Chemoresistance or the specific resistance acquired by cells to the action of certain chemicals commonly hinders the treatment of cancer. Existing ways to address this issue revolve around using competitive inhibitors, but have limited success. Now, a research team led by Assistant Professor Edward Chow of the Cancer Science Institute of Singapore (CSI) at the National University of Singapore has found that binding multiple molecules of a common leukaemia drug with nanodiamonds can neutralize chemoresistance.

The novel work, carried out in collaboration with Professor Dean Ho of the School of Dentistry at the University of California, Los Angeles (UCLA), was published in Nanomedicine: Nanotechnology, Biology and Medicine recently.

An artistic rendering of nanodiamonds delivery of Daunorubicin against chemoresistant cells. Image courtesy of the National University of Singapore

According to information from CSI, leukaemia makes up about 40 per cent of all childhood cancers in Singapore and throughout the world. While it is one of the most treatable forms of cancers with a cure rate of 70 per cent in childhood leukaemia, Singapore sees some 250 to 300 new patients every year.

Asst Prof Chow, who is also with the Department of Pharmacology at the Yong Loo Lin of Medicine at NUS, elaborated on the use of nanodiamonds, which are carbon-based particles of 2 to 8 nanometres in diameter. “(They) offer a promising combination of biocompatibility and the capability to enhance therapeutic efficacy. Furthermore, our initial safety tests both in vitro and in vivo indicate that they are well tolerated, which is a promising step towards continued translational development,” he said.

The researchers bound the surfaces of nanodiamonds to Daunorubicin, one of the most common drugs used to treat leukaemia, to make a hybrid nanodiamond-drug complex. When introduced to leukaemic cells, the nanodiamonds in the complex were able to carry the drug to the cancer cells without being pumped out. The tiny particles can be easily released without blocking up blood vessels or causing any side effects.

With this discovery, “nanodiamonds are promising therapeutic vehicles,” noted Prof Ho, who is also Co-Director of the Jane and Jerry Weintraub Center for Reconstructive Biotechnology at UCLA. “One of our current goals is to determine which drugs could be optimally delivered by the nanodiamonds towards specific disease models that would best benefit a patient in the future,” he added.

The researchers plan to further develop and ensure the safety evaluation of the nanodiamond systems, as well as work on the drug-delivery complexes in clinical settings.