09
February
2015
|
20:04
Asia/Singapore

Nanodiamonds target chemoresistant cancer

Asst Prof Chow (right) and graduate student Wang Xin preparing a solution using nanodiamonds

Researchers from the Cancer Science Institute of Singapore (CSI Singapore) and Department of Pharmacology at NUS, and the School of Dentistry at the University of California, Los Angeles (UCLA) have demonstrated the promising use of nanodiamonds in delivering cancer drugs to kill chemoresistant liver cancer stem cells more effectively and safely.

Led by Assistant Professor Edward Chow, Junior Principal Investigator at CSI Singapore, the research team consisted of graduate students Wang Xin and Masturah Mohd Abdul Rashid, undergraduate student Casuarine Low Xinyi, Dr Hou Weixin, Dr Toh Tan Boon and Ms Lissa Nurrul Abdullah from CSI Singapore and Department of Pharmacology, as well as Professor Dean Ho from UCLA School of Dentistry, who also serves as Co-Director of The Jane and Jerry Weintraub Center for Reconstructive Biotechnology. The findings were first published online in ACS Nano, the official journal of the American Chemistry Society, in December 2014.

Chemoresistance is a primary cause of treatment failure in cancer, resulting in treatment failure in 90 per cent of metastatic cancers. It is also a common property of tumour-initiating cancer stem cells. In the study, the research team attached Epirubicin, a common chemotherapy drug, onto nanodiamonds'microscopic carbon particles with a structure resembling conventional diamonds'to create a nanodiamond-Epirubicin drug delivery complex (EPND). Unlike standalone Epirubicin, the EPNDs are able to destroy chemoresistant cancer stem cells and prevent the formation of secondary tumours.

Asst Prof Chow explained: "The gaps between the blood vessels and tumour are larger than the gaps between the blood vessels in normal tissue. As nanoparticles are larger than the gaps in healthy tissue, they will preferentially home into the tumour. With EPND's avoidance of healthy cells, a normally lethal quantity of Epirubicin is converted to a safe and effective drug reservoir when packaged with nanodiamonds. Thus, the nano delivery platform presents a viable alternative for patients who are unable to withstand the toxic side effects of standard chemotherapy drugs.

Nanodiamonds can be loaded with an array of compounds, from drugs and targeting components to imaging agents, to treat a broad range of cancers. Furthermore, the good retention rate of EPND in tumour cells enables more effective killing of the malignant cells. Being carbon-based, nanodiamonds are highly biocompatible and safe for living tissues. "Everything we've done, every experiment we've run to evaluate their toxicity has shown that they're very well-tolerated and safe, shared Asst Prof Chow. As they tend not to form larger macrostructures due to their shape, the nanoparticles do not clog up biological systems.

The NUS team is collaborating with Prof Ho and Professor Li Jianzhong at Peking University to conduct preclinical trials on anthracycline delivery with nanodiamonds using rodents and large animal models. The investigators plan to begin clinical trials for humans in two years' time.