Senescence: The new weapon in the fight against cancer
With old age comes a resolute hardiness; an accumulation from years of life experience. The refusal to yield to the trials and tribulations of modern daily life is an asset of sorts. And one that also manifests in our biology. Senescence – a phenomenon generally associated with ageing – also brings its benefits.
Senescence is the process by which cells lose their ability to divide. It generally occurs at the end of a long and fruitful cellular life, after some fifty or so divisions. When it arises prematurely, however, triggered by certain stresses, such as cancer, it can play a protective role according to a wave of recent research. The process of cellular senescence plays a key part in the body’s attempts to slow the spread of tumours. Harnessing and controlling the underlying molecular mechanisms will not only help us understand the true nature of ageing, but also pave the way for new cancer treatments.
Scientists are constantly investigating the details of how different cancer therapies battle against disease. Recently, such studies have yielded an unexpected result. “In the last few years a number of papers have, without necessarily looking for it, found that different therapeutic approaches seem to converge. They all activate senescence in tumour cells. This acts as a barrier to tumour progression,” explains Jesus Gil (Cell Proliferation Group), co-author of a new review in Trends in Cell Biology. The review brings these studies together for the first time, and has identified the potential that senescence has for spawning entirely new forms of cancer treatment.
“So what would happen if we triggered senescence, directly?” asks Gil. Such an approach, termed prosenescence, is a very real possibility. “Studies have shown that, in theory, if you potentiate senescence, you can develop beneficial therapies for cancer.” The Cell Proliferation Group has long been interested in looking at the compounds secreted by senescent cells. While they have ceased to divide, these cells remain metabolically active. They secrete factors that can further promote senescence, and alter the local microenvironment. These secretions are easily targeted by drugs, making tampering with senescence that much more straightforward for scientists. “We already know of antibodies and small chemical compounds that can target these factors. Knowing that senescent cells have this potent secretory response, and that this is important to influence senescence itself is of therapeutic interest.”
Along with novel cancer treatments, this kind of research strategy may also unearth the key to ageing. A paper published in Nature in 2011 showed that senescence is involved in ageing. “Using a mouse model system, the study showed that if you get rid of senescent cells, you can ameliorate some of the symptoms of ageing. Not only in cancer, but in some age-related pathologies, targeting senescence could have very beneficial results.” So will it help us live longer? Not quite. This research hints at improving the quality of life, rather than lifespan itself. But as Acosta and Gil’s review highlights, the possibilities are great.
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Acosta, J. C., Gil, J., (2012). Senescence: a new weapon for cancer therapy. Trends Cell Biol. Abstract
