Collective programmed cell death protects blind mice from cancer
Blind mice are apparently immune to cancer by nature. An international team of researchers led by Vera Gorbunova from the Institute of Biology at the University of Rochester in New York has now found out how the underground blind mice protect themselves from developing cancer. Their findings could help to significantly improve cancer therapy in the future, the scientists report in the journal "Proceedings of the National Academy of Sciences" (PNAS).
It has long been known that blind mice (Spalax) are virtually immune to cancer. "Out of thousands of blind mice kept in the laboratory, there was not a single case of a tumor over the course of 40 years," while up to 90 percent of laboratory animals in the closely related mice die of cancer, emphasize Gorbunova and colleagues. In the case of blind mice, in the event of uncontrolled cell growth, the signaling substance beta-interferon is released, which causes the programmed collective cell death. In this way, no tumor can develop in the organism of the blind mice. In their studies, the discovered mechanism eliminated entire cell cultures within a very short time, the researchers write in the journal "PNAS".
Signaling causes uncontrolled growth to cause collective cell death. To understand the mechanism responsible for the increased cancer resistance of the blind mice, "we examined the growth of fibroblasts of the species Spalax judaei (Judean mountain blind mouse) and Spalax Golani (Golan Heights blind mouse)", report Vera Gorbunova and colleagues. The researchers removed fibroblasts (special connective tissue cells) from the lungs and skin from the blind mice and observed the growth of cell cultures in nutrient media under the influence of growth-promoting substances. The connective tissue cells of the blind mice initially showed massive growth with seven to 20 population doublings before the cells began to release the signaling substance beta-interferon, which resulted in the necrotic cell death of the culture within three days, the scientists report. For years, the researchers have been cultivating connective tissue cells from 20 different rodent species, "but have never observed such a synchronous death of cell cultures," they say.
Natural protection against cancer According to the scientists, this is the first to clearly demonstrate why the blind mice have such immunity to cancer. The programmed cell death in the form of apoptosis is brought about by the release of interferon in the event of uncontrolled cell growth. The effect was also observed when interferon was added to young, still growing fibroblast cultures. "Knowledge of such natural anti-cancer mechanisms could help to develop new therapies for human cancers," said researchers at the University of Rocherster, the Roswell Park Cancer Institute in Buffalo (USA) and the University of Haifa (Israel). A special gene in the circuit, which is crucial for apoptosis in mammals, initiates programmed cell death in blind mice in the event of excessive, uninhibited cell growth.
Blind mice with unique properties The rat-sized blind mice are adapted in many ways to their underground way of life. The animals use their disproportionately large incisors to dig the passages and structures underground. Skin has grown over their eyes as they are not needed for life underground. The blind mice can survive even in extremely oxygen-poor air. In addition, the blind mice are extremely durable compared to other rodents with an age of up to 21 years, write Gorbunova and colleagues. Ordinary rats, for example, only reach an age of around four years. In the eyes of the scientists, however, the uniqueness of blind mice is largely determined by their resistance to cancer. Why exactly these underground animals in the course of evolution have developed such efficient protection against uncontrolled cell growth or tumors remains open for the time being. (fp)
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