New research suggests that cancer cells influence the cells around them to produce more of protein that promotes angiogenesis – or the formation of blood vessels – increasing the supply of blood to the tumor. As tumors generate a more complex network of blood vessels which supply it with nutrients, the cancer is able to grow.
The finding was a product of research conducted at the Institute of Cancer Research (ICR) in London, in collaboration with the Cancer Research UK Beatson Institute in Glasgow. The results of the study were published in the journal, Current Biology.
“Cancers can’t gather together the resources they need to grow and spread all by themselves,” said Dr. Andrew Reynolds, head of the tumor biology group at ICR, and a senior author on the article. “They need the support of surrounding healthy cells.”
The fields of transcriptomics – the study of all RNA transcripts produced in the cell – and proteomics – the study of all of the proteins that make up a cell – are helping researchers identify the key factors leading to cancer cell growth. Researchers have identified that changes in some types of RNA can lead to abnormal production of proteins that could contribute to tumor spread.
The new study focused on the role of transfer RNA (tRNA) – a nucleic acid involved in protein production – in the functioning of cancer cells. According to the researchers, while this type of RNA is very common inside the cell, it’s often not regarded as an important factor to take into account when studying the cell’s transcriptome.
“However it is now becoming clear that cellular levels of tRNAs are key to the control of gene expression in a number of different contexts,” said the authors. Reynolds and his team found that initiator methionine tRNA is involved in production of a type of collagen that promotes angiogenesis in tumors.
Fibroblast cells are responsible for making collagen – a structural protein – in healthy tissues throughout the body. The majority of the collagen made by these fibroblasts, is type 1.
The researchers found that when fibroblasts are adjacent to a tumor, they begin to synthesis type 2 collagen, which supports blood vessel formation around the cancer cells. In comparing normal human tissue from cells taken from breast cancer patients, the researchers found that those fibroblast cells that were manipulated by malignant breast cancers, had both higher levels of inhibitor methionine tRNA and type 2 collagen, when compared to healthy cells.
The study serves to further highlight the importance of the surrounding environment in promoting tumor growth and development. “Our study shows that a specific type of transfer RNA can ramp up production of collagen II protein in fibroblasts, stimulating the blood vessel growth in tumors that promotes cancer growth,” said Reynolds. “Our results could open up new approaches to treatment, such as drugs that are designed to disrupt cancer’s ability to manipulate its environment.”