The podcast of This American life that aired this past weekend offered an interesting glimpse into the world of cancer research. A pair of researchers, one a professor at Thomas Jefferson University and the other a music teacher, were studying whether pulsing sound waves could selectively kill cancer cells. The collaboration started off great but things started to go down hill.
One of the things that was interesting to see was how beginning researchers often get excited by preliminary data and think they’ve hit the jackpot. They don’t realize how critical the controls are. Nor do they realize how much effort it takes to reproduce and validate the experimental results. I have to admit the tedious work involved in validating results is part of what drove me out of the lab.
Category: Cancer (page 3 of 5)
Blind mole rats fight off tumorigenic cells by necrosis since their cells are unable to undergo apoptosis. From Science News:
Blind mole rats ought to be more susceptible to cancer because their cells can’t kill themselves through a type of cell suicide called apoptosis. Low oxygen conditions, such as those common in blind mole rats’ burrows, usually cause cells to commit suicide. To survive underground, the blind rodents had to evolve a countermeasure, a mutation in a cancer-fighting protein called p53. That mutation prevents cells from undergoing apoptosis, a type of cell death in which cells dismantle themselves from the inside — and a process used to kill off cancer cells. Human cancer patients often have similar mutations, which prevent tumor cells from dying.
But blind mole rat cells find a way to off themselves. Growing cells in laboratory dishes, Vera Gorbunova of the University of Rochester in New York and colleagues found that the animals’ cells die on cue after three days. The cells release a chemical called interferon-beta, which the immune system normally uses to fight viruses. In this case, the chemical caused blind mole rat cells to burst open in a violent death known as necrosis.
For more check the link above or read the article at PNAS.
In a study recently published in Nature scientists use magnets to kill cancer. To do this, the researchers introduced zinc doped iron nanoparticles which they conjugated to an antibody for the protein death receptor 4 into a culture of colon cancer cells (DLD-1). When a magnetic field is subsequently applied the nanoparticles cause the cells containing them to enter into an apoptotic cycle and die. From Science News:
In the past, scientists have explored killing cancer using tiny iron-containing nanoparticles that latch onto malignant cells and heat up when exposed to a magnetic field. In the new work, a bit of protein guides each nanoparticle to death receptor 4, an aptly named handle on the outside of a cell that acts as a molecular doomsday switch. Exposing the cells to a magnetic field makes the nanoparticles clump together. This clumping pulls together the three molecular prongs that make up the switch, activating it and triggering a process that leads to the cell’s demise.
The scientists from Yonsei University in South Korea tried the approach with a dish of colon cancer cells. Within 24 hours, more than half of the cells exposed to the magnetic field were dead, the team reports online October 7 in Nature Materials.
“They’ve identified a major opportunity for magnetic nanoparticles,” says bioengineer Andrew MacKay of the University of Southern California. “This might be a new way to do really targeted therapeutics.”
Figuring out how to target only particular cells is an ongoing problem, though. Death receptor 4 sits on normal cells too, which can also be destroyed via remote-controlled magnetism. When the researchers tested their approach on developing zebra fish, the tails of the exposed fish developed a kink where cells were killed off in a particular area.
Exciting stuff. Scientists still don’t know if this can be developed into a meaningful therapy. Many cells in the body contain death receptor 4 including healthy cells and they would also be effected by this treatment. More work needs to be done to improve selective delivery of these nanoparticles to cancer cells. They are currently exploring other targets that may improve the nanoparticles’ selectivity.