Cancer Antigen Discovery Is Enabled by RNA Sequencing of Highly Purified Malignant and Nonmalignant Cells.

Abstract

PURPOSE:

Broadly expressed, highly differentiated tumor-associated antigens (TAA) can elicit antitumor immunity. However, vaccines targeting TAAs have demonstrated disappointing clinical results, reflecting poor antigen selection and/or immunosuppressive mechanisms.

EXPERIMENTAL DESIGN:

Here, a panel of widely expressed, novel colorectal TAAs were identified by performing RNA sequencing of highly purified colorectal tumor cells in comparison with patient-matched colonic epithelial cells; tumor cell purification was essential to reveal these genes. Candidate TAA protein expression was confirmed by IHC, and preexisting T-cell immunogenicity toward these antigens tested.

RESULTS:

The most promising candidate for further development is DNAJB7 [DnaJ heat shock protein family (Hsp40) member B7], identified here as a novel cancer-testis antigen. It is expressed in many tumors and is strongly immunogenic in patients with cancers originating from a variety of sites. DNAJB7-specific T cells were capable of killing colorectal tumor lines in vitro, and the IFNγ+ response was markedly magnified by control of immunosuppression with cyclophosphamide in patients with cancer.

CONCLUSIONS:

This study highlights how prior methods that sequence whole tumor fractions (i.e., inclusive of alive/dead stromal cells) for antigen identification may have limitations. Through tumor cell purification and sequencing, novel candidate TAAs have been identified for future immunotherapeutic targeting.

• Authors: Martin J Scurr, Alex Greenshields-Watson, Emma Campbell, Michelle S Somerville, Yuan Chen, Sarah L Hulin-Curtis, Stephanie E A Burnell, James A Davies, Michael M Davies, Rachel Hargest, Simon Phillips, Adam D Christian, Kevin E Ashelford, Robert Andrews, Alan L Parker, Richard J Stanton, Awen Gallimore, Andrew Godkin
• Journal: Clinical cancer research : an official journal of the American Association for Cancer Research (Clin Cancer Res) Vol. 26 Issue 13 Pg. 3360-3370 (07 01 2020) ISSN: 1557-3265 [Electronic] United States
• PMID: 32122920 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: ©2020 American Association for Cancer Research.

Chemical References

• Antigens, Neoplasm
• Antineoplastic Agents

Topics

• Antigens, Neoplasm (genetics, immunology)
• Antineoplastic Agents (pharmacology)
• Cell Line, Tumor
• Cytotoxicity, Immunologic
• Gene Expression Profiling (methods)
• Gene Expression Regulation, Neoplastic
• High-Throughput Nucleotide Sequencing
• Humans
• Immunophenotyping
• Leukocytes, Mononuclear (immunology, metabolism)
• Neoplasms (genetics, immunology)
• Sequence Analysis, RNA
• T-Lymphocytes (immunology, metabolism)
• Tumor Cells, Cultured