The protein mTor which is involved in the growth and proliferation of cells was expected be a first rate target for developing an anti-cancer treatment. However, different tests aimed at inhibiting mTor showed disappointing results.  What was the reason for this disappointment? A study in which Françoise Remacle participated explains why the protein could not be inhibited: oxygen pressure is greatly reduced in most solid tumors which are in a state of hypoxia in comparison with normal cells which have a pressure of 21% (normoxia). When oxygen pressure is reduced to very low levels, between 1.5% and 2%, mTor inhibitors are not effective. An original approach, based on concepts of physical chemistry has been published in the PNAS journal

In 2008, the number of individuals who died as a result of cancer reached 7.6 million, which means that this disease is the cause of around 13% of deaths in the world. According to the World Health Organisation (WHO), this figure is likely to increase and should reach 13.1 million by 2030… While research makes it possible to detect and better treat the different types of cancer, the battle is far from being won and the race against time to develop anti-cancer treatments continues apace. In this race against time, the starting point is to identify potential therapeutic targets, that is to say molecules which can be inhibited or stimulated in order to slow down or halt the cancer process.

Among the many targets identified by scientists, the mTor protein (which stands for “Mammalian Target of Rapamycin”) seemed particularly interesting given the different criteria it satisfied and it was hoped that its inhibition could become an excellent anti-cancer treatment option in the future.

A target of choice in the fight against cancer

The study of mTor has made it possible to demonstrate the involvement of this protein in various signaling pathways which are known to be disrupted in cancer cells. In fact, mTor is involved in the proliferation and growth of cells in tumor angiogenesis, cell metabolism etc. As these cellular processes are exacerbated in the case of cancer, many scientists thought that inhibiting mTor would prevent a tumor from growing and spreading. For this reason, different teams of researchers initiated studies aimed at testing the effect of mTor inhibitors on the progression of different types of tumors. “However, even though mTor seemed to be a target of choice on paper, a large part of these tests proved disappointing.  The response of mTor to the inhibitors was not good”, explains Françoise Remacle, Director of research at the FNRS and director of the Laboratory of Theoretical Physical Chemistry of the University of Liege. Why were the results so disappointing? This question remained unanswered until now. Thanks to an original approach based on concepts of physical chemistry, Françoise Remacle, in collaboration with researchers from the Hebraic University of Jerusalem, the Institute of Technology of California and the University of California in Los Angeles has shed light on this mystery.