Abstract
Abstract: :
Purpose: The aim of this study is to describe the cell proliferation profile of five uveal melanoma cell lines, using various techniques such as immunohistochemistry (IH), DNA flow cytometry (DFC) and tritiated thymidine uptake (TTU), and then compare this profile with the metastatic potential (MP) of the cell lines (92.1, SP6.5, OCM-1, UW-1, MKT-BR), determined in a previously reported immunosuppressed rabbit model of uveal melanoma. Methods: Paraformaldehyde-fixed cytospins of the 5 cell lines were immunostained using a monoclonal antibody against proliferating cell nuclear antigen (PCNA). The percentage of PCNA positive cells was recorded for each cell line. DFC with Propidium Iodide was performed, giving a percentage of cells in S, G1 and G2 phases and then the cell lines were ranked according to the S phase fraction (SPF). A TTU experiment was carried out to measure the DNA synthesis rate of each cell line over a 6-hour period and then the cell lines were ranked accordingly. Both cell line ranks, according to SPF and DNA synthesis rate, were compared with the previously determined rank of cell line MP (92.1≷SP6.5≷ OCM-1=UW-1≷MKT-BR no MP). Results: At least 90% of the cells in each cell line were shown to be positive for PCNA. From DFC, the percentage of cells in each cell cycle phase was: for 92.1, 14.9% of cells were in S, 78.3% in G1 and 6.8% in G2, for SP6.5, 13.6% of cells were in S, 79.6% in G1, and 6.8% in G2, for OCM-1, 18.4% of cells were in S, 77% in G1, and 4.6 in G2, for UW-1, 12.5% of the cells were in S, 82.2% in G1 and 5.3% in G2, for MKT-BR, 15.7% of cells were in S, 79.2% in G1, and 5.1% in G2. The cell line rank according to SPF was OCM-1≷ MKT-BR≷ 92.1≷SP6.5≷ UW-1. The cell line rank according to DNA synthesis rate was 92.1≷SP6.5≷MKT-BR≷OCM-1≷UW-1. The TTU experiment is to be repeated for a total of three trials. Conclusion: PCNA is a reliable marker for proliferating cells. However, it was not useful in ranking the 5 cell lines. DFC indicated that the majority of cells in the 5 cell lines were in the G1 phase of the cell cycle. SPF is part of the profile but did not correlate with MP. TTU showed that the cell lines with the highest DNA cell proliferation synthesis rates (92.1, SP6.5) are the cell lines with the highest metastatic potential.
Keywords: 434 immunohistochemistry • 413 flow cytometry • 523 proliferation