Researcher investigate 2-drug synergy to treat drug-resistant chronic myeloid leukemia

October 24, 2012

(Medical Xpress)—An interdisciplinary team of researchers has dissected a case of synergy in drug-resistant chronic myeloid leukemia to understand the mechanism by which two drugs, danusertib and bosutinib, work together to overcome resistance in the BCR-ABL gatekeeper mutation-specific disease. The team includes a researcher at Moffitt Cancer Center and colleagues at the CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences in Austria and the Massachusetts Institute of Technology. The goal is to address an unmet medical need because this BCR-ABL mutation confers resistance to all currently approved kinase inhibitors for chronic myeloid leukemia.

The study appeared in the Sept. 30 online version of Nature Chemical Biology.

"Treatment of rapidly improved after the introduction of the first BCR-ABL inhibitor, (imatinib)," said study co-author Uwe Rix, Ph.D., an assistant member of the Moffitt's Department and Experimental Therapeutics Program. "However, it soon became apparent that a broad spectrum of possible necessitated second- and third-generation BCR-ABL inhibitors. Although these are mostly very successful, none of the currently approved options has been effective in patients with chronic myeloid leukemia who harbor the BCR-ABL gatekeeper mutation."

The researchers investigated the and logic underlying the synergistic interaction between danusertib and bosutinib, which is specific for BCR-ABL gatekeeper mutation-transformed cells. They applied a novel systems pharmacology approach involving a combination of different proteomics and methods.

"We found previously unappreciated features of both agents," Rix said. "The synergy did not correlate with direct inhibition of BCR-ABL. Instead, our observations converged on the downstream MAPK signaling cascade as the predominantly affected pathway in the synergistic inhibition of BCR-ABL."

The researchers said the combination of both compounds impaired the activity of c-MYC, a gene regulator that codes a transcription factor playing a well-established but a not well understood role in a broad spectrum of human cancers.

"In the context of chronic myeloid leukemia, c-MYC is required for BCR-ABL-mediated transformation," Rix explained. "What is intriguing is that chronic myeloid leukemia cells with the BCR-ABL gatekeeper mutation seem to be more dependent on the MAPK/c-MYC signaling axis than BCR-ABL wild-type cells. Thus, challenging c-MYC with drugs appears promising in these resistant cells, but steps have only recently been made."

The researchers concluded that they have unraveled the action and impact of a "new synergistic drug interaction between danusertib and bosutinib in a clinically relevant, highly drug-resistant disease setting" by revealing a "non-obvious synergistic mechanism elicited by several off targets of the two small molecules."

"We believe this strategy of gaining a functional understanding of drug synergy may serve as a model for further mode-of-action studies," they concluded.

More information: www.nature.com/nchembio/journa … df/nchembio.1085.pdf

Related Stories

Recommended for you

No dye: Cancer patients' gray hair darkened on immune drugs

July 21, 2017
Cancer patients' gray hair unexpectedly turned youthfully dark while taking novel drugs, and it has doctors scratching their heads.

Shooting the achilles heel of nervous system cancers

July 20, 2017
Virtually all cancer treatments used today also damage normal cells, causing the toxic side effects associated with cancer treatment. A cooperative research team led by researchers at Dartmouth's Norris Cotton Cancer Center ...

Molecular changes with age in normal breast tissue are linked to cancer-related changes

July 20, 2017
Several known factors are associated with a higher risk of breast cancer including increasing age, being overweight after menopause, alcohol intake, and family history. However, the underlying biologic mechanisms through ...

Immune-cell numbers predict response to combination immunotherapy in melanoma

July 20, 2017
Whether a melanoma patient will better respond to a single immunotherapy drug or two in combination depends on the abundance of certain white blood cells within their tumors, according to a new study conducted by UC San Francisco ...

Discovery could lead to better results for patients undergoing radiation

July 19, 2017
More than half of cancer patients undergo radiotherapy, in which high doses of radiation are aimed at diseased tissue to kill cancer cells. But due to a phenomenon known as radiation-induced bystander effect (RIBE), in which ...

Definitive genomic study reveals alterations driving most medulloblastoma brain tumors

July 19, 2017
The most comprehensive analysis yet of medulloblastoma has identified genomic changes responsible for more than 75 percent of the brain tumors, including two new suspected cancer genes that were found exclusively in the least ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.