Glioblastoma, the highest mortality rate cancer, is generally treated by surgery. However, there is a high tendency of recurrence because it is very difficult to remove the infiltrating tumor cells inside the normal brain parenchyma as it can damage the healthy brain. Nanoparticle-based drug delivery systems (DDS) can target the tumor either actively through ligand-receptor interactions or passively via the enhanced permeability and retention effect. But, the nanoparticles are predominantly distributed in the perivascular space of the recrudescent tumor.
In this context, researchers at China Pharmaceutical University in Nanjing (China) have used neutrophils (NEs), the most abundant type of immune cells, as DDS because they can recognize postoperative inflammatory signals. They designed NEs that carry liposomes containing the anticancer drug paclitaxel (PTX). The NEs can penetrate inflamed brain tumors and are able to target the infiltrating glioma cells distal to the surgical region. The inflammatory signals present in the brain at high concentrations triggered the release of the liposomes containing PTX, allowing the delivery of the drug into the remaining invading tumor cells. As a consequence, the recurrent growth of tumors was slowed efficiently and the mice survival rates were significantly improved. But, the regrowth of tumors could not be completely inhibited. Nevertheless, this work shows that cell-mediated DDS, in particular endogenous immunocytes, have great potential in cancer treatment.