Graphene shown to neutralize cancer stem cells

Elite materials like graphene usually aren’t just lone success stories. Generally, the whole family of related materials — oxides, nitrides, or other derivatives — are all sought after for unique applications. As it typically happens, folks first imagine using a promising new material to store bits or energy, but then settle for trying to make better battery terminals. Eventually someone gets bold enough to want to stick it in your brain, either by crafting fine electrodes or synthesizing molecular scale vehicles for drug delivery. Ultimately, if it’s really good, they just grind it up raw and sprinkle it on cancer cells in the hope it will be the magic bullet that spares the good and conquers the evil.

Graphene oxide has now reached the pinnacle of any material’s evolution, successfully proving itself in the lab against six kinds of cancer cells. Researchers from the University of Manchester have found that flaked graphene oxide preferentially hits these cancers where it hurts most, right in the stem cells. These are the guys that not only are often responsible for starting the tumor, but they also tend to stick around after the radiation, chemotherapy, and surgery to reseed a tumor just when it looks like it was defeated.

Researchers at University of Manchester previously won the Nobel Prize for their groundbreaking work on graphene. They are kind of like the Rice University of graphene. Rice was where the late Richard Smalley won his prize for C60 fullerenes and carbon nanotubes, and where new applications are still similarly developed for that class of materials. Graphene oxide is technically less of a traditional oxide structure and more of what is called an epoxide. Epoxide groups are oxygen atoms that bond to and bridge two different groups, much like we might imagine happens in epoxies. The actual structure of graphene oxide varies significantly and depends on how it was synthesized, but generally, the interlayer spacing is much greater.

Exactly what this all means for killing the worst of the worst remains to be seen. The authors report that the selective toxicity may be explained by various chemical effects as opposed to some kind of mechanical process (perhaps as we might imagine in the case of asbestos needles). In particular, they suggest that key signalling pathways only active in cancer stem cells are inhibited by the graphene oxide flakes. The genes they mention have names like WNT and Notch — esoteric gene names more typically bandied about when discussing the early development of the organism. It may be a bit of a stretch at this point to remove all doubt that these genes are the essential players involved. However, it is certainly possible to gain experimental evidence for theories along these lines in a cell culture setting like the researchers used.

Because this is ET, we are going to let you in on a special term that even professional oncologists have probably never even heard of. That word is anoikis, which is Greek for “the state of being without a home.” One characteristic of cancer stem cells is their ability to survive in new places they have never seen. Places without the familiar extracellular matrix environment that most other mortal cells require to maintain their footing, or to become invasive. In the cancer world, anoikis is the special form of molecular suicide that many cells choose for themselves when they are removed from their comfortable matrix and cultured in a suspension. Usually this a clean process where the cell digests its own contents and recycles them for use by another.

The ability of graphene oxide to target the cells that survive the harsh conditions of living in a free-floating tumor spheroid is what is so attractive here. The researchers imagine using it in some kind of a washing solution that is pumped into the cancer area after surgery to expunge any stem cell survivors. Expunging means destroying any vestige of hope that a particular cancer cell lineage may ever return to wage war on the body. Such lavages are now used in the OR, but generally they leave much to be desired. If the researchers successes in cultured cells hold in actual bodies then graphene oxide may graduate from being the curious material it is now to being an actual drug. At that point, anything may be possible for graphene medical applications.