Honokiol extract holds promise as adjunct treatment for bladder and kidney cancers

The botanical extract honokiol, a biologically active molecule isolated from the bark of Magnolia spp., holds promise as an adjunct treatment for aggressive bladder and kidney cancers, as reported in two new studies. New research on honokiol in bladder cancer was presented at the American Association for Cancer Research (AACR) Annual Meeting 2015. Research on honokiol's effect on renal cancer metastasis was published in the April 2015 issue of the International Journal of Oncology.

The preclinical in vivo study, "Honokiol inhibits bladder tumor growth by suppressing EZH2/miRNA-143 axis," was conducted at Nanjing University, China, and looked specifically at the ability of honokiol to reduce the expression of the enzyme EZH2. A histone methyltransferase, EZH2 is known to play essential roles in cancer cell proliferation, survival, invasiveness and stem cell maintenance in urinary bladder cancer. This study demonstrated honokiol's ability to reduce the expression of EZH2, which also correlated with declines in other proteins involved in cancer invasiveness. These results were presented today at the AACR Annual Meeting 2015, in Philadelphia, PA.

"This study demonstrated that honokiol significantly inhibited bladder cancer aggressiveness and tumor progression, adding to the large body of anti-cancer data on this botanical extract," states principle investigator, Jun Yan. "The inhibition of bladder cancer stemness can effectively support against cancer relapse and metastasis, making honokiol an important adjuvant in the prevention and treatment of aggressive bladder cancer, as well as other cancers."

The preclinical in vitro study on honokiol and renal cancer cell metastasis, "Honokiol suppresses metastasis of renal cell carcinoma by targeting KISS1/KISS1R signaling," was conducted at the Cancer Research Laboratory, Methodist Research Institute, Indiana University Health, IN. Results from this study, published in the International Journal of Oncology, showed honokiol suppressed metastasis in aggressive renal cell carcinoma (RCC), in a dose-dependent manner. Specifically, researchers found that honokiol markedly upregulated the metastasis-suppressor gene (KISS1) and its receptor (KISS1R), in the highly metastatic renal cancer cell line, 786-0. This is critical, since 25-30% of patients with RCC have metastatic spread by the time they are diagnosed, with 5-year survival rates <10%.

"Previous studies have confirmed honokiol targets multiple signaling pathways involved in cancer proliferation: NF-kB, STAT3, mTOR, EGFR and others. This new study demonstrating honokiol's ability to upregulate the metastasis-suppressor gene KISS1 in aggressive renal cancer cell lines, adds to our understanding of the diverse protective actions that honokiol performs at the cellular and genetic levels," states Dr. Isaac Eliaz, MD, MS, LAc, (Amitabha Medical Clinic, Santa Rosa, CA), one of the lead investigators involved in this study. "Given honokiol's diverse mechanisms against cancer, including synergy with certain chemotherapy drugs and inhibition of multi-drug resistance, progression to clinical trials is urgently needed to explore this unique compound as a viable adjunct treatment against multiple types of cancer."