Eight hours of resistance

Weizmann Institute of Science scientists have discovered a group of cells that suppress increased cell division - which can cause the development of a malignant tumor

In our environment there is no shortage of temptations to break the law, but only a person with "the mental foundation required to commit a crime" (as the jurists say), will become a criminal. So are the cells: in our body many growth factors are constantly operating, but only cancer cells are easily affected by them, and are "tempted" to divide again and again. In contrast, healthy cells respond to the growth factors and divide only after being exposed to them for eight hours. What happens in the healthy cell, which resists the call to divide, during these eight hours? And more importantly, what is not working properly during these hours in a cancer cell? Why do the cancer cells succumb to the effect and divide so easily?

A new study by Weizmann Institute of Science scientists, recently published in the scientific journal Molecular Cell, led to answers to these questions. The scientists found that when the cell first receives a signal from a growth factor, ten groups of genes are activated in the cell, including about 8,000 genes. One group stands out in importance. It includes about a dozen genes that are controlled by a protein called p53, the cancer suppressor, and they prevent cell division. Only if the growth signal continues for eight hours does p53 release its grip on the cell's DNA, allowing it to divide. The cell acts here like a careful driver, who begins his journey by pressing the brakes to stabilize the car and prevent skidding and overturning: activating p53 as soon as the cell receives a signal from a growth factor prevents immediate division. In this way, a healthy cell ensures that the division will not be carried out as a result of receiving accidental, incorrect and unnecessary growth signals, and that the cell will only divide when a prolonged and necessary signal arrives. In cancer cells, this mechanism is not normal, because in most of them the p53 is damaged or missing. Thus, any occasional growth factor causes them to divide and leads to the growth of a malignant tumor
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This multidisciplinary research was carried out in collaboration between three research groups at the Weizmann Institute of Science, led by Prof. Yosef Jordan from the Department of Biological Control, Prof. Eitan Domani from the Department of Physics of Complex Systems, and Prof. Moshe Oren from the Department of Molecular Biology of the Cell. The research was coordinated by former research student Dr. Yara Tsong, and participated in by Aldama Shoshana Chen, Roy Avraham, Dr. Matia Laureula, Yotam Dreyer, Dr. Tal Shai, Efrat Shema and Efrat Lidor-Nili. Clinical researchers also participated in the study: Dr. Yasmin Yaakov-Hirsh, Dr. Ninet Amarilio and Prof. Gideon Ravavi from the Haim Sheba Medical Center, as well as Dr. Willing Lu and Dr. Gordon Mills from the Am Cancer Research Center. enough. Anderson of the University of Texas.

The study sheds new light on the difference between healthy cells and cancer cells. It may help develop a new and effective approach to cancer treatment using chemotherapy drugs. The cancer sometimes develops resistance to these treatments, among other things because the treatment puts the body in a bind, thus causing the formation of growth factors that cause cell division, so that the treatment, in the end, fails itself. A better understanding of the action of growth signals may allow the administration of chemotherapy treatments at intervals that prevent the increased division of cancer cells.