Abstract 57: Twist1 modifies the metabolic state of breast cancer cells through transcriptional activation of a key regulator of glycolysis
Authors: Casas Esmeralda , Santidrian Antonio F. , Lorger Mihaela , Torkamani Ali , Ratnikov Boris , Saayman Sheena M. , Steele Julie B. , Jeffrey Smith W. , Felding Brunhilde 
Published: July 2016

Abstract
The shift from a normal to high glycolytic state (Warburg effect) is a central hallmark of almost every cancer and a strong driving force for cancer cell survival and disease progression. Importantly, studies - including our own - have shown that normalization of metabolic state in cancer cells can halt or reverse malignancy. To date, the intrinsic and extrinsic factors that drive metabolic shifts in cancer cells are not entirely clear. A better understanding of how the metabolic state of cancer cells is regulated will give us important tools to inhibit disease progression. We have established a novel model of breast cancer progression consisting of three cancer cell lines established from the primary tumor (TES1) and two sites of metastasis (TES2b and TESPE) of the same patient. We compared gene expression profiles between primary and recurrent tumor cells to identify factors that regulate disease progression and dissemination. Key differences between cells derived from primary and recurrent disease were an activation of genes involved in glycolysis and genes involved in activation and maintenance of the epithelial to mesenchymal transition (EMT) program, a powerful driver of cancer metastasis. Our analyses on a functional relationship between EMT and activation of glycolysis uncovered a direct link between the malignancy-driving EMT mechanism in breast cancer progression and metabolic reprogramming of the tumor cells. Specifically, we identified Twist1, a pro-metastatic master regulator of EMT as a direct modulator of a key glycolytic enzyme known to modulate the rate of glycolysis, 6-Phosphofructo-2-kinase/Fructose-2,6-bisphosphatase 3 (PFKFB3). We found that Twist1 binds directly to the promoter region of PFKFB3 and induces expression of the enzyme. Additionally, inhibition of Twist1 expression in TES2b (TES2b-shTwist1) cells decreased glycolytic flux, while Twist1 overexpression in HMLE immortalized human breast epithelial cells (HMLE-Twist1) increased glycolytic activity and simultaneously decreased cellular respiration. Metabolomics analyses of HMLE vs. HMLE-Twist1 cells using Gas Chromatography Mass Spectroscopy (GCMS) indicated that Twist1 expression is sufficient to induce drastic changes in the overall metabolic state of the cells, including glutamine metabolism and availability of TCA cycle intermediates and amino acids. Together, our findings are significant as they underscore the importance and potency of EMT activation in cancer and uncover a novel mechanism by which EMT activation through Twist1 drives metabolic alterations that fuel cancer progression and metastasis. Results from this study will ultimately aid in the discovery and development of new paradigms to fight cancer mortality rates around the world.
Citation Format: Esmeralda Casas, Antonio F. Santidrian, Mihaela Lorger, Ali Torkamani, Boris Ratnikov, Sheena M. Saayman, Julie B. Steele, Smith W. Jeffrey, Brunhilde Felding. Twist1 modifies the metabolic state of breast cancer cells through transcriptional activation of a key regulator of glycolysis. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 57.