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Garlic holds promise to combat deadly brain tumor
Dawn Brazell | Public Relations | September 24, 2013
|Neuroscience research studied a compound in garlic - diallyl trisulfide (DATS) and found it's potentially a potent weapon against glioblastoma.|
|Photos by Sarah Pack|
If you weren’t already a fan of garlic, here’s new scientific evidence of its cancer-fighting properties.
Researcher Arabinda Das, Ph.D., said it was exciting to land the cover of the August issue of the Journal of Neuro-Oncology with the first direct evidence that the compound DATS, found in garlic, is effective in blocking pathways of the proliferation of cancer cells and ultimately may help reduce tumor growth in patients with glioblastoma, the most lethal brain tumor.
It’s a brain cancer that remains incurable despite aggressive chemotherapy, radiation and surgical interventions. That the study found a 60-to-74-percent rate in the shrinkages of tumors has the team of clinicians and researchers involved with this study cautiously thrilled.
Neuro-oncologist Pierre Giglio, M.D., said it’s rare to get good results in the clinic. There’s only one drug being used – Avastin – that produces response rates, and those generally are in the 30-to-40-percent range, he said.
“In the clinic, I declare victory when I don’t see any change in the tumor. When you get a response that cuts the tumor down by that sort of percentage, I can’t stress how exciting it would be if that would translate to a clinical truth. This paper showed the efficacy, and it was quite stunning,” he said, cautioning that it will take time for the results to be translated for clinical use. “What works in the lab sometimes does not work in the clinic.”
Das said it has long been known that plant derivatives have beneficial effects in many diseases. Plant derivatives that are or will be studied include lemon, mushroom, green tea, turmeric, soybeans and ginger. “We have been working on several of these which are known to have anti-tumorigenic properties, and garlic compound is one of the agents, among many, we have chosen to study,” he said.
Researchers tested the garlic-derived organo-sulfur compound DATS in two ways. They applied it directly to glioblastoma cells taken from tumors removed from patients, and they also placed these cells in immunosuppressed mice using an orthotopic xenograft model, in which the tumor cells are implanted in the tumor site of origin, a technique advantageous for its ability to mimic local tumor growth and pathways of metastasis.
Giglio said it seems that glioblastoma cancer cells have multiple pathways within them that allow them to grow, divide quickly, invade the brain and form blood vessels for themselves. “In a nutshell, they have a lot of strategies that allow them to evade the body’s immune defense systems, evade the treatments that we may give, and most importantly, develop a resistance to the treatments that we give.”
Das said the DATS compound seems to have a selective effect on the cancerous cells and not the normal cells. Researchers want to explore all mechanisms by which the compound may be working against cancer cells. The response rate suggests it works in more than one pathway to block the cancer, he said.
“We demonstrated shrinkage of tumors in these animals and showed that DATS reduced division of cells within the tumors and worked against multiple proteins and pathways that promote tumor growth,” Das said.
There are several research projects planned to further this work. Das will be working with Giglio and Amy-Lee Bredlau, M.D., director of the Pediatric Brain Tumor Program and a pediatric neuro-oncologist, to develop a highly-purified DATS gel capsule for a human safety and tolerability phase I study. “We are hoping to be able to do this in the next 12 months.”
The broad long-term objective is to use the information obtained from this study to develop a therapeutic strategy for the induction of apoptosis, or cell death, of glioblastoma and recommend this natural compound as a therapeutic strategy for trials in glioblastoma patients.
The study found the compound didn’t impair liver functioning. Das said most medications pass through the liver and are broken down in this organ. Many medical agents carry warnings about possible liver injury, and it is always encouraging to note that the liver is not affected by the garlic compound at the doses used in the study.
Researchers caution that they are not recommending garlic consumption as a cure for glioblastoma or other cancers. “Our research shows promise but recommendations for actual treatment of cancer with DATS would be premature.”
Should patients want to take advantage of any potential anti-cancer benefits from garlic now, they should know to take certain precautions, he said. For example, it’s important to cut and peel a piece of fresh garlic and let it sit for fifteen minutes before eating or cooking it. This time lapse allows for the release of an enzyme (allinase) that produces the anti-cancer compounds. Consumers using this as a nutritional supplement also should know that eating too much garlic may cause diarrhea, allergies and internal bleeding, so it is important to monitor garlic consumption.
Meanwhile, Das and colleagues will take the clues from this study to further their work. Das said the success of this study depended on a strong team of clinicians and researchers. The team included clinicians Giglio, Scott M. Lindhorst, M.D. and Bredlau; surgeons Sunil J. Patel,. W. Alex Vandergrift and Abhya K. Varma; basic scientists Das and Naren L. Banik, Ph.D., and researcher Swapan K. Ray, Ph.D. of the University of South Carolina.
This collaboration of clinicians, surgeons and neuro-oncology researchers is opening up new opportunities for discoveries. Das said in the future, researchers will be able to take patient tumors and have them tested in their laboratory model to see the efficacy of certain drugs. “We can personalize it based on the response of the tumor.”
Plans also are on the table to test the DATS compound in a larger animal model and eventually as a nasal application to be delivered in a nanoparticle. Giglio said the hope is that the nanoparticles will prove small enough to pass through the blood-brain barrier allowing the compounds they carry to leach out very slowly to the area of the brain tumor. The first clinical trial will be with an oral preparation of some type of gel capsule, followed later by nanoparticle research depending on finding funding for these projects.
Given how difficult this glioblastoma can be to fight – it ranks in the top three cancers in how fast it may kill people – this breakthrough is energizing to the team collaborating to find clues to how to stop it, Das said.
“We just want to be able to help these patients.”