| Rational Cell membrane-derived microparticles as the critical mediators of intercellular communication,have gained much interest for use as natural delivery drug systems.Objectives Here,we examined the therapeutic potential of autologous tumor cell-derived microparticles(ATMPs)in the context of malignant pleural effusion(MPE).Methods We first used immunocompetent mouse models of MPE induced by murine LLC and colon adenocarcinoma cells to define the impact of TMPs-MTX on MPE control.Therapeutic effects of TMPs-MTX were evaluated by MPE volume,pleural tumor burden and survival.For mechanistic studies,systemic and intratumoral immunological parameters were analyzed by flow cytometry.To explore the role of macrophages in TMP-MTX treatment,pharmacological macrophage inhibition by clodronate liposomes was carried out.Mice used for these studies were on the C57BL/6 background and randomly assigned to treatment groups four days after pleural tumor inoculation.The sample sizes were selected on the basis of the results of pilot experiments to gain a significant difference of relevant statistical tests between experimental groups.Specific sample sizes for experimental groups and their respective controls,as well as experimental replicates,were indicated in the figure legends.The detail regarding injection,grouping,intervention,harvest,sample handle and survival analysis have been described in the supplementary materials.After observing that TMPs-MTX could effectively restrict MPE growth and provide a significant survival benefit in MPE models,we started a prospective,randomized,double-blind study(clinical trial identifier NCT02657460),with the primary objectives of safety and feasibility.No dose escalation was planned.Main results We first confirmed the potential effect of the vector itself,tumor cell-derived microparticles(TMPs)shedding from tumor cells induced under UV radiation,on MPE.In vitro TMPs-MTX(TMPs packaging chemotherapeutic drugs methotrexate)treatment results in cell death of tumor cells and macrophages rather than T cells.In MPE models induced by murine Lewis lung carcinoma and colon adenocarcinoma cells,TMPs-MTX markedly restrained MPE growth and provided a significant survival benefit.Further immune infiltrates analysis demonstrated that TMPs-MTX strongly reduced F4/80~+tumor-associated macrophages accompanied by an increase of T cells in MPE and pleural tumors.Mirrored to that in the animal models,intrapleural administration of ATMPs-MTX(ATMPs packaging methotrexate)to patients led to striking reductions of tumor cells and CD163~+macrophages in MPE,which translated into clinical objective responses in advanced lung cancer patients with malignant pleural effusion without any toxic effects of grade 3 or higher.Moreover,TMPs-MTX treatment can stimulate CD4~+T cells to release IL-2 and CD8~+cells to release IFN-γin clinical study.Conclusions We constructed a platform for targeted chemotherapy based on ATMPs,and our studies highlighted the potential of ATMP-based dual-functional microparticle technologies as chemo-immunotherapeutic agents.Our study demonstrated that ATMPs-MTX can be highly active in both C57BL/6 MPE models and lung adenocarcinoma patients with MPE.Therapeutic efficacy with prolonged survival was achieved by ATMPs-MTX in experimental MPE models,and positive clinical responses were observed in lung adenocarcinoma patients with MPE.Although clinical benefit could not be definitively determined from this small study,our results have shown that ATMPs-MTX are safe,nontoxic,and tolerable when delivered by intrapleural administration.Additionally,we observed immune alterations in our animal and clinical experiments.Our study provides a promising strategy to treat advanced lung cancer with MPE by converting autologous tumor cell-released vesicles into a intrinsically biocompatible drug carriers,providing early evidence for the initiation of larger and robust clinical trials to assess the efficacy of these drug vectors. |
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