Frazer Institute, The University of Queensland, Brisbane, Queensland, Australia.
Frazer Institute, The University of Queensland, Brisbane, Queensland, Australia
J Immunother Cancer. 2024 Jan 31;12(1):e007960. doi: 10.1136/jitc-2023-007960.
Skin cancers, particularly keratinocyte cancers, are the most commonly diagnosed tumors. Although surgery is often effective in early-stage disease, skin tumors are not always easily accessible, can reoccur and have the ability to metastasize. More recently, immunotherapies, including intravenously administered checkpoint inhibitors, have been shown to control some skin cancers, but with off-target toxicities when used in combination. Our study investigated whether peritumoral administration of an antibody combination targeting PD-1, 4-1BB (CD137) and VISTA might control skin tumors and lead to circulating antitumor immunity without off-target toxicity.
The efficacy of combination immunotherapy administered peritumorally or intravenously was tested using transplantable tumor models injected into mouse ears (primary tumors) or subcutaneously in flank skin (secondary tumors). Changes to the tumor microenvironment were tracked using flow cytometry while tumor-specific, CD8 T cells were identified through enzyme-linked immunospot (ELISPOT) assays. Off-target toxicity of the combination immunotherapy was assessed via serum alanine aminotransferase ELISA and histological analysis of liver sections.
The data showed that local administration of antibody therapy eliminated syngeneic murine tumors transplanted in the ear skin at a lower dose than required intravenously, and without measured hepatic toxicity. Tumor elimination was dependent on CD8 T cells and was associated with an increased percentage of CD8 T cells expressing granzyme B, KLRG1 and Eomes, and a decreased population of CD4 T cells including CD4FoxP3 cells in the treated tumor microenvironment. Importantly, untreated, distal tumors regressed following antibody treatment of a primary tumor, and immune memory prevented growth of subcutaneous flank tumors administered 50 days after regression of a primary tumor.
Together, these data suggest that peritumoral immunotherapy for skin tumors offers advantages over conventional intravenous delivery, allowing antibody dose sparing, improved safety and inducing long-term systemic memory. Future clinical trials of immunotherapy for primary skin cancer should focus on peritumoral delivery of combinations of immune checkpoint antibodies.
皮肤癌，特别是角质形成细胞癌，是最常见的诊断肿瘤。尽管手术在早期疾病中通常有效，但皮肤肿瘤并不总是容易接近，可以复发并具有转移能力。最近，免疫疗法，包括静脉注射检查点抑制剂，已被证明可以控制一些皮肤癌，但与联合使用时具有非靶向毒性。我们的研究调查了针对 PD-1、4-1BB（CD137）和 VISTA 的抗体联合进行肿瘤周围给药是否可以控制皮肤肿瘤并导致循环抗肿瘤免疫而没有非靶向毒性。
使用注射到小鼠耳朵（原发性肿瘤）或皮下侧翼皮肤（继发性肿瘤）的可移植肿瘤模型测试了肿瘤周围或静脉内给予联合免疫疗法的疗效。通过流式细胞术跟踪肿瘤微环境的变化，同时通过酶联免疫斑点（ELISPOT）测定鉴定肿瘤特异性 CD8 T 细胞。通过血清丙氨酸氨基转移酶 ELISA 和肝组织学分析评估联合免疫疗法的非靶向毒性。
数据表明，与静脉内给药相比，局部给予抗体治疗可在较低剂量下消除在耳部皮肤中移植的同种异体小鼠肿瘤，且无测量的肝毒性。肿瘤消除依赖于 CD8 T 细胞，并与处理肿瘤微环境中表达颗粒酶 B、KLRG1 和 Eomes 的 CD8 T 细胞的百分比增加以及包括 CD4FoxP3 细胞在内的 CD4 T 细胞的百分比降低有关。重要的是，在未处理的情况下，原发性肿瘤的抗体治疗后，未治疗的远端肿瘤消退，并且免疫记忆可防止原发性肿瘤消退 50 天后给予皮下侧翼肿瘤的生长。
总之，这些数据表明，皮肤肿瘤的肿瘤周围免疫疗法优于传统的静脉给药，允许抗体剂量节约、提高安全性并诱导长期的全身记忆。原发性皮肤癌免疫治疗的未来临床试验应侧重于免疫检查点抗体的肿瘤周围给药组合。
