Head and neck cancers are responsible for the deaths of more than 20,000 people in the US every year, highlighting the need for new prevention and treatment strategies for the cancers. Now, a new study reveals how a compound found in the bark and leaves of the magnolia tree could provide just that.
Researchers from the Birmingham Veteran Affairs Medical Center, AL, and the University of Alabama at Birmingham (UAB) found the compound – called honokiol – blocked a protein that drives tumor growth in squamous cell head and neck cancers, most commonly caused by tobacco and alcohol use.
Senior study author Dr. Santosh K. Katiyar, of the Comprehensive Cancer Center and the departments of chemistry and dermatology at UAB, and colleagues publish their findings in the journal Oncotarget.
The researchers note that honokiol is well known for its medicinal properties. The compound has been used in traditional Chinese and Japanese medicine for the treatment of anxiety and stress for hundreds of years.
In recent years, however, studies have indicated that honokiol also holds some anticancer properties, with researchers finding it prevents or reduces tumor growth in models of breast, skin, prostate and nonsmall cell lung cancers.
For their study, Dr. Katiyar and colleagues set out to see whether the magnolia compound may be effective against head and neck cancers.
According to the National Cancer Institute, head and neck cancers – including cancers of the larynx, throat, lips, mouth, nose and salivary glands – account for around 3% of all cancers in the US.
A protein called epidermal growth factor receptor (EGFR) is overexpressed in around 90% of all cases of squamous cell head and neck cancers, the researchers say, making the protein a promising drug target.
One drug already approved by the US Food and Drug Administration (FDA) for treatment of head and neck cancers – Cetuximab – targets EGFR, as do some small molecule inhibitors, such as gefitinib (Iressa), that are currently under investigation for this use. But Dr. Katiyar and colleagues say there are some downsides to such drugs.
“The poor response rates, toxicity and resistance of these drugs or inhibitors have limited their use as therapeutic agents for HNSCC [head and neck squamous cell carcinoma],” he explains. “Therefore, development of less toxic and less resistance-associated alternative treatment options is urgently needed.”
As such, the team assessed the effects of honokiol when introduced to human cell lines of a number of head and neck cancers, including cancers of the oral cavity, larynx, tongue and pharynx. The compound was also tested on mice that had tumors of these cancers implanted.
In both the human cancer cell lines and mouse models, the researchers found honokiol was able to bind to and reduce expression of EGFR, which stopped the growth of cancer cells.
What is more, the researchers found honokiol binds more strongly to EGFR than the drug gefitinib, suggesting it may be a more effective treatment strategy against head and neck cancers.
Commenting on their findings, Dr. Katiyar says:
“Conclusively, honokiol appears to be an attractive bioactive small molecule phytochemical for the management of head and neck cancer which can be used either alone or in combination with other available therapeutic drugs.”
Earlier this month, Medical News Today reported on a study detailing how another natural compound may have anticancer properties. Researchers from Canada revealed how avocatin B – a compound found in avocados – could help treat leukemia.