Experimental Drug May Significantly Reduce Metastatic Breast Cancer Tumors

Treatment shows the potential to turn metastatic breast tumors into low-grade tumors.

While still in the early stages of development, researchers have found a potential drug that may reduce metastatic breast tumors into low-grade tumors.

David L. Spector, PHD, director of research at Cold Spring Harbor laboratory, is using a drug to hit a cancer target called Malat1, which is part of a class of nucleic acids called long non-coding RNAs, or IncRNAs.

A lot of cancer-fighting drugs are made up of chemicals or proteins that target cellular proteins. However, in this case both the candidate drug and the target are nucleic acids.

In a previous study, Spector and his team were able to knock out the Malat1 gene in mice, leaving them with no abnormalities. This time he looked to breed mice with human-like breast cancer with mice that lacked Malat1.

Since knocking out a gene in humans is something that is not performed, Spector wanted to create a drug that can mimic this attack on the Malat1 gene.

Spector and his team collaborated with Ionis Pharmaceuticals and used a nucleic acid called antisense oligonucleotide (ASO), which bounded to Malat1 IncRNA.

"We got an amazing result," Spector says. "By removing Malat1 -- this one, single long non-coding RNA -- we made a dramatic impact on the primary breast tumors in these mice. The tumors took on a wholly new character.”

While performing tests, they found impressive results in mice whose cancer mimicked human metastatic breast cancer. Although metastatic cancer was not completely destroyed, it was reduced by 70%. The tumors, which were no longer thriving, became low-grade tumors that held a resemblance to cysts and were filled with a fluid containing milk protein.

Although the function of Malat1 is unknown, researchers have found that there is an ample amount of it in IncRNAs. Through these findings, researchers argue there is even more Malat1 in some malignant tumors.