RESUMO
In MCF-7 breast cancer cells epidermal growth factor (EGF) induces cell proliferation, whereas heregulin (HRG)/neuregulin (NRG) induces irreversible phenotypic changes accompanied by lipid accumulation. Although these changes in breast cancer cells resemble processes that take place in the tissue, there is no understanding of signalling mechanisms regulating it. To identify molecular mechanisms mediating this cell-fate decision process, we applied different perturbations to pathways activated by these growth factors. The results demonstrate that phosphoinositide 3 (PI3) kinase (PI3K) and mammalian target of rapamycin (mTOR) complex (mTORC)1 activation is necessary for lipid accumulation that can also be induced by insulin, whereas stimulation of the extracellular-signal-regulated kinase (ERK) pathway is surprisingly dispensable. Interestingly, insulin exposure, as short as 4 h, was sufficient for triggering the lipid accumulation, whereas much longer treatment with HRG was required for achieving similar cellular response. Further, activation patterns of ATP citrate lyase (ACLY), an enzyme playing a central role in linking glycolytic and lipogenic pathways, suggest that lipids accumulated within cells are produced de novo rather than absorbed from the environment. In the present study, we demonstrate that PI3K pathway regulates phenotypic changes in breast cancer cells, whereas signal intensity and duration is crucial for cell fate decisions and commitment. Our findings reveal that MCF-7 cell fate decisions are controlled by a network of positive and negative regulators of both signalling and metabolic pathways.
Assuntos
Neoplasias da Mama/metabolismo , Sistema de Sinalização das MAP Quinases , ATP Citrato (pro-S)-Liase/genética , ATP Citrato (pro-S)-Liase/metabolismo , Neoplasias da Mama/genética , Neoplasias da Mama/patologia , Feminino , Humanos , Insulina/genética , Insulina/metabolismo , Células MCF-7 , Alvo Mecanístico do Complexo 2 de Rapamicina , Complexos Multiproteicos/genética , Complexos Multiproteicos/metabolismo , Proteínas de Neoplasias/genética , Proteínas de Neoplasias/metabolismo , Neuregulina-1/genética , Neuregulina-1/metabolismo , Fosfatidilinositol 3-Quinases/genética , Fosfatidilinositol 3-Quinases/metabolismo , Serina-Treonina Quinases TOR/genética , Serina-Treonina Quinases TOR/metabolismoRESUMO
The paper presents a detailed study of the biological effects of two amino acid hydroxyurea derivatives that showed selective antiproliferative effects in vitro on the growth of human tumor cell line SW620. Tested compounds induced cell cycle perturbations and apoptosis. Proteins were identified by proteomics analyses using two-dimensional gel electrophoresis coupled to mass spectrometry, which provided a complete insight into the most probable mechanism of action on the protein level. Molecular targets for tested compounds were analyzed by cheminformatics tools. Zinc-dependent histone deacetylases were identified as potential targets responsible for the observed antiproliferative effect.
Assuntos
Aminoácidos/química , Antineoplásicos/química , Hidroxiureia/análogos & derivados , Animais , Antineoplásicos/farmacologia , Antineoplásicos/uso terapêutico , Apoptose/efeitos dos fármacos , Sítios de Ligação , Pontos de Checagem do Ciclo Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Neoplasias do Colo/metabolismo , Neoplasias do Colo/mortalidade , Neoplasias do Colo/patologia , Eletroforese em Gel Bidimensional , Histona Desacetilases/química , Histona Desacetilases/metabolismo , Humanos , Hidroxiureia/farmacologia , Hidroxiureia/uso terapêutico , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Simulação de Acoplamento Molecular , Estrutura Terciária de Proteína , Proteoma/análise , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por MatrizRESUMO
Hydroxyurea has been used for decades and it is still valuable for the treatment of some types of cancer. It inhibits ribonucleotide reductase (RNR) enzyme known to be crucial in the conversion of ribonucleotides into deoxyribonucleotides. However, nowadays the main focus has shifted to structurally similar hydroxamic acid derivatives that target specific enzymes involved in cancer progression such as histone deacetylases, matrix metalloproteinases and also RNR.