HOUSTON A small slice of RNA inhibits prostate cancer metastasis by suppressing a surface protein commonly found on prostate cancer stem cells. A research team led by scientists at The University of Texas MD Anderson Cancer Center reported today in an advance online publication at Nature Medicine.
"Our findings are the first to profile a microRNA expression pattern in prostate cancer stem cells and also establish a strong rationale for developing the microRNA miR-34a as a new treatment option for prostate cancer," said senior author Dean Tang, Ph.D., professor in MD Anderson's Department of Molecular Carcinogenesis.
MicroRNAs, or miRNAs, are short, single-stranded bits of RNA that regulate the messenger RNA expressed by genes to create a protein.
Cancer stem cells are capable of self-renewal, have enhanced tumor-initiating ability and are generally more resistant to treatment than other cancer cells. They are associated with tumor recurrence and metastasis, the lethal spreading of cancer to other organs. These capacities are more prevalent in cancer cells that feature a specific cell surface protein called CD44, Tang said.
"CD44 has long been linked to promotion of tumor development and, especially, to cancer metastasis," Tang said. "Many cancer stem cells overexpress this surface adhesion molecule. Another significant finding from our study is identifying CD44 itself as a direct and functional target of miR-34a."
MicroRNA goes up, CD44 and cancer stem cells fall
In a series of lab experiments with cell lines, human xenograft tumors in mice and primary human prostate cancer samples, the researchers demonstrated that miR-34a inhibits prostate cancer stem cells by suppressing CD44.
"There are many companies developing microRNA-based drugs," Tang said. "Delivery of miRNAs is a challenge, but the field is moving fast through the preclinical stage."
Scientists from Austin-based Mirna Therapeutics collaborated on the study. Mirna has eight microRNAs in preclinical development, including miR-34a.
|Contact: Scott Merville|
University of Texas M. D. Anderson Cancer Center