Combination of chemotherapy and PD-1 blockade induces T cell responses to tumor non-mutated neoantigens
Alessio Grimaldi, Ilenia Cammarata, Carmela Martire, Chiara Focaccetti, Silvia Piconese, Marta Buccilli, Carmine Mancone, Federica Buzzacchino, Julio Rodrigo Giròn Berrìos, Nicoletta D’Alessandris, Federica Tomao, Felice Giangaspero, Marino Paroli, Rosalba Caccavale, Gian Paolo Spinelli, G. Girelli, Giovanna Peruzzi, Paola Nisticò, Sheila Spada, Mariangela Panetta, Fabiana Letizia Cecere, Paolo Visca, Francesco Facciolo, Flavia Longo, Vincenzo Barnaba
Abstract
Abstract Here, we developed an unbiased, functional target-discovery platform to identify immunogenic proteins from primary non-small cell lung cancer (NSCLC) cells that had been induced to apoptosis by cisplatin (CDDP) treatment in vitro, as compared with their live counterparts. Among the multitude of proteins identified, some of them were represented as fragmented proteins in apoptotic tumor cells, and acted as non-mutated neoantigens (NM-neoAgs). Indeed, only the fragmented proteins elicited effective multi-specific CD4 + and CD8 + T cell responses, upon a chemotherapy protocol including CDDP. Importantly, these responses further increased upon anti-PD-1 therapy, and correlated with patients’ survival and decreased PD-1 expression. Cross-presentation assays showed that NM-neoAgs were unveiled in apoptotic tumor cells as the result of caspase-dependent proteolytic activity of cellular proteins. Our study demonstrates that apoptotic tumor cells generate a repertoire of immunogenic NM-neoAgs that could be potentially used for developing effective T cell-based immunotherapy across multiple cancer patients.