INT'L GUEST SPEAKER: Professor Robert Gillies, Moffit Cancer Centre, University of South Florida, Tampa USA : ‘Causes and Consequences of The Hostile Microenvironment of Tumors’
Cancers progress through a series of events that can be characterized as “somatic evolution.” A central premise of Darwinian evolutionary theory is that the environment imparts pressure to select for species that aremost fit within that particularmicroenvironmental context. Furthermore, the rate of evolution is proportional to both (1) the strength of the environmental selection and (2) the phenotypic variance of the selected population. It is notable that, during the progression of cancers from carcinogenesis to local invasion to metastasis, the selective landscape continuously changes, and throughout this process, there is increased selection for cells that have alteredmetabolic phenotypes: implying that these phenotypes impart a selective advantage during the process of environmental selection.
One of the most prevalent selected phenotypes is that of aerobic glycolysis, that is, the continued fermentation of glucose even in the presence of adequate oxygen. The mechanisms of this so-called “Warburg effect” have been well studied, and there are multiple models to explain how this occurs at the molecular level. Herein, we propose that unifying insights can be gained by evaluating the environmental context within which this phenotype arises. In other words, we focus not on the “how” but the “why” do cancer cells exhibit high aerobic glycolysis. This is best approached by examining the sequelae of aerobic glycolysis that may impart a selective advantage. Many of these have been considered, including generation of anabolic substrates, response rates of glycolysis vis-à-vis respiration, and generation of antioxidants. Afurther sequeala considered here is that aerobic glycolysis results in a high rate of lactic acid production; resulting in acidification of the extracellular space. Indeed, it has been shown that a low extracellular pH promotes local invasion, promotes metastasis, and inhibits antitumor immunity. In naturally occurring cancers, lowextracellular pH is a strong negative prognostic indicator of metastasisfree survival. Furthermore, it has been shown that inhibition of extracellular acidosis can inhibitmetastasis and promote antitumor immunity. Hence, we propose that excess acid production confers a selective advantage for cells during the somatic evolution of cancers.
Date: 4 December 2015, 13:00 (Friday, 8th week, Michaelmas 2015)
Venue: Sherrington Building, off Parks Road OX1 3PT
Venue Details: Sherrington Building (DPAG Large Lecture Theatre, Ground Floor, OX1 3PT), off Parks Road OX1 3PT.
Speaker: Professor Robert Gillies (Moffit Cancer Centre, University of South Florida, Tampa USA)
Organising department: Department of Physiology, Anatomy and Genetics (DPAG)
Organiser: Sarah Noujaim (University of Oxford, Department of Physiology Anatomy and Genetics)
Organiser contact email address:
Host: Professor Maike Glitsch (DPAG, University of Oxford)
Part of: DPAG Head of Department Seminar Series
Topics: Tumors
Booking required?: Not required
Audience: Members of the University only
Editor: Sarah Noujaim