#howmatters: ingredients for cancer drug delivery
Last week, Chobani Yogurt came out with a new ad campaign intended to promote its “all-natural” ingredients list. A series of witty messages revealed themselves each time a hungry yogurt eater popped the lid on one of their Chobani100 yogurt cups.
Example: “Nature got us to 100 calories, not scientists. #howmatters.”
Not surprisingly, scientists took issue with this portrayal. They successfully hijacked the hashtag and came out with an awesome Twitter campaign of their own, promoting the prettier, not-so-scary side of science:
There are lots of things in nature…actually all of the things…that are made out of chemicals but aren’t bad for you. Take spices. Here are a few scary chemical formulas and their prettier, less intimidating versions:
Capsaicin:
AKA, cayenne pepper:
Crocin:
AKA, saffron:
and curcumin:
AKA, a chemical contained in turmeric…
…and a powerful anti-cancer agent.
And this, folks, is where our story really begins. As early as the 7th century, A.D., traditional Chinese and Indian medicine was using turmeric (and by default, curcumin) as a treatment for various conditions including everything from the common cold to parasitic worms. Later, lab studies have confirmed that curcumin kills cancer cells grown outside the body. A few animal studies have shown similar results, but in those cases there’s been a bit of a problem: curcumin is acidic, meaning it spits out hydrogen atoms when it goes into solution. The internal environment of our bodies, on the other hand, is neutral, and that disconnect makes it very difficult to a) get the compound into the body in the first place, and b) once it’s in there, get it to where it needs to go: namely, the cancer cells.
New research from the lab run by professor Tom Webster, chair of the Department of Chemical Engineering at Northeastern, provides a handy solution to the curcumin conundrum: a nanoparticle delivery system that “opens like a flower” under acidic conditions, and then closes back up again under basic conditions.
The particle was developed by graduate student Run “Kanny” Chang, MS’14, and brings with it a couple of convenient advantages. First off, it’s able to encapsulate drug compounds like curcumin in such a way that makes them more compatible with the internal environment of our bodies (as described above). But, additionally, the surface of the particle can be decorated with all sorts of special targeting moieties that make it seek and destroy cancer cells specifically, bypassing healthy cells. Once a particle gloms onto a cancer cell, the cell engulfs it and welcomes it into its interior death chamber.
This is normal behavior: healthy cells do the same thing, it’s a process called “endocytosis” and it’s meant to take bad stuff out of the cellular environment and break it down into less toxic, biodegradable components. How does endocytosis go about doing that conversion? Easy, it creates a little pocket called a lysosome, inside of which is a highly acidic vestibule. And what happens to Chang’s nanoparticles in acidic environments? They open up like little flowers!
“Since the nanoparticles can encapsulate curcumin in their inner hydrophobic cores, they could deliver curcumin intracellularly and release drug in endosomes and lysosomes,” Chang said. “Therefore, compared to the free curcumin molecules, the anti-cancer ability of curcumin could be increased dramatically.”
In other words, when the cancer cell engulfs one of these nanoparticles and creates a lysosome around it, it’s simultaneously unleashing the very thing that will spell its demise!
How’s that for a natural ingredients list? Yeah, I thought so.