The Christmas Berry Plant and Potential Help for an Eye Disease

The Christmas berry (Ardisia crenata) is an attractive shrub in the primrose family, or the Primulaceae. It grows in the wild and as a cultivated plant. Scientists have discovered that in lab equipment a specific chemical from the plant destroys a particular kind of human cancer cell. This doesn't necessarily mean that the chemical can be used to treat cancer in humans, but the discovery is certainly interesting and may eventually have practical benefits.

The Christmas Berry plant

Credit: Dick Culbert, CC BY-2.0 License

The Christmas or Coral Berry Plant

Ardisia crenata is also known as the coral berry plant. The plant produces white to pale pink flowers in the summer and then attractive red berries at Christmas and beyond. The shrub has thick, leathery leaves that have a glossy green appearance. They are roughly oval in shape and have a pointed tip and scalloped edges. I think it's understandable why the plant is liked. The shrub generally reaches a height of one-and-a-half to three feet but is capable of reaching six feet. It reproduces by seeds and by vegetative cuttings.

The Christmas berry is native to East and Southeast Asia. It requires some shade and in nature grows as an understory plant in the forest. In the right environment, the plant grows well outdoors in
North America—sometimes too well. It's considered to be an invasive plant in certain areas, so it's often best to keep it indoors. Other plants besides Ardisia crenata are sometimes referred to a "Christmas berries". It's important that anyone interested in obtaining a plant looks at its scientific name to check whether it's really the species that they want.

Credit: Bruce Blaus, CC BY-3.0 License

The Uvea of the Eye

The new discovery is related to the uvea of the eye. The human eyeball is composed of three layers: the outer sclera, which is visible at the front of the eyeball as the white of the eye, a middle layer, and the inner retina. The middle layer as a whole is known as the uvea. It consists of the iris at the front of the eye, the ciliary body, and the choroid, which contains blood vessels.

In the illustration above, the ciliary body is shown but not labelled. It's the pink projection above and below the lens. There's only one ciliary body in an eye. It's a circular structure, which is why it looks as though there are two ciliary bodies in the eye section shown in the illustration. The structure contains the ciliary muscle, which changes the shape of the lens. It also secretes a fluid called aqueous humour. This fluid has important functions in the front part of the eyeball.

Uveal Melanoma Research

In uveal melanoma, the cells that become cancerous are the melanocytes. The function of the cells is to make a pigment called melanin. Some treatments for uveal melanoma are available. Unfortunately the cancer sometimes spreads to the liver, which can make it harder to treat. An improved treatment would be a wonderful advance.

The recent research related to uveal melanoma is exciting and hopeful, but it's important to remember that the results were obtained in lab equipment and not in living organisms. The researchers were associated with the Sidney Kimmel Cancer Center and the Ichan School of Medicine at Mt. Sinai in the United States.

The scientists investigated the effect of a Christmas berry chemical on uveal melanoma cells. The experimental compound was obtained from the plant's leaves and has the rather unappealing name of FR900359. Thankfully, the name is often abbreviated as FR. It was actually discovered thirty years ago. 

The researchers found that the chemical blocks a particular type of G protein located on the surface of cancerous uveal cells. The protein normally acts as a signaling molecule. In uveal melanoma, the protein molecule is mutated (altered), triggering a process that causes cells to become cancerous. When moderate doses of FR blocked the mutated proteins in the lab experiment, the uveal cells "appeared to revert from cancerous cells to typical uveal cells". Higher doses of FR killed the cancerous cells.

Future Research

The researchers plan to test the chemical on lab animals. If this effort is successful and the chemical is shown to be safe, they plan to test it on humans. The leader of the research team says that he's "very optimistic". Time will tell whether his optimism is justified. I very much hope that it is.

References

Ardisia crenata information from the Invasive Species Compendium (ISC)

A Christmas berry plant compound and uveal melanoma from the EurekAlert news service

Elephant Genes and Protection From Cancer

Very interesting research has revealed why elephants—at least in captivity—have a much lower cancer rate than us. Elephants live about as long as humans yet have far more cells. Like all cells, elephant ones could potentially become cancerous. It would seem that elephants should have a higher rate of cancer than humans instead of a lower one because of their larger size and their greater number of cells. Researchers have discovered two interesting genetic reasons that might explain why this isn’t the case.

An estimated 17 percent of humans worldwide die from cancer, but less than five percent of captive elephants—who also live for about 70 years, and have about 100 times as many potentially cancerous cells as humans—die from the disease. Quote from the University of Chicago Medical Center via the phys.org news service

An African elephant

ajoheyho, CC0 public domain license

The P53 Gene

A gene known as P53 seems to be important in protecting elephants from cancer. It’s sometimes referred to as a master tumour suppressor gene. We have the gene, too. The difference is that we have only one copy of the gene (on paired chromosomes) while elephants have twenty. The activated gene causes the destruction of cells with DNA damage. This damage often precedes the conversion of the cell to a cancerous one. The extra genes in elephants likely enables their body to destroy more potentially dangerous cells.

A Resurrected Pseudogene

The second genetic benefit in elephants is linked to something called a pseudogene, which is sometimes referred to as a dead gene. When genes are copied, a mistake is sometimes made and non-functional copies are produced. While the researchers were studying P53 genes in elephant cells, they encountered an active form of the LI6 gene, which was a surprise. The gene was inactivated long ago in the elephant’s evolutionary history and was though to be still “dead”.

The full name of the LI6 gene is the leukaemia inhibitory factor 6 gene. Like other genes, it codes for proteins. In this case, the protein molecules travel to the mitochondria of cells with damaged DNA. As a result, the mitochondria of the cell are damaged and the cell dies. Mitochondria generate most of the energy required by the cell and are vital organelles. Studies in elephant cells suggest that the P53 gene activates the LI6 gene.

A young African elephant

Mariamichelle, CC0 public domain license

Manipulating the Human Genome

More studies are needed in order to understand the function and interactions of the elephant genes. The exploration might not only be fascinating biologically but also useful in understanding and treating cancer in humans. Researchers are making progress in treating cancer and have made significant discoveries recently, but the disease is still serious. Although we are smaller than elephants, we have many cells and many chances for DNA errors and damage to occur.  The actual number of cells in the human body is unknown.

The short answer is that the body of an average man contains around 30 to 40 trillion cells. The long answer is that scientists do not yet know the exact number. Plus, it depends on whether or not you include the bacteria that are present in and on our bodies. Quote from Yelia Hewings-Martin, Medical News Today

Humans have 20,000 to 25,000 genes. Gene activation and activity are complex processes. Trying to manipulate the human genome without understanding what we’re doing could have unintended consequences. Still, the research in elephant cells may help us learn about useful genes or chemicals in human cells and perhaps lead to beneficial discoveries that don't require the manipulation of genes. Understanding the human body and developing better treatments for diseases are wonderful goals.

References

Resisting cancer by waking a zombie gene from the phys.org news service
Cancer rarely strikes elephants from National Geographic
Number of cells in the human body from Medical News Today