"Roles of telomeres and telomerase in human health and disease"
Dr Elizabeth H. Blackburn, Morris Herzstein Endowed Professor in Biology & Physiology, Department of Biochemistry & Biophysics, University of California
Wednesday 3 September 2008, 6.30 for 7 pm
Conference Room 1, Darlington Centre, City Road
ABSTRACT
Telomeres consist of simple DNA sequences, which bind cellular protein factors and make a 'cap', thus securing each end of every chromosome. Without telomeric DNA and its special way of replicating, chromosome ends dwindle away as their telomeric DNA erodes, eventually causing cells to stop dividing altogether. Telomerase, a specialized ribonucleprotein reverse transcriptase, is important for long-term eukaryotic cell proliferation and genomic stability, because it replenishes the DNA at telomeres. Thus, depending on cell type, telomerase partially or completely counteracts the progressive shortening of telomeres that otherwise occurs. Telomerase is over-active in many human malignancies, and a potential target for anti-cancer approaches.
Human telomerase activity is present not only in malignant cancer cells, but also in stem cells and germline tissues. Although telomerase activity is normally diminished in adult human somatic cells, throughout life a minimal level of telomerase is still required for replenishment of tissues, such as the immune system. In collaborative studies we showed that telomerase activity in peripheral blood mononuclear cells of the body is depressed by care-giving stress in a cohort of care-giver mothers: the longer the care-giving situation had lasted, and the higher the quantifiable level of perceived stress, the lower the telomerase, and the shorter the telomeres. Low telomerase levels in the normal white blood cells was associated with six prominent risk factors, including chronic psychological stress, for cardiovascular disease. Furthermore, a recent collaborative interventional, longitudinal clinical study was performed with early prostate cancer patients. We found that following a 3-month period of documented comprehensive health intervention, telomerase increased - within the healthy range - in normal white blood cells, in association with quantified improvements in cardiovascular disease risk factors and the patients' prostate cancer biopsy gene profiles. Implications of these and related findings for human disease progression and health will be discussed.
The speaker's presentation can be found here: Elizabeth Blackburn's Talk (~5 MB PDF).
BIOGRAPHICAL NOTESProf. Blackburn is a leader in the area of telomere and telomerase research. She discovered the molecular nature of telomeres - the ends of eukaryotic chromosomes that serve as protective caps essential for preserving the genetic information - and discovered the enzyme telomerase, which replenishes telomeres. Throughout her career, Blackburn has been honoured by her peers as the recipient of many prestigious awards, including The Albert Lasker Medical Research Award in Basic Medical Research (2006), and she is the 2008 North American Laureate for L'Oreal-UNESCO For Women in Science. In 2007 she was named one of TIME Magazine's 100 Most influential People.