Dissecting the treatment-naive ecosystem of human melanoma brain metastasis

Cell. 2022 Jul 7;185(14):2591-2608.e30. doi: 10.1016/j.cell.2022.06.007.

Abstract

Melanoma brain metastasis (MBM) frequently occurs in patients with advanced melanoma; yet, our understanding of the underlying salient biology is rudimentary. Here, we performed single-cell/nucleus RNA-seq in 22 treatment-naive MBMs and 10 extracranial melanoma metastases (ECMs) and matched spatial single-cell transcriptomics and T cell receptor (TCR)-seq. Cancer cells from MBM were more chromosomally unstable, adopted a neuronal-like cell state, and enriched for spatially variably expressed metabolic pathways. Key observations were validated in independent patient cohorts, patient-derived MBM/ECM xenograft models, RNA/ATAC-seq, proteomics, and multiplexed imaging. Integrated spatial analyses revealed distinct geography of putative cancer immune evasion and evidence for more abundant intra-tumoral B to plasma cell differentiation in lymphoid aggregates in MBM. MBM harbored larger fractions of monocyte-derived macrophages and dysfunctional TOX+CD8+ T cells with distinct expression of immune checkpoints. This work provides comprehensive insights into MBM biology and serves as a foundational resource for further discovery and therapeutic exploration.

Keywords: brain metastasis; chromosomal instability; melanoma; neuronal-like cell state; single-cell genomics; spatial transcriptomics; tumor-microenvironment.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, N.I.H., Extramural

MeSH terms

  • Brain Neoplasms* / drug therapy
  • Brain Neoplasms* / secondary
  • CD8-Positive T-Lymphocytes / pathology
  • Ecosystem
  • Humans
  • Melanoma*
  • RNA-Seq