Soluble NKG2D ligands impair CD8+ T cell antitumor function dependent of NKG2D downregulation in neuroblastoma

T cell-based immunotherapy has achieved remarkable beneficial clinical outcomes. Tumor-derived NKG2D ligands (NKG2DL) allow tumors to escape immunologic surveillance. However, the mechanism underlying NKG2DL-mediated immune escape in neuroblastoma (NB) remains incompletely understood. In the present study, first soluble NKG2DL, soluble major histocompatibility complex (MHC) class-I-related chain A and soluble UL-16 binding proteins expression levels were determined in both the serum from patients with NB and in NB cell line culture supernatants. NB cell-derived sNKG2DL was initially cleaved by ADAM10 and ADAM17. Furthermore, sNKG2DL expression levels were positively correlated with the immunosuppressive microenvironment and poor prognosis. Tumor-derived sNKG2DL induced degradation of NKG2D on CD8⁺ T cells and impaired CD8⁺ T cell proliferation, IFN-γ production, and CD107a translocation. More importantly, blockage of sNKG2DL increased the antitumor activity of CD8⁺ T cells. Thus, the results showed that NB-induced immunosuppression was achieved through tumor-derived sMICA and sULBP-2, and blockage of the tumor-derived sNKG2DLs with sNKG2DL neutralizing antibodies was a novel strategy to recover T-cell function and enhance antitumor immunotherapy.

Cancer-associated fibroblasts at the unfavorable desmoplastic stroma promote colorectal cancer aggressiveness: potential role of ADAM9

The tumor microenvironment plays a key role in cancer aggressiveness. Desmoplastic reaction (DR), morphologically classified as Mature, Intermediate and Immature types, has previously been shown to be highly prognostic in colorectal cancer (CRC) and it consists to a large extent of cancer-associated fibroblasts (CAFs). The aim of this study was to characterize the molecular background of DR and understand the effects of CAFs in tumor aggressiveness. The prognostic significance of DR was initially examined in 1,497 patients. Then CAFs originating from patient tissues with different DR types were isolated and their impact on tumor growth was examined both in vitro and in vivo. DR was shown to be highly prognostic, with patients within the Immature DR group conferring the worst relapse-free survival. The conditioned media of CAFs from tumor with Immature-type DR (CAFs^Immature ) significantly increased proliferation and migration of CRC cell lines and growth of CRC-derived organoids compared to that of CAFs from Mature-type DR (CAFs^Mature ). Subcutaneous or orthotopic implantation of CRC cells together with CAFs^Immature in mice significantly promoted tumor growth and dissemination compared to implantation with CAFs^Mature . Systematic examination of the expression of "a disintegrin and metalloproteinases" (ADAMs) in CAFs isolated from CRC tissues showed that the secreted isoform of ADAM9 (ADAM9s) was significantly higher in CAFs^Immature than in CAFs^Mature . Knockdown of ADAM9s in CAFs^Immature abrogated the promoting effects on CRC cell proliferation and migration. CAFs-derived ADAM9s is implicated in deteriorating survival in CRC patients with Immature-type DR by increasing tumor cell proliferation and dissemination. This article is protected by copyright. All rights reserved.

Extracellular Matrix Enzymes and Immune Cell Biology

Remodelling of the extracellular matrix (ECM) by ECM metalloproteinases is increasingly being associated with regulation of immune cell function. ECM metalloproteinases, including Matrix Metalloproteinases (MMPs), A Disintegrin and Metalloproteinases (ADAMs) and ADAMs with Thombospondin-1 motifs (ADAMTS) play a vital role in pathogen defence and have been shown to influence migration of immune cells. This review provides a current summary of the role of ECM enzymes in immune cell migration and function and discusses opportunities and limitations for development of diagnostic and therapeutic strategies targeting metalloproteinase expression and activity in the context of infectious disease.