Cannabinoid compounds may inhibit growth of colon cancer cells
Medical marijuana has gained attention in recent years for its potential to relieve pain and short-term anxiety and depression. Now, Penn State College of Medicine researchers say some cannabinoid compounds may actually inhibit the growth of colon cancer cells in the lab.
The researchers tested the effects of synthetic cannabinoid compounds on colon cancer cells in an experiment in test tubes. While the compounds most commonly associated with cannabis — THC and CBD — showed little to no effect, 10 other compounds were effective at inhibiting cancer cell growth.
Kent Vrana, chair of the Department of Pharmacology at Penn State College of Medicine, said the study — recently published in Cannabis and Cannabinoid Research — helped identify compounds that could be tested further to understand their anti-cancer properties.
“Now that we’ve identified the compounds that we think have this activity, we can take these compounds and start trying to alter them to make them more potent against cancer cells,” Vrana said. “And then eventually, we can explore the potential for using these compounds to develop drugs for treating cancer.”
Colorectal cancer is one of the most common cancers diagnosed in the United States, according to the National Cancer Institute, with an estimated 140,250 newly diagnosed cases and 50,630 deaths in 2018. While medical cannabis has largely been used in recent years for palliative care, the researchers said some previous studies suggested that certain cannabinoid compounds may have the potential to inhibit or prevent the growth of tumors.
To explore how effective cannabinoids were at reducing the viability of colon cancer cells specifically, the researchers tested how 370 different synthetic cannabinoid compounds affected seven types of human colon cancer cells.
“There are many different ways cells can become cancerous,” Vrana said. “Each of the seven cells we tested had a different cause or mutation that led to the cancer, even though they were all colon cells. We didn’t want to test these compounds on just one mutation or pathway to cancer.”
The researchers incubated the cancer cells in a lab for eight hours before treating them with the cannabinoid compounds for 48 hours. Any compounds that showed signs of reducing the viability of one kind of cancer cell was then used to treat all seven kinds of cells.
After further screening and analysis, the researchers identified 10 compounds that inhibited the growth of almost all seven types of colon cancer types tested. But while the researchers were able to identify these compounds, Vrana said they are still unsure about how exactly the compounds worked to reduce the viability of the cancer cells.
“The 10 compounds we found to be effective fall into three classes, so they’re similar to each other but with small changes,” Vrana said. “We know how one of them works, which is by inhibiting the division of cells in general. We also found that the most potent and effective compounds don’t seem to work through traditional marijuana receptors, although we’re not sure of the exact mechanism yet.”
Vrana said certain types of cells, like skin and colon cells, are more susceptible to cancers because they divide very frequently: “Every time a cell divides, there’s the chance that it will mutate and keep dividing when it shouldn’t, which is how cancers can start. So if we block that signal that’s telling cancer cells to continue to divide, that could be a way to stop that cancer.”
Vrana said that because the other compounds did not seem to be working through traditional cannabinoid signaling pathways, future research will focus on better understanding how the compounds interact with cancer cells and whether researchers can make the compounds more potent and effective.
Medical marijuana has gained attention in recent years for its potential to relieve pain and short-term anxiety and depression. Now, researchers say some cannabinoid compounds may actually inhibit the growth of colon cancer cells in the lab.
CBD oil and cancer: 9 things to know
BY Cynthia DeMarco
CBD oil (cannabidiol) is everywhere these days. Once available only at novelty or vitamin shops, it’s now also at your local grocery store, pharmacy or even yoga studio.
It comes in many forms: oils that are dropped under the tongue, roll-ons that are applied to the skin and even solutions for vaping. Some producers extract CBD oil and add it into foods to create edible products.
But what is CBD oil exactly, and how does it affect cancer patients? Can it really treat — or even cure — cancer or relieve its symptoms? To separate fact from fiction, we spoke with our Kimberson Tanco, M.D. Here’s what he wants cancer patients to know.
What is CBD oil, and how does it differ from marijuana and hemp?
Marijuana and hemp are both varieties of the cannabis sativa plant. Both contain cannabidiol (CBD) and tetrahydrocannabinol (THC) — the two most-common, known active ingredients.
The main difference is that hemp has far less THC than a typical marijuana plant. And unlike THC, CBD is not a psychoactive agent, so there’s less possibility that it will cause the same mental confusion, drowsiness or hallucinations that often come with THC.
Is there any truth to the claims that CBD oil can cure cancer?
Right now, no. There is no evidence that CBD oil can cure cancer.
What, if anything, can CBD oil do to alleviate the symptoms of cancer or the side effects of cancer treatment?
It’s hard to say if CBD oil can alleviate cancer symptoms or cancer treatment side effects, because the studies are pretty mixed and even fewer are standardized.
There have been reports that cannabinoids like THC and CBD may be helpful for nausea and vomiting and anorexia, as well as neuropathy, anxiety, depression and insomnia. Synthetic cannabinoids like dronabinol have been approved for use with chemotherapy-induced nausea and vomiting, but have not been shown to be superior to conventional anti-nausea medications.
Have any CBD-oil derived products been approved by the U.S. Food and Drug Administration (FDA) to treat cancer, its symptoms, or the side effects caused by its treatment?
Have any products using CBD-oil been approved by the FDA to treat anything?
Yes. Epidiolex. It was originally approved in 2018 for the treatment of two conditions, both related to epilepsy: Lennox-Gastaut syndrome and Dravet syndrome. But aside from Epidiolex, no CBD product has been approved by the FDA for any other medical purpose.
What are the dangers of using CBD oil?
Quality, cleanliness and regulation are the biggest concerns.
All drugs and dietary supplements are regulated by the FDA. But as long as CBD oil is not marketed as a medicine or a dietary supplement, producers can get around that policy. So right now, CBD oil is very unregulated. That means it’s hard to know how much CBD or THC is really in any given product. Certain hemp CBD products have been found to contain significantly less CBD or more THC than advertised.
In terms of purity, THC and CBD are both extracted from hemp and marijuana using essentially similar processes. But trace amounts of THC could still end up in CBD oil. And if the THC is at a high enough concentration, it could produce the psychoactive effects that THC is known for.
Second, if a lab produces both CBD and THC products, there can be cross-contamination — whether it’s through extraction, handling or packaging.
Third, the plant itself may have higher levels of THC than expected. This could be due to its environment, prolonged flowering periods or cross-contamination and pollination between male and female plants, resulting in offspring with higher THC content. This especially affects hemp plants, which should have less than 0.3% THC levels.
Finally, there have been some reports of people getting infections after using CBD and cannabis products. This is especially concerning for immunocompromised patients, who are already susceptible to bacterial and fungal infections.
Studies on a certain CBD manufacturer showed its products were contaminated with a chemical known as 5F-ADB, which mimics THC. 5F-ADB is classified by the U.S. Drug Enforcement Administration as illegal, potentially addictive and with no accepted medical use.
Other sorts of substances have been found in CBD products, too, such as dextromethorphan, which is an ingredient in cough medicines. Heavy metals like lead and arsenic, pesticides and mold have also been found in CBD products.
Does CBD oil have any side effects?
CBD oil can adversely affect liver function. In fact, this is on the warning label for Epidiolex.
And in lab studies, CBD has been shown to inhibit certain enzymes responsible for the metabolism of drugs, such as CYP2D6 and CYP3A4. This can affect how drugs work and affect our bodies, either by reducing their efficiency or making them more dangerous. This includes chemotherapy and other medications.
This is very important for cancer patients to understand, as many people think CBD oil is not a medicine. They think of it more as a vitamin or a supplement, so they might not let their doctors know they’re using it. Patients might not realize it can be potentially harmful. So, it’s very important to tell your doctor if you’re using CBD oil.
Is CBD oil even legal?
CBD has a very complex legal status right now.
At the national level, any product of marijuana — including CBD — is still technically illegal when used medically. Although the 2018 Farm Bill legalized the production of hemp nationally, that’s only permitted if it’s not marketed for medical use or as a dietary supplement. CBD products intended for medical use should undergo an FDA review process.
State laws vary. In Texas, the Compassionate Use Act allows for the use of medical marijuana for certain conditions. Originally only for intractable epilepsy, the law was expanded this year to include cancer and certain neurodegenerative conditions, such as Parkinson’s and multiple sclerosis.
But the application of this law is pretty jumbled right now. So, while it may be legal to use CBD in a state like Colorado or Alaska, if an employer follows federal regulations, the standardization and quality of a CBD product matters. Because if there’s even a small percentage of THC in that product, then a drug test might come back positive. And this could result in legal issues for the user.
What’s the most important thing cancer patients should know about CBD oil?
There’s still a lot to learn. So always let your health care team know if you are using CBD oil. That way, we can make sure nothing interacts adversely with your cancer treatments or other medications.
Also, avoid products with health-related claims on their labels. The only product approved by the FDA for its medical value is Epidiolex.
Wondering whether you should use CBD oil to cope with cancer treatment and its side effects? We spoke with Kimberson Tanco, M.D., to separate fact from fiction.