PhotoAdmittedly, it's a novel therapeutic approach to treating breast cancer. A drug called a “notch inhibitor” targets cancer stem cells by making them more susceptible to traditional cancer drugs.

These drugs, say Loyola University Medical Center researchers, are effective in killing mature cancer cells. But a handful of cancer stem cells are resistant to such drugs. They survive and go on to develop into new tumor cells.

A pilot study at Loyola found that the "notch inhibitor" appears to block this process by turning off key genes.

"Our results suggest a potential role that notch inhibitors could play in optimizing existing therapies and in overcoming resistance to cancer drugs," said Kathy Albain, MD, who led the study.

The so-called notch protein promotes tumor growth and survival and is present on the surface of cancer stem cells. The protein latches on to other cells, and the resulting "molecular handshake" activates various genes in the stem cells. Activating these genes, in effect, makes the stem cells resistant to common cancer drugs.

The study

The study included 20 patients who finished all therapy. The women all had early-stage, estrogen-receptor-positive breast cancer.

Following treatment with the notch inhibitor, patients underwent biopsies to provide tumor specimens. Researchers found that the drug turned off the key genes that in effect would have kept the tumor stem cells resistant to conventional drugs.

"The notch inhibitor appears to be doing what it is intended to do," said Clodia Osipo, PhD, a breast cancer scientist in Loyola's Cardinal Bernardin Cancer Center.

What's next? Researchers proposed a randomized clinical trial, in which patients who received estrogen-blocking drugs before surgery would be compared to patients who received estrogen-blocking drugs plus a notch inhibitor.

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