TP B.2 - MelBrainSys

In vitro validation of driver candidates and key pathways of melanoma brain metastases

The aim of the MelBrainSys consortium is to identify candidates and key signaling pathways driving growth and survival of melanoma metastases in the brain by investigating the epigenomic differences between brain and organ melanoma metastases. For this purpose, multi-omics data (gene expression and methylome differences and DNA variation) of a unique cohort of brain and organ metastasis pairs from the same patients will be analyzed in B.1 to acquire candidates that significantly differ between the metastasis pairs. In this subproject, promising brain-specific candidate genes identified in the bioinformatics analyses will be validated in further experiments. We would thereby like to give special attention to candidates that are involved in signaling pathways known to be important in cancer development and progression such as the MAPK and PI3K/AKT growth and survival pathways. As such, it was already shown by others as well as our group that the PI3K/AKT survival pathway was activated in melanoma brain but not other organ metastases. In the first experiments, the expression levels of the candidates will be altered in primary brain melanoma cell lines using different technologies including CRISPR/Cas9. The cell lines will be distributed to the other subprojects for characterization (B.3-4), but will also be used in this subproject to investigate the role of the candidates in cellular processes such as cell death, tumor growth, migration and invasion using cell culture assays. Studies will include 2D and 3D cultures of primary melanoma cells grown alone or in co-culture with normal brain tissue cells, e.g. astrocytes, in order to mimic the natural brain environment. Data from all subprojects (B.2-4) will be added to a model-based algorithm (B.1) that will predict the most promising therapeutic targets and treatment strategies for melanoma brain metastases. In order to validate these therapeutic targets from the algorithm, a tissue microarray of additional matched-pair and individual brain metastases will be established in this subproject. Ultimately, this interdisciplinary approach will identify novel potential treatment strategies for melanoma brain metastases that can be investigated in clinical trials.