Navigation Links
Researchers uncover mechanisms of estrogen in promoting cell death in breast cancer

A laboratory study has uncovered new details about how estrogen can activate natural pathways that kill certain breast cancer cells or tumors. The results raise the possibility that estrogen therapy may overcome resistance to certain breast cancer hormonal therapies. The study appears in the December 7 issue of the Journal of the National Cancer Institute.

When cancer treatments such as chemotherapy or hormonal therapy fail to cause tumor regression, the cause is often a malfunction of a natural pathway called apoptosis, which breaks down cells in the body. Many breast cancer cells require estrogen for survival (called estrogen receptor–positive breast cancers), and apoptosis of such cells can be induced with treatments that block estrogen, such as tamoxifen, fulvestrant, or aromatase inhibitors. Paradoxically, some cells can become adapted to survive when deprived of estrogen and undergo apoptosis in the presence of estradiol. However, the mechanism by which estrogen promotes apoptosis is not well understood.

To try to understand how the estrogen estradiol induces apoptosis in cells, V. Craig Jordan, Ph.D., D.Sc., of the Fox Chase Cancer Center in Philadelphia, and colleagues developed a line of breast cancer cells, called MCF-7:5C, that are resistant to estrogen withdrawal and that undergo apoptosis when treated with very small concentrations of estradiol. The researchers treated MCF-7:5C cells with estradiol and fulvestrant, and they also injected the cancer cells into mice to study estradiol's influence on apoptosis in tumors.

They found that estradiol induces apoptosis by activating the so-called intrinsic apoptotic pathway. This pathway is controlled by proteins on the membrane of cell organelles called mitochondria. Estradiol increased the expression of several proteins on the membrane of cell mitochondria, led to depolarization of the mitochondrial membrane, and stimulated the release of a molecule called cytochrome c int o the cell's interior, where it could activate several cellular enzymes, called caspases, which in turn initiate cell degradation. They also found that estradiol caused complete tumor regression in mice that had been injected with the MCF-7:5C breast cancer cells.

"These laboratory data have important clinical implications, particularly for the use of aromatase inhibitors as long-term therapy," write the authors, "and they suggest that, if and when resistance to aromatase inhibition occurs, a strategy of treatment with estrogen ?may be sufficient to kill the cancer and control disease progression."


'"/>

Source:Journal of the National Cancer Institute


Related biology news :

1. Researchers discover way to make cells in the eye sensitive to light
2. Researchers find how protein allows insects to detect and respond to pheromones
3. Researchers Uncover Key Step In Manufacture of Memory Protein
4. Researchers reveal the infectious impact of salmon farms on wild salmon
5. Researchers identify target for cancer drugs
6. Researchers discover molecule that causes secondary stroke
7. Researchers find missing genes of ancient organism
8. Researchers trace evolution to relatively simple genetic changes
9. Researchers add new tool to tumor-treatment arsenal
10. UF Researchers Map Bacterial Proteins That Cause Tooth Loss
11. VCU Researchers Identify Networks Of Genes Responding To Alcohol In The Brain
Post Your Comments:
*Name:
*Comment:
*Email:


(Date:4/24/2017)... Janice Kephart , former 9/11 ... Partners, LLP (IdSP) , today issues the following ... March 6, 2017 Executive Order: Protecting the ... be instilled with greater confidence, enabling the reactivation ... applications are suspended by until at least July ...
(Date:4/13/2017)... MONICA, Calif. , April 13, 2017 ... New York will feature emerging and evolving ... Summits. Both Innovation Summits will run alongside the expo ... of speaker sessions, panels and demonstrations focused on trending ... coast,s largest advanced design and manufacturing event will take ...
(Date:4/11/2017)... 11, 2017 No two people are ... the New York University Tandon School of Engineering ... found that partial similarities between prints are common ... mobile phones and other electronic devices can be ... vulnerability lies in the fact that fingerprint-based authentication ...
Breaking Biology News(10 mins):
(Date:10/12/2017)... ... October 12, 2017 , ... The ... three Winners and six Finalists of the 2017 Blavatnik Regional Awards for Young ... Family Foundation and administered by the New York Academy of Sciences to honor ...
(Date:10/12/2017)... ... October 12, 2017 , ... ... with the addition of its newest module, US Hemostats & Sealants. , SmartTRAK’s ... hemostats, absorbable hemostats, fibrin sealants, synthetic sealants and biologic sealants used in surgical ...
(Date:10/11/2017)... ... 11, 2017 , ... At its national board meeting in ... Sheikh, the co-founder, CEO and chief research scientist of Minnesota-based Advanced Space Technology ... in ARCS Alumni Hall of Fame . ASTER Labs is a technology ...
(Date:10/11/2017)... USA (PRWEB) , ... October 11, 2017 , ... ComplianceOnline’s ... take place on 7th and 8th June 2018 in San Francisco, CA. The Summit ... as well as several distinguished CEOs, board directors and government officials from around the ...
Breaking Biology Technology: