A bee sting is known to pump poison into a victim, this has been harnessed by researchers at Washington Univerity School of Medicine. The work centres around attaching a major component of be stings to nano-spheres, nicknamed ‘nanobees’ and targeting them to tumours.
The effectivness of the technique was shown in a mouse model. The nanobees carrying the bee toxin melittin selectively carried the toxin to tumour cells whilst protecting other cells from the destructive toxin.
Mellitin is a small peptide, which is known to strongly adhere to cells surfaces and create pores in the cells killing them.
There has been much interest in Melittin for a while, as in high concentrations it is known to be antimicrobial and very effective at destroying cells, thus potent as an anti-cancer therapy once correctly targeted.
After injecting mice with the mellitin harbouring nano-spheres mice breast cancer tumours slowed by 25%, and mice with melanomas were found to have on average melanoma size reduction by 88% compared to untreated tumours.
This technique works because blood vessels supplying tumours are far more leaky than the average blood vessel. This means the nanobees can concentrate more easily around the tumours then in other tissues. This is known as ‘the enhanced permeability and retention effect of tumours’
However The technique did not rely solely on this effect. In conjunction with this the nanobees were targeted to additional components found in growing blood cells, which is common during cancer angiogenesis. This further limited the effect on healthy tissue and increased the selectivity for cancerous tissue.
As a main conclusion the study found that the melittin attached to the nano-spheres was harmless to the mice. But if melittin were to be injected into the blood stream not atached to the nano-spheres it would cause widespread destruction of the circulating red blood cells. This means there is great promise for attaching very poisoness chemotherapies to nano-spheres targeting them to tumours and preventing the usual side effects of these therapies whilst also increasing their effectiveness. – CT