Characterization of vemurafenib-resistant melanoma cell lines.

PEREZ C; CAMPO L; FALCON C; ALVAREZ SE

Congreso; SAIC 2019; 2019

In the last years, the incidence of melanoma, the most aggressive skin cancer, has increased rapidly. Approximately half of melanoma patients display the V600E mutation in the BRAF protein, which stimulates ERK activation and promotes proliferation. The FDA approves the use of 4 therapeutic agents that reduce ERK activity: i) Vemurafenib (VEM) and Dabrafenib (BRAF inhibitors) and ii) Trametinib and Cobimetinib (MEK inhibitors). Indeed, VEM is approved by ANMAT in Argentina. Unfortunately, the durability of the response is limited and the tumors quickly become resistant. The aim of this work was to generate and characterize VEM-resistant melanoma cell lines as tools to study possible resistance mechanisms in tumor cells. VEM-resistant cell variants were obtained by continuous exposure of original parental cells to increasing concentrations (0,01 ? 1µM) of VEM during 3 months. Inhibition of ERK signaling was analyzed by western blot and viability was determined by MTT assay. In addition, cell migration was evaluated in a modified Boyden Chamber. As assessed by inverted microscopy, Lu1205 melanoma-resistant cells exhibit a bigger volume and more prolongations and lamellipodia than their sensitive parents. In agreement, VEM-resistant Lu1205 cells showed greater migratory capacity than their parents under normal culture conditions. Moreover, in the presence of VEM (1M), levels of phospho-ERK were higher in resistant cells. On the other hand, no changes were detected in phospho-Akt levels, indicating that VEM only affects ERK signaling. In conclusion, the VEM-resistant melanoma cells obtained in our laboratory constitute a good model to study possible mechanisms involved in the development of resistance to BRAF inhibitors. Moreover, it will be useful to develop new inhibitors that may improve the response and durability of current therapies against melanoma, and potentially diminish resistance occurrence.