July 9, 2013
New Compound May Be Future Of Breast Cancer Treatment
[ Watch the Video: New Anti-Cancer Compound Shows Promise For Breast Cancer ]
Rebekah Eliason for redOrbit.com - Your Universe Online
Researchers found a group of anti-cancer compounds known as BH3-mimetics are effective for treating estrogen receptor-positive (ER-positive) forms of breast cancers when used with tamoxifen, a drug currently used to treat breast cancer. Breast cancer is comprised of roughly 70 percent ER-positive types.
Professor Geoff Lindeman, Dr Francois Vaillant and Dr Delphine Merino led a team of researchers at Merion Institute's Breast Cancer Laboratory. The team anticipates results from their study to instigate BH3-mimetic clinical trials treating ER-positive breast cancers.
Professor Lindeman, a medical oncologist at The Royal Melbourne Hospital, explained that BCL-2 is a protein found in high levels in 85 percent of ER-positive breast cancers. This protein, known to researchers as the pro-survival protein, enables many cancer cells to become immortal by resisting cancer treatments such as chemotherapy. BH3-mimetics, the compound of interest, works to neutralize the BCL-2 protein and increase the likelihood of cancer cells dying.
Lindeman said, "Drs Vaillant and Merino looked at the effect of adding BH3-mimetics to the standard hormone treatment, tamoxifen, used for a subtype of ER-positive cancers called luminal B cancers, which had high levels of BCL-2. They found that a BH3-mimetic called ABT-199/GDC-0199 improved the effectiveness of hormone therapy by stopping or delaying the growth of these aggressive tumors. In one of the tumor models, the combined treatment caused complete disappearance of the tumor, while standard treatment had only a partial and unsustained benefit."
Professor Visvader emphasized the need for better treatments of poor prognosis aggressive ER-positive breast cancers known as luminal B. In order to understand how human cancer cells respond to treatment, samples of breast tumor cells donated by Melbourne women currently undergoing cancer surgery were tested.
"We are excited by these results and what they could mean for women with breast cancer," said Professor Visvader. "ER-positive breast cancers are the most common type of breast cancer, so even a small improvement could have a substantial impact if more effective upfront treatment could prevent relapse. It is very early days, however, and the findings will need to be rigorously tested in clinical studies."
Professor Lindeman expressed his desire that the recently established Centre for Translational Breast Cancer Research, TransBCR, would contribute to future clinical trials for the novel combination treatment. "Australian women who donated their tumor samples for research helped make this discovery possible. It would be great to see Australians among the first to benefit from clinical trials, should they proceed."
It was the watershed discovery during the late 1980s made by researchers at the Walter and Eliza Hall Institute of BCL-2 proteins promoting cancer cell survival that instigated over two decades of research culminating in the design of BH3-mimetics. The new compound, ABT-199/GDC-0199, was discovered by scientists at Abbott, now AbbVie. The drug is currently developed by a member of the Roche group, Genentech, and AbbVie.
This study was published in the journal Cancer Cell and was supported by the Australian National Health and Medical Research Council, Victorian Government, Australian Cancer Research Foundation, National Breast Cancer Foundation and Qualtrough Family Bequest.