Abstract
Purpose :
Uveal melanomas represent one of the most common and fatal malignancies of the eye in adults.
Neuropilin-2 (NRP) is a transmembrane protein involved in, among other things, vascular and lymphatic development by regulating (lymph)-angiogenesis. Neuropilin-2 is also detected in many cancer entities, as well as expressed in other cell types, such as endothelial and immune cells, which may regulate functions such as (lymph)-angiogenesis and immune escape in the tumor microenvironment.
Methods :
The aim of the project was, inter alia, to determine the expression of neuropilin-2 in different uveal melanoma cell lines and to clarify whether neuropilin-2 is overexpressed in highly invasive and aggressive cell lines. In addition, the impact of neuropilin-2 on cell viability and proliferative behavior and apoptosis in uveal melanoma cell lines also were evaluated. The experiments were performed with 6 different cell lines of uveal melanome, three without chromosomal aberrations and three displaying loss of one chromosome 3. Neuropilin-2 expression was analyzed by flow cytometry and quantitative real-time PCR, both on proteomic and transcriptomic level. Viability was detected using a luminescence based assay, proliferation by flow cytometry detecting proliferation marker Ki-67. Level of apoptotic activity was measured by luminescent detection of Caspase9.
Results :
We were able to demonstrate that neuropilin-2 is expressed in all of the cell lines we tested and that its expression was significantly higher in so-called high-risk cell lines of uveal melanoma. Furthermore, both the inhibition of neuropilin-2 with a neutralizing antibody and a CRISPR-Cas9 generated knockout of NRP2 had an impact on cell line proliferation and viability and apoptosis. Thus, inhibition and knockout significantly decreased viability and proliferation, while apoptosis marker expression increased on a significant level.
Conclusions :
Thus these results showed that neuropilin-2 plays an important role in viability, induction of apoptotis and proliferation in uveal melanoma cell lines, the role of neuropilin-2 requires further investigation and may present a novel approach to therapy of uveal melanoma in future.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.