A new virtue may soon be added to the health benefits associated with beans, nuts, and cereals. All of these foods contain the inositol phosphate IP5--a compound that even at low dose limits the supply of blood to tumor cells and inhibits tumor growth in mice, according to new findings.
One goal of drug designers has been to prevent tumors from making new blood vessels, a process known as angiogenesis. Angiogenesis depends upon the activation of a cellular pathway known as PI3K/Akt, but identifying nontoxic compounds that can inhibit this pathway has proved tricky.
One possibility is an inositol phosphate called IP5, a compound naturally present in beans, nuts, and cereals. Yet little is known about its potential efficacy as an antitumor agent. So Marco Falasca of the University College London Sackler Institute in the United Kingdom and colleagues decided to put IP5 to the test. They first induced angiogenesis in mice through the injection of a growth factor called FGF-2 and measured blood vessel development in the presence and absence of synthesised IP5. While FGF-2 boosted the formation of new blood vessels, IP5 had a clear inhibitory effect, reducing the number of new blood vessels by half.
In another set of experiments, the team implanted human ovarian carcinoma cells into mice. Twelve days later they injected the animals with either IP5 or cisplatin, a common ovarian cancer treatment. IP5 worked as well as cisplatin in reducing the volumes of the tumors, the team reports today in Cancer Research.
IP5 seems a good candidate to eventually join the list of angiogenesis inhibitors already approved by the U.S. Food and Drug Administration, says cell biologist Judah Folkman of Harvard Medical School in Boston, Massachusetts. "It may be useful in combination [with other inhibitors]," he says, and there may be fewer problems with side-effects and drug resistance.