Scientists track the influence of a cancer inhibitor on a single DNA molecule

Jun 25, 2007

Researchers in Delft University of Technology’s Kavli Institute of Nanoscience in The Netherlands have cast new light on the workings of the important cancer inhibitor topotecan. Little had been known about the underlying molecular mechanism, but the Delft scientists can now view the effects of the medicine live at the levelin of a single DNA molecule.

The research is being published this week in the journal Nature. The lead author of the article, Daniel Koster, will receive his PhD at TU Delft on Monday June 25, partly on the results described in the article.

The medicine investigated, topotecan, interacts with an important protein (TopoIB), causing a (cancer) cell to malfunction. The TopoIB protein is responsible for the removal of loops from DNA, which arise amongst other things during cell division. The TopoIB protein binds to the DNA molecule, clamps around it and cuts one of the two DNA strands, after which it allows it to unwind and finally joins the broken ends together.

PhD candidate Daniel Koster, Master’s student Elisa Bot and researcher Nynke Dekker of the Molecular Biophysics group of the Kavli Institute of Nanoscience Delft have managed to unravel this mechanism in an extremely direct manner. In the laboratory they fixed a single DNA molecule between a glass plate and a magnetic sphere. With the help of two magnets they could both pull and twist the DNA molecule. When they added TopoIB to a twisted piece of DNA, they saw that the loops were slowly removed.

What is exceptional is that the action of one TopoIB enzyme on one DNA molecule could be observed live. In collaboration with St. Jude Children’s Research Hospital Memphis (USA) the mechanism could also be observed in living yeast cells.

Source: Delft University of Technology

Explore further: Unplanned hospitalizations with GI cancer patients common

add to favorites email to friend print save as pdf

Related Stories

Arguments made in ex-dictator's suit against game

2 hours ago

(AP)—A judge has heard arguments from lawyer and former New York City Mayor Rudy Giuliani calling for the dismissal of a lawsuit filed against video game giant Activision by former Panamanian dictator Manuel Noriega.

All in a flap: Seychelles fears foreign bird invader

2 hours ago

It was just a feather: but in the tropical paradise of the Seychelles, the discovery of parakeet plumage has put environmentalists in a flutter, with a foreign invading bird threatening the national parrot.

Twitter tweets start to sing

2 hours ago

Twitter began letting people instantly listen to music and other audio by clicking on tweets from the popular messaging service.

Recommended for you

Blood biomarker may detect lung cancer

9 hours ago

A new study shows that patients with stage I to stage III non-small cell lung cancer have different metabolite profiles in their blood than those of patients who are at risk but do not have lung cancer. The study abstract ...

ACG: Recent increase in incidence of young-onset CRC

Oct 20, 2014

(HealthDay)—The incidence of young-onset colorectal cancer (CRC) is increasing, and the disease is more aggressive pathologically. These findings are being presented at the annual meeting of the American ...

User comments : 0