A new drug candidate reduced the growth of tumors in a mouse model of triple negative breast cancer (TNBC) by targeting the RNA, or expression, of a gene only expressed in the diseased cells. These results hold promise for developing a new generation of drugs that could precisely treat a variety of diseases.1
“This is the first example of taking a genetic sequence and designing a drug candidate that works effectively in an animal model against triple negative breast cancer,” said Matthew Disney, PhD, professor, Department of Chemistry, The Scripps Research Institute, Jupiter, Florida.
“The study represents a clear breakthrough in precision medicine, as this molecule only kills the cancer cells that express the cancer-causing gene, not healthy cells. These studies may transform the way the lead drugs are identified, by using the genetic makeup of a disease.”
This study, published in the Proceedings of the National Academy of Sciences, described a compound called Targaprimir-96, which can cause breast cancer cells to kill themselves in a process called apoptosis. Targaprimir-96 achieves this by targeting a specific RNA that only the tumor cells express.
This research bypassed the often time-consuming and expensive high-throughput screens that can test millions of drug candidates by using a computational approach (Informa) that focuses on creating compounds that bind to specific sections of RNAs, particularly microRNAs.
MicroRNAs are particularly small RNAs that adjust the expression levels of genes. MicroRNAs achieve this modulation by binding to the transcripts of those genes and preventing protein production from those genes. Some microRNAs are involved in the development of diseases. In this case, microRNA-96 promotes cancerous growth by decreasing programmed cell death. MicroRNA-96 was the target of this research.
After the discovery of targaprimir-96 as a drug candidate targeting microRNA-96, researchers administered it to a mouse model of TNBC for 21 days. Tumor cells produced less microRNA-96, increasing apoptosis. Tumor growth decreased significantly, and healthy cells were unaffected.
“In the future we hope to apply this strategy to target other disease-causing RNAs, which range from incurable cancers to important viral pathogens such as Zika and Ebola,” said Sai Pradeep Velagapudi, PhD, a research associate in the Disney laboratory, and first author of the study.
1. Velagapudi SP, Cameron MD, Haga CL, et al. Design of a small molecule against an oncogenic noncoding RNA [published online May 11, 2016]. Proc Natl Acad Sci U S A. doi:10.1073/pnas.1523975113.