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Drug-carrying nanoparticles to fight cancer cells

Inside the particles is the drug niclosamide, a drug that is usually taken to treat infections, but in the field of fighting cancer stem cells it succeeds in blocking pathways of gene expression that give cells their special properties

Nanoparticles capable of targeted delivery of drugs to cancer stem cells (yellow), those rare cells within the tumor (blue) that allow the tumor to return or spread. [Courtesy: Dipanjan Pan]
Nanoparticles capable of targeted delivery of drugs to cancer stem cells (yellow), those rare cells within the tumor (blue) that allow the tumor to return or spread. [Courtesy: Dipanjan Pan]

[Translation by Dr. Nachmani Moshe]
Researchers have been able to send tiny nanoparticles loaded with the drug to the task of locating and eliminating cancer stem cells, those rare and elusive cells that can cause another outbreak of cancer, even many years after the first outbreak. Inside the particles is the drug niclosamide, a drug that is usually taken to treat infections, but in the field of fighting cancer stem cells, it succeeds in blocking pathways of gene expression that give cells their special properties.

In a study conducted by Dipanjan Pan, a professor of bioengineering at the University of Illinois, scientists were able to design nanoparticles that specifically bind to a protein found on the surface of stem cells that cause breast cancer. Inside the particles is the drug niclosamide, a drug that is usually taken to treat infections, but in the field of fighting cancer stem cells it succeeds in blocking pathways of gene expression that give the cells their special properties that allow them to thrive and spread.

"It is extremely important to provide treatments for existing tumors; At the same time, it is equally important to encourage long-term survival and prevention of the recurrence of cancer," explains the lead researcher. "We are interested in destroying the cells that are hidden inside the tissue and that cause the cancer to break out again or spread to other parts of the body." Cancer stem cells make up a small part of tumor cells, but only one or two cells are needed for a new tumor to grow, explains the researcher. The challenge for doctors and researchers is not only in finding these cells, but also in treating them.

The research group created nanoparticles that bind purposefully and selectively to a protein called CD44, which appears only on the outer surface of cancer stem cells, and tested their activity against breast cancer tumors in cell cultures and live mice. "I call them GPS-targeted nanoparticles because they seek out only those cells that have the properties of cancer stem cells. In the next step, they bind to these cells and release the drug," explains the researcher. "To our knowledge, this is the first ever demonstration of nanoparticles targeting a drug to cancer stem cells."

The researchers used their nanoparticles to deliver niclosamide, a drug that is on the World Health Organization's list of essential drugs, a list that lists the safest and most effective drugs in the world. In an earlier study, the same researchers discovered that the substance niclosamide reacts within a defined pathway of gene expression within cancer stem cells.

In the new study, published long ago in the scientific journal Molecular Cancer Therapeutics, the cancer stem cells lost their unique properties after treatment with these nanoparticles, a result that prevents them from reappearing or forming new metastases. The researchers also demonstrated a significant reduction in the overall proliferation of the cancer cells, both in the cell cultures and in the mice themselves.

By using a drug whose effectiveness has already been proven in the past and nanoparticles that are simple to manufacture, the lead researcher hopes that this system can become an accessible and inexpensive treatment to prevent the recurrence of cancerous tumors in patients. "We deliberately used an extremely cheap drug - it is a generic drug and we are able to synthesize it in large quantities," explains the researcher. "We are also able to produce the nanoparticles on a large scale - these are specially defined and differentiated polymers, so we know exactly which system we have in hand. The rest of the process is simply independent steps that progress normally."

"Our research is also important for researchers who will work in the future in the field of cancer stem cells," says one of the researchers. "We described and were able to confirm the proteins and genes responsible for vital processes in these cells, and our findings are a starting point for the development of more effective medical treatments." The researchers are currently looking at ways to develop combined treatments that will be able to deliver drugs against the main cancer cells, such as standard chemotherapy drugs, and together with them unique substances directed against the cancer stem cells. In addition, the researchers are testing the drug delivery system based on nanoparticles in larger laboratory animal models, with the aim of advancing the method even closer to clinical trials in humans.

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The news about the study

Nanoparticles capable of targeted delivery of drugs to cancer stem cells (yellow), those rare cells within the tumor (blue) that allow the tumor to return or spread. [Courtesy: Dipanjan Pan]

One response

  1. It's been three years since then and we still don't see any change. I'd love to hear details if there are any

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