Spike in Protein Flags Cancer Growth

Prostate cancer progression may be found early by elevated levels of protein

(RxWiki News) High levels of certain proteins appear to stimulate tumor growth. Newly discovered proteins can help doctors identify patients who are at increased risk for aggressive prostate cancer.

Scientists have recently found that the protein cyclin D1b triggers the expression of genes that allows prostate cancer to grow and metastasize.

This team of scientists has also found that elevated levels of Cyclin D1b occur in up to 80 percent of late-stage prostate cancers.

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Karen Knudsen, PhD, professor in the departments of cancer biology, urology and radiation oncology at Thomas Jefferson University and deputy director for basic science at the Kimmel Cancer Center in Philadelphia, headed a group that conducted lab studies focusing on the cyclin D1b protein.

Prior research has shown that cyclin D1 is an important regulator of cell growth. Overexpression of cyclin D1 has been linked to the development and spread of cancer. Investigators have identified two types of this protein, which they’ve labeled cyclin D1a and cyclin D1b.

Professor Knudsen and her colleagues found that the cyclin D1b variant, but not cyclin D1a, regulates a large gene network in prostate cancer. Cyclin D1b works together with androgen receptor (AR) signaling to fuel metastasis (the spread of prostate cancer to the bone and other organs).

Professor Knudsen said that many patient studies have shown that “AR signaling is critical for progression to metastatic disease.”

Androgen is a male sex hormone and testosterone is the primary androgen. Cells have receptors on their surfaces that receive chemical signals from the body and tell the cells how to function. Androgen receptors in prostate cells take instructions from testosterone.

Malfunctioning androgen receptors, however, spur cancer growth.

This preclinical research from the Kimmel Cancer Center builds on previous studies that have shown that cyclin D1b expression is higher in early stages of prostate cancer.

In addition, the scientists discovered that cyclin D1b promotes the expression of a gene called SNAI2 or Slug. Slug enhances the ability of cells to colonize soft tissues, which results in a higher incidence of metastasis in the liver and lung, according to lab studies.

“Cyclin D1b and Slug can likely be used as biomarkers to identify patients with an increased risk of metastasis, and will eventually provide us with novel ‘druggable’ targets, which can be exploited to dramatically reduce the incidence of these lethal metastatic tumors,” said Professor Knudsen.

The study was published online on December 21 in the Journal of Clinical Investigation.

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Review Date: 
December 29, 2012