A team of Swiss and Italian researchers has worked out why cancer cells are able to divide indefinitely, the study sheds new light on the structure of our chromosomes and our understanding of
how our cells divide.
The work, which was partly funded by the EU’s Sixth Framework Programme, is published online by the journal Science.
Our genetic material, DNA, is packaged into chromosomes, at the ends of which are structures called telomeres. These regions of repeated chains of DNA are often compared to the plastic tips of
shoe laces because they prevent the chromosomes from fraying during cell division. However, every time a cell divides, the telomeres get a little bit shorter. When they get too short, they set
off an alarm system that stops the cell from dividing further.
However, sometimes the system goes wrong, leaving cells with damaged chromosomes or cell lines which become ‘immortal’; both of these situations lead to diseases such as cancer. It is thought
that some 90% of cancer cells have telomere maintenance activity.
Now, the researchers have found out more about telomere function. It has long been known that the double stranded DNA in our chromosomes is transcribed into single stranded RNA (ribonucleic
acid), which is used by the cell to carry out tasks such as making proteins. Scientists thought that telomeres were ‘silent’, and that their DNA was never transcribed into RNA.
In this latest study, the scientists discovered that in fact telomeric DNA is transcribed into RNA, and that this RNA is regulated by the same enzyme which is responsible for maintaining the
telomeres in embryonic cells and some stem cells so that they keep dividing.
The scientists believe that their findings could lead to the development of new drugs against diseases caused by telomere malfunctions.
‘It’s too early to give yet a definitive answer,’ said senior author Joachim Lingner of the Swiss Institute for Experimental Cancer Research. ‘But the experiments published in the paper suggest
that telomeric RNA may provide a new target to attack telomere function in cancer cells to stop their growth.’