10:15am Tuesday 10 December 2019

‘Smart bomb’ developed to target childhood leukemia

Cristy Lytalby Cristy Lytal 

Fatih Uckun Scientist Fatih Uckun at a 2013 retreat (Photo/Cristy Lytal)

Fatih Uckun, Jianjun Cheng and their colleagues have taken the first steps toward developing a so-called “smart bomb” to attack the most common and deadly form of childhood cancer called B-lineage acute lymphoblastic leukemia.

In a study in the new peer-reviewed, open-access journal EBioMedicine, the researchers describe how this approach could eventually prove lifesaving for children who have relapsed after initial chemotherapy and face a less than 20 percent chance of long-term survival.

We knew that we could kill chemotherapy-resistant leukemia cells if we only knew what made them so resistant.

Fatih Uckun

“We knew that we could kill chemotherapy-resistant leukemia cells if we only knew what made them so resistant. Once we determined the mechanism, the next step was obvious — to rationally design a drug that would take out that specific target,” said Uckun, professor of research pediatrics at the Keck School of Medicine of USC and head of translational research in leukemia lymphoma at the Children’s Center for Cancer and Blood Diseases of Children’s Hospital Los Angeles.

Resisting chemotherapy

The target of the smart bomb is a defective gene that results in the production of an abnormal form of the protein CD22, which causes cancer stem cells to proliferate and resist chemotherapy. This defective gene can thwart standard treatments for recurrent disease — including “supralethal” chemotherapy, total-body irradiation and bone marrow transplantation.

Uckun’s team designed synthetic pieces of genetic material, called RNAi, with the capability to shut down this defective gene. Then Uckun joined forces with Cheng, associate professor of materials science and engineering at the University of Illinois at Urbana-Champaign and an affiliate with the NCI Alliance for Nanotechnology in Cancer. Cheng’s team engineered a small subunit of protein, called a polypeptide, to function as delivery system to send the RNAi to its target.

The resulting smart bomb has a diameter of only 100 nanometers, making it one of the new generation of nanomedicines that can target disease at a molecular level.

“The goal is to translate our recent research discoveries in nanotechnology and biotherapy into effective patient-tailored treatment programs for the most common form of childhood cancer,” said Uckun, a principal investigator with the university-wide USC Stem Cell initiative, which brings together more than 100 faculty members from all disciplines.

Uckun and his team were supported by funding from USC Stem Cell’s Regenerative Medicine Initiative, a university-wide program kick-started by $1.2 million in funding from Carmen A. Puliafito, dean of the Keck School of Medicine of USC. The award facilitates collaborative interactions among the USC-based regenerative medicine community.

Additional funding came from the U.S. Department of Health and Human Services (grant numbers P30CA014089, U01-CA-151837 and R01CA-154471) from the National Cancer Institute and the Director’s New Innovator Award (grant number 1DP2OD007246-01) from the National Institutes of Health. The Nautica Triathlon and its producer, Michael Epstein, Couples Against Leukemia Foundation and Saban Research Institute Merit Awards also supported the research.


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