WNT5A-ROR2 axis mediates VEGF dependence of BRAF mutant melanoma

Area of Science:

• Oncology
• Molecular Biology
• Cancer Research

Background:

• Metastatic melanoma remains a significant cause of cancer mortality.
• BRAF-mutant melanomas (BRAFMut) exhibit a poorer prognosis compared to wild-type (BRAFWT) tumors.
• Adjuvant anti-VEGF bevacizumab showed an unexpected benefit in BRAFMut patients in the AVAST-M trial.

Purpose of the Study:

• To elucidate the mechanisms responsible for bevacizumab sensitivity in BRAFMut melanomas.
• To investigate the role of specific molecular pathways in BRAFMut melanoma progression and treatment response.

Main Methods:

• In vitro and in vivo studies using isogenic melanoma cell lines with BRAFV600E knock-in.
• Analysis of gene expression differences between BRAFV600E and BRAFWT melanoma cells.
• Assessment of tumor growth, vascularity, and necrosis in xenograft models treated with bevacizumab.

Main Results:

• BRAFV600E clones exhibited higher VEGF secretion, accelerated growth, and increased vascularity compared to BRAFWT cells.
• Bevacizumab treatment significantly delayed tumor growth, reduced vascularity, and increased necrosis specifically in BRAFV600E xenografts.
• The WNT5A-ROR2 signaling axis was identified as a key regulator of VEGF secretion and was upregulated in BRAFV600E melanomas.

Conclusions:

• The WNT5A-ROR2 pathway is implicated in the enhanced VEGF secretion, vascularity, and bevacizumab sensitivity observed in BRAFMut melanomas.
• Targeting the WNT5A-ROR2 axis presents a potential therapeutic strategy for improving outcomes in BRAFMut melanoma.
• Understanding these molecular mechanisms can guide the development of more effective melanoma treatments.