New approach to fight kidney, breast cancer

A potentially powerful new approach to treating two lethal metastatic cancers - triple negative breast cancer and clear cell renal cell carcinoma, the most common form of kidney cancer - has been discovered by researchers at Mayo Clinic in Florida.

In the online issue of Molecular Cancer Therapeutics, they report that two drugs, romidepsin and decitabine, work cooperatively to activate a potent tumour suppressor gene that is silenced in these cancers.

Once the gene, secreted frizzled related protein one or sFRP1, went to work after the drugs were used, the laboratory tumour cells stopped growing and died.

Both drugs are approved by the Food and Drug Administration to treat blood cancer and are being tested individually in numerous solid cancers in which sFRP1 is disabled. This study was the first to test the use of both in these metastatic cancers linked to sFRP1, and the results are very encouraging, says senior investigator John Copland, Ph.D., a Mayo Clinic molecular biologist.

"We now have the basis for a clinical trial aimed at providing effective therapy for two drug-resistant cancers and perhaps many more tumour types in the future," Dr. Copland says. In addition to breast and kidney cancer, sFRP1 is disabled in colon, ovarian, lung, liver and other tumor types.

Dr. Copland and his colleagues earlier discovered that sFRP1 was silenced in certain cancers. This new work demonstrates that its expression can be restored by romidepsin, which is a histone deacetylase inhibitor, and decitabine, a methyltranferase inhibitor. Both are epigenetic drugs, modifying genes in a way that affects whether they are turned on or off.