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Identification of NDUFAF1 in mediating K-Ras induced mitochondrial dysfunction by a proteomic screening approach
Peng Wang1,2, Ming Song1, Zhao-lei Zeng1
1Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center of Cancer Medicine, Guangzhou, China.
Abstract:
Increase in aerobic glycolysis and mitochondrial dysfunction are important biochemical features observed in human cancers. Recent studies suggest oncogenic K-Ras can cause suppression of mitochondrial respiration and up-regulation of glycolytic activity through a yet unknown mechanism. Here we employed proteomic approach and used a K-RasG12V inducible cell system to investigate the impact of oncogenic K-Ras on mitochondria and cell metabolism. Mitochondria isolated from cells before and after K-Ras induction were subjected to protein analysis using stable isotope labeling with amino acids (SILAC) and liquid chromatography coupled with mass spectrometry (LC-MS). 70 mitochondrial proteins with significant expression alteration after K-Ras induction were identified. A majority of these proteins were involved in energy metabolism. Five proteins with significant decrease belong to mitochondrial respiratory chain complex I. NADH dehydrogenase 1 alpha subcomplex assembly factor 1 (NDUFAF1) showed most significant decrease by 50%. Such decrease was validated in primary human pancreatic cancer tissues. Knockdown of NDUFAF1 by siRNA caused mitochondrial respiration deficiency, accumulation of NADH and subsequent increase of glycolytic activity. Our study revealed that oncogenic K-Ras is able to induce significant alterations in mitochondrial protein expression, and identified NDUFAF1 as an important molecule whose low expression contributes to mitochondrial dysfunction induced by K-Ras.
Insights
Oncogenic K-Ras alters mitochondrial protein expression, decreasing NDUFAF1 and impairing respiration. This leads to increased glycolysis, a key feature of cancer metabolism.
Area of Science:
- Biochemistry
- Molecular Biology
- Cancer Research
Background:
- Increased aerobic glycolysis and mitochondrial dysfunction are hallmarks of human cancers.
- Oncogenic K-Ras is implicated in suppressing mitochondrial respiration and upregulating glycolysis via unknown mechanisms.
Purpose of the Study:
- To investigate the impact of oncogenic K-Ras on mitochondrial function and cellular metabolism using a proteomic approach.
- To identify specific mitochondrial proteins affected by oncogenic K-Ras.
Main Methods:
- Utilized a K-RasG12V inducible cell system and isolated mitochondria.
- Employed stable isotope labeling with amino acids (SILAC) and liquid chromatography-mass spectrometry (LC-MS) for proteomic analysis.
- Validated findings in primary human pancreatic cancer tissues and used siRNA for gene knockdown.
Main Results:
- Identified 70 mitochondrial proteins with altered expression post-K-Ras induction, predominantly involved in energy metabolism.
- Observed a significant decrease in five proteins of the mitochondrial respiratory chain complex I, notably NADH dehydrogenase 1 alpha subcomplex assembly factor 1 (NDUFAF1) by 50%.
- Knockdown of NDUFAF1 resulted in mitochondrial respiration deficiency, NADH accumulation, and increased glycolytic activity.
Conclusions:
- Oncogenic K-Ras induces significant alterations in mitochondrial protein expression.
- NDUFAF1 is identified as a key molecule whose reduced expression contributes to K-Ras-induced mitochondrial dysfunction and metabolic reprogramming in cancer.
