This Is the Future of the Fight Against Cancer [Medicine]

Look close. You may be staring at the end of cancer. Those tiny black dots are nanobots delivering a lethal blow to a cancerous cell, effectively killing it. The first trial on humans have been a success, with no side-effects:

It sneaks in, evades the immune system, delivers the siRNA, and the disassembled components exit out.

Those are the words of Mark Davis, head of the research team that created the nanobot anti-cancer army at the California Institute of Technology. According to a study to be published in Nature, Davis' team has discovered a clean, safe way to deliver RNAi sequences to cancerous cells. RNAi (Ribonucleic acid interference) is a technique that attacks specific genes in malign cells, disabling functions inside and killing them.

The 70-nanometer attack bots—made with two polymers and a protein that attaches to the cancerous cell's surface—carry a piece of RNA called small-interfering RNA (siRNA), which deactivates the production of a protein, starving the malign cell to death. Once it has delivered its lethal blow, the nanoparticle breaks down into tiny pieces that get eliminated by the body in the urine.
The most amazing thing is that you can send as many of these soldiers as you want, and they will keep attaching to the bad guys, killing them left, right, and center, and stopping tumors. According to Davis, 'the more [they] put in, the more ends up where they are supposed to be, in tumour cells.' While they will have to finish the trials to make sure that there are no side-effects whatsoever, the team is very happy with the successful results and it's excited about what's coming:

What's so exciting is that virtually any gene can be targeted now. Every protein now is druggable. My hope is to make tumours melt away while maintaining a high quality of life for the patients. We're moving another step closer to being able to do that now.

Hopefully, they will be right.
[Gizmodo via Caltech via Nature]

Nanobees Sting Tumors to Death

We have known for many years that melittin, an ingredient in bee venom, is a poison to tumor cells. Development of therapeutic uses of the substance has been stymied by the fact that melittin does damage to healthy cells as well. Now researchers from Washington University in St. Louis have developed nanoparticles called 'nanobees' that can ferry the melittin directly to tumor cells with great specificity.
The Wall Street Journal reports:

Among Dr. Soman's first experiments was to see how melittin interacted with the nanoparticles. He found that not only did it attach quickly to the outer, lipid layer of the nanoparticles, but that the attachment was stable, suggesting that the nanoparticle-melittin combination, or nanobee, might be able to circulate in the body and not attack healthy cells.
The next issue was to figure out how to get the melittin, once it came upon a tumor, to detach from the nanoparticle and transfer to the cancer cells, taking its cell-killing properties with it. The researchers accomplished this by attaching a third component to the mix—a ligand, which is a chemical that binds two distinct compounds. The ligand they used in this case—which Dr. Schlesinger likens to a "molecular ZIP Code"—has an affinity for attaching to a receptor plentiful in newly formed blood vessels. That's useful in cancer treatment because tumors tend to form new blood vessels to feed themselves and grow.
The scientists began testing the resulting mix, which resembles a milky substance, in mice in 2007. They tried it on a few dozen lab mice with three kinds of tumors: a mouse form of skin cancer; a form of human breast cancer transplanted into the mice; and precancerous lesions caused by human papillomavirus, which can cause cervical cancer in humans.
After about two weeks of treatment, the nanobees slowed the growth of the breast-cancer tumors, shrank the melanoma tumors and reduced the precancerous lesions, compared with control groups that received saline injections and nanoparticles lacking melittin.

Full paper in J. Clin. Invest.: Molecularly targeted nanocarriers deliver the cytolytic peptide melittin specifically to tumor cells in mice, reducing tumor growth
Link to WSJ: The Buzz: Targeting Cancer With Bee Venom ...
[Medgadget]