Featured Research

from universities, journals, and other organizations

Potential solution to melanoma's resistance to vemurafenib

Date:
February 28, 2012
Source:
Moffitt Cancer Center
Summary:
Researchers have found that the XL888 inhibitor can prevent resistance to the chemotherapy drug vemurafenib, commonly used for treating patients with melanoma.

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."


Story Source:

The above story is based on materials provided by Moffitt Cancer Center. Note: Materials may be edited for content and length.


Journal Reference:

  1. K. H. T. Paraiso, E. Haarberg, E. Wood, V. W. Rebecca, Y. A. Chen, Y. Xiang, A. Ribas, R. S. Lo, J. S. Weber, V. K. Sondak, J. John, A. A. Sarnaik, J. Koomen, K. S. M. Smalley. The heat shock protein-90 inhibitor XL888 overcomes BRAF inhibitor resistance mediated through diverse mechanisms. Clinical Cancer Research, 2012; DOI: 10.1158/1078-0432.CCR-11-2612

Cite This Page:

Moffitt Cancer Center. "Potential solution to melanoma's resistance to vemurafenib." ScienceDaily. ScienceDaily, 28 February 2012. <www.sciencedaily.com/releases/2012/02/120228185828.htm>.
Moffitt Cancer Center. (2012, February 28). Potential solution to melanoma's resistance to vemurafenib. ScienceDaily. Retrieved April 17, 2014 from www.sciencedaily.com/releases/2012/02/120228185828.htm
Moffitt Cancer Center. "Potential solution to melanoma's resistance to vemurafenib." ScienceDaily. www.sciencedaily.com/releases/2012/02/120228185828.htm (accessed April 17, 2014).

Share This



More Health & Medicine News

Thursday, April 17, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Could Even Casual Marijuana Use Alter Your Brain?

Could Even Casual Marijuana Use Alter Your Brain?

Newsy (Apr. 16, 2014) — A new study conducted by researchers at Northwestern and Harvard suggests even casual marijuana use can alter your brain. Video provided by Newsy
Powered by NewsLook.com
Thousands Of Vials Of SARS Virus Go Missing

Thousands Of Vials Of SARS Virus Go Missing

Newsy (Apr. 16, 2014) — A research institute in Paris somehow misplaced more than 2,000 vials of the deadly SARS virus. Video provided by Newsy
Powered by NewsLook.com
Formerly Conjoined Twins Released From Dallas Hospital

Formerly Conjoined Twins Released From Dallas Hospital

Newsy (Apr. 16, 2014) — Conjoined twins Emmett and Owen Ezell were separated by doctors in August. Now, nearly nine months later, they're being released from the hospital. Video provided by Newsy
Powered by NewsLook.com
Ebola Outbreak Now Linked To 121 Deaths

Ebola Outbreak Now Linked To 121 Deaths

Newsy (Apr. 15, 2014) — The ebola virus outbreak in West Africa is now linked to 121 deaths. Health officials fear the virus will continue to spread in urban areas. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins