June 11 (UPI) -- A cancer drug already approved by the Food and Drug Administration has shown potential for treating aggressive liver cancer in children, according to a study on human tumor cells.
Scientists at Cincinnati Children's Hospital Medical Center found that the drug Olaparib helps block a protein in the cell nucleus, called PARP1. Their findings were published Monday in the Nature journal Communications Biology.
In tests on 51 hepatoblastoma tumor samples, researchers found found highly elevated levels of the protein.
"Our findings provide a strong rationale for testing PARP1 inhibitors to treat aggressive pediatric liver cancer, but additional research is needed before we can verify this and recommend that it be tried in patients," Dr. Nikolai Timchenko, head of the Liver Tumor Biology, Liver Tumor Program at the medical center, said in a press release. "This includes testing inhibitors in laboratory mouse models of hepatoblastoma to see if they work in a living organism."
Timchenko noted that findings in laboratory models often are not effective in the clinical treatment of patients.
Hepatoblastoma is a rare malignant tumor that primarily develops in young children, accounting for approximately 1 percent of all cancers under the age of 15, according to a report in the National Institutes of Health.
Children exposed to hepatitis B or hepatitis C infection at an early age, or those who have biliary atresia, face an increased risk for developing the cancer, according to Stanford Children's Hospital.
"While overall survival for children with HBL has improved over the years through cisplatin-based chemotherapy and subsequent resection, a substantial number of patients experience metastasis or are faced with aggressive tumors that are unresectable and do not respond favorably to chemotherapy," the Cincinnati researchers wrote.
Timchenko said PARP1, which modifies chromatin structure in the cell nucleus, drives the chemotherapy-resistant form of liver cancer.
The researchers learned that PARP1 binds to DNA regions within many cancer-related genes and activates their expression in hepatoblastoma to drive the disease.
But when the drug blocked PARP1 in the tumor cells, the cancer progress slowed or stopped.
HCC is the most common type of primary liver cancer, accounting for 75 percent to 90 of all liver cancer cases, according to the Mayo Clinic. It occurs often in people with chronic liver diseases, including cirrhosis caused by hepatitis B or hepatitis C infection.