Transcriptome and metabolomic studies of cancer cells as a tool for understanding the metabolic adaptation process

Abstract

Tumor cells have altered metabolism compared to quiescent cells, needing constant supplements of macromolecular precursors to sustain their growth and proliferation. The glutaminolytic and glycolytic pathways are the main generators of these metabolic precursors used for the synthesis of proteins, nucleic acids and lipids. The uptake and metabolism of glucose with significant secretion of lactate even in the presence of oxygen (making it different from the lactic fermentation), known as aerobic glicolysis or Warburg effect, as well as the increased levels of glutaminolysis in cancer cells, have been recognized as hallmarks of the tumor transformation and correlate with their high energy and biosynthetic demands. It was only in the last ten years that researchers started to understand how these pathways are up-regulated in tumor cells through the action of different oncogenes and the absence of certain tumor suppressors. However, little is known about how these two pathways are coordinated in order to ensure the continuous proliferation phenotype of tumors. The metabolic phenotype of a cell is not static, but emerges from the coordinated and dynamic network of interactions between genes, proteins and metabolites. Given the complexity of these relationships, the application of systematic studies, such as transcriptomics and metabolomics, has the potential to contribute to the understanding of biological mechanisms of tumors. The objective of this project is to have the gene expression profile of glucose and glutamine metabolic genes by using modern high-throughput sequencing techniques (RNAseq), and the metabolomic profile by nuclear magnetic resonance (metabolic flux of glucose and glutamine labeled with 13C and 15N) of cell lines of breast cancer with different phenotypes for the presence of the progesterone receptor (PR), the estrogen receptor (ER) and the membrane receptor Her2. Specifically, we will evaluate the lines MCF10, MCF7, SKBR3, BT-549, Hs 578T, MDA-MB-231, MDA-MB-436 and MDA-MB-453 which have different backgrounds of genetic lesions. Many of them exhibit a phenotype described as triple-negative (PR-, ER-, Her2-), known to be difficult to treat due to their resistance to existing hormonal therapies. Moreover, they have been described to have increased glucose uptake compared with the non-triple negative types. With these analyzes, the objective is to trace the process of tumor metabolic adaptation by recognizing the "metabolic pathways" used between the different tumor cell lines analyzed with focus on their correlation with the hormone receptors status. In a larger perspective, new genes important for the process can be recognized, as well as isoforms and mutations not previously appreciated, which can lead to the proposal of new forms of therapeutic intervention of the breast cancer triple-negative. (AU)