Micro-environmental cross-talk in an organotypic human melanoma-in-skin model directs M2-like monocyte differentiation via IL-10

Cancer Immunol Immunother. 2020 Nov;69(11):2319-2331. doi: 10.1007/s00262-020-02626-4. Epub 2020 Jun 7.

Abstract

Preclinical assessment of novel therapies to fight cancer requires models that reflect the human physiology and immune response. Here, we established an in vitro three-dimensional (3D) reconstructed organotypic human melanoma-in-skin (Mel-RhS) model to investigate cellular and molecular features of tumor formation over a period of 6 weeks. Tumor nests developed over time at the epidermal-dermal junction and spread towards the dermis, in places disrupting the basement membrane. This coincided with secretion of matrix metalloproteinase 9 (MMP-9) by melanoma cells. These features resemble the initial stages of invasive melanoma. Interestingly, while the SK-MEL-28 cell line did not secrete detectable levels of interleukin-10 (IL-10) in traditional two-dimensional monolayers, it did express IL-10 in the 3D Mel-RhS, as did the surrounding keratinocytes and fibroblasts. This cellular cross-talk-induced secretion of IL-10 in the Mel-RhS indicated the generation of an immune suppressive microenvironment. Culture supernatants from Mel-RhS interfered with monocyte-to-dendritic-cell differentiation, leading to the development of M2-like macrophages, which was in part prevented by antibody-mediated IL-10 blockade. Indeed, high-dimensional single-cell analysis revealed a shift within the monocyte population away from a CD163+PD-L1+ M2-like phenotype upon IL-10 blockade. Thus, the 3D configuration of the Mel-RhS model revealed a role for IL-10 in immune escape through misdirected myeloid differentiation, which would have been missed in classical monolayer cultures.

Keywords: IL-10; M2 macrophages; Melanoma; Reconstructed human skin; Tumor microenvironment; Tumor progression.

MeSH terms

  • Cell Differentiation / immunology*
  • Cell Line, Tumor
  • Humans
  • Interleukin-10 / immunology*
  • Macrophages / immunology*
  • Melanoma / immunology*
  • Monocytes / immunology
  • Organ Culture Techniques / methods
  • Skin
  • Skin Neoplasms / immunology*
  • Tumor Escape / immunology*
  • Tumor Microenvironment / immunology

Substances

  • IL10 protein, human
  • Interleukin-10

Supplementary concepts

  • Melanoma, Cutaneous Malignant

Grant support