ZEB1 and Uveal Melanoma Invasiveness

Area of Science:

• Ophthalmology
• Oncology
• Molecular Biology

Background:

• Uveal melanoma (UM) is the most common adult intraocular tumor.
• ZEB1, a transcription factor, influences epithelial-to-mesenchymal transitions (EMTs) and cell plasticity.
• The role of ZEB1 in UM invasiveness and its relationship with VEGF signaling is not fully understood.

Purpose of the Study:

• To investigate the correlation between ZEB1 expression, tumor invasiveness, and melanocyte differentiation in UM.
• To examine the relationship between ZEB1, vascular endothelial growth factor (VEGF-A/VEGFR2), and UM cell characteristics.
• To evaluate the therapeutic potential of ZEB1 modulation in UM.

Main Methods:

• Characterization of eight UM cell cultures using electron transmission microscopy (ETM) for melanosomes.
• Quantification of ZEB1, VEGF-A, and VEGFR2 levels via RT-PCR, Western blot, ELISA, and flow cytometry.
• Assessment of ZEB1 knockdown effects on UM cell proliferation and sensitivity to aflibercept (Eylea) using MTT and real-time assays.

Main Results:

• Invasive UM tumors with high melanocyte differentiation showed varying ZEB1 levels; ZEB1-low cells were associated with spindle cell tumors.
• UM cell sensitivity to aflibercept inversely correlated with VEGFR2 levels.
• ZEB1 knockdown blocked VEGF-A production, while anti-VEGF treatment increased ZEB1 expression, indicating a regulatory loop.

Conclusions:

• ZEB1 acts as a positive regulator of VEGF-A expression in UM cells.
• A ZEB1 feedback loop sensitive to VEGF-A concentration likely exists.
• ZEB1 silencing presents a potential auxiliary strategy for combined UM cell-killing therapies.