Tumors might grow faster at night: Hormone that keeps us alert also suppresses the spread of cancer

Tumors

A recent finding that was published in the journal “ Nature Communications by researchers at the Weizmann institute report a surprising finding. It says that during the nighttime, the cancer cells are more active and that they spread quickly during this period. Their findings also suggest that by administering certain therapies in time with the body's day-night cycle may boost their effectiveness. The environment in our body is just right for the cancer to spread while we are asleep “ the cancer cells grow while we are unaware and spread their tentacles as quickly as possible.

There was an investigation to understand the relationship between different receptors in the cell “ a complex network that is still not fully understood by scientist via which this finding arose. It was seen that the receptors “ the protein molecules which are present on the cells' surface or in the cells “take in the biochemical messages which are secreted by the other cells. They then pass them on into the cell's interior. The research team was led by Dr. Mattia Lauriola, who is a postdoctoral fellow in the research group of Prof. Yosef Yarden of the Weizmann Institute’s Biological Regulation Department. He along with Prof. Eytan Domany of the Physics of Complex Systems Department, focussed on two particular receptors. The first one is EGFR which is an epidermal growth factor receptor. It promotes the growth and migration of cells including cancer cells. The second one is characterized by its capability to bind to a steroid hormone called glucocorticoid. This hormone plays an important role in maintaining the body's energy levels during the day. It is also important for the metabolic exchange of materials. Also known as the stress hormone for its level rise in stressful situations and it brings the body to a state of full alert.

The cell receives all sorts of messages all at once with multiple receptors. However, some messages take precedence over others. In the experiment, the researchers found that EGF receptors promote the activity of cell migration, but is suppressed when the GC receptors are bound to their steroid messenger.

It is seen that the levels of the steroid are highest during waking hours and they plummet during sleep. The scientists were curious to know how this would affect the second receptor. When the levels were checked in mice, it was found that there was quite a significant difference. It was concluded that the receptor is much more active during sleep than during waking hours.

The next step in the experiment was to find out how relevant these findings were for cancer – in particular the ones which use the EGF receptors to grow and spread. For this the scientists gave Lapatinib which is a new generation cancer drug to the mouse model. This drug is particularly used to treat breast cancer and is supposed to inhibit EGFR and hence prevent the growth and migration of the cancer cells. The drug was given to mice at different times in the day.

The results showed that there was a significant difference in the sizes of tumor in the difference groups of mice “ depending on the time when the drug was administered “during sleep or while awake. The results of the experiment suggest that the levels of the GC steroid have a significant role to play in cancer growth. The scientists have concluded that it could be more effective to administer certain anticancer drugs at night.

Yarden said that what they are proposing is not a new treatment but a new schedule to administer some of the current drugs. It should be increase the effectiveness of the cancer treatment.

References

https://wis-wander.weizmann.ac.il/tumors-might-grow-faster-at-night

https://www.nature.com/ncomms/2014/141003/ncomms6073/metrics/news