RAD6B Loss Disrupts Expression of Melanoma Phenotype in Part by Inhibiting WNT/β-Catenin Signaling

Area of Science:

• Oncology
• Molecular Biology
• Genetics

Background:

• Canonical Wnt signaling is crucial for melanocyte development and melanoma.
• RAD6B, a ubiquitin-conjugating enzyme, enhances beta-catenin stability and activity, creating a feedback loop with Wnt signaling.
• The role of RAD6B in melanoma progression is not fully understood.

Purpose of the Study:

• To investigate the function of RAD6B in melanoma development and progression.
• To evaluate RAD6B as a therapeutic target in melanoma.

Main Methods:

• RAD6B was targeted using CRISPR/Cas9 gene editing and a small-molecule inhibitor (SMI#9).
• Melanoma cell proliferation, protein expression, migration, invasion, tumor growth, and metastasis were assessed.
• RNA-sequencing and RT-PCR were used to analyze gene expression changes, including Wnt signaling pathway components.

Main Results:

• RAD6B inhibition or knockout reduced melanoma cell proliferation, migration, invasion, tumor growth, and lung metastasis.
• Targeting RAD6B downregulated key proteins like beta-catenin, MITF, SOX10, and vimentin.
• RAD6B disruption led to reduced expression of WNT1 and beta-catenin-regulated genes involved in melanocyte development and pigmentation.

Conclusions:

• RAD6B plays a significant role in melanoma development beyond its DNA repair function.
• Targeting RAD6B represents a promising therapeutic strategy for melanomas with aberrant Wnt signaling.