Center for Immuno-Oncology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA
Center for Immuno-Oncology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA.
J Immunother Cancer. 2024 Nov 18;12(11):e009868. doi: 10.1136/jitc-2024-009868.
Adoptive T-cell therapy has demonstrated clinical activity in B-cell malignancies, offering hope for its application to a broad spectrum of cancers. However, a significant portion of patients with solid tumors experience primary or secondary resistance to this treatment modality. Target antigen loss resulting either from non-uniform antigen expression or defects in antigen processing and presentation machinery is one well-characterized resistance mechanism. Constitutively expressed membrane-anchored interleukin-12 (caIL-12) has demonstrated enhanced antitumor activity and low systemic exposure in multiple preclinical adoptive T-cell treatment models with homogeneous tumor antigen expression. In this study, we assess the therapeutic impact of caIL-12 on target antigen-negative variants in syngeneic mouse models.
Target antigen-positive tumors were generated by transducing B16F10 melanoma cells (B16) or Lewis Lung Carcinoma cells (LLC) with a construct expressing the OVA antigen, SIINFEKL, tagged to ubiquitin (B16-U-OVA, LLC-U-OVA), while B16 or LLC tumors served as antigen-negative variants. C57BL/6J mice were subcutaneously injected with heterogeneous tumors composed of 80% B16-U-OVA and 20% B16. Bilateral tumors were established by injecting the left flank with B16-U-OVA or LLC-U-OVA tumors and the right flank injected with B16 or LLC tumors. The tumor-bearing mice then underwent 5.5 Gy total body irradiation, followed by adoptive transfer of OT-I TCR-T cells engineered with or without caIL-12.
TCR-T cells (OT-I) delivered caIL-12 to the B16-U-OVA tumor sites and induced robust tumor control and survival benefits in mice bearing a heterogeneous tumor with OVA-negative variants. caIL-12 exerted its effect on OVA-negative B16 variants primarily by priming and activating endogenous antitumor CD8 T cells via antigen spreading. In addition, antigen spreading induced by OT-I-caIL-12 resulted in controlling OVA-negative tumors implanted at distant sites. This therapeutic effect required antigen-specific TCR-T cells and caIL-12 to colocalize at the tumor site, along with endogenous CD8 T cells capable of recognizing shared tumor antigens.
Expression of caIL-12 by tumor-targeting T cells demonstrated therapeutic effect against target-antigen-negative tumor variants, primarily through the induction of antigen spreading. These findings highlight the potential of caIL-12 to address challenges of antigen escape and tumor heterogeneity that may limit the efficacy of T-cell therapy against solid tumors.
过继性 T 细胞疗法在 B 细胞恶性肿瘤中显示出临床活性，为其在广泛的癌症中的应用带来了希望。然而，相当一部分实体瘤患者对这种治疗方式存在原发性或继发性耐药。靶抗原丢失的原因要么是由于抗原表达不均匀，要么是由于抗原加工和呈递机制的缺陷，这是一种特征明确的耐药机制。在具有同质肿瘤抗原表达的多种过继性 T 细胞治疗模型中，组成型表达的膜锚定白细胞介素-12（caIL-12）表现出增强的抗肿瘤活性和较低的全身暴露。在这项研究中，我们评估了 caIL-12 对同种异体小鼠模型中靶抗原阴性变体的治疗影响。
通过转导 B16F10 黑色素瘤细胞（B16）或 Lewis 肺癌细胞（LLC），构建表达 OVA 抗原、SIINFEKL、与泛素连接的构建体，生成靶抗原阳性肿瘤，B16-U-OVA 或 LLC-U-OVA，而 B16 或 LLC 肿瘤作为抗原阴性变体。C57BL/6J 小鼠皮下注射由 80% B16-U-OVA 和 20%B16 组成的异质肿瘤。通过在左侧肋部注射 B16-U-OVA 或 LLC-U-OVA 肿瘤，在右侧肋部注射 B16 或 LLC 肿瘤，建立双侧肿瘤。然后对荷瘤小鼠进行 5.5Gy 全身照射，然后过继转移工程化的 OT-I TCR-T 细胞，这些细胞带有或不带有 caIL-12。
TCR-T 细胞（OT-I）将 caIL-12 递送至 B16-U-OVA 肿瘤部位，并在携带具有 OVA 阴性变体的异质肿瘤的小鼠中诱导强烈的肿瘤控制和生存获益。caIL-12 通过抗原扩展主要通过激活和激活内源性抗肿瘤 CD8 T 细胞对 OVA 阴性 B16 变体发挥作用。此外，OT-I-caIL-12 诱导的抗原扩展导致控制远处部位植入的 OVA 阴性肿瘤。这种治疗效果需要抗原特异性 TCR-T 细胞和 caIL-12 在肿瘤部位共定位，以及能够识别共享肿瘤抗原的内源性 CD8 T 细胞。
肿瘤靶向 T 细胞表达 caIL-12 对靶抗原阴性肿瘤变体表现出治疗效果，主要通过诱导抗原扩展。这些发现强调了 caIL-12 克服抗原逃逸和肿瘤异质性挑战的潜力，这些挑战可能限制 T 细胞疗法对实体瘤的疗效。
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