Glioblastoma is the deadliest form of brain cancer, with a five-year survival rate below 5%. One of the biggest obstacles is the brain's own defense system: the blood-brain barrier, which blocks most drugs from reaching tumors.

Researchers at Oregon State University believe they may have found a way to overcome both the barrier and the tumor-targeting challenge at once. Oleh Taratula, Olena Taratula, and Yoon Tae Goo of the OSU College of Pharmacy developed lipid nanoparticles — tiny fat-based carriers — loaded with genetic material and engineered to slip through the blood-brain barrier and preferentially target glioblastoma cells.

In a study published in the Journal of Controlled Release, the team tested the approach in mice. The sugar-coated nanoparticles successfully delivered a tumor-suppressing therapy across the blood-brain barrier, increasing median survival by 50% compared with untreated animals.

Sugar coating helps entry

The key sugar was mannose, closely related to glucose. Cells lining blood vessels in the brain contain a transporter called GLUT1 that normally moves glucose into the central nervous system — but it can recognize mannose too.

The challenge was that glucose is already abundant in the blood. The researchers solved this by packing the nanoparticle surface densely with mannose.

'Blood contains relatively high concentrations of glucose, and that's what the nanoparticles are competing against for GLUT1's attention,' explained Oleh Taratula. 'For the nanoparticles to get it, they need a densely coated sugar surface, and that's our central innovation. By chemically connecting mannose to cholesterol, a major structural component of the nanoparticles, we improved surface coverage sixfold.'

Tumor cells become targets

Once inside the brain, the nanoparticles took advantage of another property of glioblastoma: its cells express GLUT1 at three times the levels of normal brain tissue. This meant the particles preferentially accumulated in tumor tissue.

The cargo inside the nanoparticles was messenger RNA (mRNA) directing cells to produce PTEN, a tumor-suppressing protein often lost in glioblastoma. Restoring PTEN helps reestablish control over cell growth.

'Glioblastoma is metabolically reprogrammed and expresses GLUT1 at three times the levels of normal brain tissue, so the particles preferentially accumulate in tumor tissue after crossing the blood-brain barrier,' said Olena Taratula. 'Across repeated dosing, tumor shrinkage occurred without any measurable organ toxicity.'

Glioblastoma remains difficult

The findings are preclinical, meaning they come from animal research rather than human trials. Many promising cancer therapies in mice do not ultimately work the same way in people. Still, the work targets two major barriers that have long limited glioblastoma treatment: reaching the brain and concentrating therapy inside the tumor.

In the United States, glioblastoma occurs at a rate of 3.19 cases per 100,000 people. The median age at diagnosis is 64, and more than 95% of patients live less than five years after diagnosis. The research was supported by the National Cancer Institute and the Eunice Kennedy Shriver National Institute of Child Health and Human Development.

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