Large-scale analysis of cell-cell communication reveals angiogenin-dependent tumor progression in clear cell renal cell carcinoma.

Cellular crosstalk in the tumor microenvironment (TME) is still largely uncharacterized, while it plays an essential role in shaping immunosuppression or anti-tumor response. Large-scale analyses are needed to better decipher cell-cell communication in cancer. In this work, we used original and publicly available single-cell RNA sequencing (scRNAseq) data to characterize in-depth the communication networks in human clear cell renal cell carcinoma (ccRCC). We identified 50 putative communication channels specifically used by cancer cells to interact with other cells, including two novel angiogenin-mediated interactions. Expression of angiogenin and its receptors was validated at the protein level in primary ccRCC. Mechanistically, angiogenin enhanced ccRCC cell line proliferation and down-regulated secretion of IL-6, IL-8, and MCP-1 proinflammatory molecules. This study provides novel biological insights into molecular mechanisms of ccRCC, and suggests angiogenin and its receptors as potential therapeutic targets in clear cell renal cancer.

Methods for Establishing a Renal Cell Carcinoma Tumor Spheroid Model With Immune Infiltration for Immunotherapeutic Studies.

Tumor spheroids play an increasingly important role in cancer research. Their ability to recapitulate crucial features of tumor biology that are lost in the classically used 2D models along with their relative simplicity and handiness have made them the most studied 3D tumor model. Their application as a theranostic tool or as a means to study tumor-host interaction is now well-established in various cancers. However, their use in the field of Renal Cell Carcinoma (RCC) remains very limited. The aim of this work is to present methods to implement a basic RCC spheroid model. These methods cover the steps from RCC tumor dissociation to spheroid infiltration by immune cells. We present a protocol for RCC dissociation using Liberase TM and introduce a culture medium containing Epithelial Growth Factor and Hydrocortisone allowing for faster growth of RCC primary cells. We show that the liquid overlay technique allows for the formation of spheroids from cell lines and from primary cultures. We present a method using morphological criteria to select a homogeneous spheroid population based on a Fiji macro. We then show that spheroids can be infiltrated by PBMCs after activation with OKT3 or IL-15. Finally, we provide an example of application by implementing an immune spheroid killing assay allowing observing increased spheroid destruction after treatment with PD-1 inhibitors. Thus the straightforward methods presented here allow for efficient spheroid formation for a simple RCC 3D model that can be standardized and infused with immune cells to study immunotherapies.

Tumor infiltrating and peripheral CD4+ILT2+ T cells are a cytotoxic subset selectively inhibited by HLA-G in clear cell renal cell carcinoma patients.

HLA-G: ILT2 has recently been positioned as a major immune checkpoint in urologic cancers. In clear cell renal cell carcinoma (ccRCC), tumor-infiltrating CD8+ T cells expressing ILT2 are a highly cytotoxic cell population, distinct from PD1+ T cells, and whose function is inhibited by HLA-G+ targets. Here we report that ILT2 receptor can also be expressed by CD4+ T cells in urologic cancer patients. In the course of deciphering the role of these ILT2+CD4+ T cells, we found a statistical association between the tumor context and these T cells, and a positive correlation between the levels of peripheral and intra-tumoral CD4+ILT2+ T cells. Phenotypic analyses revealed that CD4+ILT2+ T cells express memory T cell (CD27-CD28-CD57+) and cytotoxicity (Tbet+Perforin+KLRG1+NKp80+GPR56+) markers, consistent with a CD4+CTL phenotype. Functional assays showed that ccRCC-infiltrating CD4+ILT2+ T cells indeed have high cytolytic properties and therefore function as proper CD4+CTLs, but are selectively inhibited by HLA-G+ targets. Clinical relevance was provided by immunohistochemical analyses on ccRCC tumor lesions with HLA-G+ HLA class II+ tumor cells next to CD4+ T cell infiltrates. Our findings provide evidence supporting that ILT2+ T cells constitute a reservoir of intratumor cytotoxic T cells that is not targeted by the current checkpoint inhibitors, but could be by anti-HLA-G/anti-ILT2 antibodies as novel immunotherapy in HLA-G+ tumors.

Prediction of non-muscle-invasive bladder cancer recurrence by measurement of checkpoint HLAG's receptor ILT2 on peripheral CD8+ T cells.

BACKGROUND AND OBJECTIVE: Recurrence of non-muscle invasive bladder cancer (NMIBC) after initial management occurs in 60-70% of patients. Predictive criteria for recurrence remain only clinical and pathological. The aim of this study was to investigate the prognostic significance of the proportion of checkpoint HLA-G's receptor ILT2-expressing peripheral CD8+ T cells. RESULTS: The proportion of CD4+ILT2+and CD8+ILT2+ T cells was not increased in NMIBC compared to controls. However, a strong association was found between recurrence and CD8+ILT2+ T cell population levels (p = 0.0006). Two-year recurrence-free survival was 83% in patients with less than 18% CD8+ILT2+ T cells, 39% in the intermediary group, and 12% in patients with more than 46% CD8+ILT2+ T cells. Multivariate analyses demonstrated that the proportion of CD8+ILT2+ T cells was an independent predictive factor for recurrence. Adding CD8+ILT2+ T cells population level to clinical variables increased the predictive accuracy of the model by 4.5%. MATERIALS AND METHODS: All patients treated for NMIBC between 2012 and 2014 were included prospectively. Blood samples, tumor and clinico-pathological characteristics were collected. HLA-G expression was measured using IHC, and CD8+ILT2+ T cell levels using flow cytometry. Association between HLA-G and CD8+ILT2+ T cell population levels with NMIBC risk of recurrence was investigated using Cox regression analyses. Prediction was measured using the concordance index statistic. CONCLUSIONS: We demonstrated a strong association between the proportion of circulating CD8+ILT2+ T cells and NMIBC risk of recurrence. Gain in prediction was substantial. If externally validated, such immunological marker could be integrated to predict NMIBC recurrence.