Cancer cooperation "makes treatment difficult"
26 Jan 2015
A team of researchers at the University of East Anglia (UEA) has made steps in understanding why many cancers are difficult to treat and often return following treatment.
According to research, cellular cooperation helps fuel the production of growth factors - diffusible molecules produced by the cancer cells that are essential for a tumour’s progression.
However, new findings published today in the journal PNAS could lead to a novel treatment involving genetically modified cancer cells being reinserted into a tumour, the UEA researchers said.
“Our genetically modified cells create a sort of tumour within the tumour, driving the original cancer cells to extinction
Lead researcher Marco Archetti
Lead researcher Marco Archetti, from UEA’s School of Biological Sciences, said: “The cancerous cells that make up a tumour often show different profiles - for example in their shape and appearance, in the genes they express, or their potential to spread to other parts of the body.
“This is called ’tumour heterogeneity’, and these differences make cancer diagnosis and treatment difficult.”
Archetti said that it is unclear whether current therapies, that do not factor in cell cooperation, will ever be fully effective in treating cancer.
“Mortality rates for cancer have not increased much over the past 50 years, and the best-selling drugs extend survival by four months only on average. We can do better than that,” Archetti said.
“The problem with current therapies is that they do not take into account that cancer is a process of clonal selection within the body: mutant, resistant cells develop and lead to relapse.”
To better understand this process, the UEA team studied pancreatic cancer cells in the lab and used mathematical models to show why heterogeneity persists within a tumour.
“We have shown that cancer cells that do not produce growth factors can ’free-ride’ on the growth factors produced by other cooperative cancer cells. The two types - co-operators and free-riders - can form a heterogeneous tumour under certain circumstances,” Archetti said.
“Cancer is an evolutionary process of selection among cells on the timescale of an individual’s lifetime, and when a drug modifies the amount of available growth factors it also makes the tumour evolve. A heterogeneous tumour can easily adapt to changing amounts of growth factors, which is why current therapies against cancer are unstable and why relapses happen post treatment.”
While also repeating its initial experiments with other cancer types, the UEA team is now attempting to develop a new kind of cell therapy.
The team is planning to genetically modify cancer cells by removing the genes which control the production of growth factors. The researchers will then reinsert these modified cells into the tumour.
“Our genetically modified cells create a sort of tumour within the tumour, driving the original cancer cells to extinction, but eventually the new genetically modified cells cannot survive on their own and the tumour will collapse - this is the idea,” Archetti said.
