April 2010: Complex Systems, Dr. John Pepper from the University of Arizona to speak on drug-resistant pathogens

Thursday, April 29, 7:30 p.m.
Wendy Williamson Auditorium

Friday, April 30, Noon
CPISB, Room 120

Dr. John Pepper will speak on "Cancer as a Complex Adaptive System" on Thursday, April 29 at 7:30 p.m. at the Wendy Williamson Auditorium. Here is the abstract for his Thursday talk:

Cancer is an exceptionally difficult medical challenge because it is a complex adaptive system driven by its own internal evolutionary dynamics.

My colleagues and I have applied multilevel selection theory to developing and testing the first general theory for cancer biology. The key characteristics of cancer are shaped by two distinct but interacting levels of selection: A history of selection among individuals has shaped human defenses against, and vulnerabilities to, cancer. On a smaller scale, within each body and each life span, somatic cells also meet the conditions for evolution by Darwinian selection: cell reproduction with heritable variation that affects cell survival and replication.

Consequently, somatic selection among cells favors the dismantling of normal genetic constraints on cell proliferation and survival. This eventually results in uncontrolled cell proliferation followed by malignant tissue invasion. By illuminating its underlying causal dynamics, evolutionary theory provides a general framework for understanding many aspects of cancer. Several conceptual and analytical tools from evolutionary biology can be applied directly to cancer biology, including somatic phylogenetic reconstruction of cancer cells, and the analysis of cellular adaptation and convergent evolution. This theory has important implications both for cancer research and for cancer medicine.

On Friday, April 30 at noon, Dr. Pepper will speak on "Applying Evolutionary Theory to Defeat Drug Resistant Pathogens." Here is the abstract on his Friday talk:

Many of our greatest current and emerging medical challenges involve drug-resistant pathogens. Acquired drug resistance is a central problem in cancer medicine, and also drives the population-wide evolution of drug resistant infectious disease.

The source of these problems is well understood. Drug resistance is caused by selection and evolution in populations of pathogen cells, and exacerbated by our standard approach to drug development. We usually try to control disease by using drugs that kill pathogen cells.

Unfortunately, such drugs act as powerful selective agents, driving evolution by eliminating drug-sensitive cells, and leaving any resistant mutants to proliferate with reduced competition. Because of this, the high pathogen-cell toxicity that we strive for does not always predict long-term success of the drugs we develop. Based on our improving understanding of pathogen ecology and evolution, I propose an alternative approach that can provide drugs that control disease, and do not quickly lose effectiveness to evolved drug resistance. This approach is based on attacking cooperation among pathogen cells instead of killing the cells directly.

For more information, please contact Cheryl Wright at (907) 786-1196.