Medical

Cancer-killing nanoparticles sneak through defenses camouflaged in tumor cells

Cancer-killing nanoparticles s...
Researchers at Penn State have camouflaged drug-delivering nanoparticles by wrapping them inside cancer cells
Researchers at Penn State have camouflaged drug-delivering nanoparticles by wrapping them inside cancer cells
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A diagram of the Penn State team's new nanoparticles, carrying a high amount of a drug payload and wrapped in a protective layer of camouflage – cells from the cancer itself
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A diagram of the Penn State team's new nanoparticles, carrying a high amount of a drug payload and wrapped in a protective layer of camouflage – cells from the cancer itself
Researchers at Penn State have camouflaged drug-delivering nanoparticles by wrapping them inside cancer cells
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Researchers at Penn State have camouflaged drug-delivering nanoparticles by wrapping them inside cancer cells

Cancer has a few tricks up its sleeve to defend itself from the body's immune system, but a new therapy designed by researchers at Penn State has now turned one of those tactics against it. The team camouflaged a cancer-killing drug using cells from the tumor itself, allowing them to sneak medicine past the tumor's defenses like a nanoscale Trojan horse and deliver a killing blow from the inside.

Once it sets up shop somewhere in the body, cancer puts up "walls" of blood vessels that are hard to get drugs past, and at the same time disguises itself from the immune system using particles called extracellular vesicles. Drugs can also have trouble surviving the journey. Previous treatments have tried to overcome these hurdles by wrapping drugs in spider silk, attaching gold nanoparticles to white blood cells so they can hitchhike into tumors, or having antibody-coated nanoparticles latch onto tumors before alerting the immune system to attack.

For the new work, the Penn State scientists decided to turn cancer's craftiness against itself. First, they developed nanoparticles made of metal-organic frameworks (MOFs), which pack an extremely high surface area on the inside. That allows them to carry quite a high amount of a given payload – in this case, a natural toxin called gelonin.

A diagram of the Penn State team's new nanoparticles, carrying a high amount of a drug payload and wrapped in a protective layer of camouflage – cells from the cancer itself
A diagram of the Penn State team's new nanoparticles, carrying a high amount of a drug payload and wrapped in a protective layer of camouflage – cells from the cancer itself

Then comes the camouflage. The researchers harvested extracellular vesicles from the tumor, and used them to wrap up their nanoparticles. That has a two-pronged benefit: for one, it hides the nanoparticles from the immune system, which might mistake them for dangerous invaders and destroy them. Plus, it guides the particles to where the tumor is hiding, then fools the cancer into letting them through the gates.

Once inside the cancer cells, the nanoparticles begin to dissolve thanks to the higher acidity environment, releasing the gelonin to kill the cell.

"We designed a strategy to take advantage of the extracellular vesicles derived from tumor cells," says Siyang Zheng, senior author of the study. "We remove 99 percent of the contents of these extracellular vesicles and then use the membrane to wrap our metal-organic framework nanoparticles. If we can get our extracellular vesicles from the patient, through biopsy or surgery, then the nanoparticles will seek out the tumor through a process called homotypic targeting."

The team tested the technique in small animal models with promising results. And because MOFs can carry so much, fewer nanoparticles are needed, meaning there's little toxicity to healthy cells. The researchers say that the concept could also be applied to other drugs that need to avoid the attention of the immune system.

The research was published in the Journal of the American Chemical Society.

Source: Penn State University

2 comments
EZ
"The researchers say that the concept could also be applied to other drugs that need to avoid the attention of the immune system." Drugs and bugs--like Ebola, Anthrax or HIV? Sounds like a new James Bond move plot. Lets hope certain government agencies don't get ahold of it. Or people like George Soros.
JeffK
Any tool is dangerous in the wrong hands; eternal vigilance is the price of freedom. Having just lost our 31 year old daughter-in-law to a Glioblastoma, I am heartened by the many new modalities being developed to deliver killing blows to malignancies that New Atlas is reporting. There are many more families out there going through Hell, hoping and praying for better weapons to fight the scourge of cancer.