Metformin promotes survivin degradation through AMPK/PKA/GSK-3β-axis in non-small cell lung cancer

Area of Science:

• Oncology
• Molecular Biology
• Pharmacology

Background:

• Metformin, a common antidiabetic drug, exhibits anticancer properties across various cancer types.
• The precise molecular mechanisms underlying metformin's anticancer activity are not fully understood.
• Survivin, an inhibitor of apoptosis protein, is crucial in regulating cell death and is often overexpressed in cancers.

Purpose of the Study:

• To investigate the role of survivin in metformin's anticancer effects in non-small cell lung cancer (NSCLC) cells in vitro.
• To elucidate the molecular pathway through which metformin influences survivin expression and stability.

Main Methods:

• Utilized A549 and H460 human non-small cell lung cancer cell lines.
• Assessed metformin's effects on cell apoptosis, survivin expression, and protein stability.
• Investigated the involvement of adenosine 5 -monophosphate-activated protein kinase (AMPK), protein kinase A (PKA), and glycogen synthase kinase 3β (GSK-3β) signaling pathways.
• Employed activators (8-Br-cAMP, forskolin), inhibitors (LiCl, Compound C), and small interfering RNA (siRNA) to modulate pathway components.

Main Results:

• Metformin induced significant apoptotic cell death in NSCLC cell lines.
• Metformin suppressed survivin expression, reduced its stability, and promoted proteasomal degradation.
• Metformin inhibited PKA activity and activated GSK-3β.
• AMPK activation was observed following metformin treatment.
• Inhibition of AMPK reversed metformin-induced survivin degradation and restored PKA/GSK-3β activity.

Conclusions:

• Metformin exerts anticancer effects in non-small cell lung cancer by promoting survivin degradation.
• The mechanism involves the activation of the AMPK/PKA/GSK-3β signaling axis.
• This study provides novel insights into metformin's molecular anticancer mechanisms.