Cancer is the second leading cause of death in the world after cardiovascular diseases. In 2015, 8.8 million people died according to the WHO. One in six deaths is believed to be due to cancer. Today, American researchers have made discoveries that could lead to new therapies to prevent the growth of cancer cells. Indeed, they managed to recreate a key process involved in cell division in the test tube, discovering the vital role played by a high protein in more than 25% of all cancers. The results of their experiments have been described in two articles published simultaneously in the journals eLife and Nature Communications.
When cells divide, a structure made up of thousands of filaments called microtubules attaches to the chromosomes and attracts an equal number of them into each new cell that forms. Each of them is assembled from individual tubulin molecules. Since chromosome segregation errors can lead to cancer, they must assemble into microtubules at the right time and in the right place to form an efficient spindle-shaped apparatus. Also, nucleation of branched microtubules, in which a new microtubule is formed from the side of an existing microtubule, is very important because it allows the cell to form a large number of microtubules which all point to the chromosomes.
“To better understand the nucleation mechanism of branching microtubules, we set out to reconstruct the process outside the cell using purified proteins”, explains Sabine Petry, assistant professor of molecular biology at Princeton (United States) ) who directed the research.
The key role of the TPX2 protein
In the article in eLife, the researchers tell how they recreated the nucleation of branched microtubules in a test tube. In that of Nature Communication, they reveal that TPX2, a protein with high levels in more than 25% of all cancers and involved in the nucleation of branched microtubules, behaves like a liquid by promoting the nucleation of branched microtubules.
The two studies therefore show that TPX2, previously neglected, plays a major role in the nucleation of branching microtubules. It first moves to the microtubules to assemble all the other components which then give rise to a branching microtubule and does so by behaving like a liquid.
According to the researchers, cellular signals can regulate the condensation of TPX2 so that it only occurs when a cell divides and must form a spindle. “Our conclusions on the behavior of TPX2 could guide future therapeutic efforts aimed at modulating cell division (…) In addition, our reconstruction of the nucleation of branched microtubules is an important step towards the reconstruction of the entire spindle apparatus, as well than other cellular structures that depend on this microtubule assembly path, ”they conclude.
In France, 157,400 cancer deaths in 2018
In France, cancers are the leading cause of death in men and the second in women. According to the national cancer institute, in 2018, cancer would have resulted 157,400 dead. In men, prostate cancer is the most common (50,000 new cases in 2015), followed by lung and colorectal cancer (31,000 and 23,000 new cases in 2018, respectively). The most common cancer in women is breast cancer (58,000 new cases in 2018). Then come colorectal and lung cancer (20,000 and 15,000 respectively).
According to a national study carried out in 2014, 63.5% of cancer survivors suffer from sequelae due to illness or treatment and, among those employed at the time of diagnosis, 20% do not work anymore five years later.
Interested in this topic ? Come and discuss it on our forum!
–
–
