Abstract 3870: Ruxolitinib diminishes cell proliferation and invasiveness in BRAF mutated metastatic melanoma

Introduction: Treatment with a BRAF inhibitor of unresectable or metastatic melanoma with a BRAF V600E or V600K mutation has an estimated 5-year survival rate of 34%, with 19% being progression free. To improve outcomes, we hypothesize that the blocking of the JAK/STAT pathway via the use of Ruxolitinib, a direct JAK2 inhibitor, may decrease proliferation and invasiveness in BRAF mutated melanoma in vitro. Methods: BRAFV600E mutated melanoma cell line, SK-MEL-1, was obtained from ATCC. The effect of Ruxolitinib of proliferation was measured via a proliferation assay. Cells were treated with 0nM Ruxolitinib and 10nM Ruxolitinib for 24 hours, then counted with a hemocytometer. The effect of Ruxolitinib on invasiveness was evaluated through an invasion assay. After 24-36 hours, cells that invaded through a Matrigel coated membrane were fixed and stained with crystal violet, and then subsequently imaged by an inverted microscope. The number of invaded cells was quantified, and the total number of invaded cells was calculated by averaging the cell density (cells/um2) for each image and then multiplying that by the total membrane area. All data was normalized to their respective controls and analyzed using the appropriate statistical analysis. Results: In cells containing a BRAF mutation, Ruxolitinib caused a decrease in erythropoietin (EPO) induced proliferation. Modulation of EPOR with EPO, 10nM Ruxolitinib, and 10nM Ruxolitinib with EPO yielded a mean fold change over control in proliferation of 1.55 (95% CI: 1.16-1.94), 0.96 (95% CI: 0.84-1.09), and 1.24 (95% CI: 0.77-1.72), respectively (p=0.0254). In metastatic melanoma cells, Ruxolitinib significantly reduced invasiveness by a 0.48-fold change over control in proliferation. Additionally, Ruxolitinib blocked EPO induced increase in invasion, as EPO caused a 2.2-fold increase over control in invasiveness, however with the addition of Ruxolitinib there was a -0.04-fold change over control in invasion. Discussion: Here we show that JAK2 inhibition with Ruxolitinib diminishes erythropoietin (EPO) induced cell proliferation in an in-vitro model of invasive BRAF-mutated melanoma. We also show that Ruxolitinib decreases the invasive nature of metastatic melanoma, at baseline and when induced by EPO. Erythropoietin Receptor (EPOR) transduces signal through JAK/STAT and potentially contributes to a more aggressive phenotype. This provides initial evidence for future studies exploring the therapeutic role of Ruxolitinib in BRAF mutated melanoma. We further hypothesize that Ruxolitinib can be used in conjunction with BRAF inhibitors, such as Dabrafenib, to improve outcomes in metastatic melanoma. Citation Format: Raza Ahmed, Jayesh Menon, Rishka Raj, Rakesh Singh, Philip Friedlander, Omar Aljitawi. Ruxolitinib diminishes cell proliferation and invasiveness in BRAF mutated metastatic melanoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 3870.