Until about twenty-five years ago, it was believed that olfactory receptors (smell receptors) were only present in the nose. This changed in the early 1990s when researchers began to discover that they were in all sorts of places, including the lungs, heart, liver, skin, testes, kidneys, intestines and even sperm. This may seem unbelievable until the mechanism of an olfactory receptor is more fully understood. Most of us are aware only of how they help us to recognize different scents, but if we consider that their primary job is to serve as sensitive chemical receptors, it’s not difficult to understand why they are in other parts of our bodies.
In her TedMed talk, Dr. Jennifer Pluznick of Johns Hopkins School of Medicine explains that these specialized cells are present in organs and bodily fluids because of their ability to detect the presence of certain substances within them. Dr. Pluznick’s work is concerned with the role that sensory receptors (smell and taste receptors) play in kidney function. She points out that while the kidney doesn’t exactly “smell” or “taste” the morning coffee you drank, sensory receptors there may be able to detect a change in the chemical composition of your blood and make adjustments to maintain homeostasis (balance) within your system. Because more of our DNA is devoted to genes for different olfactory receptors than for any other protein, it stands to reason that they would serve more than one purpose.
* * * * *
In May of this year, researchers at Duke University published a study in Frontiers in Oncology that focuses on an olfactory cell that is present in unusually high numbers in prostate cancer. Scientists found that when this receptor (known as OR51E2) is activated, the tumor transforms into a more aggressive, castration-resistant cancer. Needless to say, identifying molecules that activate or block this receptor could change the course of cancer treatment. After skin cancer, prostate cancer is the most common type in men with one in nine being diagnosed during their lifetimes. It is also the second leading cause of death after lung cancer, with one in forty-one men dying of it.
Using odorants as therapy to treat cancer is still a long way off, but it is an exciting avenue of research that holds much promise. Watch Dr. Pluznick’s seven minute-long TedMed talk.