β-Catenin Expression and Activation in Conjunctival Melanoma

Area of Science:

• Ophthalmology
• Oncology
• Molecular Biology

Background:

• Conjunctival melanoma is a rare malignancy.
• The Wnt signaling pathway is implicated in various cancers, including melanoma.
• Beta-catenin is a key mediator of the canonical Wnt pathway.

Purpose of the Study:

• To investigate the role of the canonical Wnt pathway, through beta-catenin activation, in the progression of conjunctival melanoma.
• To evaluate beta-catenin expression in conjunctival nevi, primary acquired melanoses (PAM), and conjunctival melanomas.

Main Methods:

• Immunohistochemistry was used to assess beta-catenin localization in 43 conjunctival nevi, 48 PAM, and 44 conjunctival melanomas.
• In vitro experiments involved stimulating 4 conjunctival melanoma cell lines and 1 skin melanoma cell line with Wnt3a or Wnt5a.
• Wound healing assays were conducted to assess cell motility after Wnt5a stimulation.

Main Results:

• Nuclear beta-catenin expression was observed in 16% of nevi, 15% of melanomas, and 4% of PAM.
• Membranous beta-catenin expression was present in nearly all samples.
• In vitro, Wnt3a or Wnt5a stimulation did not induce nuclear beta-catenin translocation or increase cell motility.

Conclusions:

• Nuclear beta-catenin localization and activation appear limited in conjunctival melanoma.
• The findings suggest that targeting ARF6 for beta-catenin inhibition may not be a viable treatment strategy for conjunctival melanoma.
• Canonical and noncanonical Wnt pathway activation did not significantly impact beta-catenin localization in conjunctival melanoma cells in vitro.