Scientists at the University of Manchester say they have used graphene to target and neutralize cancer stem cells while not harming other cells. This new development opens up the possibility of preventing or treating a broad range of cancers, using a non-toxic material, according to the researchers.
In a study (“Graphene oxide selectively targets cancer stem cells, across multiple tumor types: Implications for non-toxic cancer treatment, via differentiation-based nano-therapy”) in Oncotarget, the team led by Professor Michael Lisanti, M.D., Ph.D., and Aravind Vijayaraghavan, Ph.D., reported that graphene oxide, a modified form of graphene, acts as an anticancer agent that selectively targets cancer stem cells (CSCs). In combination with existing treatments, this could eventually lead to tumor shrinkage as well as prevent the spread of cancer and its recurrence after treatment, noted Dr. Lisanti. However, more preclinical studies and extensive clinical trials will be necessary to move this forward into the clinic to ensure patient benefit.
“Cancer stem cells possess the ability to give rise to many different tumour cell types,” explained Dr. Lisanti, director of the Manchester Center for Cellular Metabolism within the university’s Institute of Cancer Sciences. “They are responsible for the spread of cancer within the body, which is responsible for 90% of cancer deaths. They also play a crucial role in the recurrence of tumors after treatment. This is because conventional radiation and chemotherapies only kill the 'bulk' cancer cells, but do not generally affect the CSCs.”
“Graphene oxide is stable in water and has shown potential in biomedical applications,” added Dr. Vijayaraghavan. It can readily enter or attach to the surface of cells, making it a candidate for targeted drug delivery. In this work, surprisingly, it's the graphene oxide itself that has been shown to be an effective anticancer drug.
“Cancer stem cells differentiate to form a small mass of cells known as a tumour-sphere,” continued Dr. Vijayaraghavan. “We saw that the graphene oxide flakes prevented CSCs from forming these, and instead forced them to differentiate into non-cancer stem cells.
“Naturally, any new discovery such as this needs to undergo extensive study and trials before emerging as a therapeutic. We hope that these exciting results in laboratory cell cultures can translate into an equally effective real-life option for cancer therapy.”
The team prepared a variety of graphene oxide formulations for testing against six different cancer types (breast, pancreatic, lung, brain, ovarian, and prostate). The flakes inhibited the formation of tumor sphere formation in all six types, suggesting that graphene oxide can be effective across all, or at least a large number of different cancers, by blocking processes which take place at the surface of the cells.
“Mechanistically, we present evidence that GO exerts its striking effects on CSCs by inhibiting several key signal transduction pathways (WNT, Notch and STAT-signaling) and thereby inducing CSC differentiation,” wrote the investigators. “Thus, graphene oxide may be an effective non-toxic therapeutic strategy for the eradication of cancer stem cells, via differentiation-based nano-therapy.”
The researchers suggest that, used in combination with conventional cancer treatments, this approach may deliver a better overall clinical outcome.