A GOLD STAR FOR CANCER RESEARCH: NANOPARTICLES DEFEND NEW CANCER DRUGS

By: Kavita Chandra

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My father’s voice faltered as my family sat around the kitchen table. He was young for such a diagnosis. No one expected prostate cancer.

I was speechless. At first, time seemed to slow down while I tried to process the news. As a daughter, my heart was overwhelmed with sadness. As a scientist, my brain kicked into researcher mode. Though I knew very little about the state of cancer therapies at the time, my father’s diagnosis and its effect on my family led me and my research down a path toward new cancer therapeutics.

The normal method of treatment for most cancers is chemotherapy, essentially an indiscriminate carpet-bombing strategy. Chemotherapy works by damaging all cells, cancer and healthy alike, as they rapidly divide. This method is not only inefficient but ruins healthy parts of the body. I knew there had to be something better than launching a toxic assault on patients like my father.

I and other researchers in the field want to target and kill only cancer cells, minimizing the uncomfortable and dangerous side effects common to chemotherapy. Biological processes like how we digest food, fight off bacteria, and even breathe depend on what occurs on a microscopic scale. For better results, I believe we must bring the fight against cancer to this level.

Enter Gold Nanostars: star-shaped metallic particles so small that 2,000 laid end-to-end would be the width of a single human hair. If these stars were the size of a tennis ball a cancer cell would be the size of a football field. So how can these stars cause something so much larger to die? While gold nanostars may be tiny, we’re not deploying just one; scientists are deploying an army of millions, and they are loaded up with cancer-killing drugs.

The drugs we use are comprised of DNA. These DNA-drugs target the protein nucleolin on the cell surface and then penetrate within, annihilating the cancer cells. But DNA is fragile; it disintegrates in the blood. The DNA-drug needs a vehicle, like an armored car, to survive the journey. Gold nanostars provides stability and protection for the DNA-drugs during transit through the bloodstream.

These DNA-nanostar constructs are precision weaponry designed to exclusively target cancer cells. There is just one catch: in transit the nanostars must be securely attached to keep the DNA intact, but once they enter the cancer cell this bond must be broken. Once they’ve infiltrated the targeted cancer, we detach the DNA-drug from the nanostar by blasting them with light.

Light radiation heats up the nanostars, breaking the bonds. My specific research is to refine the size and shape of these nanostars, which changes how they interact with light. Optimized nanostars heat up very quickly and need very little light to detach. In our lab experiments, DNA-drugs separate almost instantaneously with one short sequence of a harmless amount of light. Once this happens the DNA drugs perform their final task: killing cancer cells.

While my nanostar army might seem like a golden opportunity, there are thousands of researchers working on targeted, nano-scale therapies across the globe. There are seven FDA-approved nanoparticle cancer therapies in the US right now, with many more in the pipeline. In the not-too-distant future patients could have shorter courses of less-intensive treatments to combat cancer on a cellular level.

Although this technology was too nascent for my father, his personal war against cancer ended happily. But I believe the current standard of care is too toxic. Harmful chemotherapy is still the basis of treatment, regardless of cancer type, and I, along with many other researchers, want to build a different future. Together we can imagine beating cancer without chemotherapy.

This article began as a class assignment for Skills & Careers in Science Writing, a graduate-level science writing course focusing on building compelling narratives and employing storytelling techniques to illuminate contemporary research. The course is a partnership between Science in Society and the Medill School of Journalism, Media, and Integrated Marketing Communications at Northwestern University.