Making new cells - Getting ready to divide

The spindle When a cell gets ready to divide it copies all of its DNA, which is packaged up to form chromosomes - human cells have 23 pairs of these. These chromosomes must then be shared equally between the two 'daughter' cells.

To do this, the cell builds a molecular scaffold known as the spindle, made from tiny tube-shaped proteins called microtubules. These are built by centrosomes – tiny structures in the cell. The microtubules attach to DNA, pulling apart the pairs of chromosomes. In the picture on the right, the spindle is represented by the purple lines attached to the DNA spirals, while the centrosomes are the purple dots.

If the spindle is faulty, then the daughter cells may end up with the wrong number of chromosomes, which can lead to cancer. Some cancer drugs, such as taxol, work by blocking the spindle, so tumour cells can’t divide at all. But they can also stop healthy cells from dividing, causing side effects.

Cancer Research UK scientists have made great strides in understanding how the spindle grows and works. And we are continuing to fund pioneering research in this area.

Studying the spindle

A surplus of centrosomes

A dividing cell Many of our scientists are studying different aspects of the spindle, using a variety of laboratory models. For example, we have funded the work of Professor Iain Hagan since the early 90s. He and his team at the Paterson Institute for Cancer Research in Manchester are studying how the spindle forms in yeast cells. The insights from these simple cells are shedding light on spindle formation in our own cells, and how this goes wrong in cancer.

In Oxford, Professor Jordan Raff is using the latest microscopy techniques to study how the spindle forms in fruit fly cells. This means the researchers can directly see the effects of faulty proteins linked to cancer. The molecules involved in spindle formation are very similar in humans and fruit flies, making them a valuable model.

And in Cambridge, Professor David Glover is also studying the formation of the spindle in fruit flies. Over the years, he has discovered several important proteins that are involved in forming the spindle, including Polo kinase and Aurora kinase. Both of these are often faulty in cancer cells, making them divide incorrectly. Researchers are now developing and testing drugs to block these faulty proteins, which could lead to new treatments for cancer.

Dividing cell (credit Christina Karlsson) In the image on the right, you can see the centrosomes - the structures that produce microtubules - in a healthy cell getting ready to divide (two green spots). Many cancer cells have more than two centrosomes, so they produce an abnormal spindle. This increases the chances of the cell having problems as it tries to divide, and the daughter cells can end up with the wrong amount of DNA.

Professor Andrew Fry in Leicester is investigating how this happens, and how we can use this knowledge to treat cancer by blocking faulty centrosomes and spindles.