Controlling ‘bad cholesterol’ production could prevent the growth of cancer and explain why obese people are prone to the disease, suggests a new study.
Researchers found cancer cells expand by controlling the body’s lipid metabolism.
Several previous studies have recognised a link between obesity and cancer.
Now Professor Richard Lehner has taken his research further to understand how tumour cells grow through scavenging very low-density lipoproteins (VLDL) and low-density lipoproteins (LDL) – known as the “bad cholesterol” – and what mechanisms can be used to reduce the malignant cells’ growth.
The two year study, by Prof Lehner’s group at the University of Alberta in Canada, in collaboration with colleagues at the Medical University of Graz in Austria was published in the journal Cell Reports.
The data gathered from their experiments suggest a feed-forward loop, in which tumours not only use lipids as “building blocks” to grow, but they can regulate their host’s lipid metabolism to increase production of these lipids.
The “bad cholesterol” binds to LDL receptors in the liver, the organ in charge of degrading it and excreting it from the organism as bile.
Prof Lehner said: “Cancer cells need lipids to grow.
“They can make their own lipids or get more from the host because these cells grow so fast.
“The tumour signals to the liver: ‘I need more cholesterol for growth’ and the liver is reprogrammed to secrete those lipids.”
He said one of the key factors for the process are proteins we all have that, in larger quantities, may cause a decrease in the amount of LDL receptors to excrete the cholesterol.
The tumour affects these proteins to reduce clearance of cholesterol from the blood, leaving the LDL for cancer to feed off of it.
The findings led the researchers to an interesting hypothesis: minimising the liver’s production of LDL would deprive a tumour from its constant supply and therefore reduce its possibility of growth.
Their experiments in pre-clinical models proved to be successful, confirming lower tumour development with the regulation of the proteins that affect production of VLDL – precursors of LDL – and uptake of LDL by receptors from the liver.
The next step for Prof Lehner and his team will be to test existing medications that would help in limiting the production of cholesterol on patients undergoing cancer treatment – adding them to their current therapies.
He said: “There are medications approved that we can test.
“They were not developed for cancer, they were manufactured for people with hypercholesterolemia – a chronic condition where patients have very high level of cholesterol in their blood, but it will be interesting for us to test them with cancer patients and see if there is improvement.”
He added: “The collaboration with Austria was to set the concept of the investigation.
“We have a great group here, great cancer researchers. We are in good hands to continue.”
He said if potential clinical trials prove to be effective, doctors could have an improved way to help cancer patients: eliminating the tumour, while preventing it from growing at the same time.
