How Cells Communicate
Scientists at UCLA and Charles R. Drew University of Medicine and Science have discovered a possible method by which cancer cells and dying cells communicate with nearby normal nerve cells without being physically connected to them. Normal communication is done by chemical, hormonal or other physical connection. What this implies is unclear but it is certainly intriguing.
Dr. Keith Norris, senior author of the research and assistant dean for clinical and translational science at the David Geffen School of Medicine at UCLA, said the study contributes to the understanding of cell communication, which until now was known to take place only through direct contact or direct stimulation of receptors in the cells of molecules known as ligands or in hormones, signaling factors, nerves and other pathways.
Cells communicate with each other via direct contact, over short distances (paracrine signaling), or over large distances and/or scales (endocrine signaling).
Some cell-to-cell communication requires direct cell—cell contact. Some cells can form gap junctions that connect their cytoplasm to the cytoplasm of adjacent cells. In cardiac muscle, gap junctions between adjacent cells allows for action potential propagation from the cardiac pacemaker region of the heart to spread and coordinately cause contraction of the heart.
Cells receive information from their neighbors through a class of proteins known as receptors. Notch is a cell surface protein that functions as a receptor. Animals have a small set of genes that code for signaling proteins that interact specifically with Notch receptors and stimulate a response in cells that express Notch on their surface. Molecules that activate (or, in some cases, inhibit) receptors can be classified as hormones, neurotransmitters, cytokines, and growth factors, but all of these are called receptor ligands. The details of ligand-receptor interactions are fundamental to cell signaling,
It now appears, the researchers say, that cells may be able to effectively communicate through physical barriers. Their study appears in the January 2013 issue of the peer-reviewed American Journal of Translational Research.
For the study, Norris and his colleagues reported on how normal nerve cells isolated in an enclosed chamber behave during a function known calcium signal processing. The team found that when these isolated nerve cells were surrounded by other normal nerve cells outside the barrier, they had the same calcium signaling properties.
However, when the normal isolated nerve cells were surrounded by cancer cells or dying cells, they processed the calcium signals differently, suggesting there was communication from the surrounding cells. The physical barrier between the cells prevented hormonal, ligand-receptor and other traditional forms of cell-to-cell communication.
Co-authors Dr. Christopher Reid and Victor Chaban of the Life Sciences Institute at Drew University noted that this novel finding may represent a potentially higher form of cell communication. Discovering that cancer cells and dying cells may have a previously undiscovered communication method with other cells may lead to new treatments for cancer, aging and other diseases, they said. Further studies are needed to uncover how the non-physical communication occurs.
"Understanding the many ways in which cells communicate is an important step toward developing new approaches to treat disease" said Dr. Steven M. Dubinett, executive director of the UCLA Clinical and Translational Science Institute (UCLA CTSI).
For further information see Cells.
Signalling image via Wikipedia.