Plant Lectins and Cancer
Nature is smart. Lectins from plants inhibit cancer naturally.
Researchers from the University of Tokyo have discovered that a lectin naturally contained in Wisteria japonica seeds selectively binds to several types of cancer. And other plant lectins have been found to have this capability.
The researchers conducted laboratory tests using seeds from three different plants – Wisteria floribunda (Japanese wisteria), Wisteria brachybotrys, and Wisteria japonica (Japonica). The researchers extracted agglutinizing lectins from each of the seeds of these three plants.
What are agglutinizing lectins?
Agglutinizing lectins often play a protective role in nature, where they protect their host from the intrusion of certain molecules or even bacteria or viruses. For this reason practically every plant will contain some lectins.
Agglutinizing lectins appear throughout nature within many different species. The word agglutinin comes from agglutinare, which means “to glue.”
Agglutinizing lectins will thus bind with and sometimes “clump” different types of elements. They may bind to bacteria, or they might bind to red blood cells. Or they may simply bind to sugars, or even antibodies.
In the case of the lectins within the Japonica tree, and compared to the other three species of Wisteria, the researchers extracted and purified lectins that were found to bind to N-acetylgalactosamine. This is a galactose sugar combined with an amino acid—a component of living cells involved in intercellular communication and thus a part of most of most living cells.
But in this case, the researchers found these lectins were smart – and one was smarter than the other two. The researchers tested all three against a host of different cells, including human cancer cells that had been collected from cancer patients.
These included human squamous cell carcinoma, cancer cells from the kidney, liver cancer cells and lung cancer cells among others. The researchers also tested the Wisteria lectins against normal (healthy) cells.
One lectin was more selective
The two Wisteria plants were found to bind with all of the cancer cells.
But the lectin from the Wisteria japonica was found to bind only with the skin cancer cells, the kidney cells and the lung cancer cells.
The researchers indicated this meant the Wisteria japonica lectin could be used as a diagnostic tool – and possibly even a treatment tool – against these forms of cancer.
The researchers noted:
“In addition, histochemical analysis of human squamous cell carcinoma tissue sections
demonstrated that Wisteria japonica lectin specifically bound to differentiated
cancer tissues but not normal tissue. This novel binding characteristic of
Wisteria japonica lectin has the potential to become a powerful tool for clinical
Other agglutinating lectins take out cancer cells
The fact that lectins will selectively bind to cancerous cells have been seen among other types of plant lectins, including wheat germ agglutinin (WGA) and others. In a university study from Argentina, WGA was found to selectively bind to polycystic ovary cells. Other studies have shown WGA will not only bind but inhibit growth of colon cancer cells in the gut.
In these studies, the WGA and other lectins would selectively differentiate between the cancer cells and the healthy cells around them—leaving the healthy cells intact.
The general take-away relates to utilizing those elements in nature that can help protect us. Lectins within plants help protect the plant from foreign forces that endanger the plant’s survival. Now we are finding that these same elements can help us protect our own bodies.
This is really not a new thing – though our realization might be. For decades researchers have known that the same antioxidants that help neutralize free radicals within our bodies are produced by plants to help protect themselves from the environment around them.
And surely we are slowly learning just how smart nature is. Hopefully we will all learn this sooner so we can halt the continuing decimation of so many smart plant species around the world.
Soga K, Teruya F, Tateno H, Hirabayashi J, Yamamoto K. Terminal N -acetylgalactosamine-specific leguminous lectin from Wisteria japonica as a probe for human lung squamous cell carcinoma. PLoS One. 2013 Dec 13;8(12):e83886. doi: 10.1371/journal.pone.0083886.
Glavas-Dodov M, Steffansen B, Crcarevska MS, Geskovski N, Dimchevska S, Kuzmanovska S, Goracinova K. Wheat germ agglutinin-functionalised crosslinked polyelectrolyte microparticles for local colon delivery of 5-FU: in vitro efficacy and in vivo gastrointestinal distribution. J Microencapsul. 2013;30(7):643-56. doi: 10.3109/02652048.2013.770099.
Barbeito CG, Ortega HH, Matiller V, Gimeno EJ, Salvetti NR. Lectin-binding pattern in ovarian structures of rats with experimental polycystic ovaries. Reprod Domest Anim. 2013 Oct;48(5):850-7. doi: 10.1111/rda.12174.
Shi YQ, He Q, Zhao YJ, Wang EH, Wu GP. Lectin microarrays differentiate carcinoma cells from reactive mesothelial cells in pleural effusions. Cytotechnology. 2013 May;65(3):355-62. doi: 10.1007/s10616-012-9474-x.