Schmidt Cameron A, McLaughlin Kelsey L, Boykov Ilya N, Mojalagbe Rafiq, Ranganathan Arthi, Buddo Katherine A, Lin Chien-Te, Fisher-Wellman Kelsey H, Neufer P Darrell
East Carolina Diabetes and Obesity Institute, Greenville, NC, USA.
Dept. of Physiology, Brody School of Medicine, East Carolina University, Greenville, NC, USA.
Cancer Metab. 2021 Jan 19;9(1):3. doi: 10.1186/s40170-021-00241-0.
Hepatocellular carcinoma (HCC) is the most prevalent form of liver malignancy and carries poor prognoses due to late presentation of symptoms. Treatment of late-stage HCC relies heavily on chemotherapeutics, many of which target cellular energy metabolism. A key platform for testing candidate chemotherapeutic compounds is the intrahepatic orthotopic xenograft (IOX) model in rodents. Translational efficacy from the IOX model to clinical use is limited (in part) by variation in the metabolic phenotypes of the tumor-derived cells that can be induced by selective adaptation to subculture conditions.
In this study, a detailed multilevel systems approach combining microscopy, respirometry, potentiometry, and extracellular flux analysis (EFA) was utilized to examine metabolic adaptations that occur under aglycemic growth media conditions in HCC-derived (HEPG2) cells. We hypothesized that aglycemic growth would result in adaptive "aerobic poise" characterized by enhanced capacity for oxidative phosphorylation over a range of physiological energetic demand states.
Aglycemic growth did not invoke adaptive changes in mitochondrial content, network complexity, or intrinsic functional capacity/efficiency. In intact cells, aglycemic growth markedly enhanced fermentative glycolytic substrate-level phosphorylation during glucose refeeding and enhanced responsiveness of both fermentation and oxidative phosphorylation to stimulated energy demand. Additionally, aglycemic growth induced sensitivity of HEPG2 cells to the provitamin menadione at a 25-fold lower dose compared to control cells.
These findings indicate that growth media conditions have substantial effects on the energy metabolism of subcultured tumor-derived cells, which may have significant implications for chemotherapeutic sensitivity during incorporation in IOX testing panels. Additionally, the metabolic phenotyping approach used in this study provides a practical workflow that can be incorporated with IOX screening practices to aid in deciphering the metabolic underpinnings of chemotherapeutic drug sensitivity.
肝细胞癌（HCC）是最常见的肝脏恶性肿瘤形式，由于症状出现较晚，预后较差。晚期HCC的治疗严重依赖化疗药物，其中许多药物靶向细胞能量代谢。啮齿动物肝内原位异种移植（IOX）模型是测试候选化疗化合物的关键平台。从IOX模型到临床应用的转化疗效（部分）受到肿瘤来源细胞代谢表型变异的限制，这种变异可由对传代培养条件的选择性适应诱导产生。
在本研究中，采用了一种详细的多层次系统方法，结合显微镜、呼吸测定法、电位测定法和细胞外通量分析（EFA），来研究肝癌来源（HEPG2）细胞在无糖生长培养基条件下发生的代谢适应性变化。我们假设无糖生长将导致适应性“有氧平衡”，其特征是在一系列生理能量需求状态下氧化磷酸化能力增强。
无糖生长并未引起线粒体含量、网络复杂性或内在功能能力/效率的适应性变化。在完整细胞中，无糖生长在重新添加葡萄糖期间显著增强了发酵性糖酵解底物水平磷酸化，并增强了发酵和氧化磷酸化对刺激能量需求的反应性。此外，与对照细胞相比，无糖生长使HEPG2细胞对维生素K3原的敏感性提高了25倍。
这些发现表明，生长培养基条件对传代培养的肿瘤来源细胞的能量代谢有重大影响，这可能对纳入IOX测试组期间的化疗敏感性有重要意义。此外，本研究中使用的代谢表型分析方法提供了一种实用的工作流程，可与IOX筛选实践相结合，以帮助解读化疗药物敏感性的代谢基础。
