During pregnancy, breast epithelial cells undergo tremendous proliferation with the number of cells increasing over ten times. After babies are weaned, these epithelial cells undergo programmed cell death, reverting the breast epithelium back to a non-pregnant state.

Many researchers think it's just this ability to proliferate so rapidly that predisposes cells in the breast to a high risk of cancer. So Michael Karin and colleagues at the University of California, San Diego, in La Jolla, investigated the role of a subunit (alpha) of a regulatory protein kinase complex called I-kappa-B kinase (or IKK) in breast tissue.

To find out how IKK-alpha could be important in breast tissue, the team created mice carrying a dysfunctional copy of the gene coding for the IKK-alpha protein. They found the mutant mice were generally healthy, but that the females couldn't breastfeed their young because their breast tissue didn't grow properly during pregnancy.

The discovery that inactivation of IKK-alpha blocks the proliferation of breast gland cells could be relevant to researchers aiming to block the proliferation of breast tumour cells.

“Since the mutation of IKK-alpha causes a very specific defect in mammary gland in mice with no adverse effect on other organs, it is an ideal target for drug development,” says Karin.


[Contact: Michael Karin]

14-Dec-2001