(SACRAMENTO, Calif.) A team of researchers from UC Davis, UC San Diego and other institutions has identified a key mechanism behind aggressive prostate cancer. Published on August 14, 2013 in Nature, the study shows that two long non-coding RNAs (PRNCR1 and PCGEM1) activate androgen receptors, circumventing androgen-deprivation therapy. In their active state, these receptors turn on genes that spur growth and metastasis, making these cancers highly treatment-resistant. The study illustrates how prostate cancer can thrive, even when deprived of hormones, and provides tempting targets for new therapies.
"Androgen-deprivation therapy will often put cancer in remission, but tumors come back, even without testosterone," said contributor Christopher Evans, professor and chair of the Department of Urology at the UC Davis School of Medicine. "We found that these long non-coding RNAs were activating the androgen receptor. When we knocked them out, cancer growth decreased in both cell lines and tumors in animals."
Evans' UC Davis group was part of a larger team, led by Michael Geoff Rosenfeld, professor at the Howard Hughes Medical Institute in the School of Medicine at UC San Diego, which has been eager to determine how androgen-dependent cancers become androgen-independent (also called castration-resistant). These prostate cancers are very aggressive and usually fatal, but their continued growth, despite being deprived of hormones, is just now being better understood. It's not unlike removing the key from a car ignition, only to have the vehicle re-start on its own.
In this case, the aberrant starting mechanisms are long non-coding RNAs, a class of genetic material that regulates gene expression but does not code for proteins. Using patient samples from UC Davis, the group determined that both PRNCR1 and PCGEM1 are highly expressed in aggressive tumors. These RNAs bind to androgen receptors and activate them in the absence of testoster
|Contact: Dorsey Griffith|
University of California - Davis Health System