掲載種別：研究論文（学術雑誌）   国際・国内誌：国際誌  

Neoantigens are crucial for antitumor immunity and immune checkpoint inhibitor (ICI) efficacy by triggering strong immune responses. However, conventional methods for identifying neoantigens, such as whole-exon sequencing and short-read RNA sequencing (RNA-seq), appear to be insufficient, and the tumor mutational burden cannot sufficiently predict ICI efficacy. In this study, we employed a proteogenomic approach using long-read RNA-seq with Pacific Biosciences Single-Molecule Real-Time Sequencing technology to analyze full-length transcripts in combination with the human leukocyte antigen ligandome. As a result, many neoantigen candidates were identified, which were unregistered in a comprehensive database, including those from non-coding regions. Additionally, we validated the responses of specific T cell receptors (TCRs) to these candidates and identified several pairs of TCRs and neoantigens. These findings highlight the presence of more diverse neoantigens than expected that cannot be identified by conventional methods.

DOI： 10.1016/j.celrep.2025.116781

PubMed

掲載種別：研究論文（学術雑誌）  

DOI： 10.1158/2326-6066.30029287

国際・国内誌：国際誌  

DOI： 10.1038/s41586-025-09408-x

PubMed

制御性T細胞(Treg細胞)に対する抗原刺激の程度がTreg細胞におけるPD-1発現やin vivo腫瘍に対する抗PD-1抗体療法耐性に及ぼす影響について検討した。その結果、高い抗原性を有する抗原に対して、Treg細胞がより高レベルのPD-1発現を獲得することを見出した。担癌マウスモデルにおいて、Treg細胞に対する抗原性が高い腫瘍では、PD-1陽性Treg細胞が浸潤しており、抗PD-1抗体療法に耐性を示した。PD-1陽性Treg細胞ではCTLA-4発現が高いことから、抗CTLA-4モノクローナル抗体(mAb)との併用により耐性が克服可能であることが示された。抗PD-1抗体単独療法に一次耐性を示した後、抗PD-1抗体と抗CTLA-4 mAbの併用療法に反応した患者では、Treg細胞の腫瘍内浸潤が多かった。以上より、Treg細胞に対する高い抗原性は、Treg細胞におけるPD-1高発現を誘導しPD-1抗体療法への耐性を与えるが、抗CTLA-4 mAbとの併用療法により克服可能であることが示された。

国際・国内誌：国際誌  

DOI： 10.1038/s41586-025-08764-y

PubMed

掲載種別：研究論文（学術雑誌）   国際・国内誌：国際誌  

Regulatory T (Treg) cells have an immunosuppressive function, and programmed death-1 (PD-1)-expressing Treg cells reportedly induce resistance to PD-1 blockade therapies through their reactivation. However, the effects of antigenicity on PD-1 expression in Treg cells and the resistance to PD-1 blockade therapy remain unclear. Here, we show that Treg cells gain high PD-1 expression through an antigen with high antigenicity. Additionally, tumors with high antigenicity for Treg cells were resistant to PD-1 blockade in vivo due to PD-1+ Treg-cell infiltration. Because such PD-1+ Treg cells have high cytotoxic T lymphocyte antigen (CTLA)-4 expression, resistance could be overcome by combination with an anti-CTLA-4 monoclonal antibody (mAb). Patients who responded to combination therapy with anti-PD-1 and anti-CTLA-4 mAbs sequentially after primary resistance to PD-1 blockade monotherapy showed high Treg cell infiltration. We propose that the high antigenicity of Treg cells confers resistance to PD-1 blockade therapy via high PD-1 expression in Treg cells, which can be overcome by combination therapy with an anti-CTLA-4 mAb.

DOI： 10.1111/cas.70029

PubMed

掲載種別：研究論文（学術雑誌）   国際・国内誌：国際誌  

Cancer cells in the tumour microenvironment use various mechanisms to evade the immune system, particularly T cell attack1. For example, metabolic reprogramming in the tumour microenvironment and mitochondrial dysfunction in tumour-infiltrating lymphocytes (TILs) impair antitumour immune responses2-4. However, detailed mechanisms of such processes remain unclear. Here we analyse clinical specimens and identify mitochondrial DNA (mtDNA) mutations in TILs that are shared with cancer cells. Moreover, mitochondria with mtDNA mutations from cancer cells are able to transfer to TILs. Typically, mitochondria in TILs readily undergo mitophagy through reactive oxygen species. However, mitochondria transferred from cancer cells do not undergo mitophagy, which we find is due to mitophagy-inhibitory molecules. These molecules attach to mitochondria and together are transferred to TILs, which results in homoplasmic replacement. T cells that acquire mtDNA mutations from cancer cells exhibit metabolic abnormalities and senescence, with defects in effector functions and memory formation. This in turn leads to impaired antitumour immunity both in vitro and in vivo. Accordingly, the presence of an mtDNA mutation in tumour tissue is a poor prognostic factor for immune checkpoint inhibitors in patients with melanoma or non-small-cell lung cancer. These findings reveal a previously unknown mechanism of cancer immune evasion through mitochondrial transfer and can contribute to the development of future cancer immunotherapies.

DOI： 10.1038/s41586-024-08439-0

PubMed

掲載種別：研究論文（学術雑誌）   国際・国内誌：国際誌  

DOI： 10.1002/bcp.70264

PubMed

担当区分：筆頭著者   国際・国内誌：国際誌  

DOI： 10.1038/s41408-024-01064-0

PubMed

担当区分：責任著者   掲載種別：研究論文（学術雑誌）   国際・国内誌：国際誌  

T cell exhaustion is a major contributor to immunosuppression in the tumor microenvironment (TME). Blockade of key regulators of T cell exhaustion, such as PD-1, can reinvigorate tumor-specific T cells and activate anti-tumor immunity in various types of cancer. Here, we identified that CD106 was specifically expressed in exhausted CD8+ T cells in the TME using single-cell RNA-sequencing. High CD106 expression in the TME in clinical samples corresponded to improved response to cancer immunotherapy. CD106 in tumor-specific T cells suppressed anti-tumor immunity both in vitro and in vivo, and loss of CD106 in CD8+ T cells suppressed tumor growth and improved response to PD-1 blockade. Mechanistically, CD106 inhibited T-cell receptor (TCR) signaling by interacting with the TCR/CD3 complex and reducing its surface expression. Together, these findings provide insights into the immunosuppressive role of CD106 expressed in tumor-specific exhausted CD8+ T cells, identifying it as a potential biomarker and therapeutic target for cancer immunotherapy.

DOI： 10.1158/0008-5472.CAN-23-0453

PubMed

担当区分：責任著者   掲載種別：研究論文（学術雑誌）   国際・国内誌：国際誌  

Immune checkpoint inhibitors exert clinical efficacy against various types of cancer through reinvigoration of exhausted CD8+ T cells that attack cancer cells directly in the tumor microenvironment (TME). Using single-cell sequencing and mouse models, we show that CXCL13, highly expressed in tumor-infiltrating exhausted CD8+ T cells, induces CD4+ follicular helper T (TFH) cell infiltration, contributing to anti-tumor immunity. Furthermore, a part of the TFH cells in the TME exhibits cytotoxicity and directly attacks major histocompatibility complex-II-expressing tumors. TFH-like cytotoxic CD4+ T cells have high LAG-3/BLIMP1 and low TCF1 expression without self-renewal ability, whereas non-cytotoxic TFH cells express low LAG-3/BLIMP1 and high TCF1 with self-renewal ability, closely resembling the relationship between terminally differentiated and stem-like progenitor exhaustion in CD8+ T cells, respectively. Our findings provide deep insights into TFH-like CD4+ T cell exhaustion with helper progenitor and cytotoxic differentiated functions, mediating anti-tumor immunity orchestrally with CD8+ T cells.

DOI： 10.1016/j.celrep.2024.113797

PubMed

Abstract

Background: Immune checkpoint inhibitors (ICIs) exert clinical efficacy against various types of cancer through reinvigoration of exhausted CD8+ T cells that attack cancer cells directly in the tumor microenvironment (TME). However, compared to CD8+ T cell exhaustion, the role of CD4+ T cell exhaustion in antitumor immunity remains unclear.

Methods and Results: From single-cell sequencing for tumor-infiltrating lymphocytes (TILs) from patients with melanoma and mouse models, we found that CXCL13, which is highly expressed in tumor-infiltrating exhausted CD8+ T cells, induces PD-1+CXCR5+CD4+ follicular helper T (TFH)-like cell infiltration, which could contribute to antitumor immunity. Furthermore, a part of the TFH-like cells in the TME exhibits cytotoxicity and directly attacks MHC-II-expressing tumors. RNA velocity and latent time analysis in single-cell sequencing for melanoma TILs showed that the differentiation of TFH-like cells from the naive CD4+ T cells were different from that of other CD4+ T cells. In addition, the TFH-like cytotoxic CD4+ T cells were at the late stage of differentiation and some non-cytotoxic TFH-like cells might differentiate into TFH-like cytotoxic CD4+ T cells. We additionally found considerable overlapped clonotypes between the cytotoxic and non-cytotoxic clusters. TFH-like cytotoxic CD4+ T cells have high LAG-3/BLIMP1 and low TCF1 expression without self-renewal ability, whereas non-cytotoxic TFH-like cells express low LAG-3/BLIMP1 and high TCF1 with self-renewal ability, closely resembling the relationship between terminally differentiated and stem-like progenitor exhaustion in CD8+ T cells, respectively.

Conclusion: Our findings provide novel insights into TFH-like CD4+ T cell exhaustion with helper progenitor and cytotoxic differentiated functions, which mediates antitumor immunity orchestrally with CD8+ T cells.

Citation Format: Joji Nagasaki, Wenhao Zhou, Shusuke Kawashima, Takamasa Ishino, Katsushige Kawase, Youki Ueda, Kazuo Yamashita, Tomofumi Watanabe, Takashi Inozume, Yosuke Togashi. CD4+T cell exhaustion in the tumor microenvironment and antitumor immunity [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 7536.

DOI： 10.1158/1538-7445.am2024-7536

J-GLOBAL

Abstract Background: Immune checkpoint inhibitors (ICIs) exert clinical efficacy against various types of cancer through reinvigoration of exhausted CD8+ T cells that attack cancer cells directly in the tumor microenvironment (TME). However, compared to CD8+ T cell exhaustion, the role of CD4+ T cell exhaustion in antitumor immunity remains unclear. Methods and Results: From single-cell sequencing for tumor-infiltrating lymphocytes (TILs) from patients with melanoma and mouse models, we found that CXCL13, which is highly expressed in tumor-infiltrating exhausted CD8+ T cells, induces PD-1+CXCR5+CD4+ follicular helper T (TFH)-like cell infiltration, which could contribute to antitumor immunity. Furthermore, a part of the TFH-like cells in the TME exhibits cytotoxicity and directly attacks MHC-II-expressing tumors. RNA velocity and latent time analysis in single-cell sequencing for melanoma TILs showed that the differentiation of TFH-like cells from the naive CD4+ T cells were different from that of other CD4+ T cells. In addition, the TFH-like cytotoxic CD4+ T cells were at the late stage of differentiation and some non-cytotoxic TFH-like cells might differentiate into TFH-like cytotoxic CD4+ T cells. We additionally found considerable overlapped clonotypes between the cytotoxic and non-cytotoxic clusters. TFH-like cytotoxic CD4+ T cells have high LAG-3/BLIMP1 and low TCF1 expression without self-renewal ability, whereas non-cytotoxic TFH-like cells express low LAG-3/BLIMP1 and high TCF1 with self-renewal ability, closely resembling the relationship between terminally differentiated and stem-like progenitor exhaustion in CD8+ T cells, respectively. Conclusion: Our findings provide novel insights into TFH-like CD4+ T cell exhaustion with helper progenitor and cytotoxic differentiated functions, which mediates antitumor immunity orchestrally with CD8+ T cells. Citation Format: Joji Nagasaki, Wenhao Zhou, Shusuke Kawashima, Takamasa Ishino, Katsushige Kawase, Youki Ueda, Kazuo Yamashita, Tomofumi Watanabe, Takashi Inozume, Yosuke Togashi. CD4+T cell exhaustion in the tumor microenvironment and antitumor immunity [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 7536.