Two drugs approved by the Food and Drug Administration for blood cancer treatment may also be used to treat triple negative breast and kidney cancer, researchers say.

The drugs are romidepsin and decitabine. Together they can activate a gene sFRP1 (secreted frizzled related protein one) that can stop the growth of cancer cells.

"We now have the basis for a clinical trial aimed at providing effective therapy for two drug-resistant cancers and perhaps many more tumor types in the future," said Dr. John Copland, biologist from Mayo Clinic. 

The trials were conducted on cell lines of cancers where the combination of drugs was effective in halting the cell growth.

"Individually, each drug did not induce any form of cell death but, together, they killed all of the different cell lines of kidney and triple negative breast cancer that we tested in the laboratory," said Simon Cooper, a Mayo Clinic molecular biologist who specializes in renal cancer and lead author of the study.

Nearly, 80,000 people are affected each year by these two types of cancers in the United States.

It was observed that certain types of cancer suppress the gene sFRP1. Activation of this gene by the drugs can stop the growth of cancer cells. Even cancers that affect colon, ovary and lungs grow by suppressing this gene.

Researchers say that this gene could act as a biomarker to test the effectiveness of the combination drug therapy on certain kinds of cancers.

"But now, not only do we have a very promising lead on future therapy, but if this combination treatment works as we hope it does, we will have a biomarker to be able to test which patients might benefit the most. In other words, a biopsy test could identify patients whose tumors had lost sFRP1 function," said Edith Perez, MD, deputy director of Mayo Clinic Cancer Center and co-author of the study. 

The combination therapy can help fight cancers that have become resistant to other drugs and as these drugs are clinically approved the human trial phase would be faster.

"This type of interdisciplinary preclinical research effort is important, not only because of the value of the science, but also because the drugs are already in the clinic and that will facilitate translational efforts and hopefully confirm the preclinical findings in patients with advanced malignancies," said Michael Menefee, MD, an oncologist and co-author of the study. 

The study was published in Molecular Cancer Therapeutics