 HB 中的代谢和干性程序中的作用尚不清楚。
使用 NCBI GEO 的基因表达谱数据和免疫组织化学验证分析人源和鼠源 HB 中的 BEX1 表达。使用 Seahorse 细胞外通量分析仪、超高效液相色谱-质谱联用（LC-MS）、流式细胞术、qRT-PCR、Western Blot、球体形成实验和稀释异种移植肿瘤形成实验分析代谢和干性特征。
我们的结果表明，BEX1 的过表达显著增强了 HB 细胞中的瓦博格效应。此外，糖酵解抑制在很大程度上减弱了 BEX1 对 HB 细胞生长和自我更新的影响，表明 BEX1 通过调节瓦博格效应促进 HB 细胞的干性维持。机制上，BEX1 通过下调过氧化物酶体增殖物激活受体-γ（PPARγ）来增强瓦博格效应。此外，PDK1 是 PPARγ 诱导抑制 HB 中瓦博格效应所必需的。此外，BEX1 通过以 PPARγ/PDK1 依赖的方式增强瓦博格效应来支持 HB 的干性。
BEX1 和 PDK1 高表达的 HB 患者预后不良。BEX1 通过调节瓦博格效应促进 HB 细胞的干性维持，这取决于 PPARγ/PDK1 轴。吡格列酮可通过上调 PPARγ 来靶向 BEX1 介导的 HB 干性特性。
