Breast Cancer Cell Line-Specific Responses to Insulin: Effects on Proliferation and Migration

Area of Science:

• Endocrinology
• Oncology
• Cell Biology

Background:

• The diabetic microenvironment, marked by hyperglycemia and hyperinsulinemia, influences breast cancer (BC) progression.
• Cellular mechanisms linking the diabetic microenvironment to BC progression require further elucidation.

Purpose of the Study:

• To investigate the effects of supra-physiological glucose and insulin levels on hormone-responsive (MCF-7) and triple-negative (MDA-MB-231) BC cell models.
• To analyze the impact of hyperinsulinemia on PI3K/AKT and MAPK pathways, cell proliferation, cell cycle, and migration in distinct BC subtypes.

Main Methods:

• Exposure of MCF-7 and MDA-MB-231 cells to high glucose and/or high insulin conditions.
• Analysis of AKT and MAPK pathway activation (phosphorylation).
• Assessment of cell proliferation, cell cycle distribution, and cell migration.

Main Results:

• High insulin activated the AKT pathway in both cell lines.
• Hyperinsulinemia stimulated proliferation and altered cell cycle distribution only in MCF-7 cells.
• High glucose alone did not affect proliferation; high insulin did not further increase proliferation when combined with high glucose.
• MDA-MB-231 cells showed increased migration but not proliferation after chronic hyperinsulinemia exposure.
• AKT inhibition blocked the proliferative stimulus in MCF-7 cells.

Conclusions:

• Chronic hyperinsulinemia, not hyperglycemia, exerts subtype-specific effects on breast cancer.
• Hyperinsulinemia promotes proliferation in hormone-responsive BC cells via AKT activation.
• Hyperinsulinemia enhances migration in triple-negative BC cells.
• Targeting insulin pathways may offer therapeutic potential for specific breast cancer subtypes.