Navigation Links
New drug strategy attacks resistant leukemia and lymphoma

BOSTON--Scientists at the Dana-Farber/Children's Hospital Cancer Center have developed an anti-cancer peptide that overcomes the stubborn resistance to chemotherapy and radiation often encountered in certain blood cancers when the disease recurs following initial treatment.

The strategy could pave the way for much needed new therapies to treat relapsed and refractory blood cancers, which are difficult to cure because their cells deploy strong protein "deflector shields" to neutralize the cell death signals that chemotherapy agents used against them initially, say the researchers.

The prototype compound, called a "stapled BIM BH3 peptide," is designed to disable the cancer's defenses by hitting a family of protein targets that regulate cell death.

In proof-of-concept studies in mice with transplanted, drug-resistant leukemia tumors, the compound alone suppressed cancer growth, and when paired with other drugs, showed synergistic anti-cancer activity, say researchers led by Loren Walensky, MD, PhD, of Dana-Farber/Children's Hospital Cancer Center.

Their paper has been posted online by the Journal of Clinical Investigation and will appear in the journal's June issue. Walensky is the senior author and James LaBelle, MD, PhD, is the first author.

A cell's "fate" when and whether it lives or dies depends on a tug-of-war between pro-death and anti-death forces within the cell that serve as a check-and-balance system to maintain orderly growth. The system is regulated by the BCL-2 family of proteins, which contains both pro-death and pro-survival members.

When cells are no longer needed or are damaged beyond repair, the body activates pro-death BCL-2 proteins to shut down mitochondria the power plants of the cell resulting in an orchestrated cellular destruction known as apoptosis, or programmed cell death.

Many cell-killing cancer treatments work by triggering these "executioner proteins" to cause tumor cells to commit suicide in this fashion. But cancer cells can escape their death sentence and even become immortal by hyperactivating the survival arm of the family; these proteins intercept the executioner proteins and block their lethal mission.

"When cancers recur, they activate not just one type of survival protein, but many," explains Walensky, whose laboratory has extensively studied the cell-death system and makes compounds to manipulate it for research and therapeutic purposes.

"It's as if relapsed cancers 'learned' from their initial exposure to chemotherapy such that when they come back, they put up a variety of formidable barriers to apoptosis," he adds. "To reactivate cell death in refractory hematologic cancers, we need new pharmacologic strategies that broadly target these obstacles and substantially lower the apoptotic threshold."

When cancers specifically rely on one or two survival proteins, treating them with selective BCL-2 inhibitors can be very effective at eliminating the cancer cells' survival advantage. But relapsed cancers often evade such agents by deploying a battery of alternate survival proteins, so what's needed, Walensky says, are "next-generation" compounds that can block a wider range of survival proteins without jeopardizing normal tissues.

In the current research, the scientists built a chemically-reinforced peptide containing the death-activating BH3 domain of an especially potent killer protein, BIM, which is able to tightly bind with and neutralize all of the BCL-2 family survival proteins. This 'stapled' peptide, which incorporates the natural structure and properties of BIM BH3, not only disables the survival proteins, but also directly activates pro-death BCL-2 family proteins in cancer cells, making them self-destruct. Importantly, non-cancerous cells and tissues were relatively unaffected by the treatment.

"The diversity of BCL-2 family survival proteins blunts the anti-tumor activity of essentially all cancer treatments to some degree," Walensky points out. "By using Nature's solution to broad targeting of the BCL-2 pathway with a stapled BIM BH3 peptide, our goal is to eliminate cancer's protective force field and enable the arsenal of cancer treatments to do their job."


Contact: Bill Schaller
Dana-Farber Cancer Institute

Related medicine news :

1. Strategy discovered to activate genes that suppress tumors and inhibit cancer
2. Discovery suggests new combination therapy strategy for basal-like breast cancers
3. White House Drug Policy Shifts Strategy
4. Scripps research scientists illuminate cancer cells survival strategy
5. Scientists report first step in strategy for cell replacement therapy in Parkinsons disease
6. Novel strategy stymies SARS et al.
7. UCSF tapped for US National AIDS Strategy initiative
8. Federal government releases environmental, health, and safety research strategy for nanotechnology
9. Miriam Hospital researchers pilot new acute hepatitis C screening strategy for HIV-infected patients
10. Strategy for improving health care for uninsured, low-income, and minorities in the US
11. New strategy likely to speed drug development for rare cancers
Post Your Comments:
Related Image:
New drug strategy attacks resistant leukemia and lymphoma
(Date:6/27/2016)... ... June 27, 2016 , ... A revolution is underway. ... transport experience for the millions of people who require these medical transport services ... industry through the use of technology. Now, SmartEMS has put forth an industry-changing ...
(Date:6/26/2016)... , ... June 26, 2016 , ... Pixel Film Studios ... X. , "Film editors can give their videos a whole new perspective by using ... - CEO of Pixel Film Studios. , ProSlice Levels contains over 30 Different ...
(Date:6/25/2016)... , ... June 25, 2016 , ... ... policy issues and applications at AcademyHealth’s Annual Research Meeting June 26-28, 2016, at ... on several important health care topics including advance care planning, healthcare costs and ...
(Date:6/25/2016)... (PRWEB) , ... June 25, 2016 , ... First ... United States, named Dr. Sesan Ogunleye, as the Medical Director of its new Mesquite-Samuell ... facility Medical Director of our new Mesquite location,” said Dr. James M. Muzzarelli, Executive ...
(Date:6/25/2016)... Canada (PRWEB) , ... June 25, 2016 , ... Conventional ... pursuit of success. In terms of the latter, setting the bar too high can ... risk more than just slow progress toward their goal. , Research from ...
Breaking Medicine News(10 mins):
(Date:6/24/2016)... Research and Markets has announced the addition of ... report to their offering. ... The World Market for Companion Diagnostics covers the world market ... the report includes the following: , World ... Region (N. America, EU, ROW), 2015-2020 , World IVD ...
(Date:6/24/2016)...   Pulmatrix, Inc ., (NASDAQ: PULM ... announced today that it was added to the Russell ... comprehensive set of U.S. and global equity indexes on ... milestone for Pulmatrix," said Chief Executive Officer Robert ... progress in developing drugs for crucial unmet medical needs, ...
(Date:6/24/2016)...  Arkis BioSciences, a leading innovator in the ... cerebrospinal fluid treatments, today announced it has secured ... led by Innova Memphis, followed by Angel Capital ... Arkis, new financing will accelerate the commercialization of ... of its in-licensed Endexo® technology. ...
Breaking Medicine Technology: