ATG5 Mediates a Positive Feedback Loop between Wnt Signaling and Autophagy in Melanoma

Area of Science:

• Oncology
• Molecular Biology
• Cellular Biology

Background:

• Autophagy contributes to anticancer agent resistance.
• Wnt5A expression is linked to melanoma therapy resistance and invasion.
• Wnt5A inhibits β-catenin, a key signaling molecule.

Purpose of the Study:

• To investigate the relationship between Wnt5A and autophagy in melanoma.
• To explore the feedback loop between Wnt5A, autophagy, and β-catenin.
• To assess the therapeutic implications of targeting autophagy in Wnt5A-expressing melanoma.

Main Methods:

• Analysis of human melanoma biopsies for Wnt5A and β-catenin expression.
• Functional studies in melanoma cell lines and mouse models.
• Genetic manipulation of autophagy factor ATG5 and β-catenin activity.
• In vitro and in vivo treatment with the lysosomotropic compound Lys05.

Main Results:

• Melanoma cells with high Wnt5A and low β-catenin exhibit increased basal autophagy.
• Blocking autophagy (ATG5 knockdown) in Wnt5A-high cells reduced Wnt5A and increased β-catenin.
• Wnt5A-high melanoma cells showed reduced sensitivity to Lys05, which was reversed by inducing β-catenin.

Conclusions:

• A feedback loop exists between Wnt5A, autophagy, and β-catenin in melanoma.
• Wnt5A influences melanoma cell sensitivity to autophagy-targeting agents.
• Therapeutic strategies targeting autophagy in melanoma should consider Wnt pathway status.