A novel CLDN6 nanobody-based bispecific T-cell engager delivered by self-amplifying RNA platform exhibits potent antitumor efficacy

Sep 23, 2026

Ovarian cancer remains a highly lethal gynecologic malignancy with limited early detection and frequent relapse. Claudin-6 (CLDN6), minimally expressed in normal tissues but frequently upregulated in ovarian cancer, represents a promising tumor-specific target. Bispecific T-cell engagers (BiTEs) redirect cytotoxic T cells toward tumor cells, yet protein-based BiTEs often face folding, aggregation, and in vivo stability issues. This study develops CLDN6-nanobodies and builds a CLDN6-Nb-BiTE encoded by self-amplifying mRNA delivered via lipid nanoparticles, achieving stable expression, antigen-dependent cytotoxicity, cytokine release, and durable tumor control without systemic toxicity.

LanguageEnglish

CategoryHealthcare

FormatPDF

Pages20

Reading Time50 min

AccessFree to download

Introduction

Background on ovarian cancer and recurrence

CLDN6 as a tumor-specific target

Therapeutic strategies including BiTEs and related approaches

Zhu et al. Journal of Nanobiotechnology (2026) 24:415 [https://doi.org/10.1186/s12951-026-04319-z](https://doi.org/10.1186/s12951-026-04319-z) Journal of Nanobiotechnology RESEARCH Open Access A novel CLDN6 nanobody-based bispecific T-cell engager delivered by self-amplifying RNA platform exhibits potent antitumor efficacy Zhixiong Zhu1†, Jia Li1†, Qizhong Lu1†, Wanqin Zeng1, ZhengyuYu2, Nanxi Liu1, Zongliang Zhang1, Zeng Wang1, NianYang1, Yongdong Chen1, Huaqing Lu1, Long Xu1, Chunlai Nie1*, Hexian Li1* and Aiping Tong1,3* Abstract Ovarian cancer remains a highly lethal gynecologic malignancy with limited early detection and frequent relapse. Claudin-6 (CLDN6), minimally expressed in normal tissues but frequently upregulated in ovarian cancer, represents a promising tumor-specific target. Bispecific T-cell engagers (BiTEs) effectively redirect cytotoxic T cells toward tumor cells. However, previous studies have reported that protein-based BiTEs, particularly scFv-based constructs, may encounter challenges related to protein folding, aggregation, and in vivo stability. To address these limitations, CLDN6-nanobodies were developed through our screening platform, which display cross-species reactivity to human, murine and non-human primate CLDN6 . Using this binder, we constructed CLDN6 nanobody-based BiTE (CLDN6-Nb-BiTE) encoded by self-amplifying mRNA (sa-mRNA) and delivered by lipid nanoparticles (LNPs), providing a functional alternative to protein administration. The LNP-sa-mRNA formulation was stable and uniform, enabling robust CLDN6-Nb-BiTE expression, antigen-dependent cytotoxicity, and cytokine release in vitro, while sustained CLDN6-Nb-BiTE production in vivo promoted T-cell recruitment and durable tumor control without systemic toxicity. Overall, our work introduces the first CLDN6-Nb-BiTE delivered by sa-mRNA, establishing a foundation for next-generation ovarian cancer immunotherapy. Keywords Claudin-6, Self-amplifying RNA, T Cell Engager, Nanobody, Ovarian Cancer †Zhixiong Zhu, Jia Li and Qizhong Lu contributed equally to this work and are therefore co-first authors. *Correspondence: Chunlai Nie [niecl1022@scu.edu.cn](niecl1022@scu.edu.cn)[ ](niecl1022@scu.edu.cn)Hexian Li [harmony4067@163.com](harmony4067@163.com)[ ](harmony4067@163.com)Aiping Tong[aipingtong@scu.edu.cn](aipingtong@scu.edu.cn) Full list of author information is available at the end of the article © The Author(s) 2026. Open Access This article is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License, which permits any non-commercial use, sharing, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if you modified the licensed material. You do not have permission under this licence to share adapted material derived from this article or parts of it. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit [http://creati](http://creati)[vecommons.org/licenses/by-nc-nd/4.0/](vecommons.org/licenses/by-nc-nd/4.0/.)[.](vecommons.org/licenses/by-nc-nd/4.0/.) Zhu et al. Journal of Nanobiotechnology (2026) 24:415 Page 2 of 20 Graphical Abstract Introduction Ovarian cancer is one of the most lethal gynecologic malignancies [1], with a five-year survival rate of less than 25%[2]. Owing to the absence of specific symptoms in early disease, most cases are detected at an advanced stage [3]. Standard treatment typically consists of cytoreductive surgery followed

FAQs

Why is CLDN6 considered a promising target for ovarian cancer therapy?

CLDN6 is largely absent in normal tissues but frequently upregulated in ovarian cancer and several other cancers, including serous ovarian carcinoma. Its tumor-associated expression supports targeted therapeutic strategies.

What limitations affect conventional protein-based BiTEs constructed from scFvs?

Protein-based BiTEs may have suboptimal folding efficiency and a tendency to aggregate. These issues can reduce biological activity and complicate manufacturability and in vivo stability.

How does the self-amplifying mRNA-LNP approach improve delivery of CLDN6-Nb-BiTE?

The lipid nanoparticle formulation was stable and uniform, enabling robust CLDN6-Nb-BiTE expression. It supports antigen-dependent cytotoxicity and cytokine release in vitro, and sustained in vivo production that promotes T-cell recruitment and durable tumor control without systemic toxicity.

Sep 23, 2026

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