Study: Honokiol reduces proliferation of renal cell carcinoma

A new study shows that honokiol, a small molecule polyphenol extract derived from Magnolia officinalis bark, reduces proliferation of renal cell carcinoma. Conducted by researchers at the Cancer Research Laboratory at Indiana University Health, Indiana University School of Medicine, the preclinical study showed that honokiol (HonoPure®, EcoNugenics, Santa Rosa, CA) inhibited two highly aggressive renal cell carcinoma (RCC) cell lines. The extract also restricted the invasive potential of renal carcinoma cells, and modulated expression of genes involved in the suppression of metastasis. These results were presented at the 2014 American Association for Cancer Research Annual Meeting in San Diego, CA.

"This is an excellent first step toward developing a new treatment for aggressive renal cancer," says lead investigator Dr. Daniel Sliva, adjunct associate professor at the Indiana University School of Medicine. "This cancer is well known for its ability to metastasize. However, honokiol may be able to limit proliferation, suppress invasiveness and help prevent the cancer from spreading."

Because of its indistinct symptoms, RCC is often diagnosed in later stages, making it particularly deadly. As many as 70 percent of RCC patients experience recurrent disease, despite surgery. Around 25 percent develop metastases. Furthermore, few effective therapies are available.

Results of this study were particularly strong for one of the cell lines, showing that honokiol inhibited migration in a dose-dependent manner. DNA analysis also showed honokiol increased expression of specific genes which suppress metastasis. Because metastasis is often what kills patients, finding a way to control it could save lives.

Derived from Magnolia officinalis bark which is used throughout traditional Asian medicine, honokiol has demonstrated the ability to inhibit a number of cancers through multiple mechanisms of action. Specifically, the extract has been shown to modulate genes associated with cancer growth and aggressiveness. Previous preclinical research found honokiol inhibits multiple cancer cell types: breast, prostate, colon, liver, lung, pancreatic, skin, blood; induces apoptosis of cancer cells through multiple pathways; inhibits angiogenesis and proliferation through the lymph system, and acts as a powerful anti-inflammatory, antioxidant agent, among other findings.

"This study substantiates the need for further research which could lead to more effective cancer treatments," says Dr. Sliva. "Our next step is to better understand the molecular mechanisms underlying honokiol's anticancer activity, confirm our results with preclinical studies in mice, and progress to human clinical trials."