Ferroptosis and autophagy are the two forms of the regulation of cell death that play important roles in cancer therapy. However, little is known about the combination of the therapeutic effects of ferroptosis and autophagy in cancer therapy. Here, in this study, we constructed a novel carrier-free nanodrug called nanoparticle ferritin-bound erastin and rapamycin (NFER). The NFER nanodrug was prepared by the emulsification technique; it exhibited an average size of 78.8 nm and zeta potential of −25.9 ± 3.3 mV. Controllable drug encapsulation efficiency and loading ratios in NFER could be obtained. This nanodrug showed high stability in both water and PBS for several days. The release studies demonstrated that rapamycin and erastin could reach equilibrium after 24 h and 36 h, respectively; the maximum values of the released percentages of both reached beyond 30%. An in vitro study revealed that NFER showed robust ferroptosis-inducing capability by the downregulation of glutathione peroxidase-4 (GPX4) and lipid peroxidation accumulation. The autophagy process induced by rapamycin in NFER also played an important role in strengthening ferroptosis. The selective cancer cell killing ability of NFER was verified in cancer cells and normal cells. The ferroptosis-induced cytotoxicity was confirmed through several ferroptosis and autophagy inhibitors. Furthermore, the NFER nanodrug showed an improved control of tumor recurrence in the 4T1 tumor resection model. In summary, these results demonstrated that NFER exhibited excellent properties as a nanodrug, and the cell death induced by NFER was through an autophagy-associated ferroptosis pathway. This study based on protein nanodrug-induced autophagy-associated ferroptosis would provide a new insight into cancer therapy.

Studies have shown that ursolic acid (UA) and empagliflozin (EM) exert therapeutic effects in the treatment of diabetic nephropathy (DN), but both drugs have disadvantages. This study explores the effect of combining these drugs compared to that of either monotherapy. A diabetic rat model was established by feeding a high-fat diet (HFD) with high-sugar content and administering a low dose of streptozotocin (STZ) via intraperitoneal injection. UA (50 mg/kg/day, po), EM (10 mg/kg/day, po) or both were administered for 8 weeks. The development of DN was determined by observing increases in urine protein, serum creatinine, urea nitrogen, and uric acid and abnormal changes in kidney morphology. UA and EM either alone or in combination can alleviate the increases in blood glucose, glycosylated haemoglobin, blood lipid levels, inflammatory factors (TNF-α, IL-1β, IL-6), oxidation factors (SOD, MDA, GSH, CAT, NO), renal fibrosis and pro-fibrosis factors (FN, E-cad, MMP-9, TIMP-1, SMA-α, TGF-β1, SMAD, MAPK). The treatments could also ameliorate DN by preventing the abnormal proliferation of glomerular mesangial cells under high-glucose conditions, aberrant apoptosis and excessive production of reactive oxygen species (ROS). In addition, UA reduces the increase in LDL-L, reverses abnormal bladder morphology and mitigates the increase in colony count caused by EM, and the combination treatment can overcome the disadvantages of the slow hypoglycaemic effect of UA. In short, UA combined with empagliflozin is more effective than either monotherapy in the treatment of DN and can cancel the adverse effects of each other. The protective effect of this regimen on the kidney may be related to reducing inflammation, oxidative stress and renal fibrosis.