But scientists say it may be possible to kill those stem cells by attaching a chemo drug to nanodiamonds.
They tested this idea using the commonly used chemo drug Epirubicin, which they attached to nanodiamonds, carbon structures with a diameter of about five nanometers, to develop a nanodiamond-Epirubicin drug delivery complex (EPND).
The researchers found that while both standard Epirubicin as well as EPND were capable of killing normal cancer cells, only EPND was capable of killing chemoresistant cancer stem cells and preventing secondary tumor formation in xenograft models of liver cancer.
The study was published in ACS Nano and led by Edward Chow, assistant professor at the National University of Singapore.
Compared to other approaches, delivery of existing chemotherapy drugs with nanomaterials provide a broader range of protection in a package that is both safer and more effective.
The findings show that delivery of Epirubicin by nanodiamonds resulted in a normally lethal dosage of Epirubicin becoming a safe and effective dosage.
As such, delivery of chemotherapy drugs by nanodiamonds not only enables enhanced killing of chemoresistant cancer stem cells, but may be a useful alternative for patients who cannot tolerate the toxic side effects of standard chemotherapy drugs.
Researchers say this approach is not limited to liver cancer and could potentially treat other cancers driven by resistant stem cells.
Source: National University of Singapore