Nanoparticle used in CalTech study: Credit: Caltech/Derek BartlettThere's often a big difference between how a drug or method of delivery works in a lab and how successful it is in human trials. So, it's big news for researchers from the California Institute of Technology (CalTech) that they were able, for the first time, to successfully kill cancer cells in human patients using a new RNA interference (RNAi) therapy delivered via a special nanobot. This nanobot targets the messenger RNA (mRNA) to stop the production of protein in the cancer cell, thus starving the cancer from its source of survival.
Interfering RNAs are a new type of therapy that attack cancers and other diseases at the genetic level; its discovery in 1998 won Andrew Fine and Craig Mello the 2006 Nobel Prize in Physiology or Medicine. But the Caltech researchers were the first to create the right nanobot to deliver the siRNAs and they were able to inject the drug-filled nanobots directly into the patients' bloodstreams.
This electron micrograph shows the presence of numerous siRNA-containing targeted nanoparticles both entering and within a tumor cell.: Credit: Caltech/Swaroop Mishra
"There are many cancer targets that can be efficiently blocked in the
laboratory using siRNA, but blocking them in the clinic has been
elusive," says Antoni Ribas, associate professor of medicine and
surgery at UCLA's Jonsson Comprehensive Cancer Center. "This is because
many of these targets are not amenable to be blocked by traditionally
designed anti-cancer drugs. This research provides the first evidence
that what works in the lab could help patients in the future by the
specific delivery of siRNA using targeted nanoparticles. We can start
thinking about targeting the untargetable.”
The siRNA delivery is reported in the advance March 21, 2010 online edition of Nature.