Showing posts with label chromosomes. Show all posts
Showing posts with label chromosomes. Show all posts

Tuesday, June 1, 2010

No Relaxing for Cancer Cells

No relaxing for cancer cells

Many tumour cells would not be viable due to aberrant chromosome distribution if they had not developed a special trick. Scientists from the German Cancer Research Centre have investigated which genes are responsible for this survival strategy of cancer cells.

The revealed that cancer cells rely on the tension of specific protein fibers to be able to multiply. Thus, proteins which maintain this tension are promising targets for new, target-specific anticancer drugs: If they are switched off, cancer cells die.

The two centrosomes of a cell are responsible for cell division to proceed correctly. From these polar bodies in the cytoplasm protein fibers form which correctly distribute the duplicated chromosome set to the newly forming daughter cells. Seen under the microscope, these fibers have the shape of a spindle.

Cancer cells, however, often have more than two centrosomes. As a result, their spindle fibers do not necessarily assume the normal shape of a spindle with two poles; instead, they can have a dysfunctional, multipolar shape. Such malformed spindles distribute the chromosomes unevenly among the daughter cells, which are then no longer viable.

Hence, tumor cells only survive if they manage to partition their chromosomes correctly in spite of extra centrosomes. To do so, many cancer cells have developed a special trick: They form clusters of centrosomes.

Two clusters are formed per cell and a functioning bipolar spindle can develop between these two. Professor Dr. Alwin Krämer, head of a Clinical Cooperation Unit of DKFZ and Heidelberg University Hospitals has recognized this trick as a previously underrated Achilles’ heel of cancer cells, which might be used for destroying them.

Jointly with colleagues from DKFZ, Heidelberg University Hospitals, Mannheim Medical Faculty and Mayo Clinic in the U.S., he systematically investigated the question of which genes enable cancer cells to form centrosome clusters and, thus, to escape cell death.

Saturday, March 27, 2010

UK Boy has world's rarest Genetic Disorder


Every little boy is unique to their parents but six year old Mackenzie Fox-Byrne is also special to the scientific world. He is thought to have the world's rarest genetic disorder because he is the only person on earth known to suffer from it.

Mackenzie, whose condition has given him learning difficulties and left him unable to speak, is the result of a gene mutation doctors have never seen before.

his development appeared to be behind that of her other children, Kamara, 14, and Katie, 12.

At three months old, he was still not lifting his head from his cot, he found it difficult to hold down food and had trouble sleeping.

Doctors initially feared he might have the muscle-wasting disease Muscular Dystrophy, but instead tests results showed a much more bewildering picture.

Mrs Fox-Byrne, 40, of Market Drayton, Shropshire, said: "They knew it was unique and told me excitedly that they had found something rare that no one else has.

"Unfortunately, that was all they could tell me. They couldn't tell me how he is going to progress or whether he might fall ill in the future.

"No one else on earth has ever had this condition."

Mackenzie's test results showed he had a triplication of a small region on the long arm of his X-chromosome.

At the moment the little boy cannot speak, has low muscle tone, is still in nappies and has no sense of danger.

He also has learning difficulties which mean he has the mental age of a two-year-old and goes to a special school in Shrewsbury.

Mrs Fox-Byrne, who lives with her partner Andy, 47, said: "It's quite terrifying to be told he is the only person in the world to have this condition.

"Although we worry about what might happen to him in the future, I just try to put it out of my mind. You could go crazy thinking about it."

Karen Temple, professor of medical genetics at Wessex Clinical Genetics Service confirmed Mackenzie was a totally unique case.

She said: "We have to learn what we can from the little boy as he grows up.

"The problem with Mackenzie isn't that he has got genes missing – as is the case sometimes – it's that he has got extra parts.

"This little boy has had this chromosome problem since he was conceived, we can learn from how he is now and that helps us to predict his future."