PhD Scientific Days 2025

Poster Session II. - B: Molecular Medicine

EV pretreatment enhances melanoma cell migration despite dual MAPK pathway inhibition

Name of the presenter

Németh Afrodité

Institute/workplace of the presenter

Pázmány Péter Catholic University

Authors

Afrodité Németh¹, Alexandra Simon¹, Gréta Lilla Bányai¹, Tamás Márton Garay²

1: Pázmány Péter Catholic University
2: Pázmány Péter Catholic University, Semmelweis University

Text of the abstract

Introduction:
Extracellular vesicles (EVs) are lipid bilayer-enclosed nanoparticles released by all cell types, playing key roles in intercellular communication and cancer progression. In previous work, we found that EVs promote melanoma cell migration even under BRAF inhibitor (BRAFi) treatment. However, this effect was diminished when MEK inhibitors (MEKi) were combined with BRAFi, possibly because those cell lines were not exposed to MEKi previously. To address this, we developed a melanoma cell line resistant to both encorafenib (BRAFi) and binimetinib (MEKi) to study EVs involvement in resistance.
Methods:
Resistant clones were generated by long-term low-dose drug exposure and validated by SRB assays. Morphology and behavior were assessed via videomicroscopy, proliferation via cell counting, and migration through semi-automated tracking with CellTracker. EVs were isolated from both sensitive and resistant cells and characterized by Qubit (protein), SPV (lipid), and NTA (particle content and size). EVs effects were tested using two strategies: (1) co-treatment with drugs and EVs, and (2) EV pretreatment 24 hours prior to drug exposure.
Results:
Resistant cells showed altered morphology resembling epithelial-to-mesenchymal transition (EMT), with elongation and decreased circularity. Their proliferation and migration were reduced, while the produced EVs’ lipid content was significantly elevated. EVs treatment did not increased cell proliferation under BRAFi-MEKi treatment, however, EV pretreatment enhanced migration under dual drug pressure. Simultaneous EV-drug treatment failed to show such effect.
Conclusion:
These results suggest that EVs contribute to therapy resistance not only through binding or encapsulating the drug but also by transferring complex signals that modulate cell behavior over time. The enhanced migration following EV pretreatment implies a potential role in metastasis even under targeted therapy.