High-dimensional Cytometry (ExCYT) and Mass Spectrometry of Myeloid Infiltrate in Clinically Localized Clear Cell Renal Cell Carcinoma Identifies Novel Potential Myeloid Targets for Immunotherapy

Debebe Theodros,Benjamin M Murter,John-William Sidhom,Thomas R Nirschl,David J Clark,Lijun Chen,Ada J Tam,Richard L Blosser,Zeyad R Schwen,Michael H Johnson,Phillip M Pierorazio,Hui Zhang,Sudipto Ganguly,Drew M Pardoll,Jelani C Zarif

doi:10.1074/mcp.ra120.002049

Abstract

Renal Cell Carcinoma (RCC) is one of the most commonly diagnosed cancers worldwide with research efforts dramatically improving understanding of the biology of the disease. To investigate the role of the immune system in treatment-naïve clear cell Renal Cell Carcinoma (ccRCC), we interrogated the immune infiltrate in patient-matched ccRCC tumor samples, benign normal adjacent tissue (NAT) and peripheral blood mononuclear cells (PBMCs isolated from whole blood, focusing our attention on the myeloid cell infiltrate. Using flow cytometric, MS, and ExCYT analysis, we discovered unique myeloid populations in PBMCs across patient samples. Furthermore, normal adjacent tissues and ccRCC tissues contained numerous myeloid populations with a unique signature for both tissues. Enrichment of the immune cell (CD45+) fraction and subsequent gene expression analysis revealed a number of myeloid-related genes that were differentially expressed. These data provide evidence, for the first time, of an immunosuppressive and pro-tumorigenic role of myeloid cells in early, clinically localized ccRCC. The identification of a number of immune proteins for therapeutic targeting provides a rationale for investigation into the potential efficacy of earlier intervention with single-agent or combination immunotherapy for ccRCC.

Highlights

Using ExCYT, genomics, and Mass Spectrometry, we were able to uncover immune cell marker alterations that provide new insight into the biology of early stage clear cell Renal Cell Carcinoma (ccRCC)
To investigate the role of the immune system in treatmentnaïve clear cell Renal Cell Carcinoma, we interrogated the immune infiltrate in patient-matched ccRCC tumor samples, benign normal adjacent tissue (NAT) and peripheral blood mononuclear cells
Using MS and flow cytometry, our results reveal differences in myeloid populations found in the peripheral blood mononuclear cells (PBMCs) across patients, and unique myeloid populations between NAT and ccRCC tissues

Summary

Introduction

Using ExCYT, genomics, and Mass Spectrometry, we were able to uncover immune cell marker alterations that provide new insight into the biology of early stage ccRCC. Enrichment of the immune cell (CD451) fraction and subsequent gene expression analysis revealed a number of myeloid-related genes that were differentially expressed These data provide evidence, for the first time, of an immunosuppressive and protumorigenic role of myeloid cells in early, clinically localized ccRCC. We interrogated the immune infiltrate of seven patient-matched clear cell Renal Cell Carcinoma (ccRCC) tumors, normal adjacent tissue (NAT) and peripheral blood mononuclear cells (PBMCs) isolated from whole blood. Immune cell (CD451) enrichment and gene expression analysis revealed numerous differentially expressed myeloid genes These data provide evidence of an immunosuppressive and pro-tumorigenic role of myeloid cells in clinically localized ccRCC. Identification of numerous novel immune proteins for therapeutic targeting may delay progression of disease and provides a rationale for the investigation of early intervention with single-agent or combination immunotherapy for ccRCC.

Methods

Results

Conclusion