肿瘤引起的炎症与肿瘤微环境在肿瘤进展过程中密切相关。S100A8是一种Toll样受体4 (TLR4)内源性配体，被称为肿瘤微环境和预转移巢形成中的关键分子。我们首次利用丙氨酸扫描生成了一种新型多价S100A8竞争性抑制肽（双价肽3A5）对抗TLR4 / MD-2。双价肽3A5抑制了S100A8介导的人结肠癌SW480细胞内白细胞介素-8和血管内皮生长因子的产生。在SW480移植的异种移植模型中，双价肽3A5以剂量依赖性方式抑制肿瘤进展。我们证明了使用双价肽3A5和贝伐单抗联合治疗能够协同抑制SW480型异种移植模型的肿瘤生长。我们利用同基因小鼠模型发现，双价肽3A5可提高抗程序性死亡（PD）1抗体的疗效和肺转移。此外，通过基于肽3A5的多价肽库筛选，我们发现了另外两个候选物：双价ILVIK和四价ILVIK。值得注意的是，多价ILVIK而不是单价ILVIK显示出对抗TLR4 / MD-2复合物的竞争性抑制活性，并在SW480型异种移植模型中表现出抗肿瘤活性。由于大多数肿瘤细胞包括SW480细胞也表达TLR4，因此S100A8抑制肽会针对肿瘤微环境和肿瘤细胞。因此，多价S100A8抑制肽将为侵袭性癌症提供新的药物选择。© 2023年作者。

The tumor-elicited inflammation is closely related to tumor microenvironment during tumor progression. S100A8, an endogenous ligand of Toll-like receptor 4 (TLR4), is known as a key molecule in the tumor microenvironment and premetastatic niche formation. We firstly generated a novel multivalent S100A8 competitive inhibitory peptide (divalent peptide3A5) against TLR4/MD-2, using the alanine scanning. Divalent peptide3A5 suppressed S100A8-mediated interleukin-8 and vascular endothelial growth factor production in human colorectal tumor SW480 cells. Using SW480-transplanted xenograft models, divalent peptide3A5 suppressed tumor progression in a dose-dependent manner. We demonstrated that combination therapy with divalent peptide3A5 and bevacizumab synergistically suppressed tumor growth in SW480 xenograft models. Using syngeneic mouse models, we found that divalent peptide3A5 improved the efficacy of anti-programmed death (PD)1 antibody, and lung metastasis. In addition, by using multivalent peptide library screening based on peptide3A5, we then isolated two more candidates; divalent ILVIK, and tetravalent ILVIK. Of note, multivalent ILVIK, but not monovalent ILVIK showed competitive inhibitory activity against TLR4/MD-2 complex, and anti-tumoral activity in SW480 xenograft models. As most tumor cells including SW480 cells also express TLR4, S100A8 inhibitory peptides would target both the tumor microenvironment and tumor cells. Thus, multivalent S100A8 inhibitory peptides would provide new pharmaceutical options for aggressive cancers.© 2023. The Author(s).