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Abstract：
The efficacy of checkpoint blockade immunotherapies in colorectal cancer is currently restricted to a minority of patients diagnosed with mismatch repair-deficient tumors having high mutation burden. However, this observation does not exclude the existence of neoantigen-specific T cells in colorectal cancers with low mutation burden and the exploitation of their anti-cancer potential for immunotherapy. Therefore, we investigated whether autologous neoantigen-specific T cell responses could also be observed in patients diagnosed with mismatch repair-proficient colorectal cancers.
Whole-exome and transcriptome sequencing were performed on cancer and normal tissues from seven colorectal cancer patients diagnosed with mismatch repair-proficient tumors to detect putative neoantigens. Corresponding neo-epitopes were synthesized and tested for recognition by in vitro expanded T cells that were isolated from tumor tissues (tumor-infiltrating lymphocytes) and from peripheral mononuclear blood cells stimulated with tumor material.
Neoantigen-specific T cell reactivity was detected to several neo-epitopes in the tumor-infiltrating lymphocytes of three patients while their respective cancers expressed 15, 21, and 30 non-synonymous variants. Cell sorting of tumor-infiltrating lymphocytes based on the co-expression of CD39 and CD103 pinpointed the presence of neoantigen-specific T cells in the CD39+CD103+ T cell subset. Strikingly, the tumors containing neoantigen-reactive TIL were classified as consensus molecular subtype 4 (CMS4), which is associated with TGF-β pathway activation and worse clinical outcome.
We have detected neoantigen-targeted reactivity by autologous T cells in mismatch repair-proficient colorectal cancers of the CMS4 subtype. These findings warrant the development of specific immunotherapeutic strategies that selectively boost the activity of neoantigen-specific T cells and target the TGF-β pathway to reinforce T cell reactivity in this patient group.
Whole-exome and transcriptome sequencing were performed on cancer and normal tissues from seven colorectal cancer patients diagnosed with mismatch repair-proficient tumors to detect putative neoantigens. Corresponding neo-epitopes were synthesized and tested for recognition by in vitro expanded T cells that were isolated from tumor tissues (tumor-infiltrating lymphocytes) and from peripheral mononuclear blood cells stimulated with tumor material.
Neoantigen-specific T cell reactivity was detected to several neo-epitopes in the tumor-infiltrating lymphocytes of three patients while their respective cancers expressed 15, 21, and 30 non-synonymous variants. Cell sorting of tumor-infiltrating lymphocytes based on the co-expression of CD39 and CD103 pinpointed the presence of neoantigen-specific T cells in the CD39+CD103+ T cell subset. Strikingly, the tumors containing neoantigen-reactive TIL were classified as consensus molecular subtype 4 (CMS4), which is associated with TGF-β pathway activation and worse clinical outcome.
We have detected neoantigen-targeted reactivity by autologous T cells in mismatch repair-proficient colorectal cancers of the CMS4 subtype. These findings warrant the development of specific immunotherapeutic strategies that selectively boost the activity of neoantigen-specific T cells and target the TGF-β pathway to reinforce T cell reactivity in this patient group.
摘要：
检查点阻断免疫疗法在结直肠癌中的功效目前仅限于少数被诊断为具有高突变负担的错配修复缺陷型肿瘤的患者。然而,这一观察结果并不排除新抗原特异性T细胞在低突变负荷的结直肠癌中的存在,以及它们在免疫治疗中的抗癌潜力的利用.因此,我们调查了在被诊断为错配修复技术高的结直肠癌患者中是否也能观察到自体新抗原特异性T细胞应答.
对7名被诊断为具有错配修复能力的肿瘤的结直肠癌患者的癌症和正常组织进行全外显子组和转录组测序，以检测推定的新抗原。合成相应的新表位,并通过从肿瘤组织(肿瘤浸润淋巴细胞)和用肿瘤材料刺激的外周单核细胞分离的体外扩增的T细胞测试其识别。
在三名患者的肿瘤浸润淋巴细胞中检测到新抗原特异性T细胞反应性，而他们各自的癌症表达15、21和30个非同义变体。基于CD39和CD103共表达的肿瘤浸润性淋巴细胞的细胞分选确定了CD39+CD103+T细胞亚群中新抗原特异性T细胞的存在。引人注目的是，含有新抗原反应性TIL的肿瘤被分类为共有分子亚型4（CMS4），这与TGF-β通路激活和较差的临床结果有关。
我们已经在CMS4亚型的错配修复有效的结直肠癌中检测到自体T细胞的新抗原靶向反应性。这些发现保证了特异性免疫治疗策略的发展，该策略选择性地增强新抗原特异性T细胞的活性并靶向TGF-β途径以增强该患者组中的T细胞反应性。
对7名被诊断为具有错配修复能力的肿瘤的结直肠癌患者的癌症和正常组织进行全外显子组和转录组测序，以检测推定的新抗原。合成相应的新表位,并通过从肿瘤组织(肿瘤浸润淋巴细胞)和用肿瘤材料刺激的外周单核细胞分离的体外扩增的T细胞测试其识别。
在三名患者的肿瘤浸润淋巴细胞中检测到新抗原特异性T细胞反应性，而他们各自的癌症表达15、21和30个非同义变体。基于CD39和CD103共表达的肿瘤浸润性淋巴细胞的细胞分选确定了CD39+CD103+T细胞亚群中新抗原特异性T细胞的存在。引人注目的是，含有新抗原反应性TIL的肿瘤被分类为共有分子亚型4（CMS4），这与TGF-β通路激活和较差的临床结果有关。
我们已经在CMS4亚型的错配修复有效的结直肠癌中检测到自体T细胞的新抗原靶向反应性。这些发现保证了特异性免疫治疗策略的发展，该策略选择性地增强新抗原特异性T细胞的活性并靶向TGF-β途径以增强该患者组中的T细胞反应性。
