Simvastatin induces apoptosis in PTEN‑haploinsufficient lipoma cells

Area of Science:

• Oncology
• Molecular Biology
• Pharmacology

Background:

• Adipose tissue tumors (lipomas) are common in patients with germ line mutations in the phosphatase and tensin homolog (PTEN) gene.
• Simvastatin is known to have antitumor properties.

Purpose of the Study:

• To investigate the effects of simvastatin on the growth of human PTEN haploinsufficient lipoma cells.
• To determine if simvastatin upregulates PTEN expression in lipomas.

Main Methods:

• Treatment of human lipoma cells with simvastatin.
• Assessment of cell viability, apoptosis, and PTEN expression (mRNA and protein).
• Analysis of protein kinase B, mammalian target of rapamycin (mTOR) pathway, and 4E-binding protein (4E-BP)-1 phosphorylation.
• Investigation of peroxisome proliferator-activated receptor (PPAR)γ involvement using small interfering RNA (siRNA).

Main Results:

• Simvastatin reduced lipoma cell viability and induced apoptosis.
• Simvastatin increased cellular PTEN mRNA and protein expression.
• Simvastatin attenuated the phosphorylation of protein kinase B and downstream mTOR targets, including 4E-BP-1.
• Simvastatin upregulated PTEN transcription via increased PPARγ expression.
• PPARγ knockdown abrogated simvastatin's effect on PTEN protein but not apoptosis.

Conclusions:

• Simvastatin demonstrates anti-lipoma effects by reducing cell viability and inducing apoptosis.
• Simvastatin upregulates PTEN expression, potentially through PPARγ activation.
• Simvastatin may be a therapeutic option for patients with inoperable PTEN haploinsufficient lipomas.