A new study on the effect of opiates on cell reproduction may facilitate eventual use of such drugs in the treatment of cancer. This research -- carried out by Prof. Zvi Vogel and Dr. Jacob Barg of the Weizmann Institute's Department of Neurobiology along with Prof. Carmine Coscia of the St. Louis University School of Medicine -- was inspired by recent scientific papers documenting the inhibitory effects of opiates on DNA production in the fetal brain, as well as intestinal, lung and breast cancer cells.
In this study, parts of which were recently published in the Journal of Neurochemistry, the rate of DNA synthesis in fetal rat brain cells was measured. The researchers used aggregates of nerve cells and glial brain tissue supporting cells in order to mimic as closely as possible the situation in the developing brain.
The researchers found that of the three known types of opiate receptors in brain cells -- mu, kappa and delta -- only the first two are associated with inhibition of DNA synthesis, while the third is inactive. In addition, they demonstrated that opiates impede a key step in the transmission of intercellular messages ? phosphoinositol signal transduction -- which is also known to be linked to DNA synthesis. It is likely, therefore, that the capacity to impede phosphoinositol signal transduction is what enables opiates to inhibit DNA synthesis during brain development.
It is hoped that this fresh information may contribute to the development of new opiates capable of selectively slowing DNA synthesis in malignant cells with opiate receptors, thereby repressing the spread of certain tumors while leaving normal cells unharmed. "The side effects of opiates," says Dr. Barg, "are generally less severe than those of standard cancer therapies. A cancer victim would derive double benefit from these substances if they could be made to not only kill pain, but also to impede the spread of tumors."
Prof. Vogel holds the Ruth and Leonard Simon Professorial Chair.