WASHINGTON, D.C. - Overexpression of a specific type of microRNA can derail treatment by disabling an important molecular brake on breast cancer cell proliferation, according to evidence presented by researchers from The University of Texas M. D. Anderson Cancer Center at the American Association for Cancer Research 101st Annual Meeting 2010.
The study showed that MiRNA-21 interferes with trastuzumab (Herceptin) therapy by blocking the phosphates and tensing homolog gene known as PTEN.
"PTEN acts as a tumor suppressor and is involved in regulating cell proliferation and death," said Sumaiyah K. Rehman, first author of the study and a graduate research assistant in the Department of Molecular and Cellular Oncology at M. D. Anderson. "When it is expressed normally, cells proliferate more slowly and senesce, or stop growing."
Mutations in the PTEN gene play a role in many types of cancer and influence both the development of breast cancers and their response to treatment.
"We know that there are signaling pathways in cancer cells that drive malignancy and progression," said senior author Dihua Yu, M.D., Ph.D., professor and deputy chair of the Department of Molecular and Cellular Oncology. "PTEN acts as a brake on those monogenic signaling pathways, and PTEN loss has been found in about 40 percent of breast cancers. So it is well-documented that PTEN loss is correlated with a poor clinical outcome in breast cancer patients."
Interfering with a targeted therapy
MicroRNAs (MiRNA) are snippets of RNA that influence gene expression by targeting specific messenger RNAs (mRNA). mRNAs are responsible for ensuring that proteins and their products are produced correctly, and interference from miRNAs can disrupt or alter this normal protein production.
"MiRNAs are molecules that exist in our cells and regulate a variety of physiological functions," said Rehman, who also is a graduate student at The University
|Contact: Scott Merville|
University of Texas M. D. Anderson Cancer Center