Degradation of AMPK‐α1 sensitizes BRAF inhibitor‐resistant melanoma cells to arginine deprivation

Autor: Macus Tien Kuo, Miguel Suarez, Xiaoqing Han, Sumedh S. Shah, Medhi Wangpaichitr, Ying-Ying Li, Niramol Savaraj, Chunjing Wu, Shu Mei Chen, Lynn G. Feun, Jeffrey S. Prince
Jazyk: angličtina
Rok vydání: 2017
Předmět:
0301 basic medicine
Proto-Oncogene Proteins B-raf
Cancer Research
Proteasome Endopeptidase Complex
autophagy
Arginine
Ubiquitin-Protein Ligases
Mice
Nude
Apoptosis
AMP-Activated Protein Kinases
lcsh:RC254-282
03 medical and health sciences
Downregulation and upregulation
Cell Line
Tumor
Genetics
medicine
Animals
Humans
metabolic reprogramming
Protein kinase B
Melanoma
Protein Kinase Inhibitors
Ubiquitins
Research Articles
biology
MEK inhibitor
Autophagy
Glucose transporter
ubiquitin‐proteasome system
General Medicine
medicine.disease
lcsh:Neoplasms. Tumors. Oncology. Including cancer and carcinogens
AMPK‐α1
DNA-Binding Proteins
030104 developmental biology
Oncology
E3 ubiquitin ligase
Drug Resistance
Neoplasm
BRAF inhibitor‐resistant melanoma
Proteolysis
Cancer research
biology.protein
Molecular Medicine
GLUT1
Female
Research Article
Zdroj: Molecular Oncology, Vol 11, Iss 12, Pp 1806-1825 (2017)
Molecular Oncology
ISSN: 1574-7891
1878-0261
Popis: Melanomas harboring BRAF mutation (V600E) are known to recur frequently following treatment with BRAF inhibitors (BRAFi) despite a high initial response rate. Our previous study has uncovered that BRAFi-resistant melanoma (BR) cells are vulnerable to arginine deprivation. It has been reported that naive melanoma cells undergo autophagy and re-express argininosuccinate synthetase 1 (ASS1) to enable them to synthesize arginine for survival when encountering arginine deprivation. Abolishing these two factors in BR cells confers sensitivity to arginine deprivation. In this report, we further demonstrated that downregulation of AMPK-α1 in BR cells is a major factor contributing to impairment of autophagy as evidenced by decreased autophagosome formation. These BR cells also showed a metabolic shift from glucose to arginine dependence, which was supported by decreased expressions of GLUT1 (glucose transporter) and hexokinase II (HKII) coupled with less glucose uptake but high levels of arginine transporter CAT-2 expression. Furthermore, silencing CAT-2 expression also distinctly attenuated BR cell proliferation. Notably, when naive melanoma cells became BR cells by long-term exposure to BRAFi, a stepwise degradation of AMPK-α1 was initiated via ubiquitin-proteasome system (UPS). We discovered that a novel E3 ligase, RING finger 44 (RNF44), is responsible for promoting AMPK-α1 degradation in BR cells. RNF44 expression in BR cells was upregulated by transcription factor CREB triggered by hyperactivation of ERK/AKT. High levels of RNF44 corresponding to low levels of AMPK-α1 appeared in BR xenografts and melanoma tumor samples from BR and BRAFi/MEK inhibitor (MEKi)-resistant (BMR) melanoma patients. Similar to BR cells, BMR cells were also sensitive to arginine deprivation. Our study provides a novel insight into the mechanism whereby BRAFi or BRAFi/MEKi resistance drives proteasomal degradation of AMPK-α1 and consequently regulates autophagy and metabolic reprogramming in melanoma cells.
Databáze: OpenAIRE
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