Decoding molecular programs in melanoma brain metastases

Melanoma brain metastases (MBM) variably respond to therapeutic interventions; thus determining patient's prognosis. However, the mechanisms that govern therapy response are poorly understood. Here, we use a multi-OMICS approach and targeted sequencing (TargetSeq) to unravel the programs that potentially control the development of progressive intracranial disease. Molecularly, the expression of E-cadherin (Ecad) or NGFR, the BRAF mutation state and level of immune cell infiltration subdivides tumors into proliferative/pigmented and invasive/stem-like/therapy-resistant irrespective of the intracranial location. The analysis of MAPK inhibitor-naive and refractory MBM reveals switching from Ecad-associated into NGFR-associated programs during progression. NGFR-associated programs control cell migration and proliferation via downstream transcription factors such as SOX4. Moreover, global methylome profiling uncovers 46 differentially methylated regions that discriminate BRAF(mut) and wildtype MBM. In summary, we propose that the expression of Ecad and NGFR sub- classifies MBM and suggest that the Ecad-to-NGFR phenotype switch is a rate-limiting process which potentially indicates drug-response and intracranial progression states in melanoma patients. Melanoma brain metastases (MBM) show heterogeneous therapeutic response determined by incompletely understood mechanisms. Here, the authors use a multi-OMICS approach and targeted sequencing (TargetSeq) to decipher programs that may define molecular subsets of MBM and their response to therapy.

• VetBiobank
• VetImaging

Natl Ctr Tumor Dis NCT
Universitätsmedizin Greifswald
Helmholtz Zentrum Dresden Rossendorf
German Cancer Research Center
Berlin Brandenburg Ctr Regenerat Therapies
Humboldt Universität zu Berlin
Veterinärmedizinische Universität Wien
Universität des Saarlandes
Technische Universität Dresden
Saarland University
Charité – Universitätsmedizin Berlin
Helmholtz Association
Freie Universität Berlin