In a second report this week on scientists’ use of nanotechnology to battle cancer, researchers at MIT announced a new way to use nanoparticles to give cancerous cells a one-two punch.
MIT reported that researchers used nanoparticles to carry two drugs and release them one at a time. The treatment was shown to “dramatically shrink” lung and breast tumours in mice.
“I think it’s a harbinger of what nanomedicine can do for us in the future,” said Paula Hammond, an MIT professor of engineering, in a statement. “We’re moving from the simplest model of the nanoparticle – just getting the drug in there and targeting it – to having smart nanoparticles that deliver drug combinations in the way that you need to really attack the tumour.”
The university explained that first the nanoparticles disarm the cancer cell’s defenses by releasing a drug called Erlotinib – also known as Tarceva – which shuts down one of the pathways that promote uncontrolled tumour growth. Then the nanoparticles release another drug called Doxorubicin – also known as Adriamycin.
Once weakened by the administering of the Erlotinib, the cancer cells are more susceptible to being treated with the second drug.
Double whammy
“It’s like rewiring a circuit,” said Michael Yaffe, an MIT professor. “When you give the first drug, the wires’ connections get switched around so that the second drug works in a much more effective way.”
Scientists have known that treating cancer patients with the prolonged attack of two or more drugs can bring greater success than using one medication. In more recent years, they’ve also determined that the specific timing of the drug delivery has a significant affect on the outcome.
According to MIT, using Erlotinib and Doxorubicin in a specifically timed succession proved a powerful tool to beat back a specific type of breast cancer known as triple-negative tumours, an aggressive cancer that tends to strike young women.
To deliver these drugs, the scientists turned to nanotechnology.
The researchers designed the nanoparticle so that the Erlotinib is embedded in the outer layer of it, while Doxorubicin is inside the particle’s core. The particles are coated with a polymer, protecting them from breaking down in the body or being filtered out by the liver and kidneys.
Once the particles reach the tumour, they work their way inside the cancerous cells and begin to break down. Since the Erlotinib is in an outer layer of the particles, it is released first. By the time the second drug is released, the first drug has had enough time to weaken the cancer’s defenses.
“There’s a lag of somewhere between four and 24 hours between when Erlotinib peaks in its effectiveness and the doxorubicin peaks in its effectiveness,” said Yaffe.
The treatment has been tested on triple-negative breast tumours, along with non-small-cell lung tumors. Both types of cancers were shrunk significantly, according to MIT.
Earlier this week, researchers at Johns Hopkins University reported that they have used nanoparticles as Trojan horses that deliver ‘death genes’ to kill brain cancer cells beyond the reach of surgeons.
This particular nano-based treatment, which focused on glioblastomas, the most lethal and aggressive form of brain cancer, uses biodegradable nanoparticles that deliver genes that induce death in cancer cells but don’t affect healthy cells.
The Johns Hopkins treatment has been tested on mice but not on humans.
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