AGS-67E

Although antibody-drug conjugates offer advanced targeted anticancer therapy that overcomes the limitations of conventional chemotherapy and therapeutic antibodies, they are restricted in their capacity to carry multiple hydrophobic payloads. Protein nanocages have emerged as versatile therapeutic platforms for targeted drug delivery, offering advantages like precise molecular assembly, biocompatibility, and multivalent targeting. This study presents the development of engineered E2 nanocages functionalized with anti-HER2 single-chain variable fragments (scFv) using the SpyTag/SpyCatcher ligation system to achieve controlled scFv display valency. The results demonstrate that increasing anti-HER2 scFv valency enhances HER2 binding affinity via avidity effects, with the highest valency nanocages showing the highest binding avidity. Furthermore, cysteine residues were introduced into the E2 nanocages to enable conjugation with monomethyl auristatin E (MMAE) through maleimide chemistry, achieving efficient drug loading. The resulting MMAE-conjugated nanocages displayed potent, subnanomolar cytotoxicity in HER2-positive SKBR3 and BT-474 cell lines while sparing HER2-negative MDA-MB-231 cells at concentrations up to 1 nM. These results underscore the critical role of scFv valency in enhancing HER2 targeting and highlight the potential of E2 protein nanocages as specific, potent platforms for targeted cancer therapy. In this study, we developed an enhanced targeted drug delivery system using E2 nanocages and scFv with SpyCatcher/SpyTag ligation to regulate binding avidity and encapsulate hydrophobic drugs. The modular design and pH-sensitive dissociation of these nanocages establish a foundation for next-generation precision medicine strategies.

Adoptive T cell therapy (ACT) is an emerging cancer immunotherapy undergoing clinical evaluation, showing significant promise in the treatment of solid tumors. However, the clinical translation of ACT is hindered by its time-, labor-, and financial-consuming procedures, heterogeneity of cytotoxic T lymphocytes (CTLs), and immunosuppressive tumor microenvironment. Herein, we have developed a bionic cytotoxic T lymphocyte-inspiring microscale system (CTLiMS) composed of mesoporous silica dioxide microspheres containing membrane-disrupting boron clusters (BICs) and proapoptotic monomethyl auristatin E (MMAE) peptides. The BICs were found to disrupt the integrity of cancer cell membranes and enhance the internalization of MMAE, effectively mimicking the biological functions of perforin and granzymes released by CTLs to destroy cancer cells. As expected, the CTLiMSs demonstrated exceptional in vitro anticancer activity, inducing cancer cell apoptosis and exhibiting strong antiproliferative effects. Notably, CTLiMS treatment was demonstrated to induce immunogenic cell death of cancer cells as a result of Ca²⁺ and MMAE influx and subsequent production of reactive oxygen species. The animal studies demonstrated that the CTLiMS treatment led to efficient repression of the tumor growth. Furthermore, the CTLiMS administration resulted in favorable antitumor immunotherapeutic effects, as shown by significant inhibition of distant tumors, increased immune cell infiltration, and elevated plasma levels of pro-inflammatory cytokines. This pilot study using CTLiMSs for cancer immunotherapy offers an innovative bionic strategy for the future advancement of adoptive T cell therapy.