Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Moffitt Cancer Center Researchers Find Potential Solution To Melanoma s Resistance To Vemurafenib

Inhibitor XL888 found to restore chemotherapy sensitivity
Researchers at Moffitt Cancer Center in Tampa, Fla., and colleagues in California have found that the XL888 inhibitor can prevent resistance to the chemotherapy drug vemurafenib, commonly used for treating patients with melanoma.

Vemurafenib resistance is characterized by a diminished apoptosis (programmed cancer cell death) response. According to the researchers, the balance between apoptosis and cell survival is regulated by a family of proteins. The survival of melanoma cells is controlled, in part, by an anti-apoptotic protein (Mcl-1) that is regulated by a particular kind of inhibitor.

Their current findings, tested in six different models of vemurafenib resistance and in both test tube studies and in melanoma patients, demonstrated an induced apoptosis response and tumor regression when the XL888 inhibitor restored the effectiveness of vemurafenib.

The study appeared in a recent issue of Clinical Cancer Research, a publication of the American Association for Cancer Research.

"The impressive clinical response of melanoma patients to vemurafenib has been limited by drug resistance, a considerable challenge for which no management strategies previously existed," said study co-author Keiran S. M. Smalley, Ph.D., of Moffitt's departments of Molecular Oncology and Cutaneous Oncology. "However, we have demonstrated for the first time that the heat shock protein-90 (HSP90) inhibitor XL888 overcomes resistance through a number of mechanisms."

The diversity of resistance mechanism has been expected to complicate the design of future clinical trials to prevent or treat resistance to inhibitors such as vemurafenib.

"That expectation led us to hypothesize that inhibitor resistance might best be managed through broadly targeted strategies that inhibit multiple pathways simultaneously," explained Smalley.

The HSP90 family was known to maintain cancer cells by regulating cancer cells, making it a good target for treatment. According to the authors, the combination of vemurafenib and XL888 overcame vemurafenib resistance by targeting HSP90 through multiple signaling pathways.

There was already evidence that HSP90 inhibitors could overcome multiple drug chemotherapy resistance mechanisms in a number of cancers, including non-small lung cancer and breast cancer. Because XL888 is a novel, orally available inhibitor of HSP90, the researchers hoped that it would arrest the cancer cell cycle in melanoma cell lines.

In their study, the inhibition of HSP90 led to the degradation of the anti-apoptopiuc Mcl-1 protein. The responses to XL888 were characterized as "highly durable with no resistant colonies emerging following four weeks of continuous drug treatment." In other studies not using XL888, resistant colonies "emerged in every case," they reported.

"We have shown for the first time that all of the signaling proteins implicated in vemurafenib resistance are ‘clients' of HSP90 and that inhibition of HSP90 can restore sensitivity to vemurafenib," concluded Smalley and his colleagues. "Our study provides the rationale for the dual targeting of HSP90 with XL888 and vemurafenib in treating melanoma patients in order to limit or prevent chemotherapy resistance."

About Moffitt Cancer Center
Follow Moffitt on Facebook:
Follow Moffitt on Twitter: @MoffittNews
Follow Moffitt on YouTube: MoffittNews

Located in Tampa, Moffitt Cancer Center is a National Cancer Institute-designated Comprehensive Cancer Center, which recognizes Moffitt's excellence in research and contributions to clinical trials, prevention and cancer control. Moffitt is also a member of the National Comprehensive Cancer Network, a prestigious alliance of the country's leading cancer centers, and is listed in U.S. News & World Report as one of "America's Best Hospitals" for cancer.

Ferdie De Vega | EurekAlert!
Further information:

More articles from Life Sciences:

nachricht Biologists unravel another mystery of what makes DNA go 'loopy'
16.03.2018 | Emory Health Sciences

nachricht Scientists map the portal to the cell's nucleus
16.03.2018 | Rockefeller University

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Locomotion control with photopigments

Researchers from Göttingen University discover additional function of opsins

Animal photoreceptors capture light with photopigments. Researchers from the University of Göttingen have now discovered that these photopigments fulfill an...

Im Focus: Surveying the Arctic: Tracking down carbon particles

Researchers embark on aerial campaign over Northeast Greenland

On 15 March, the AWI research aeroplane Polar 5 will depart for Greenland. Concentrating on the furthest northeast region of the island, an international team...

Im Focus: Unique Insights into the Antarctic Ice Shelf System

Data collected on ocean-ice interactions in the little-researched regions of the far south

The world’s second-largest ice shelf was the destination for a Polarstern expedition that ended in Punta Arenas, Chile on 14th March 2018. Oceanographers from...

Im Focus: ILA 2018: Laser alternative to hexavalent chromium coating

At the 2018 ILA Berlin Air Show from April 25–29, the Fraunhofer Institute for Laser Technology ILT is showcasing extreme high-speed Laser Material Deposition (EHLA): A video documents how for metal components that are highly loaded, EHLA has already proved itself as an alternative to hard chrome plating, which is now allowed only under special conditions.

When the EU restricted the use of hexavalent chromium compounds to special applications requiring authorization, the move prompted a rethink in the surface...

Im Focus: Radar for navigation support from autonomous flying drones

At the ILA Berlin, hall 4, booth 202, Fraunhofer FHR will present two radar sensors for navigation support of drones. The sensors are valuable components in the implementation of autonomous flying drones: they function as obstacle detectors to prevent collisions. Radar sensors also operate reliably in restricted visibility, e.g. in foggy or dusty conditions. Due to their ability to measure distances with high precision, the radar sensors can also be used as altimeters when other sources of information such as barometers or GPS are not available or cannot operate optimally.

Drones play an increasingly important role in the area of logistics and services. Well-known logistic companies place great hope in these compact, aerial...

All Focus news of the innovation-report >>>



Industry & Economy
Event News

Ultrafast Wireless and Chip Design at the DATE Conference in Dresden

16.03.2018 | Event News

International Tinnitus Conference of the Tinnitus Research Initiative in Regensburg

13.03.2018 | Event News

International Virtual Reality Conference “IEEE VR 2018” comes to Reutlingen, Germany

08.03.2018 | Event News

Latest News

Wandering greenhouse gas

16.03.2018 | Earth Sciences

'Frequency combs' ID chemicals within the mid-infrared spectral region

16.03.2018 | Physics and Astronomy

Biologists unravel another mystery of what makes DNA go 'loopy'

16.03.2018 | Life Sciences

Science & Research
Overview of more VideoLinks >>>