Tumour metastasis is blocked by nanodiamonds

Dr Rajiv Saxena and Dr Sushreesangita Behera from the Faculty of Life Sciences and Biotechnology, South Asian University, New Delhi and Dr Witty Tyagi, from the Molecular Oncology Laboratory, National Institute of Immunology, New Delhi, have investigated whether nanodiamonds could stop tumour metastasis.

Nanodiamonds, two to eight nanometre carbon nanoparticles, can be easily functionalised with numerous chemical groups, such as carboxylic groups or drugs. Prior research has demonstrated that actively dividing cells have an increased likelihood of absorbing nanodiamonds. Also, research has shown that epithelial cells treated with carboxylic nanodiamonds lose their ability to travel across cell permeable cellulose membranes.

Tumour metastasis is a process requiring cell migration. In the new study, to investigate the effect of nanodiamonds on cancerous cells, the scientists treated B16F10 melanoma cells with carboxylic nanodiamonds in culture. They then tested their ability to move across and invade polycarbonate membranes with eight-micrometre pores.

The team discovered that the nanodiamonds stopped melanoma cells migrating, whilst untreated tumour cells could pass through the membrane. Mice administered with B16F10 melanoma tumour cells and then treated with carboxylic nanodiamonds showed little to no metastasis of tumours. Contrastingly, tumours grew in the untreated mice and spread to new areas of the body. Also, the survival outcomes of the treated mice were considerably better than untreated mice.

From gene expression evidence, the authors hypothesised that the nanodiamonds may inhibit the breaking away of cancer cells from the primary tumour mass, and prevent subsequent steps of metastasis, like physical movement of cells and their ability to enter blood vessels.

In the future, nanodiamonds could be used as a therapeutic agent for cancer metastasis.

This study was published in PNAS Nexus.