Brain cancer can be treated with nanoparticles

A new treatment has risen to combat an aggressive form of brain cancer, called glioblastoma. It consists of a nanoparticle coupled with a protein that only recognizes tumour cells, and a protein that is toxic to cells. The corresponding 'nanosystem' did not only directly and specifically target the malicious cells, they also destroyed them. The nanoparticle reduces toxicity for normal cells, because it guides the cell-killing protein directly to the cellular compartment where the drug is effective: the mitochondrium. This 'cell organ' is involved with the creation of energy, which the cell needs to survive. The combined drug was found to almost eradicate a tumour completely in one mouse model, while a different model showed significant delay in tumour growth.

Specific targeting is needed for glioblastoma, because it usually is not a well-defined tumour, and infiltrates healthy brain tissue. Directly targeting cancer cells is hardly new, as scientists have attempted for many years to create so-called 'magic bullets' that only target and kill the cells of choice. They are, however, not often coupled with a nanoparticle. The whole nanosystem is more effective than just the 'magic bullet' alone. In addition, because they are made out of iron-oxide, they show up on an MRI scan, which allows doctors to see where the nanosystem, and correspondingly the tumour, is located in the brain. Because the nanoparticles are part of a system that specifically targets this form of cancer, it can also be used for diagnosis.

Inside the cell, the toxic peptide targets the mitochondrium, the cellular power plant. The drug triggers an intracellular pathway that causes the cell to kill itself. When a cell kills itself, it is called apoptosis, and it is an important process in the body to maintain tissue organization. Cancer cells often have defects in their apoptosis pathways, which makes them resistant to signals that tell a cell to kill itself. However, mitochondrial leakage can turn on the apoptosis pathway, which involves proteins that are called caspases. With the treatment, the body basically gets rid of the cancer cells by itself, with a little outside encouragement.

The mouse models that were used by the scientists develop glioblastoma in much the same way that humans do. The effectiveness of the treatment is therefore very promising. It is likely that safety studies have to be carried out first, before the first human clinical trials can take place.