1. Department of Neurosurgery, Tianjin Medical University General Hospital, Lab of Neuro-oncology, Tianjin Neurological Institute, Tianjin, 300052, China.
2. Key Laboratory of Post-Neuro Injury Neuro-repair and Regeneration in Central Nervous System, Ministry of Education and Tianjin City, Tianjin, 300052, China.
3. Tianjin Key Laboratory of Composite and Functional Materials, School of Material Science and Engineering, Tianjin University, Tianjin, 300072, China.
4. Department of Neuro-Oncology and Neurosurgery, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy of Tianjin, Tianjin's Clinical Research Center for Cancer, Tianjin 300060, China.
5. Department of Neurosurgery, Affiliated Hospital of Hebei University, Hebei Key Laboratory of Precise Diagnosis and Treatment of Glioma, Baoding, 071000, China.
6. Department of Pathology, Affiliated Hospital of Hebei University, Department of Pathology, Hebei University School of Basic Medical Sciences, Baoding, 071000, China.
* These authors contributed equally to this work.
Rationale: Glioblastoma (GBM) displays a complex metabolic reprogramming in cancer cells. Adenosine triphosphate (ATP) is one of the central mediators of cell metabolism and signaling. GBM cells generate ATP by glycolysis and the tricarboxylic acid (TCA) cycle associated with oxidative phosphorylation (OXPHOS) through the breaking-down of pyruvate or fatty acids to meet the growing energy demand of cancer cells. Therefore, it's urgent to develop novel treatments targeting energy metabolism to hinder tumor cell proliferation in GBM.
Methods: Non-targeted metabolomic profiling analysis was utilized to evaluate cell metabolic reprogramming using a small molecule inhibitor (SMI) EPIC-0412 treatment. Cellular oxygen consumption rate (OCR) and the total proton efflux rate (PER), as well as ATP concentration, were tracked to study metabolic responses to specifically targeted inhibitors, including EPIC-0412, arachidonyl trifluoromethyl ketone (AACOCF3), and 2 deoxy-D-glucose (2-DG). Cancer cell proliferation was assessed by CCK-8 measurements and colony formation assay. Additionally, flow cytometry, immunoblotting (IB), and immunofluorescence (IF) analyses were performed with GBM cells to understand their tumorigenic properties under treatments. Finally, the anticancer effects of this combination therapy were evaluated in the GBM mouse model by convection-enhanced delivery (CED).
Results: We found that SMI EPIC-0412 could effectively perturb the TCA cycle, which participated in the combination therapy of cytosolic phospholipase A2 (cPLA2)-inhibitor AACOCF3, and hexokinase II (HK2)-inhibitor 2-DG to disrupt the GBM energy metabolism for targeted metabolic treatments. ATP production was significantly declined in glioma cells when treated with monotherapy (EPIC-0412 or AACOCF3), dual therapy (EPIC-0412 + AACOCF3), or triple therapy (EPIC-0412 + AACOCF3 +2-DG) regimen. Our experiments revealed that these therapies hindered glioma cell proliferation and growth, leading to the reduction in ATP production and G0/G1 cell cycle arrest. We demonstrated that the combination therapy effectively extended the survival of cerebral tumor-bearing mice.
Conclusion: Our findings indicate that the TCA-phospholipid-glycolysis metabolism axis can be blocked by specific inhibitors that significantly disrupt the tumor energy metabolism and suppress tumor proliferation in vitro and in vivo, suggesting that targeting ATP synthesis inhibition in cancer cells might be an attractive therapeutic avenue in GBM management.
Keywords: glioblastoma, ATP production, energy metabolism, convection-enhanced delivery.