Ota Yosuke, Inagaki Ryosaku, Sumida Kentaro, Nakamura Megumi, Nagai Yasuhiro, Yamamoto Setsuko
Cancer Research Unit, Sumitomo Pharma Co., Ltd., Osaka, Japan.
Front Oncol. 2024 Sep 13;14:1410373. doi: 10.3389/fonc.2024.1410373. eCollection 2024.
Toll-like receptor 7 (TLR7) acts as a crucial component of the innate immune system. Upon TLR7 binding to its ligand, myeloid cells, including dendritic cells (DCs) and macrophages, are activated and play vital roles in initiating adaptive immunity. Consequently, TLR7 agonists have been employed in cancer immunotherapy. We have synthesized DSP-0509, a systemic injectable TLR7 agonist, and in this investigation, we examined the effects of DSP-0509 on tumor-infiltrating lymphocytes (TILs) utilizing single-cell RNA sequencing (scRNA-seq) in a mouse model bearing tumors. Our results demonstrated that DSP-0509 induced an expansion of immune cell populations, such as Natural Killer (NK) cells, CD4 T cells, and CD4 regulatory T cells (Tregs). Subsequently, we combined an Indoleamine 2,3-dioxygenase 1 (IDO1) inhibitor with DSP-0509 to enhance the antitumor efficacy by reducing Tregs, as DSP-0509 led to an increase in Treg presence within tumors. Our findings demonstrated that this combination therapy effectively reduced Treg infiltration within the tumor, leading to enhanced antitumor activity. To further prevent CD8 T cell exhaustion, we combined DSP-0509 with an anti-PD-1 antibody and assessed the alterations in TILs using scRNA-seq. Our results indicated that the combination treatment significantly increased the cluster of CD8 T cells expressing Gzmb, Prf1, Ctla4, and Icos, when compared to the administration of DSP-0509 alone. Additionally, we observed a marked rise in the M1-like macrophage cluster in the combination treatment group compared to the group receiving only DSP-0509. To validate the potential of modulating myeloid cells within the tumor to enhance antitumor efficacy, we combined DSP-0509 with an inhibitor targeting the receptor tyrosine kinase AXL. In bone marrow derived macrophages (BMDMs), the AXL inhibitor further amplified DSP-0509-stimulated TNFα secretion while reducing IL-10 secretion. As a final step, we evaluated the antitumor activity by combining DSP-0509 and the AXL inhibitor in an tumor model, which demonstrated increased efficacy. In summary, our study elucidated the effects of DSP-0509 on immune activity within the tumor microenvironment. These findings provided valuable insights that pave the way for the development of novel combination immunotherapy strategies.
Toll样受体7（TLR7）是天然免疫系统的关键组成部分。当TLR7与其配体结合后，包括树突状细胞（DC）和巨噬细胞在内的髓样细胞被激活，并在启动适应性免疫中发挥重要作用。因此，TLR7激动剂已被应用于癌症免疫治疗。我们合成了一种可全身注射的TLR7激动剂DSP-0509，在本研究中，我们利用单细胞RNA测序（scRNA-seq）在荷瘤小鼠模型中研究了DSP-0509对肿瘤浸润淋巴细胞（TIL）的影响。我们的结果表明，DSP-0509可诱导免疫细胞群体的扩增，如自然杀伤（NK）细胞、CD4 T细胞和CD4调节性T细胞（Treg）。随后，我们将吲哚胺2,3-双加氧酶1（IDO1）抑制剂与DSP-0509联合使用，以通过减少Treg来增强抗肿瘤疗效，因为DSP-0509导致肿瘤内Treg数量增加。我们的研究结果表明，这种联合治疗有效地减少了肿瘤内Treg的浸润，从而增强了抗肿瘤活性。为了进一步防止CD8 T细胞耗竭，我们将DSP-0509与抗PD-1抗体联合使用，并使用scRNA-seq评估TIL的变化。我们的结果表明，与单独使用DSP-0509相比，联合治疗显著增加了表达Gzmb、Prf1、Ctla4和Icos的CD8 T细胞簇。此外，与仅接受DSP-0509的组相比，我们在联合治疗组中观察到M1样巨噬细胞簇显著增加。为了验证调节肿瘤内髓样细胞以增强抗肿瘤疗效的潜力，我们将DSP-0509与一种靶向受体酪氨酸激酶AXL的抑制剂联合使用。在骨髓来源的巨噬细胞（BMDM）中，AXL抑制剂进一步放大了DSP-0509刺激的TNFα分泌，同时减少了IL-10分泌。作为最后一步，我们在肿瘤模型中评估了DSP-0509与AXL抑制剂联合使用的抗肿瘤活性，结果显示疗效增强。总之，我们的研究阐明了DSP-0509对肿瘤微环境中免疫活性的影响。这些发现提供了有价值的见解，为新型联合免疫治疗策略的开发铺平了道路。
