A new research shows that a so-called circular RNA molecule, which has been designated as carcinogenic, is actually not found in the cancer cells. The results have just been published in Nature Communications.

In a major surprise, researchers have discovered that an otherwise extensively studied carcinogenic RNA molecule is not found in the cancerous cells at all. Instead, they suggest that the molecule contributes to the cancer developing through what is known as the microenvironment which constitutes the cancerous cells' 'neighbourhood', i.e. the cells which lie in the environment around the cancer cells in a tumour.

RNA molecules are normally linear and help to ensure that the right proteins are formed in the cells.

"Now we know that certain RNA molecules can, popularly speaking, also bite their own tails and form closed rings, and this gives them completely new properties in the cells," says the senior author of the study.The circular RNA molecule studied by the researchers is called ciRS-7.

According to the authors, an important step in understanding the carcinogenic properties of molecules is to map where these molecules are located in the tumour and which types of cell they are found in.

"We see that other benign cell types in a tumour express very high levels of CiRS-7, which means that the molecule may instead contribute to cancer development through the microenvironment."

According to the researchers, when trying to understand the molecular mechanisms that contribute to the development of cancer, it is important to look at cancer as a complex interaction between the cancer cells and the many other types of benign cell types which are found in a tumour.

"In other words, the classic cancer cell lines that are grown in the laboratory and often used to try and understand new molecular mechanisms, don't always give us an accurate view of what is in play in an actual tumour," says the author.

The author emphasizes that the results are therefore a good example of how spatial analyses of patient tumours can contribute with important knowledge that would not have been gained by analysing all RNA from a tumour in a single analysis.

The researchers are now continuing their work towards understanding why ciRS-7 is expressed at a very high level in the tumour's benign cells and whether this molecule contributes directly to the development of cancer through the microenvironment.

https://www.nature.com/articles/s41467-020-18355-2

http://sciencemission.com/site/index.php?page=news&type=view&id=publications%2Fspatial-expression&filter=22