Low-Dose Aspirin May Halt Breast Cancer

Research done in test tubes and in mice presented at a conference in Boston in the US at the weekend suggests taking low doses of aspirin on a regular basis may stop breast cancer from growing and spreading. However, cancer campaigners urge caution as the results are very early stage and have yet to be shown in patients.

The research team, from the Veterans Affairs Medical Center in Kansas City and the University of Kansas Medical Center, say tests on cancer cell lines and in mice show that aspirin not only significantly slows growth of cancer cells and shrinks tumors, but also stops tumor cells spreading to new sites.

Their study investigated the effect of aspirin on two types of cancer, including the so-called aggressive "triple-negative" breast cancer, which is immune to most treatments.

Triple-negative breast cancers are so-called because they lack receptors for estrogen, progesterone and Her2/neu.

The researchers presented their findings at the annual meeting of the American Society for Biochemistry and Molecular Biology. 

A meeting abstract of the study appears in the FASEB journal.

Aspirin's Effect on Cancer First Suggested 20 Years Ago

For over 20 years, since a study in Australia first suggested aspirin may have anti-cancer properties, researchers have been finding the headache drug may prevent and also treat all sorts of cancer. 

For example, there are reports that colon cancer survival improves with aspirin use, and thataspirin and other commonly used painkillers may also help guard against skin cancer. 

It has also has been shown to reduce the risk of squamous cell esophageal cancer andprostate cancer.

At first it was thought the effect only kicked in after ten years or so, but in 2019, three Lancetstudies of people in middle age taking low-dose aspirin suggested that the anti-cancer benefits may start after only three years.

Aspirin May Halt Cancer By Acting on Cancer Stem Cells

However, despite all this evidence, the underlying mechanism through which aspirin confers its anti-cancer benefits have been somewhat difficult to establish.

Now this latest study suggests that for breast cancer, it may be that aspirin interferes with the stem cells that are believed to fuel the growth and spread of tumors.

In a press statement, senior author Sushanta Banerjee, director of the cancer research unit and a professor at the University of Kansas Medical Center, says first-line chemotherapy does not destroy stem cells: eventually the tumor will start to grow again.

"If you don't target the stemness, it is known you will not get any effect," he adds, "It will relapse."

Banerjee and colleagues found that in the mouse model they used, cancer cells treated with aspirin formed no or only partial stem cells. 

And in lab tests, aspirin blocked the growth of two different breast cancer lines.

Aspirin Halted Triple-Negative Breast Cancer In Cell Lines

One of the cell lines the researchers used was of what is often called triple-negative breast cancer, which is a less common but much more difficult form of breast cancer to treat.

Banerjee, who is also a professor of medicine in the university's division of hematology and oncology, says he and his team are mainly interested in triple-negative breast cancer because the prognosis is very poor for patients who find themselves with this form of the disease.

The reaction from cancer campaigners has been welcoming but cautious.

According to The Independent, Eluned Hughes, of the UK charity Breakthrough Breast Cancer, urges caution over the "incredibly early stage research" which is yet to be replicated in human patients. But she says they will be watching its progress closely, "it could be promising for the future", and they hope to continue to see new options for patients.

Aspirin May Also Boost Treatments for Hormone-Positive Breast Cancers

The researchers say aspirin may also improve the effectiveness of current treatments for hormone-receptor-positive breast cancers. In their study, they found aspirin boosted the effect of tamoxifen, which is used to treat hormone-positive breast cancers.

Aspirin treats many different conditions. Banerjee says its ability to target several metabolic pathways could be why it is effective against cancer:

"Cancer is not a single-gene disease," explains Banerjee, "Multiple genes are involved."

Many people take a daily low dose of aspirin to lower their risk of a further heart attack orstroke, or if they have a high risk of either.

But taking aspirin is not without risks; for instance daily aspirin use can increase the risk of gastrointestinal bleeding.

Researchers are continuing to investigate whether the advantages outweigh the potential disadvantages.

In 2019 the National Cancer Institute invited scientists to explore how drugs like aspirin, primarily intended for other purposes, might also reduce the risk of developing cancer or extend survival for those who have it.

Banerjee says his lab will be applying for one of these grants.

Omega-3 Fatty Acids Slow Triple-Negative Breast Cancer Cell Proliferation

Omega-3 fatty acids, as well as their metabolite products, stop or slow the proliferation of triple-negative breast cancer cells better than cells from luminal types of cancer, researchers from Fox Chase Cancer Center reported at the AACR Annual Meeting 2019.

The scientists explained that omega-3 fatty acids work against all cancerous cell types, but were seen to be much more effective against the triple-negative cell lines. Proliferation in those types of cells was reduced by as much as 90%.

Sardines, tuna, trout, salmon (oily fish), flax and hemp are examples of foods rich in omega-3s. Several studies have already demonstrated their benefits in undermining the critical mechanisms in cancer cells, specifically those responsible for apoptosis (programmed cell death) and proliferation. Thomas J. Pogash explained that the team's finding underscores the vital role that compounds commonly found in our foods play in fighting off cancer.

Pogash said:

"Diet can play a critical role in breast cancer prevention. When you compare a western diet to a mediterranean diet, which has more omega-3s, you see less cancer in the mediterranean diet. They eat much more fish."

Breast cancers are not all the same; they differ at molecular levels. That is why patients do not all respond the same to treatments.

Experts categorize breast cancer tumors into four distinct groups:

• Luminal A
• Luminal B
In Luminal A and B, the luminal cells that line the milk ducts have estrogen and progesterone receptors. These patients generally have better prognoses.


• Tumors that test positive for the HER3 receptor
• Triple-negative tumors - these lack receptors for estrogen, progesterone and HER2/neu (a protein). For patients with this type of breast cancer, treatments with trastuzumab, which disrupts the HER2 receptor, and tamoxifen, which targets the estrogen receptor, do not work.

Dr. Jose Russo wrote that there are no currently available targeted therapies for women with triple-negative breast cancer. Standard care for early stage disease involves combination chemotherapies.

Russo said:

"This type of cancer, which is found more frequently in Latina and African-American women, is highly aggressive and has a low survival rate. There is not any specific treatment for it."

When a cancerous cell digests omega-3 fatty acids, they are broken down into metabolites (smaller molecules). The team wanted to determine what the effect might be of large omega-3 parent molecules, as well as their metabolic derivatives, on three luminal cell lines and seven basal-type triple-negative cell lines.

The scientists found that omega-3 and its metabolites undermine proliferation in all cell lines. However, they were dramatically more effective in inhibiting proliferation in the triple-negative cell lines.

They also found that the omega-3 metabolites reduced motility by 20% to 60% in triple-negative basal cell lines.

This study is being funded by the Komen Foundation and is part of a consortium between Fox Chase Cancer Center and Pennsylvania State University. The lead researchers are Dr. Jose Russo (at Fox Chase) and Dr. Andrea Manni (at Penn State).

Russo and team are currently working on the role of epigenetic events in the mechanism of cell transformation. They are also involved in another project which is looking at the potential action of peptides of the hormone hCG (human chorionic gonadotropin) on breast cancer prevention.

Many studies on omega-3 fatty acids

Over the last fifteen years, there have been many studies on the benefits of consuming omega-3 fatty acids. Not all of them have had positive findings. Below are some of them:

• Skin cancer - scientists form the University of Manchester, England, reported in theAmerican Journal of Clinical Nutrition (February 2019 issue) that consuming omega-3 fish oils can help prevent skin cancer.


• Memory - healthy young adults who increase their consumption of omega-3s can have better working memory, a team from the University of Pittsburgh reported in the journalPLoS ONE (October 2019 issue).


• No benefit - a team from the University Hospital of Ioannina, Ioannina, Greece, reviewed twenty studies involving 70,000 participants. They found no statistically significant evidence that omega-3 fatty acid supplementation helped reduce stroke, heart attack or premature death. They reported their findings in JAMA (September 2019 issue). The authors stressed that they did not rule out the possibility that some groups may benefit, and called for further studies to be carried out.


• Retinitis pigmentosa progression - experts from the Harvard Medical School and the Massachusetts Eye and Ear Infirmary, Boston, reported in Archives of Ophthalmology(February 2019 issue) that diets rich in omega-3 fatty acids help slow down the progression of retinitis pigmentosa.