Cancer research is advancing fast. Here at Sciencebriefss.com, we have highlighted some of the latest research news about the biology of cancer and the strategies scientists envisage to come to effective cancer treatment.

Latest research news in cancer
Latest research news in cancer

Animals and cancer research

Scientists have turned to some surprising animals to deepen our knowledge about the biological mechanisms that promote cancer development. One is the naked mole rat, a not so pleasant looking animal, although it keeps surprisingly young. Even after their reproductive age is over, their risk of dying does not increase and they may live up to 30 years. This is extraordinary for a rodent the size of a mouse. Moreover, they don’t develop cancers, even though their cells keep dividing to rejuvenate the tissues throughout their lives. Most mice cells stop dividing, which is good for the prevention of cancer, but this comes at the price of ageing. In naked mole rats, it was shown recently, metabolic processes in certain cell types are inhibited, making these cells divide more and thus slowing down aging. Therefore, researchers argue, naked mole rats must have solved the contradictory demands of cell division and ageing, making them ideal models to hunt for the biological cause of cancer.

Naked mole rats live a long life without developing cancer
Naked mole rats live a long life without developing cancer

Another interesting animal researchers are starting to look at is the Marble Crayfish, a cute-looking aquarium shrimp. After a female cloned itself in an aquarium 30 years ago, this species has invaded many different types of aquatic habitats. Although they all have the same genetic makeup, as they continue to clone themselves, they can adapt to different environments due to epigenetic mechanisms that switch off or on certain genes when needed. The process of cloning should in essence be similar to cancer development, as cancers evolve from one or few cancer stem cells that keep dividing. For this reason, researchers have announced that they will study the cloning process in crayfish more closely, and will look at epigenetics to study how gene expression is regulated under the influence of external factors.

Don’t feed the tumour, please!

Feeding habits not only have an effect on the onset of cancer, but also on metastasis and, indirectly, on the outcome of immunotherapy. For instance, a recent study describes that consumption of highly processed aliments, such as ready meals, sugary cereals, fizzy drinks, packaged baked goods and snacks, could trigger cancer in humans. This is quite alarming, considering that in western societies this type of food accounts for 50% of daily intake. Also, one should be careful with the intake of the amino acid asparagine, as this building block of proteins might stimulate metastasis. It is found in many products, which makes it difficult to avoid altogether, but is low in fruits and vegetables. Research implies that cancer patients should eat these preferentially during cancer treatment to encourage a favourable outcome.

Particular species of gut bacteria can stimulate the formation of colon tumours. Although diet influences the composition of the gut flora, it is not clear yet if the type of colon tumour that was studied (inherited colon cancer) is linked with the type of food consumed. Nevertheless, bacteria have been shown to control the outcome of immunotherapy. Patients with a diverse population of gut bacteria, probably reflecting a healthy diet, were more likely to respond well to immunotherapy than patients with less variety in their gut flora. Interestingly enough, faecal transplantations from patients that responded well to immunotherapy to mice with cancer effectively reduced tumour growth in the animals. Having the proper bacteria in the intestines helps to prevent and treat cancers.

Finally, depriving the tumours themselves from food results in growth arrest. Cancer cells have particular metabolic demands (perhaps this is already indicated by the abnormal regulation of cell metabolism in naked mole rats?), and researchers have made use of this to stop them from growing. They blocked the uptake of glutamine by developing a drug that interferes with the glutamine transporter responsible for getting this amino acid into a cancer cell. Another study reported on the use of DNA nanorobots that kill tumours by cutting off their blood supply. These robots are quite effective in doing their job in mice: the tumours became smaller. Importantly, only the blood vessels in the tumours were affected, and there was no spreading of the robots into the brain which could have induced side effects. The safe use of nanotechnology (nanomedicine) has come a step closer!

DNA nanorobots can kill tumours by cutting off their blood supply
DNA nanorobots can kill tumours by cutting off their blood supply

Stem cells: the bad and the good

An aggressive breast tumour (known as triple-negative breast cancer) that cannot be treated with chemotherapy starts with proliferation of so-called cancer stem cells. These cells have a special survival mechanism built in, that helps them divide (or clone themselves) and spread to other parts of the body. They express a protein that likely assists in cell-to-cell communication, and is linked to two other proteins that promote cancer growth. Now that researchers uncovered this mechanism, they aim to target the cancer stem cells to treat triple-negative breast cancer, which accounts for 15-20 percent of all breast cancers.

Other scientists are seeking the use stem cells to develop new treatments for cancer. They are using induced-pluripotent stem cells (iPCs) that they created by rejuvenating blood or skin cells. iPCs regain the signature capacity of stem cells: to divide and to differentiate into essentially any cell type. Importantly, they share markers with tumour cells, that also have the capacity to divide. Researchers have now injected iPCs into mice to prime the immune system to stimulate action once a tumour is formed. This is like a vaccination to prevent the flu. The vaccination protocol turned out to be quite effective, with most of the mice showing tumour regression and, at times, even elimination. We are looking forward for this approach to be confirmed and hopefully to show success in the case of human tumours.

Getting the immune system to kill cancer

Vaccination by injecting iPCs is one way to stimulate the immune system to attack a cancer, and may be classified as a form of immunotherapy. A new study shows that immunotherapy might be improved by combining it with the injection of a special virus that selectively infects and kills cancer cells. The virus exposes cancer proteins to the immune system which ensures a strong defensive immune reaction. The immune reaction is so strong that it also attacks tumours that are far away from the cancer in which the virus had been injected. The good news is that the virus is already in clinical trials, but the combination with immunotherapy has to be validated further.

A cancer-killing virus that is currently in clinical trials
A cancer-killing virus that is currently in clinical trials

Scientists have tested yet another sort of immunotherapy that effectively eradicates cancers in mice. The therapy mobilises a particular class of immune cells, called T cells, that will kill the cancer. Importantly, some of the T cells will move away from the tumour to other parts of the body. If they find another tumour (formed because of metastasis) they will attack it too. The therapy has only been tested in mice, but there is hope that cancers will completely disappear in patients following therapy validation in humans.

Conclusion

Scientists are coming to a better understanding of how cancer is brought about, and what can be done to improve existing therapies or developing new ones. Although the use of nanorobots, stem cells and viruses might become common practice one day, these fancy treatment options are mostly in experimental stage. It is for this reason that also more classical methods, such as radiotherapy, are still being optimised. A recent modelling study demonstrated that a new radiotherapy protocol could be designed that is just as effective in killing tumours as current protocols, but leads to less side effects. With all the advances in cancer research, it is realistic to expect better cancer treatment options in the future. However, for the best outcome of any treatment, it is crucial to detect cancer early, which is now becoming possible by simple measurements in the blood.

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