Cancer Cells Most Active During Sleep, Study Finds - DISCOVER Magazine

In 2017, singer-actor Olivia Newton-John announced she had breast cancer for the third time. A few years later she started experiencing back discomfort and was forced to pull out of her tour dates. The doctors initially thought sciatica was the cause but they soon realized that the cancer was spreading onto her bones. The famous Grease performer passed away of natural causes at home at Southern California in August 2022 aged 73.

Scientists are studying the way cancer spreads and how. The metastatic form of breast cancer (MBC) which is the type Newton-John suffered from, generally is a bone cancer that can spread to the liver, brain or lungs. MBC is a fatal cancer and half of women are not alive three years after diagnosis. A mere 26 percent women live beyond five years after their diagnosis.

In the majority of cases there isn’t a cure for MBC. Researchers are trying to understand more about the way cancer-spreading cells work to stop MBC prior to it forming. A study published in Nature discovered that the cancer-spreading cells were at their most aggressive and could aid researchers find finding a cure.

Sleeper Cells

There are many ways in which cancer can spread to other organs. For many people suffering from MBC the CTCs that are circulating in the body (CTCs) are the cause. CTCs break off of the tumor in breast, move to the bloodstream and make their way to various organs, and cause havoc.

The study revealed that the cells are at their most active when people are asleep. Researchers collected the blood of 30 Swiss women hospitalized for breast cancer. Nine of them were diagnosed with stages IV MBC and were not receiving treatment. The remaining had early non-metastatic breast cancers and were undergoing surgery.

Researchers took a test sample around 4:30 a.m. and another specimen at the time of 10 a.m. The team then examined the blood samples to determine if CTCs were more common in the morning or overnight sample.

The variation in CTC count in the blood samples was “night or day.” About 80 percent of CTCs were present in samples taken at 4 a.m. sample, when patients were asleep.

The team of researchers then carried out the same experiment using mice. The first step was to transplant breast cancer tumors onto the mice. Then, they took blood samples from night and day. Since mice are night creatures and prefer to sleep throughout the day, and manage their mouse-related activities in the evening The researchers wanted to determine if the CTCs were more prevalent in blood samples taken when the mice were either at “rest” as opposed to “active.”

The majority (more than 90%) of CTCs in the mice’s blood samples were found in the rest of the period. However, were these sleeper cells more prone in spreading the cancer?

Specialized Spreaders

To determine which CTC type was more effective in spreading cancer, researchers used fluorescent tags to distinguish them from active CTCs. They then injected both types of cells back to the mice.

A majority of CTCs that were responsible for the creation of new tumors did indeed originate from the other samplewhich means that they weren’t just more abundant, but they were also more powerful.

The researchers also examined the gene expression of every cell type and discovered that the CTCs released at rest were similar to the genes that are involved in the process of cell mutation and mitosis.

What causes this to happen is one of the issues that scientists are trying to answer. They believe that the remaining CTCs react to the release of hormones throughout the day, and in relation to our sleeping and waking cycles. This means that these cancer-causing cells are aware of when the body is asleep as well as when it is awake.

Understanding how the body release these harmful cells could help researchers find treatments to target rest-released CTCs at precisely the time that they do the most harm. Since breast cancer isn’t the only kind of cancer that has metastasized there’s a chance that researchers can utilize this information as a reference in their research into spreading of different types of cancers.

In the meantime, patients with cancer are advised not to skimp on their sleep. There isn’t any evidence which suggests that less sleep equals less time for sleeper cells to grow.