Impact of BRAFV600E mutation on Immunogenic Cell Death in melanoma?.

FÁTIMA MARIA MENTUCCI; ELISA AYELEN ROMERO; LAMBERTI, MARÍA JULIA

SAL LUIS

Congreso; LXXI Reunión Anual de la Sociedad Argentina de Inmunología(SAI); 2023

SAI

The BRAFV600E mutation is of paramount clinical significance in melanoma, manifesting in a considerable proportion of cases (around 50%), and correlating with escalated tumor growth, progression, and diminished overall survival rates. This prominence has propelled us into a targeted exploration of its potential impact on immunogenic cell death (ICD), a distinctive type of cellular demise that not only orchestrates cancer cell elimination but also prompts robust immune responses through the release of danger-associated molecular patterns (DAMPs). The primary focus of this study was to unravel the potential influence of this mutation on both the induction and the underlying molecular events associated with ICD. Two distinct melanoma cell lines were utilized: one harboring the wild-type BRAF (SK-MEL-2) and the other carrying the BRAFV600E mutation (LU1205). These cell lines were subjected to treatment with doxorubicin, an inducer of immunogenic cell death (ICD), as well as cisplatin, a non-ICD inducer. Remarkably, the cell line harboring the BRAFV600E mutation displayed heightened resistance to both types of treatments, when compared to the wild-type counterpart. This common resistance prompted further exploration into the relationship between the mutation and the genetic signature associated with ICD. Through comprehensive in silico analysis using data sourced from the cBioPortal (TCGA, PanCancer Atlas), a significant observation emerged: the BRAFV600E mutation correlated with heightened expression of IFNAR1 and IFNAR2 receptors, pivotal players in the release of danger-associated molecular patterns (DAMPs) and subsequent immune activation. To authenticate these results, a reporter cell line was established by introducing the pMX2-EGFP plasmid via stable transfection, followed by selective pressure with geneticin. This engineered reporter line provides a convenient avenue to confirm the mutation´s influence on type 1 interferon pathway regulation during the induction of ICD. The validation process encompassed exposure to interferon alfa (IFNα) treatment, along with the employment of a PDT-based ICD-inducing technique utilizing Me-ALA as a photosensitizing pro-drug, as previously elucidated by our research team. In conclusion, the BRAFV600E mutation´s clinical significance in melanoma, its impact on immunogenic cell death (ICD), and its association with resistance to treatment underscore the complex interplay between genetic alterations and immune responses. The observed correlation between the mutation and heightened expression of IFNAR1 and IFNAR2 receptors suggests potential avenues for targeted therapies. These findings deepen our understanding of melanoma´s biology and provide insights for future research aimed at improving treatment strategies for patients with this mutation.