Four suspects often found at the scene of the crime in cancer are guilty of the initiation and progression of breast cancer in mice that are resistant to the disease, a team led by scientists at The University of Texas M. D. Anderson Cancer Center reports in the June edition of Cancer Cell.
"We have a smoking gun" that shows it's no coincidence the three protein receptors and the enzyme that makes them are abnormally expressed in many types of cancer, said Gordon Mills, M.D., Ph.D., professor and chair of M. D. Anderson's Department of Systems Biology and senior author of the paper.
"We've compiled lots of evidence that they are associated with cancer, what's been missing is proof that they could cause cancer," Mills said. "There are no questions left, they should be targeted."
The four are three lysophosphatidic acid (LPA) receptors (LPA1, LPA2, and LPA3) and the LPA-producing enzyme, autotaxin. "Lysophosphatidic acid", Mills said, "is the single most potent known cellular survival factor." LPA binds to a series of G protein-coupled receptors to spark normal cell proliferation, viability, production of growth factors and survival. The Cancer Cell paper shows this powerful network is hijacked to initiate breast cancer and fuel tumor growth, invasion and metastasis.
The team took a strain of mice that is highly resistant to breast cancer and then created four transgenic strains, each strain expressing one of the receptors or autotaxin.
At 24 months, none of the 44 original cancer-resistant mice developed mammary gland cancer. Only one case of inflammation and two cases of a potentially precancerous accumulation of cells known as hyperplasia were noted.