| Cancer is one of the major public health problems that seriously threaten human health.Cancer immunotherapy,as one of the most promising strategies for cancer treatments,has attracted great attention in the world.Antibody-based therapy is an important part of tumor immunotherapy,and is widely used because of its high specificity,high targeting and low side effects.However,due to the complexity of tumor immunosuppressive microenvironment and the tumor immune escape mechanism,it is difficult to achieve the ideal therapeutic effect only through a single immune regulation strategy.The clinical manifestations are low response rate and limited benefit population.Thus,combination strategies have recently been described as a potential alternative.With the rapid advancements in nanotechnology,nanomedicine emerges obvious advantages for safe and effective diagnosis and treatment of cancer,especially in the field of drug delivery.Tumor specific antibodies are often used to modify nano-carriers because of their high biocompatibility and specific targeting ability.Common antibody modification methods include physical adsorption and chemical conjugation.In practice,however,these approaches often involve intricate processes and harsh conditions,which may lead to off-target or the disrupted biological activity of the specific targeting antibody.Despite the progress made in decorating NPs,their translational clinical application is restricted by various obstacles,including the foreign nature of the materials,unexpected immune responses and short circulation time.To improve the biocompatibility,natural cell membranes have been used as the biomimetic materials for drug delivery inspired by the structure and properties of cellular membranes.Furthermore,the cell membranes can artificially present a wide variety of functional molecules via gene engineering to endow the cell membrane nanovesicles with specific targeting or other biological functions.In this thesis,using cell membrane display technology and biomimetic nanotechnology,we developed a bioactive multifunctional combination platform,which can realize the directional expression of full-length antibody or bispecific antibody on the cell-membrane-derived nanovesicles.This platform can effectively integrate tumor targeted drug delivery,tumor multimodal imaging and tumor immunotherapy.We evaluated the superior effect of the bioactive multifunctional platform for tumor diagnosis and combination therapy.Our work will provide novel designs and technical methods for cancer theranostics.This paper can be summarized as the following three main contents:(1)We designed a novel cell-membrane-derived NVs called vesicular antibodies(VAs)that can display full-length monoclonal antibodies.hGC33 mAb targeting GPC3,which is highly expressed in liver tumor was expressed on the membrane surfaces of VAs via genetic engineering.Further encapsulating ICG into hGC33-VAs leads to realize the targeted multimodal imaging of in mice bearing tumors.hGC33-VAs-ICG enhanced accumulation and retention of ICG at tumors and exhibited appealing photothermal therapy efficiency in tumors under laser irradiation.(2)On the basis of cell-membrane-display technology,we displayed KM3934 mAb targeting Claudin4 on the membrane surfaces of VAs.Upon further encapsulation with Dox,KM3934-VAs-Dox can selectively deliver Dox to tumor cells.These VAs can also mediate antibody-dependent cellular cytotoxicity to eradicate tumor cells via recruitment and activation of natural killer cells in the tumor.KM3934-VAs-Dox exhibited a remarkable antitumor effect via combined chemotherapy and immunotherapy.(3)We engineered a novel cellular nanovesicles that can present anti-GPC3/CD3 bispecific antibody,which were named as vesicular immune-mobilizing T cell engagers(VITE).Upon further encapsulation with IL-2 adsorbed by aluminum hydroxide adjuvant,AI@VITE can not only significantly induce cross-linking of T cells and GPC3-expressing human liver cancer cells,but also elicit striking antitumor efficacy.Once T cells recognized their target cells in the periphery,a synapse wad formed,and the cytolytic granules were secreted to kill tumor cells with remarkable specificity.AI@VITE exhibited significant efficacy on both primary solid tumors and tumor metastasis in immunodeficient mice.In addition,AI@VITE also induced a robust antitumor efficacy in immunocompetent human CD3 transgenic mice. |
