A nanobody-enzyme fusion protein targeting PD-L1 and sialic acid exerts anti-tumor effects by C-type lectin pathway-mediated tumor associated macrophages repolarizing

Yongliang Tong; Runqiu Chen; Xinrong Lu; Cuiying Chen; Guiqin Sun; Xiaolu Yu; Shaoxian Lyu; Meiqing Feng; Yiru Long; Likun Gong; Li Chen

doi:10.1016/j.ijbiomac.2025.139953

A nanobody-enzyme fusion protein targeting PD-L1 and sialic acid exerts anti-tumor effects by C-type lectin pathway-mediated tumor associated macrophages repolarizing

Int J Biol Macromol. 2025 Jan 15:139953. doi: 10.1016/j.ijbiomac.2025.139953. Online ahead of print.

Authors

Yongliang Tong¹, Runqiu Chen², Xinrong Lu¹, Cuiying Chen³, Guiqin Sun⁴, Xiaolu Yu⁵, Shaoxian Lyu¹, Meiqing Feng⁶, Yiru Long⁷, Likun Gong⁸, Li Chen⁹

Affiliations

¹ Department of Medical Microbiology, Key Laboratory of Medical Molecular Virology of Ministries of Education and Health, School of Basic Medical Sciences, Fudan University, Shanghai, China.
² Shanghai Institute of Infectious Diseases and Biosecurity, Fudan University, Shanghai, China; Department of Microbiological and Biochemical Pharmacy, School of Pharmacy, Fudan University, Shanghai, China; State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China.
³ Department of Research and Development, Sysdiagno (Nanjing) Biotech Co., Ltd, Nanjing, Jiangsu Province, China.
⁴ School of Medical Technology and Information Engineering, Zhejiang Chinese Medical University, Hangzhou, Zhejiang Province, China.
⁵ State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China.
⁶ Shanghai Institute of Infectious Diseases and Biosecurity, Fudan University, Shanghai, China; Department of Microbiological and Biochemical Pharmacy, School of Pharmacy, Fudan University, Shanghai, China. Electronic address: [email protected].
⁷ State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China. Electronic address: [email protected].
⁸ State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China. Electronic address: [email protected].
⁹ Department of Medical Microbiology, Key Laboratory of Medical Molecular Virology of Ministries of Education and Health, School of Basic Medical Sciences, Fudan University, Shanghai, China; Translational Glycomics Research Center, Fudan Zhangjiang Institute, Shanghai, China. Electronic address: [email protected].

PMID: 39824395
DOI: 10.1016/j.ijbiomac.2025.139953

Abstract

Aberrant sialylated glycosylation in the tumor microenvironment is a novel immune suppression pathway, which has garnered significant attention as a targetable glycoimmune checkpoint for cancer immunotherapy to address the dilemma of existing therapies. However, rational drug design and in-depth mechanistic studies are urgently required for tumor sialic acid to become valuable glycoimmune targets. In this study, we explored the positive correlation of PD-L1 and sialyltransferase expression in clinical colorectal cancer tissues and identified their mutual regulation effects in macrophages. Subsequently, we characterized a new sialidase with excellent properties from human oral symbiotic bacteria and then developed a novel nanobody-enzyme fusion protein, designated as Nb16-Sia, to concurrently target the PD-L1 and sialic acid. Results from syngeneic colon tumor models reveal superior efficacy of Nb16-Sia over monotherapy and combinations, which could remodel the tumor immune microenvironment. Mechanistically, Nb16-Sia, which could repolarize macrophages from the tumor-promoting M2 to anti-tumor M1 phenotype via the C-type lectin pathway, exerted its antitumor efficacy mainly by regulating tumor-associated macrophages. Our strategy of nanobody-enzyme fusion protein effectively enables the delivery of sialidase, allows the collaboration between anti-PD-L1 nanobody and sialidase in combating tumors, and holds considerable promise for further development.

Keywords: Glycol-immunology; Nanobody-enzyme fusion protein; Sialic acid.