Metabolism & Bioenergetics MCAT Practice Question
A 58-year-old man with newly diagnosed pancreatic adenocarcinoma is enrolled in a clinical trial testing a novel glutaminase inhibitor. Baseline imaging shows a 4 cm tumor with no distant metastases. After 2 weeks of treatment, tumor biopsy reveals decreased cell proliferation and increased apoptosis despite adequate serum glucose levels (95 mg/dL) and normal ATP levels measured in tissue samples. The patient's tumor cells demonstrate impaired amino acid synthesis and reduced capacity for anabolic reactions. Which of the following best explains the mechanism by which glutaminase inhibition slows tumor growth in this patient?
Answer choices
- ADepletion of glutamate needed for TCA cycle anaplerotic reactions and biosynthetic precursorsCorrect answer
- BReduced acetyl-CoA carboxylase activity, preventing fatty acid elongation
- CDecreased NADPH production from the oxidative pentose phosphate pathway
- DImpaired Complex I function from reduced mitochondrial NADH oxidation
- EDirect inhibition of mTOR signaling through amino acid sensor deprivation
- FBlocked pyruvate carboxylase activity in the mitochondrial matrix
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