MR-visible lipids and the tumor microenvironment.

Area of Science:

• Biochemistry
• Cell Biology
• Medical Imaging

Background:

• MR-visible lipids are triglycerides and cholesterol esters within neutral lipid droplets.
• Their visibility in proton MRS stems from increased molecular motion in lipid droplets.
• These lipids are found in various cell types, including cancer, immune cells, and fibroblasts.

Purpose of the Study:

• To review the biogenesis of MR-visible lipids in different cell types.
• To explore the role of mobile lipids in cancer cells and tumors.
• To discuss their potential as biomarkers in cancer diagnosis and treatment response assessment.

Main Methods:

• Literature review focusing on MR-visible lipids in cellular and tissue contexts.
• Analysis of factors influencing mobile lipid accumulation under various conditions (stress, stimuli, apoptosis).
• Comparison of findings in cultured cells, animal tumor models, and human tumors.

Main Results:

• Mobile lipids accumulate in cancer cells and tumors, particularly high-grade brain tumors and necrotic regions, as a stress response.
• Factors like low pH, hypoxia, and inflammatory cells in the tumor microenvironment promote mobile lipid formation.
• Increased mobile lipids are observed following chemotherapy and radiotherapy in animal models.

Conclusions:

• MR-visible lipids in cancer are a stress response, potentially aiding in detoxification or energy supply in hypoxic environments.
• Mobile lipids show promise as biomarkers for cancer diagnosis and monitoring treatment efficacy.
• Despite technical challenges, early detection of mobile lipid changes post-therapy may indicate treatment response.