The study investigates the role of mitochondrial metabolism and reactive oxygen species (ROS) in Kras-mediated tumorigenicity. Key findings include: 1. **Glucose Metabolism and Pentose Phosphate Pathway**: Glucose metabolism supports the pentose phosphate pathway, which is crucial for nucleotide and phospholipid synthesis under normoxic conditions. Glycolysis primarily provides ATP for survival under hypoxic conditions. 2. **Glutamine Catabolism**: Glutamine is essential for Kras-induced anchorage-independent growth by being converted into alpha-ketoglutarate through the actions of glutaminase and alanine aminotransferase, facilitating TCA cycle intermediates. 3. **Mitochondrial ROS**: Mitochondrial metabolism generates ROS, which are critical for Kras-induced anchorage-independent growth. The Q0 site of mitochondrial complex III is the major source of ROS. Disruption of mitochondrial function, such as loss of mitochondrial transcription factor A (TFAM), reduces tumorigenesis in an oncogenic Kras-driven mouse model of lung cancer. 4. **ERK MAPK Signaling**: Mitochondrial ROS regulate cellular proliferation through the ERK MAPK pathway, dampening its activity to promote cell growth. 5. **In Vivo Studies**: Loss of mitochondrial function, as indicated by reduced TFAM levels, significantly impacts tumorigenesis in an oncogenic Kras-driven mouse model, suggesting that mitochondrial metabolism is essential for tumor growth. These findings highlight the critical role of mitochondrial metabolism and ROS in Kras-mediated tumorigenicity, providing new targets for therapeutic intervention.The study investigates the role of mitochondrial metabolism and reactive oxygen species (ROS) in Kras-mediated tumorigenicity. Key findings include: 1. **Glucose Metabolism and Pentose Phosphate Pathway**: Glucose metabolism supports the pentose phosphate pathway, which is crucial for nucleotide and phospholipid synthesis under normoxic conditions. Glycolysis primarily provides ATP for survival under hypoxic conditions. 2. **Glutamine Catabolism**: Glutamine is essential for Kras-induced anchorage-independent growth by being converted into alpha-ketoglutarate through the actions of glutaminase and alanine aminotransferase, facilitating TCA cycle intermediates. 3. **Mitochondrial ROS**: Mitochondrial metabolism generates ROS, which are critical for Kras-induced anchorage-independent growth. The Q0 site of mitochondrial complex III is the major source of ROS. Disruption of mitochondrial function, such as loss of mitochondrial transcription factor A (TFAM), reduces tumorigenesis in an oncogenic Kras-driven mouse model of lung cancer. 4. **ERK MAPK Signaling**: Mitochondrial ROS regulate cellular proliferation through the ERK MAPK pathway, dampening its activity to promote cell growth. 5. **In Vivo Studies**: Loss of mitochondrial function, as indicated by reduced TFAM levels, significantly impacts tumorigenesis in an oncogenic Kras-driven mouse model, suggesting that mitochondrial metabolism is essential for tumor growth. These findings highlight the critical role of mitochondrial metabolism and ROS in Kras-mediated tumorigenicity, providing new targets for therapeutic intervention.