Molecular mechanisms involved in 3- bromopyruvate effect in colorectal cancer cell lines
| Autor: | Vieira, Joana Margarida Pereira |
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| Přispěvatelé: | Queirós, Odília Marques de, Casal, Margarida, Universidade do Minho |
| Jazyk: | angličtina |
| Rok vydání: | 2017 |
| Předmět: | |
| Zdroj: | Repositório Científico de Acesso Aberto de Portugal Repositório Científico de Acesso Aberto de Portugal (RCAAP) instacron:RCAAP |
| Popis: | Dissertação de mestrado em Genética Molecular Tumor cells present predominantly a glycolytic profile with increased glucose consumption and lactate production, even under aerobic conditions (Warburg effect). The high glycolytic rates in several tumors lead to the production of large amounts of lactate and upregulation of monocarboxylate transporters (MCTs), whose function is to export lactate into the extracellular milieu. This metabolic reprogramming enables cells to sustain the high proliferative rates and promotes an acidic microenvironment. 3- bromopyruvate (3BP) is an alkylating agent, which targets cancer cell metabolism and it has been demonstrated to be a powerful and specific antitumor agent either in in vitro or in vivo models. 3BP is an analogous compound of lactate, whose uptake into the cell occurs through MCTs, leading to depletion of intracellular ATP and thus acting as a cytotoxic agent. As tumor cells overexpress MCTs, they can serve as trap, allowing the uptake of 3BP. However, MCTs expression can change according to microenvironment conditions, including extracellular pH, hypoxia, starvation and, in the case of colorectal cancer (CRC), by the presence of short-chain fatty acids (SCFA) produced by intestinal microbiota. The aim of this work was to understand the regulation of MCTs in these different conditions in CRC cell lines and how it correlates with 3BP toxic effect. Our study showed that the three cell lines presented different sensitivities for 3BP: HCT-15< Caco-2< HT-29. In all these cell lines, 3BP decreased lactate production and cell viability and migration capacity. Concerning the expression of MCT1 and MCT4, proteins involved in 3BP uptake, it was observed that the HCT-15 cell line, the most sensitive to 3BP, presented an increased expression of MCT1 and MCT4, while the most resistant cell lines HT-29 and Caco-2 showed a lower expression of both proteins. The effect of different environment conditions on MCT1 and MCT4 expression was evaluated in the HCT- 15 cell line. HCT-15 cells were more resistant to 3BP when exposed to hypoxia or glucose starvation, although an increase in MCT expression levels has been observed in these conditions. Treatment with both butyrate and acetate, sensitized HCT-15 cells to 3BP and an increased expression of MCT4 was observed. Thus, the overall results suggest that MCTs can be involved in 3BP mechanism of action, possibly mediating 3BP uptake into the cell, but the resistance observed under the different should involve other factors beyond MCTs. As células tumorais apresentam um perfil glicolítico com elevados níveis de consumo de glucose e produção de lactato, mesmo sob condições aeróbias (efeito Warburg). Este fenótipo glicolítico presente em vários tumores resulta na produção excessiva de lactato e na sobre-expressão dos transportadores de monocarboxilatos (MCTs), envolvidos no transporte de lactato para o meio extracelular. Esta reprogramação metabólica suporta a elevada taxa de proliferação e promove um microambiente acídico. O 3-bromopiruvato (3BP) é um agente alquilante, que tem como alvo o metabolismo células tumorais e demonstrou ser um agente antitumoral poderoso, quer em modelos in vitro quer em in vivo. O 3BP é um análogo do lactato, cuja transporte ocorre via MCTs, levando à depleção de ATP intracelular, sendo um agente citotóxico. Os MCTs podem servir como armadilha para as células tumorais, onde estão sobre-expressos, permitindo a entrada do 3BP. Porém, a expressão dos MCTs pode alterar-se com as condições do microambiente tumoral, tais como o pH extracelular, a hipoxia, a escassez de glucose e, no caso de cancro colorectal (CRC), a presença de ácidos monocarboxílicos produzidos pela flora intestinal. O objetivo deste trabalho foi compreender a regulação dos MCTs nestas condições em linhas celulares de CRC e correlacionar com o efeito tóxico do 3BP. Neste estudo mostrámos que as três linhas celulares têm sensibilidades diferentes ao 3BP: HCT-15< Caco-2 |
| Databáze: | OpenAIRE |
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