Modeling lipid homeostasis using stable isotope tracing and flux analysis

Area of Science:

• Biochemistry
• Cell Biology
• Cancer Research

Background:

• Lipid metabolism is crucial for cellular function and membrane integrity.
• Dysregulated lipid metabolism is implicated in various diseases, including cancer.
• Existing tools for quantifying lipid metabolic fluxes are limited.

Purpose of the Study:

• To develop and apply a novel method, Lipid metabolic flux analysis (Lipid-MFA), for quantifying lipid metabolic fluxes.
• To investigate lipid homeostasis in non-small cell lung cancer (NSCLC) models.
• To elucidate the role of specific lipid metabolic pathways in cancer progression.

Main Methods:

• Stable isotope tracing combined with liquid chromatography-high-resolution mass spectrometry.
• Network-based isotopologue modeling to quantify metabolic fluxes.
• Application to precision-cut lung slice cultures of NSCLC models with different genetic backgrounds (p53-deficient vs. LKB1-deficient).

Main Results:

• Lipid-MFA successfully quantified key lipid synthesis, elongation, headgroup assembly, and salvage reactions.
• Observed decreased fatty acid synthase and very long-chain fatty acid (VLCFA) elongation fluxes in p53-deficient NSCLC.
• Identified increased sphingolipid recycling and unique ceramide trafficking patterns in specific NSCLC models.

Conclusions:

• Lipid-MFA is a versatile tool for analyzing lipid homeostasis across various biological systems.
• Distinct alterations in lipid metabolism, including fatty acid synthesis and sphingolipid metabolism, are associated with specific genetic defects in NSCLC.
• This approach provides valuable insights into the molecular mechanisms underlying lipid dysregulation in cancer.