Cancer cells in mice react to the ambient temperature
Scientists have questioned the research results from countless cancer studies, because laboratory mice apparently - contrary to previous beliefs - can fight cancer more effectively at higher temperatures. As the researchers report in the "Proceedings" of the US National Academy of Sciences, tumors develop later, grow more slowly and form fewer metastases when the environment is warmer. However, mice are usually kept at much cooler temperatures for laboratory tests. This finding could potentially put the results of several studies in a different light.
Cool temperatures put mice in constant stress and make them fight cancer cells less effectively. Mice generally prefer an ambient temperature between 30 and 31 degrees Celsius, say the researchers led by Kathleen Kokolus from the Roswell Park Cancer Institute in Buffalo, New York, USA. In order to minimize the cleaning effort, mice are usually kept at room temperatures of 20 to 26 degrees. As a result, the mice change their metabolism in order to maintain an optimal body temperature. For mice, this behavior leads to constant stress, which could have influenced the results of previous studies.
To determine the extent to which this effect has an impact on cancer control, the researchers kept laboratory mice either under cooler (22 to 23 degrees Celsius) or warmer (30 to 31 degrees) temperatures. After undergoing a 14-day habituation phase, the animals injected cancer cells into the animals. It was shown that the existing tumors grew significantly more slowly at higher temperatures. In addition, significantly fewer metastases were formed.
At higher temperatures, more immune cells to fight cancer are formed. Further studies showed that at higher room temperatures, more cancer-fighting immune cells (T-lymphocytes) were formed. At cooler temperatures, the researchers observed an opposite effect.
Ultimately, it was shown that mice with cancer go to areas of their own that have an ambient temperature of around 38 degrees, write Kokolus and her team. For the future, this discovery means that the effects of room temperature must be taken more into account when studying the effects of a cancer drug. "According to our data, it is possible that our current knowledge of the ability of laboratory mice to control tumors was impaired by the fact that the tests were carried out under chronic cold stress," it continues further examinations must show. (fr)
Image: Martin Gapa / pixelio.de