Fish Oil Reduces Effectiveness of Chemotherapy
ScienceDaily (Sep. 12, 2011) – Researchers at University Medical Center
Utrecht, the Netherlands, have discovered a substance that has an adverse
effect on nearly all types of chemotherapy — making cancer cells
insensitive to the treatment. Chemotherapy often loses effectiveness over
time. It is often unclear how or why this happens.
It now appears that chemotherapy is made ineffective by two types of fatty
acid that are made by stem cells in the blood. Under the influence of
cisplatin chemotherapy, the stem cells secrete these fatty acids that induce
resistance to a broad spectrum of chemotherapies. These substances are
referred to by researchers as ‘PIFAs’ which stands for platinum-induced
fatty acids. Cisplatin is a type of chemotherapy that is widely used for the
treatment of cancer, including cancer of the lungs and ovaries.
Tumors under the skin
The researchers studied the effect of PIFA’s in mice and human cells. The
mice studied had tumors under the skin. Under normal conditions, the tumors
would decrease in size following the administration of chemotherapy. In the
study, after administering the fatty acids to the mice, the tumors were
found to be insensitive to chemotherapy. The fatty acids were isolated from
the medium in which chemotherapy exposed stem cells were grown. But also
stem cells in the blood of patients produce the fatty acids that desensitize
tumors to chemotherapy.
The fatty acids are also found in commercially-produced fish oil supplements
containing omega-3 and omega-6 fatty acids as well as in some algae
extracts. In the experiments conducted in mice, the tumors became
insensitive to chemotherapy after administration of normal amounts of fish
oil. Natural products that include fish oil are frequently used by cancer
patients in addition to their regular treatment.
“Don’t use these products”
Professor Emile Voest, a medical oncologist at UMC Utrecht, supervised the
research. “Where resistance to chemotherapy is concerned, we usually believe
that changes in the cancer cells themselves have occurred. Now we show that
the body itself secretes protective substances into the blood that are
powerful enough to block the effect of chemotherapy. These substances can be
found in some types of fish oil. Whilst waiting for the results of further
research, we currently recommend that these products should not be used
whilst people are undergoing chemotherapy.”
Researchers at the University Medical Center Utrecht, the Netherlands,
describe these findings, that will appear online on September 12, in the
journal Cancer Cell.
Story Source:
The above story is reprinted (with editorial adaptations by ScienceDaily
staff) from materials provided by University Medical Center Utrecht, via
EurekAlert!, a service of AAAS.
Journal Reference:
Jeanine M.L. Roodhart, Laura G.M. Daenen, Edwin C.A. Stigter, Henk-Jan
Prins, Johan Gerrits, Julia M. Houthuijzen, Marije G. Gerritsen, Henk S.
Schipper, Marieke J.G. Backer, Miranda van Amersfoort, Joost S.P. Vermaat,
Petra Moerer, Kenji Ishihara, Eric Kalkhoven, Jos H. Beijnen, Patrick W.B.
Derksen, Rene H. Medema, Anton C. Martens, Arjan B. Brenkman, Emile E.
Voest. Mesenchymal Stem Cells Induce Resistance to Chemotherapy through the
Release of Platinum-Induced Fatty Acids. Cancer Cell, 2011; 20 (3): 370 DOI:
10.1016/j.ccr.2011.08.010
