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: Study pinpoints microRNA tied to colon cancer tumor growth

add to favorites email to friend print save as pdf

Related Stories

Study shows sharks have personalities

29 minutes ago

Some sharks are 'gregarious' and have strong social connections, whilst others are more solitary and prefer to remain inconspicuous, according to a new study which is the first to show that the notorious ...

Desktop device to make key gun part goes on sale in US

1 hour ago

The creator of the world's first 3D plastic handgun unveiled Wednesday his latest invention: a pre-programmed milling machine that enables anyone to easily make the core component of a semi-automatic rifle.

Twitter-funded lab to seek social media insights

1 hour ago

A new Twitter-funded research project unveiled Wednesday, with access to every tweet ever sent, will look for patterns and insights from the billions of messages sent on social media.

Recommended for you

Study pinpoints microRNA tied to colon cancer tumor growth

2 hours ago

Researchers at the University of Minnesota have identified microRNAs that may cause colon polyps from turning cancerous. The finding could help physicians provide more specialized, and earlier, treatment before colon cancer ...

Obesity tied to higher cancer risk for CRC survivors

3 hours ago

(HealthDay)—Colorectal cancer (CRC) patients who are overweight or obese when diagnosed appear to face a slightly higher risk for developing a second weight-related cancer, according to research published ...

User comments : 0