The yew tree is a remarkable plant that has been used for centuries for its medicinal properties. However, it is also one of the most endangered species in the world, due to overharvesting and habitat loss.
In this article, we will explore how Chinese scientists are working to save this precious tree and unlock its potential for curing cancer.
The Secret of the Yew Tree(Photo : Yana Gorbunova/Unsplash)
The yew tree belongs to the genus Taxus, which comprises about 10 species of evergreen conifers. They are native to temperate regions of Asia, Europe, and North America.
The yew tree has a distinctive appearance, with dark green needles, red berries, and reddish-brown bark.
The yew tree has a long history of human use, dating back to ancient times. It was valued for its wood, which was used to make bows, spears, and furniture.
It was also revered for its spiritual and symbolic significance, as it was associated with death, rebirth, and immortality in various cultures.
However, the most remarkable feature of the yew tree is its ability to produce a rare and powerful anticancer compound called paclitaxel.
Paclitaxel was first discovered in 1962 by researchers from the National Cancer Institute, who isolated it from the bark of the Pacific yew tree (Taxus brevifolia).
Paclitaxel is an antimitotic agent, which means that it prevents cancer cells from dividing and multiplying. It is used to treat various forms of cancer, such as breast, ovarian, lung, and pancreatic cancer.
Paclitaxel is one of the most effective and widely used anticancer drugs in the world. However, it is also one of the most difficult and expensive to obtain.
Paclitaxel is present in very low concentrations in the yew tree, making up only about 0.004% of the bark. To produce one kilogram of paclitaxel, about 10,000 kilograms of bark are needed.
This means that thousands of yew trees have to be cut down to meet the demand for the drug.
This has led to the rapid decline and endangerment of the yew tree, especially in China, where it is classified as a first-level rare and protected species.
To solve the problem of paclitaxel scarcity and yew tree conservation, Chinese scientists have been searching for alternative and sustainable ways to produce the anticancer compound.
One of the most promising methods is to use genetic engineering to transfer the biosynthetic pathway of paclitaxel from the yew tree to another plant that can grow faster and easier.
In 2024, two Chinese professors, Yan Jianbin and Lei Xiaoguang, published a groundbreaking study in the journal Science, where they reported that they had successfully created a biosynthetic pathway for paclitaxel in tobacco plants.
Tobacco plants are known for their association with lung cancer due to cigarette consumption, but they may also hold the key to new treatments for other cancers.
The researchers explained that the synthesis of paclitaxel involves three critical processes: the formation of a skeleton, the biosynthesis of an intermediate called baccatin III, and the attachment of a side chain.
They identified and cloned the genes involved in each step and inserted them into tobacco plants using a bacterial vector.
They then tested the transgenic tobacco plants and found that they could produce baccatin III, the key precursor of paclitaxel, at a concentration of 0.2% of the dry weight.
This is 50 times higher than the concentration of paclitaxel in the yew tree bark.
The researchers also suggested that the tobacco plants could be further modified to produce paclitaxel itself, by adding another gene that catalyzes the final step of the pathway.
They estimated that the tobacco plants could produce paclitaxel at a concentration of 0.02% of the dry weight, which is still five times higher than the yew tree bark.
This would greatly reduce the cost and environmental impact of paclitaxel production, as well as provide a new source of income for tobacco farmers.
The study was hailed as a major breakthrough in the field of plant biotechnology and cancer research. It demonstrated the potential of using genetic engineering to create novel and valuable compounds from plants that are otherwise harmful or useless.
It also showed the possibility of finding new allies in nature, where enemies can become friends and vice versa.
The yew tree and the tobacco plant are two examples of how nature can offer both challenges and solutions for human health. By understanding and respecting the diversity and complexity of life, we may be able to discover new ways to fight diseases and save lives.
