Cancer and evolution #ST1 [fr]
The International Research Project CANECEV (Cancer Ecology and Evolution), inaugurated by the French President Emmanuel Macron while visiting Australia in May 2018, was selected in July 2018 by the French Research Council ANR (Agence Nationale pour la Recherche) to be funded for its project on “Ecology and evolution of transmissible cancers”, but also by the Australian Research Council (ARC) for a study on the evolution of the immune capacities of wild animals.
Prof Fréderic Thomas (CNRS) and Dr Beata Ujvari (Deakin University), the two co-directors of the International Research Project, are studying why transmissible cancers are emerging, how they are evolving, what their impacts are on ecology and evolution, and how to manage or mitigate their effects… In particular, they study the occurrence of transmissible cancers in the Tasmanian devil, a vertebrate with reduced population and genetic diversity, and in the mussel, an invertebrate with an extended population and genetic diversity. The data collected will help identify the common and specific characteristics of the emergence of these transmissible cancers. They also study the immune response of the Tasmanian devil towards the transmissible facial tumor affecting their species. Finally, they focus on the difference in expression of immune genes in captive and wild populations in order to understand the role of the genetic and phenotypic adaptation of the affected host.
These projects combine oncology, ecology, immunology, epidemiology, and evolutionary biology, all areas that, until recently, have not developed many bridges between them. Applying evolutionary principles and ecological approaches to the study of cancers allows a different understanding of the disease and its evolution, but should also improve prevention and therapies. These transdisciplinary studies reveal the ecological and evolutionary facet of cancer biology, and bring together mathematicians, cell biologists, evolutionary biologists and behavioral ecologists.
The research grants awarded to the International Research Project are a tremendous recognition of this Franco-Australian collaboration and of the importance of the research carried out. It will support the development of cross-cutting skills needed in France and Australia by involving students in bilateral projects.
By tackling cancer from the angle of evolutionary science, the evolutionary nature of the disease is highlighted, which for example allows it to develop resistance to the most aggressive anti-cancer treatments. Cancer has the same mechanisms as our cells, which specialize and differentiate themselves by activating different parts of the same genome. They do this according to a specific program which leads to a baby after nine months from the fertilized egg for example. But the program followed by cancer cells remains to be discovered.
One hypothesis is that cancer would correspond to the reactivation of ancestral programs selected during the Precambrian by unicellular organisms that survived thanks to rapid reproduction often under difficult conditions. The organisms, which later became multicellular, would have inherited these programs that became useless, and their accidental reactivation would lead to the development of the disease.
The evolution of the organisms did not destroy these old programs, because it would have taken too much energy. Natural selection promotes not survival, but reproduction. At the scale of evolution, it is better to be vulnerable to cancer having reproduced before, than completely resistant without having the ability to reproduce as resistance would take be too much energy. Thus, oncogenic processes, meaning processes fostering the development of cancers, are maintained in our bodies, and we constantly have precancerous, even cancerous cells, with which we live.
These studies can help therapies by proposing new techniques. For example by enhancing the body’s natural defenses so that the immune system better targets cancer cells, or exhausting them through false attacks such as fake drugs triggering their resistance mechanisms, or false signals triggering their DNA repair mechanisms… Other studies no longer focus on the fight against cancer cells, but on the conditions for the emergence of microenvironments conducive to their growth.
To learn more about it, click here.