Tumour growth theory announced
10 Jul 2014
Signals within most types of cancer may fuel the growth of tumours, new research suggests.
According to new findings from the Institute of Cancer Research (ICR), a network of signals active in almost all forms of cancer sends the protein factories in human cells into overdrive, shedding light on the cause of a tumour’s uncontrollable growth.
The study was published in the journal PLOS ONE, and funded by the Biotechnology and Biological Sciences Research Council (BBSRC).
“Our study provides new insights into how cancer metabolism works
ICR lead author Chris Bakal
The ICR researchers identified a molecular trigger responsible for intensifying activity of the endoplasmic reticulum (ER) - the cellular ’factory’ that makes the building blocks cancer cells need to continue growing.
A protein in the TOR signalling pathway, called SREBP, controls the flow of messages to the endoplasmic reticulum telling it to expand - and could allow cancer cells to produce enough proteins and lipids to fuel their non-stop growth, the research suggests.
In healthy cells constant growth can often overwhelm cellular factories, leading to cell stress and death.
Lead author Chris Bakal said: “The endoplasmic reticulum is the factory of our cells, creating the proteins and lipids needed for our cells to grow and proliferate.
“In cancer cells, this factory is active all the time, churning out the building blocks that cancer cells need for their rapid growth.”
Scientists at ICR used the cells of fruit flies, modified with a fluorescent marker that is activated when the cells are put under stress, to identify the signals responsible for driving up activity of the ER.
The team systematically silenced genes thought to be important to the smooth working of the ER and measured the stress signals produced in response.
They found that by silencing the TOR signalling pathway - activated in many different types of cancer - it increased ER stress in the cells. When they blocked TOR signals, cells took longer to recover from ER stress and the ER factory shrank.
“We have discovered the key role played by the TOR signalling pathway in driving the expansion of the endoplasmic reticulum, and sending a cell’s factories into overdrive,” Bakal said.
“The TOR pathway is active in many types of cancer, and our study provides new insights into how cancer metabolism works, and suggests that these metabolic signals could be excellent targets for future treatments.”
