DNA Robot Kills Cancer Cells

Scientists using nanotechnology may have come
up with a new way to attack cancer cells like this
one.
(photo: Steve Gschmeissner/Science Photo Library)

By Alla Katsnelson, Scientific American/Nature

18 February 12

NA origami, a technique for making structures from DNA, may be more than just a cool design concept. It can also be used to build devices that can seek out and destroy living cells. [View a "DNA Origami" Slide Show.]

The nanorobots, as the researchers call them, use a similar system to cells in the immune system to engage with receptors on the outside of cells.

"We call it a nanorobot because it is capable of some robotic tasks," says Ido Bachelet, a postdoctoral fellow at Harvard Medical School in Boston, Massachusetts, and one of the authors of the study, which is published in the February 17 issue of Science. Once the device recognizes a cell, he explains, it automatically changes its shape and delivers its cargo.

The researchers designed the structure of the nanorobots using open-source software, called Cadnano, developed by one of the authors--Shawn Douglas, a biophysicist at Harvard's Wyss Institute for Biologically Inspired Engineering. They then built the bots using DNA origami. The barrel-shaped devices, each about 35 nanometers in diameter, contain 12 sites on the inside for attaching payload molecules and two positions on the outside for attaching aptamers, short nucleotide strands with special sequences for recognizing molecules on the target cell. The aptamers act as clasps: once both have found their target, they spring open the device to release the payload.

"You can think about it as a sort of combination lock," says Bachelet. "Only when both markers are in place, can the entire robot open."

The researchers tested six combinations of aptamer locks, each of which were designed to target different types of cancer cells in culture. Those designed to hit a leukemia cell could pick that cell out of a mixture of cell types then release their payload--in this case, an antibody--to stop the cells from growing. They also tested payloads that could activate the immune system.

The work "takes us one more step along the path from the smartest drugs of today to the kind of medical nanobots we might imagine," says Paul Rothemund, a computational bioengineer at the California Institute of Technology in Pasadena, and inventor of DNA origami.   READ MORE

Alzheimer's Families Clamor for Drug

By SHIRLEY S. WANG

In the wake of research suggesting a skin-cancer drug may have benefits in treating Alzheimer's disease, physicians and advocacy groups are getting a flurry of calls from patients seeking to use the drug off-label.
The clamor underscores how urgently patients want solutions to the rising tide of Alzheimer's. But experts caution that more research is needed to determine whether the drug, bexarotene, is effective in humans at all, not to mention what the dosage should be.

The study, published Thursday in the journal Science, was conducted in mice, and the road to an effective Alzheimer's treatment is littered with failures that looked promising early on in animals.
"The Alzheimer's community is very desperate for anything that shows any sign of hope or promise," said Eric Hall, chief executive of the Alzheimer's Foundation of America, a New York-based advocacy organization that started to field calls from consumers as soon as the paper was published.
READ MORE

"To patients and families who are this motivated, the idea of an off-label pill is not a major leap," he said. The cost would be $1,200 or more a month and unlikely to be covered by insurance, Dr. Gandy said.

Bexarotene, marketed by Japan-based Eisai Co. as Targretin, is approved for use in a particular form of skin cancer. Once a drug is on the market, physicians are free to prescribe it for other conditions, though drug companies can't promote such off-label uses.
  

• Bexarotene (Brand name: Targretin)

• Bexarotene - Wikipedia, the free encyclopedia

• Families of Alzheimer's sufferers clamor for cancer drug

• Alzheimer's Disease Symptoms Reversed in Mice: Scientific American

• Google search results for Bexarotene

Could A Club Drug Offer 'Almost Immediate' Relief From Depression?

Club Drug "Special K"

January 30, 2012, NPR blog

Traditional antidepressants like Prozac work on a group of chemical messengers in the brain called the serotonin system. 

Researchers once thought that a lack of serotonin was the cause of depression, and that these drugs worked simply by boosting serotonin levels. 

Recent research suggests a more complicated explanation. Serotonin drugs work by stimulating the birth of new neurons, which eventually form new connections in the brain. 

Ketamine, in contrast, activates a different chemical system in the brain – the glutamate system. 

Researcher Ron Duman at Yale thinks ketamine rapidly increases the communication among existing neurons by creating new connections. 

This is a quicker process than waiting for new neurons to form and accomplishes the same goal of enhancing brain circuit activity. Ketamine has been used for decades as an anesthetic. It also has become a wildly popular but illegal club drug known as "Special K." 

Mental health researchers got interested in ketamine because of reports that it could make depression vanish almost instantly.  

Carlos Zarate ... does ketamine research at the NIH. Zarate says patients typically say, "'I feel that something's lifted or feel that I've never been depressed in my life. I feel I can work. I feel I can contribute to society.' And it was a different experience from feeling high. This was feeling that something has been removed."

Note: For many inspiring potential treatment breakthroughs in health issues, click here.