Their experimental model of colon cancer -- work done in cell cultures and animal studies -- demonstrates that the drug, Nembutal, can suppress activity in colon cancer cells the same way it inhibits certain kinds of neurotransmissions in the brain and central nervous system.
The results, presented at the annual meeting of the American Association for Cancer Research, suggest a novel approach to treatment of cancers now known to have neurotransmitter receptors on the outside of their cells. That includes, to date, colon and some ovarian cancers.
"This is the first experimental evidence that Nembutal is a potent inhibitor of colon cancer metastasis," says the study's first author, Premal Thaker, M.D., a clinical fellow in the Department of Gynecologic Oncology. "These findings may have therapeutic implications for treatment, but more work needs to be done before we know that."
Scientists have only recently discovered that the surfaces of colon cancer cells are studded with receptors for gamma-aminobutyric acid (GABA), an inhibitory neurotransmitter.
Nerve cells, or neurons, communicate by releasing neurotransmitters. These chemical messengers flow onto other neurons that act as receivers. The neurotransmitter attaches to a slot on the neuron, or receptor site. Once attached, different neurotransmitters either trigger "go" signals that allow the message to be passed on to other cells or produce "stop" signals that prevent the message from being forwarded. GABA is the most common message-altering neurotransmitter in the brain, inhibiting the transfer of other neurotransmitters as well as other chemical signals, such as hormones.
Nembutal is a member of the barbiturate family of drugs commonly known as "downers" -- acting just lik
Contact: Julie Penne
University of Texas M. D. Anderson Cancer Center