Identification of novel immune checkpoint targets and metabolic biomarkers for enhancing cancer immunotherapy efficacy

Abstract

Immune checkpoint inhibitors (ICIs) have revolutionized cancer treatment, yielding durable responses in various tumors. However, a major challenge remains, as only a subset of patients shows strong responses, while many patients exhibit resistance. To overcome these limitations, the discovery of novel immune checkpoint (ICP) targets and predictive biomarkers has emerged as a promising approach to enhance ICI efficacy. In the first part of the study, we identified contactin-4 (CNTN4) as a promising ICP that impairs T cell functions. CNTN4 was highly expressed in tumor tissues, and its interaction with amyloid precursor protein (APP) on T cells diminished TCR-related signaling and impaired antitumor immune responses. To counteract this, we developed antibodies targeting CNTN4 (GENA-104A16) and APP (5A7), both of which effectively disrupted the CNTN4-APP interaction. These antibodies restored T cell functions, increased tumor-infiltrating lymphocytes, and promoted antitumor responses in a syngeneic mouse model. These results suggest that CNTN4-APP represents a potential ICP axis that can be targeted to boost immune responses in cancer therapy. In the second part of the study, we investigated the role of metabolic pathways—particularly amino acid and bile acid metabolism—in shaping ICI efficacy in non-small cell lung cancer (NSCLC) patients. Through metabolomic profiling and machine learning analysis, we identified histidine (His) as a positive predictor of ICI response, while homocysteine (HCys), phenylalanine (Phe), and sarcosine (Sar) were associated with poor outcomes. The His/HCys+Phe+Sar ratio emerged as a robust biomarker for predicting therapeutic outcomes. Additionally, bile acids such as glycochenodeoxycholic acid (GCDCA) and taurolithocholic acid (TLCA) were linked to improved survival probability and response to ICIs, with TLCA enhancing T cell proliferation and anti-tumor immunity. We also uncovered a relationship between the gut microbiota and TLCA levels, with the Eubacterium genus influencing TLCA-related metabolism. In summary, this research provides novel insights into overcoming the limitations of ICIs through the discovery of a novel ICP target and the identification of metabolic biomarkers that influence ICI response. Our findings suggest potential strategies to enhance the efficacy of immunotherapy and pave the way for more personalized treatment approaches in cancer immunotherapy.