Browsing by Author "Yu, Chenfei"

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    Bone-Specific Enhancement of Antibody Therapy for Breast Cancer Metastasis to Bone
    (American Chemical Society, 2022) Tian, Zeru; Yu, Chenfei; Zhang, Weijie; Wu, Kuan-Lin; Wang, Chenhang; Gupta, Ruchi; Xu, Zhan; Wu, Ling; Chen, Yuda; Zhang, Xiang H.-F.; Xiao, Han; Bioengineering; Biosciences; Chemistry
    Despite the rapid evolution of therapeutic antibodies, their clinical efficacy in the treatment of bone tumors is hampered due to the inadequate pharmacokinetics and poor bone tissue accessibility of these large macromolecules. Here, we show that engineering therapeutic antibodies with bone-homing peptide sequences dramatically enhances their concentrations in the bone metastatic niche, resulting in significantly reduced survival and progression of breast cancer bone metastases. To enhance the bone tumor-targeting ability of engineered antibodies, we introduced varying numbers of bone-homing peptides into permissive sites of the anti-HER2 antibody, trastuzumab. Compared to the unmodified antibody, the engineered antibodies have similar pharmacokinetics and in vitro cytotoxic activity, but exhibit improved bone tumor distribution in vivo. Accordingly, in xenograft models of breast cancer metastasis to bone sites, engineered antibodies with enhanced bone specificity exhibit increased inhibition of both initial bone metastases and secondary multiorgan metastases. Furthermore, this engineering strategy is also applied to prepare bone-targeting antibody–drug conjugates with enhanced therapeutic efficacy. These results demonstrate that adding bone-specific targeting to antibody therapy results in robust bone tumor delivery efficacy. This provides a powerful strategy to overcome the poor accessibility of antibodies to the bone tumors and the consequential resistance to the therapy.
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    Harnessing the power of antibodies to fight bone metastasis
    (AAAS, 2021) Tian, Zeru; Wu, Ling; Yu, Chenfei; Chen, Yuda; Xu, Zhan; Bado, Igor; Loredo, Axel; Wang, Lushun; Wang, Hai; Wu, Kuan-Lin; Zhang, Weijie; Zhang, Xiang H.-F.; Xiao, Han; Bioengineering; Biosciences; Chemistry
    Antibody-based therapies have proved to be of great value in cancer treatment. Despite the clinical success of these biopharmaceuticals, reaching targets in the bone microenvironment has proved to be difficult due to the relatively low vascularization of bone tissue and the presence of physical barriers. Here, we have used an innovative bone-targeting (BonTarg) technology to generate a first-in-class bone-targeting antibody. Our strategy involves the use of pClick antibody conjugation technology to chemically couple the bone-targeting moiety bisphosphonate to therapeutic antibodies. Bisphosphonate modification of these antibodies results in the delivery of higher conjugate concentrations to the bone metastatic niche, relative to other tissues. In xenograft mice models, this strategy provides enhanced inhibition of bone metastases and multiorgan secondary metastases that arise from bone lesions. Specific delivery of therapeutic antibodies to the bone, therefore, represents a promising strategy for the treatment of bone metastatic cancers and other bone diseases. Precision modification of antibodies with bone-targeting moieties unleashes their potential for the treatment of bone metastases. Precision modification of antibodies with bone-targeting moieties unleashes their potential for the treatment of bone metastases.
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    Proximity-induced Antibody Conjugation for Cancer and Bone Metastasis Treatment
    (2023-04-21) Yu, Chenfei; Xao, Han
    Antibody-based therapies entered the clinic over 30 years ago and have become a mainstream therapeutic option for patients with malignancies, infectious diseases, and transplant rejection. Compared with traditional chemotherapy, these biotherapeutics preferentially target cells presenting tumor-associated antigens, resulting in improved treatment outcomes and reduced side effects. Despite their excellent selectivity and a broad collection of targets, the therapeutic effects of monoclonal antibodies can decrease over time due to the development of immune resistance and suppression by the immune system. To circumvent the internal resistance and boost the therapeutic effects, the modification of antibodies by various chemical molecules (e.g., drugs, nanoparticles) or biological reagents (e.g., enzymes, cytokines, other antibodies) is required. To covalently label antibodies, various methods have been developed, most commonly involving nonspecific reactions on lysine and cysteine residues. The resulting products are heterogeneous antibody conjugates which may suffer from diminished binding affinity and therapeutic index due to a lack of control over the modification ratio and sites. With the development in the fields of biorthogonal chemistry and protein engineering, site-specific antibody conjugation strategies have gone mainstream and predominantly been used for clinical treatment. The leading site-specific antibody conjugation techniques on the market, including THIOMABTM, SMARTagTM, SiteClickTM, have been proved successful. However, all these site-specific antibody conjugation methods require a certain amount of antibody engineering, which is time-consuming, expensive, and may result in low yield. Therefore, antibody scientists have a craving for the next generation of site-specific antibody conjugation methods without antibody engineering and/or UV/chemical treatment. In this dissertation, I describe how we develop a proximity-induced antibody conjugation method and how we apply the method for cancer and bone metastasis treatment. First, to suppress all the limitations mentioned above, we developed a new platform for efficient and site-specific labeling of native antibodies based on proximity-induced reactivity between a non-canonical amino acid (ncAA) and a nearby antibody lysine residue. The resulting proximity-induced conjugation technology, named pClick, does not require any antibody engineering or UV/chemical treatment, thus enabling attachment of various functional molecules to most antibodies used for research and therapy. By using this method, we collaborate with the Wistar Institute to conjugate sialidase to HIV broadly neutralizing antibodies. These conjugates selectively desialylated HIV-infected cells and enhanced natural killer cells (NK cell) capacity to kill infected cells. Second, despite the great conjugation efficiency of pClick to intact antibodies, the relatively large size and low production yield of FPheK-containing FB protein prepared by Genetic Code Expansion greatly limits the further application of this method. To expand the application of pClick, we developed a proximity-induced site-specific antibody conjugation method using solid-phase synthesized antibody affinity peptide (pClick2.0). To illustrate the utility of this concept, we have prepared well-defined antibody-drug conjugates (ADCs) and bispecific antibody (bsAb) conjugates. The resulting conjugates exhibit excellent cytotoxic anctivity against cancer cells in vitro and superb anti-tumor activity in mouse xenograft models. Third, we demonstrate the potential of combining antibody engineering and antibody conjugation method (pClick2.0) by constructing a bone-homing antibody-drug conjugate with a moderate bond-targeting capability which exhibited great efficacy to inhibit breast cancer metastases as well as multiorgan secondary metastases in xenograft models. This methodology establishes a new strategy for transitioning antibody-based therapies from antigen-sepcific to both antigen- and tissue-specific, thus providing a promising new avenue for advancing antibody therapy toward clinical translation. In summary, the work in this dissertation has shown advances in different aspects of current obstacles in site-specific antibody conjugation technology.
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    Synthesis of precision antibody conjugates using proximity-induced chemistry
    (Ivyspring, 2021) Cao, Yu J.; Yu, Chenfei; Wu, Kuan-Lin; Wang, Xuechun; Liu, Dong; Tian, Zeru; Zhao, Lijun; Qi, Xuexiu; Loredo, Axel; Chung, Anna; Xiao, Han; Bioengineering; Biosciences; Chemistry
    Rationale: Therapeutic antibody conjugates allow for the specific delivery of cytotoxic agents or immune cells to tumors, thus enhancing the antitumor activity of these agents and minimizing adverse systemic effects. Most current antibody conjugates are prepared by nonspecific modification of antibody cysteine or lysine residues, inevitably resulting in the generation of heterogeneous conjugates with limited therapeutic efficacies. Traditional strategies to prepare homogeneous antibody conjugates require antibody engineering or chemical/enzymatic treatments, processes that often affect antibody folding and stability, as well as yield and cost. Developing a simple and cost-effective way to precisely couple functional payloads to native antibodies is of great importance. Methods: We describe a simple proximity-induced antibody conjugation method (pClick) that enables the synthesis of homogeneous antibody conjugates from native antibodies without requiring additional antibody engineering or post-synthesis treatments. A proximity-activated crosslinker is introduced into a chemically synthesized affinity peptide modified with a bioorthogonal handle. Upon binding to a specific antibody site, the affinity peptide covalently attaches to the antibody via spontaneous crosslinking, yielding an antibody molecule ready for bioorthogonal conjugation with payloads. Results: We have prepared well-defined antibody-drug conjugates and bispecific small molecule-antibody conjugates using pClick technology. The resulting conjugates exhibit excellent in vitro cytotoxic activity against cancer cells and, in the case of bispecific conjugates, superb antitumor activity in mouse xenograft models. Conclusions: Our pClick technology enables efficient, simple, and site-specific conjugation of various moieties to the existing native antibodies. This technology does not require antibody engineering or additional UV/chemical/enzymatic treatments, therefore providing a general, convenient strategy for developing novel antibody conjugates.
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    ZipA Uses a Two-Pronged FtsZ-Binding Mechanism Necessary for Cell Division
    (American Society for Microbiology, 2021) Cameron, Todd A.; Vega, Daniel E.; Yu, Chenfei; Xiao, Han; Margolin, William; Bioengineering; Biosciences; Chemistry
    In most bacteria, cell division is centrally organized by the FtsZ protein, which assembles into dynamic filaments at the division site along the cell membrane that interact with other key cell division proteins. In gammaproteobacteria such as Escherichia coli, FtsZ filaments are anchored to the cell membrane by two essential proteins, FtsA and ZipA. Canonically, this interaction was believed to be mediated solely by the FtsZ C-terminal peptide (CTP) domain that interacts with these and several other regulatory proteins. However, we now provide evidence of a second interaction between FtsZ and ZipA. Using site-specific photoactivated cross-linking, we identified a noncanonical FtsZ-binding site on ZipA on the opposite side from the FtsZ CTP-binding pocket. Cross-linking at this site was unaffected by the truncation of the FtsZ linker and CTP domains, indicating that this noncanonical site must interact directly with the globular core domain of FtsZ. Mutations introduced into either the canonical or noncanonical binding sites on ZipA disrupted photo-cross-linking with FtsZ and normal ZipA function in cell division, suggesting that both binding modes are important for normal cell growth and division. One mutation at the noncanonical face was also found to suppress defects of several other canonical and noncanonical site mutations in ZipA, suggesting there is some interdependence between the two sites. Taken together, these results suggest that ZipA employs a two-pronged FtsZ-binding mechanism.