Wilms’ Tumor Primary Cells Display Potent Immunoregulatory Properties on NK Cells and Macrophages

Abstract

The immune response plays a crucial defensive role in cancer growth and metastasis and is a promising target in different tumors. The role of the immune system in Wilm’s Tumor (WT), a common pediatric renal malignancy, is still to be explored. The characterization of the immune environment in WT could allow the identification of new therapeutic strategies for targeting possible inhibitory mechanisms and/or lowering toxicity of the current treatments. In this study, we stabilized four WT primary cultures expressing either a blastematous (CD56+/CD133−) or an epithelial (CD56−/CD133+) phenotype and investigated their interactions with innate immune cells, namely NK cells and monocytes. We show that cytokine-activated NK cells efficiently kill WT cells. However, after co-culture with WT primary cells, NK cells displayed an impaired cytotoxic activity, decreased production of IFNγ and expression of CD107a, DNAM-1 and NKp30. Analysis of the effects of the interaction between WT cells and monocytes revealed their polarization towards alternatively activated macrophages (M2) that, in turn, further impaired NK cell functions. In conclusion, we show that both WT blastematous and epithelial components may contribute directly and indirectly to a tumor immunosuppressive microenvironment that is likely to play a role in tumor progression.

Pediatric Tumors-Mediated Inhibitory Effect on NK Cells: The Case of Neuroblastoma and Wilms’ Tumors

“…Interestingly, similar results were previously reported demonstrating that TIM-3 expression was downregulated on NK cells exposed to tumor targets, and this downregulation correlated with lower cytotoxicity and interferon gamma (IFN-γ) production [87]. In addition, T cell immunoglobulin and ITIM domain (TIGIT), strongly expressed in control NK cells, slightly decreased after coculture with WT primary cultures and, in both situations, was associated with impaired NK cell cytolytic functions [86], as reported elsewhere [88]. Concerning the checkpoint inhibitor PD-1, it was strongly expressed in NK cells infiltrating several tumors [53,54,[56][57][58].…”

“…Notably, when co-cultured with NK cells, they were able to impair NK cell function. Remarkably, inhibition was not dependent on the release of soluble factors by WT cells, but could only be achieved upon cell-to-cell contact [86]. Thus, WT blastemal and epithelial primary cultures appeared to inhibit NK cell cytolytic function by a mechanism different from str-WT, highlighting the existence of a complex interplay in the WT TME aiming at NK cell anergy with different strategies.…”

“…Recently, our group reported the stabilization of four WT primary cultures expressing either a blastematous (CD56 + /CD133 − ) or epithelial (CD56 − /CD133 + ) phenotype, and investigated the effect of their interactions with NK cells and monocytes [86]. Data showed that both the blastemal and epithelial WT primary cultures expressed ligands for the NK activating receptors, namely DNAM-1 (CD112 and CD155) and NKG2D (MICA/B, and ULBP2-5-6).…”

“…Concerning the checkpoint inhibitor PD-1, it was strongly expressed in NK cells infiltrating several tumors [53,54,[56][57][58]. Since WT is infiltrated by numerous NK cells [78,86] and it is also characterized by several PDL-1 positive tumor cells [86,89], it is likely that the in vivo blastematous and epithelial cells may lead to the impaired cytolytic activity of tumor-infiltrating NK cells. Interestingly, a previous paper reports opposite results, showing that the WT cell line HFWT greatly stimulates the proliferation of NK cells and of their PBMC precursors, leading to the robust expansion of NK cells able to kill fresh HFWT and K562 cells [90].…”

“…Finally, upon interaction with WT cells, monocytes became polarized towards alternatively activated M2 macrophages. In turn, M2 macrophages could further impair NK cell functions through cell-to-cell contact [86].…”