1. Inhibition of Carbohydrate Metabolism Potentiated by the Therapeutic Effects of Oxidative Phosphorylation Inhibitors in Colon Cancer Cells.
- Author
-
Guo, Lichao, Zhang, Baochen, Zhang, Wen, Xie, Yanqi, Chen, Xi, Sun, Xueke, Watt, David S., Liu, Chunming, Spielmann, H. Peter, and Liu, Xifu
- Subjects
THERAPEUTIC use of antineoplastic agents ,CARRIER proteins ,MITOCHONDRIA ,RESEARCH funding ,APOPTOSIS ,DESCRIPTIVE statistics ,COLON tumors ,ENERGY metabolism ,MICE ,CELL lines ,ANIMAL experimentation ,MOLECULAR structure ,CARBOHYDRATE metabolism ,COMPARATIVE studies ,MEMBRANE proteins - Abstract
Simple Summary: Glycolysis and oxidative phosphorylation play important roles in the progression and growth of cancers. The development of natural products and their semisynthetic derivatives for cancer treatment is a longstanding focus of our research interests. We developed compounds known as diaminobutoxy-substituted isoflavonoids (DBIs) that effectively stimulated Adenosine 5′ Monophosphate-activated Protein Kinase (AMPK) and suppressed the growth of colorectal cancer cells by specifically targeting mitochondrial complex I. We now report a new DBI analog, namely, DBI-2, with promising properties for cancer treatment. The combination of DBI-2 and BAY-876, a glucose transporter 1 inhibitor, exhibited synergistic effects on colorectal cancer cells. Furthermore, the therapeutic effectiveness of DBI-2 in colorectal cancer cell xenograft mouse models was enhanced by implementing a ketogenic diet, an outcome that indicated this drug/diet combination is a potentially promising combination strategy for cancer therapy. Cancer cells undergo a significant level of "metabolic reprogramming" or "remodeling" to ensure an adequate supply of ATP and "building blocks" for cell survival and to facilitate accelerated proliferation. Cancer cells preferentially use glycolysis for ATP production (the Warburg effect); however, cancer cells, including colorectal cancer (CRC) cells, also depend on oxidative phosphorylation (OXPHOS) for ATP production, a finding that suggests that both glycolysis and OXPHOS play significant roles in facilitating cancer progression and proliferation. Our prior studies identified a semisynthetic isoflavonoid, DBI-1, that served as an AMPK activator targeting mitochondrial complex I. Furthermore, DBI-1 and a glucose transporter 1 (GLUT1) inhibitor, BAY-876, synergistically inhibited CRC cell growth in vitro and in vivo. We now report a study of the structure–activity relationships (SARs) in the isoflavonoid family in which we identified a new DBI-1 analog, namely, DBI-2, with promising properties. Here, we aimed to explore the antitumor mechanisms of DBIs and to develop new combination strategies by targeting both glycolysis and OXPHOS. We identified DBI-2 as a novel AMPK activator using an AMPK phosphorylation assay as a readout. DBI-2 inhibited mitochondrial complex I in the Seahorse assays. We performed proliferation and Western blotting assays and conducted studies of apoptosis, necrosis, and autophagy to corroborate the synergistic effects of DBI-2 and BAY-876 on CRC cells in vitro. We hypothesized that restricting the carbohydrate uptake with a KD would mimic the effects of GLUT1 inhibitors, and we found that a ketogenic diet significantly enhanced the therapeutic efficacy of DBI-2 in CRC xenograft mouse models, an outcome that suggested a potentially new approach for combination cancer therapy. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF