Hyaluronic acid-conjugated apoferritin nanocages for lung cancer targeted drug delivery.

In this paper, we proposed a naturally derived protein cage based pH-responsive delivery system for intracellular prodrug controlled release. The drug delivery system is based on apoferritin as delivery vehicles to encapsulate the anticancer drug daunomycin (DN) and alleviate the side effect. The hydrophobic drug DN was encapsulated into the interior of apoferritin by the hydrophobic channels of the cage with swelling at slight acidic pH and electrostatic adsorption. The negatively charged poly-l-aspartic acid (PLAA) was further introduced into the apoferritin to absorb the positively charged DN. The mixture of PLAA and DN easily flew into the apoferritin cage and was stably stored in the physiological fluids. PLAA protected the leakage of DN and encapsulated a sufficient amount of drug molecules in the cage. To specifically target the tumor cells, the surface of apoferritin was modified with hyaluronic acid (HA) which can easily bind to the HA-receptor CD44. Here, human embryonic lung MRC-5 cells and lung cancer A549 cells were used to observe the specific binding of HA and morphological changes in vitro and examine the antitumor activity. This unique protein based drug delivery platform using the apoferritin cage shows great potential in the therapeutic administration of the anti-cancer agents.