Impaired pentose phosphate pathway in the development of 3D MCF-7 cells mediated intracellular redox disturbance and multi-cellular resistance without drug induction

• Main Authors: Wenjie Wang, Qingyun Cai, Fang Zhou, Jiali Liu, Xiaoliang Jin, Ping Ni, Meng Lu, Guangji Wang, Jingwei Zhang
• Format: Article
• Language: English
• Published: Elsevier 2018-05-01
• Series: Redox Biology
• Subjects: 3D cell culture; Cellular metabolomics; Pentose phosphate pathway; Redox-status; P-gp regulation
• Online Access: http://www.sciencedirect.com/science/article/pii/S2213231717308595

Although metabolic reprogramming and redox imbalance are widely reported to be involved in chemo-resistance in cancer treatment, much more attention was paid to anti-cancer drug induced effect. Our previous studies showed that cancer cells can develop P-gp overexpression-mediated intrinsic drug resistance in the formation of 3D MCF-7 multi-cellular layers (MCLs) without any drug induction. However, whether metabolic reprogramming and redox imbalance functioned during this progress remained unrevealed. In our present study, LC-Q/TOF-MS and GC-MS were used in combination for analysing intracellular metabolites. The contribution of pentose phosphate pathway (PPP) and its related redox status were checked by chemical interfering and silencing/over-expression of glucose-6-phosphate dehydrogenase (G6PD). The downstream products of G6PD were assayed by quantitative real-time PCR, western blot and flow cytometry. Results showed that not only G6PD expression but also G6PD activity was significantly lowered along with 3D MCF-7 cells culture time. Impaired PPP disturbed redox-cycling, generated reactive oxygen species (ROS), which triggered cell cycle arrest and caused the switch to Chk2/p53/NF-κB pathway-mediated P-gp induction. Our results provided a new attempt to associate intrinsic small molecule metabolites (impaired PPP) communicating with cell signalling pathways through disturbed intracellular redox status to elucidate multi-cellular resistance (MCR) in 3D MCF-7 cells, which improved the understanding of the mechanisms of P-gp up-regulation in MCR with metabolomic and related redox status support.