Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Hit multiple targets for maximum benefit in HER2-positive breast cancer, studies suggest

08.03.2011
Combining targeted therapies might be required for maximum anti-tumor activity when treating HER2-positive breast cancers, according to two new studies by Vanderbilt-Ingram Cancer Center (VICC) investigators.

The findings, reported in two papers in the Proceedings of the National Academy of Sciences (PNAS), suggest that upregulation of the HER3 receptor limits the effectiveness of two classes of targeted therapies (HER2- and PI3 kinase-targeted therapies). Therefore targeting HER3 together with these agents should improve their clinical utility.

Around 25 percent of breast cancers have increased expression of the HER2 receptor, which is associated with more aggressive tumors and a poorer prognosis. HER2-targeted therapies like trastuzumab (Herceptin) and lapatinib (Tykerb) are effective in many women with HER2-positive breast tumors.

"But even in patients who respond to HER2-targeted therapies, the clinical response tends to be short-lived and tumors become resistant," said Carlos Arteaga, M.D., professor of Medicine and Cancer Biology, and director of the VICC Breast Cancer Research Program.

HER2 is a member of the EGF receptor family involved in signaling pathways that promote cell growth. HER2 must interact and form complexes with other members of the EGF receptor family, and its main partner in activating pathways that promote tumor growth is HER3. This complex of HER2/HER3 is a potent activator of the PI3K/Akt pathway, the key survival pathway in HER2-positive cancers.

"Based on this evidence, we hypothesized that, for these therapies to have maximum effect, HER3 and its output to the PI3K/Akt pathway must be completely shut down," Arteaga said.

A postdoctoral fellow in Arteaga's laboratory, Joan Garrett, Ph.D., led experiments to examine the effect of the HER2 tyrosine kinase inhibitor, lapatinib, on HER3 expression and activity.

She found that inhibiting HER2 with lapatinib led to an increase in HER3 expression and activation in both HER2-positive human breast tumors and cell lines. Inhibiting HER3 in HER2-positive breast cancers growing in mice made tumor cells markedly more sensitive to lapatinib. Additionally, blocking both HER2 and HER3 was more effective at inhibiting the activity of PI3K/Akt pathway than either inhibitor alone.

Those results, published March 7 in PNAS, show that upregulation of HER3 limits the effectiveness of HER2-targeted therapies and that a combination of drugs that target both HER2 and HER3 should be considered for optimal clinical benefit.

Since PI3K/Akt is the key pro-survival signaling pathway downstream of HER2, the investigators also examined the utility of inhibitors of PI3K in HER2-positive breast cancer cells.

Those experiments, led by postdoctoral fellow Anindita Chakrabarty, Ph.D., and published Feb. 28 also in PNAS, showed a similar upregulation of HER3 in response to treatment with a PI3K inhibitor currently in clinical development. In turn, this compensatory upregulation of HER3 partially reactivated the PI3K/Akt pathway and limited the action of the PI3K inhibitor.

"This shows that therapeutic use of PI3K inhibitors would be limited if used as single agents in HER2-positive cancers. These results have implications for other cancers treated with this class of drugs," Arteaga said. However, he notes PI3K inhibitors might have clinical merit when used in combination with HER2-HER3 antagonists.

Since both HER3 inhibitors and PI3K inhibitors are now in clinical development, "these studies provide a scientific rationale for how a combination of the new drugs with HER2-targeted therapies might be used to provide better results for many patients with breast cancer," Arteaga said.

Arteaga is also the Donna S. Hall Chair in Breast Cancer Research and interim director of the Division of Hematology/Oncology at Vanderbilt University. The research was supported by grants from the National Institutes of Health, the American Cancer Society, the Lee Jeans Translational Breast Cancer Research Program, and a Stand Up to Cancer (SU2C)/AACR Dream Team Translational Research Grant.

Melissa Marino | EurekAlert!
Further information:
http://www.vanderbilt.edu

More articles from Studies and Analyses:

nachricht New study: How does Europe become a leading player for software and IT services?
03.04.2017 | Fraunhofer-Institut für System- und Innovationsforschung (ISI)

nachricht Reusable carbon nanotubes could be the water filter of the future, says RIT study
30.03.2017 | Rochester Institute of Technology

All articles from Studies and Analyses >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Making lightweight construction suitable for series production

More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.

Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...

Im Focus: Wonder material? Novel nanotube structure strengthens thin films for flexible electronics

Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.

"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...

Im Focus: Deep inside Galaxy M87

The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.

Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...

Im Focus: A Quantum Low Pass for Photons

Physicists in Garching observe novel quantum effect that limits the number of emitted photons.

The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...

Im Focus: Microprocessors based on a layer of just three atoms

Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.

Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Fighting drug resistant tuberculosis – InfectoGnostics meets MYCO-NET² partners in Peru

28.04.2017 | Event News

Expert meeting “Health Business Connect” will connect international medical technology companies

20.04.2017 | Event News

Wenn der Computer das Gehirn austrickst

18.04.2017 | Event News

 
Latest News

Wireless power can drive tiny electronic devices in the GI tract

28.04.2017 | Medical Engineering

Ice cave in Transylvania yields window into region's past

28.04.2017 | Earth Sciences

Nose2Brain – Better Therapy for Multiple Sclerosis

28.04.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>