Macrophage-Mediated NIR-Responsive Release Of TNFα Synergized With Photothermal Effect For Tumor-Targeted Therapy

Objective:To enhance the efficiency of antitumor agents with minimized side effects in healthy tissue is a major challenge for cancer targeting therapy.In this study,owing to macrophage possessed the properties of intrinsic tumor tropism and strong phagocytic,an intelligent and precise macrophage-based delivery system(denoted as HIMs@eM^ETs)with the abilities of NIR-responsive release of TNFαand photothermal effect（PTE）was developed using the genetically engineering technology and materials science methods for tumor-targeted therapy.Methods:Firstly,Indocyanine green（ICG）is encapsulated into hyaluronic acid（HA）coated mesoporous silica nanoparticles（MSNs）to construct“exploded switch”of non-secreted TNFαrelease（HIMs）,and characterize its physical and chemical properties.Then,the macrophage expressing of non-secreted EGFP-TNFαfusion protein(eM^ETs)was obtained with the genetically engineering technology.The intelligent and precise macrophage-based delivery system(HIMs@eM^ETs)with the abilities of NIR-responsive release of TNFαand photothermal effect（PTE）was developed via eM^ETs intracellular trapping HIMs.In vitro,we verified the photothermal effect（PTE）,tumor tropism,and near-infrared（NIR）-triggered EGFP-TNFαrelease characteristics of HIMs@eM^ETs.Further,in a subcutaneous CT26 tumor-bearing mouse model,tumor tropism of HIMs@eM^ETs was verified by Imaging of small animals in vivo and the immunofluorescence of tumor tissues after administered by intravenous injection（I.V.）.The photothermal effect（PTE）from HIMs@eM^ETs induced by NIR irradiation was detected by Near-infrared thermography.In vivo therapeutic efficacy of HIMs@eM^ETs combined with NIR irradiation was investigated via growth curve and immunofluorescence of tumor tissue,as well as mouse survival time were monitored.Moreover,the biosafety of the treatment system was assessed by pathological analysis of important tissues and organs in mice,as well as blood biochemical analysis.Results:In vitro experiments demonstrated that genetically engineered macrophage(eM^ETs)can stably express non-secretory TNFαprotein with biological activity;amino-functionalized HIMs facilitated intracellular uptake and retention of ICG in macrophages,and endowed HIMs@eM^ETs robust photothermal capability（PTE）;HIMs@eM^ETs can be"blasting"and release the EGFP-TNFαfusion protein with biological activity after responding to NIR laser irradiation.In addition,HIMs@eM^ETs retained high cell viability and tumor tropic ability of the cellular host.Moreover,in a subcutaneous CT26 tumor-bearing mouse model,we demonstrated that HIMs@eM^ETs conserved the tumoritropic ability in vivo,and the infiltrated HIMs@eM^ETs at the tumor sites effectively respond to NIR irradiation and generate PTE triggering the engineered TNFαrelease via photothermolysis of eM^ETs.HIMs@eM^ETs combined with PTE can effectively inhibit the growth of mouse tumors and significantly prolong the survival of mice.In addition,the strategy of HIMs@eM^ETs combined with PTE for tumor treatment has good biosafety in vivo.Conclusion:This study designed and prepared a near-infrared light（NIR）-responsive intelligent macrophage drug delivery system for tumor-targeted therapy.The macrophage delivery system combined photothermal therapy and biological therapy has unique spatial and temporal selectivity,and aims to achieve local targeted comprehensive treatment of tumors,and reduces the side effects caused by off-target effects of traditional treatments.