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1.
Cell Death Dis ; 11(3): 192, 2020 Mar 17.
Artigo em Inglês | MEDLINE | ID: mdl-32184394

RESUMO

Conditions of impaired adrenal function and tissue destruction, such as in Addison's disease, and treatment resistance of adrenocortical carcinoma (ACC) necessitate improved understanding of the pathophysiology of adrenal cell death. Due to relevant oxidative processes in the adrenal cortex, our study investigated the role of ferroptosis, an iron-dependent cell death mechanism and found high adrenocortical expression of glutathione peroxidase 4 (GPX4) and long-chain-fatty-acid CoA ligase 4 (ACSL4) genes, key factors in the initiation of ferroptosis. By applying MALDI mass spectrometry imaging to normal and neoplastic adrenocortical tissue, we detected high abundance of arachidonic and adrenic acid, two long chain polyunsaturated fatty acids which undergo peroxidation during ferroptosis. In three available adrenal cortex cell models (H295R, CU-ACC1 and CU-ACC-2) a high susceptibility to GPX4 inhibition with RSL3 was documented with EC50 values of 5.7 × 10-8, 8.1 × 10-7 and 2.1 × 10-8 M, respectively, while all non-steroidogenic cells were significantly less sensitive. Complete block of GPX4 activity by RSL3 led to ferroptosis which was completely reversed in adrenal cortex cells by inhibition of steroidogenesis with ketoconazole but not by blocking the final step of cortisol synthesis with metyrapone. Mitotane, the only approved drug for ACC did not induce ferroptosis, despite strong induction of lipid peroxidation in ACC cells. Together, this report is the first to demonstrate extraordinary sensitivity of adrenal cortex cells to ferroptosis dependent on their active steroid synthetic pathways. Mitotane does not induce this form of cell death in ACC cells.

2.
Nat Rev Cancer ; 16(11): 732-749, 2016 11.
Artigo em Inglês | MEDLINE | ID: mdl-27658529

RESUMO

Lipid metabolism, in particular the synthesis of fatty acids (FAs), is an essential cellular process that converts nutrients into metabolic intermediates for membrane biosynthesis, energy storage and the generation of signalling molecules. This Review explores how different aspects of FA synthesis promote tumorigenesis and tumour progression. FA synthesis has received substantial attention as a potential target for cancer therapy, but strategies to target this process have not yet translated into clinical practice. Furthermore, efforts to target this pathway must consider the influence of the tumour microenvironment.


Assuntos
Carcinogênese/metabolismo , Ácidos Graxos/biossíntese , Neoplasias/metabolismo , Progressão da Doença , Ácidos Graxos/metabolismo , Humanos , Metabolismo dos Lipídeos/fisiologia , Proteínas de Ligação a Elemento Regulador de Esterol/metabolismo , Microambiente Tumoral/fisiologia
3.
Sci Rep ; 5: 17576, 2015 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-26620400

RESUMO

Tumors are characterized by a rigid, highly cross-linked extracellular matrix (ECM), which impedes homogeneous drug distribution and potentially protects malignant cells from exposure to therapeutics. Lysyl oxidases are major contributors to tissue stiffness and the elevated expression of these enzymes observed in most cancers might influence drug distribution and efficacy. We examined the effect of lysyl oxidases on drug distribution and efficacy in 3D in vitro assay systems. In our experiments elevated lysyl oxidase activity was responsible for reduced drug diffusion under hypoxic conditions and consequently impaired cytotoxicity of various chemotherapeutics. This effect was only observed in 3D settings but not in 2D-cell culture, confirming that lysyl oxidases affect drug efficacy by modification of the ECM and do not confer a direct desensitizing effect. Both drug diffusion and efficacy were strongly enhanced by inhibition of lysyl oxidases. The results from the in vitro experiments correlated with tumor drug distribution in vivo, and predicted response to therapeutics in murine tumor models. Our results demonstrate that lysyl oxidase activity modulates the physical barrier function of ECM for small molecule drugs influencing their therapeutic efficacy. Targeting this process has the potential to significantly enhance therapeutic efficacy in the treatment of malignant diseases.


Assuntos
Antineoplásicos/farmacologia , Inibidores Enzimáticos/farmacocinética , Proteínas de Neoplasias/antagonistas & inibidores , Neoplasias Experimentais/tratamento farmacológico , Neoplasias Experimentais/enzimologia , Proteína-Lisina 6-Oxidase/antagonistas & inibidores , Animais , Linhagem Celular Tumoral , Sinergismo Farmacológico , Feminino , Humanos , Camundongos , Ensaios Antitumorais Modelo de Xenoenxerto
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