Objective To prepare glucose transporter 1(Glut1)-targeted doxorubicin(DOX)-loaded liposomes(doxorubicin/polyphyllin H-liposomes,DOX/ppH-LPs)using polyphyllin H(ppH)instead of cholesterol as the liposomal membrane material,and to investigate their in vitro synergistic anti-tumor activity against non-small cell lung cancer(NSCLC).Methods DOX/ppH-LPs were prepared using thin-film hydration,and the formulation was optimized by single-factor investigation.The optimized DOX/ppH-LPs were characterized for morphology,particle size,polydispersity index(PDI),and zeta potential with transmission electron microscopy(TEM)and dynamic light scattering(DLS).Drug loading DL%was determined by high-performance liquid chromatography(HPLC).The storage stability was evaluated by observing in PBS at 4℃for 7 d,and the serum stability was observed in DMEM containing 10%fetal bovine serum(FBS)at 37℃for 48 h.In vitro drug release was studied in PBS at pH 7.4 and pH 5.0 values,respectively.Human NSCLC A549 cells were subjected as the model,MTT assay was performed to detect the proliferation inhibition by DOX/ppH-LPs at different concentrations(0.5,5.0,15.0 μg/mL)and the control group(ppH+DOX/LPs,a physical mixture of free ppH and DOX-loaded liposomes).Fluorescence microscopy was used to observe cellular uptake of DOX/ppH-LPs and DOX/LPs(containing 5 μg/mL DOX)at 15 min and 2 h.Live/dead cell staining was applied to assess apoptosis/necrosis induced by formulations(15 μg/mL DOX)after 48 h incubation.Transwell assay was conducted to evaluate inhibitory effect on cell migration and invasion,and the targeting property and in vitro synergistic anti-NSCLC activity of DOX/ppH-LPs were then comprehensively evaluated.Results The optimal formulation of DOX/ppH-LPs was determined as hydration temperature at 50℃,6 mg DOX,2 mg ppH,and 24 mg lecithin.The prepared DOX/ppH-LPs were in spherical shape,uniform distribution,and at an average particle size of 145.13±22.14 nm,a PDI of 0.15±0.05,a zeta potential of-23.92±1.73 mV,and a DL of 10.13±0.71%for DOX and(1.22±0.21)%for ppH.DOX/ppH-LPs maintained stable particle size,PDI,and exhibited significantly unchanged zeta potential after storage in PBS at 4℃for 7 d or incubation in DMEM containing 10%FBS at 37℃for 48 h,demonstrating excellent physical and serum stability.Both liposomes showed slow release at pH 7.4 value,while drug release was significantly accelerated at pH 5.0 value(P<0.05),indicating pH-sensitive release characteristics.MTT assay revealed that DOX/ppH-LPs exerted significantly stronger cytotoxicity against A549 cells than the ppH+DOX/LPs control group(P<0.05).Compared with ppH+DOX/LPs,DOX/ppH-LPs showed remarkably enhanced cellular uptake in A549 cells(P<0.05),with more DOX localized in the nucleus.Live/dead cell staining showed that at the same DOX concentration(15 μg/mL),the proportion of apoptotic/necrotic cells induced by DOX/ppH-LPs was significantly higher than that of the DOX/LPs control group.Transwell assay demonstrated that there were significantly less cells migrating and invading through the membrane in the DOX/ppH-LPs group than the ppH+DOX/LPs group.Conclusion Glut1-targeted doxorubicin-loaded liposomes(DOX/ppH-LPs)constructed by substituting cholesterol with ppH can target NSCLC cells,significantly enhance the in vitro synergistic anti-NSCLC activity of DOX and ppH.