A mammoth undertaking

Earlier this month some researchers from California Institute of Technology published a paper in Nature with the intriguing title Evidence of RNAi in humans from systemically administered siRNA via targeted nanoparticles. Let’s pick that mess of jargon apart, shall we.

RNAi is RNA interference, which means that the cell’s normal processes are interrupted. In this case the cancer cell was prevented from making a protein that was necessary for the cell to multiply. RNAi is a general name for a family of techniques. In this paper they achieved their goals by attaching small pieces of RNA (small interfering RNA, or siRNA) to a nanoparticle that they had constructed by combining two polymers in water. This yielded a tiny cancer-specific targetted bullet. It effectively switched off the tumour by interfering with the cancer cells’ ability to multiply, but it didn’t appear to trigger any sort of immune response from the body. Because there was no immune response no side effects would be expected. Best of all, the way to administer this is to inject the nanoparticles into the bloodstream, because they find their own way to the tumour and attach themselves to it. The more nanoparticles you inject, the more the tumour gets attacked. Nanoparticles that don’t find a tumour eventually break down and are eliminated from the body in the normal way.

The research for this is still at an early stage, having just successfully completed a Phase I trial, in which human skin melanomas were shown to be treated by the nanoparticles. There is still a long way to go before this becomes a viable treatment method for cancer, but it is an intriguing possibility for the future.