Metformin-activated AMPK regulates β-catenin to reduce cell proliferation in colon carcinoma RKO cells

Area of Science:

• Cell Biology
• Metabolic Pathways
• Cancer Signaling

Background:

• Metformin is known to inhibit cell proliferation and viability.
• This effect is linked to alterations in mitochondrial energy metabolism and AMPK activation.
• The precise mechanisms, particularly concerning signaling pathways like Wnt, require further elucidation.

Purpose of the Study:

• To investigate the role of AMPK in mediating metformin's effects on cell proliferation.
• To determine the impact of metformin and AMPK activation on beta-catenin-dependent Wnt signaling.
• To elucidate the molecular mechanisms underlying metformin-induced suppression of cell growth.

Main Methods:

• Utilized RKO cells for experimental treatment with metformin.
• Assessed changes in mitochondrial oxidative phosphorylation and glycolysis.
• Measured beta-catenin expression in cytoplasm and nucleus.
• Investigated the interaction between AMPK and beta-catenin.
• Employed proteasome inhibition and AMPK inhibition to validate findings.

Main Results:

• Metformin treatment reduced mitochondrial oxidative phosphorylation and glycolysis, causing cellular energy imbalance.
• Metformin decreased both cytoplasmic and nuclear beta-catenin expression.
• Active AMPK was found to associate with beta-catenin, leading to its cytoplasmic sequestration and proteasomal degradation.
• AMPK inhibition partially reversed metformin-induced suppression of cell proliferation.
• Metformin effectively inhibited Wnt-mediated cell proliferation and beta-catenin expression.

Conclusions:

• AMPK activation plays a crucial role in metformin's anti-proliferative effects.
• AMPK suppresses beta-catenin-dependent Wnt signaling by promoting beta-catenin's cytoplasmic sequestration and degradation.
• This mechanism, alongside mitochondrial dysfunction, contributes to metformin's ability to decrease cancer cell proliferation.