Researchers from the cancer nanotechnology and signal transduction and therapeutics projects of UCLA’s Jonsson Comprehensive Cancer Center (JCCC) in the US have developed a technique that uses light to carry chemotherapy safely to cancer cells.
Jeffrey Zink, Professor of chemistry and biochemistry, and Fuyu Tamanoi, Professor of microbiology, immunology and molecular genetics, and colleagues have published their findings in the journal Small.
A light-activated drug delivery system is said to be particularly promising, because it can accomplish spatial and temporal control of drug release. Finding ways to deliver and release anticancer drugs in a controlled manner that only hits the tumour can reduce the side-effects from treatment, and also increase the cancer-killing effectiveness of the drugs. The difficulty of treating cancer often comes from trying to get anticancer chemotherapy drugs to tumour cells without damaging healthy tissue in the process. Many cancer patients experience side-effects that are the result of drug exposure to healthy tissues.
A major challenge in the development of light-activated drug delivery is to design a system that can respond to tissue-penetrating light. Tamanoi and Zink joined their teams and collaborated with Jean-Olivier Durand at the University of Montpellier, France to develop new nanoparticles that can absorb energy from tissue-penetrating light that releases drugs in cancer cells.
These nanoparticles are equipped with specially designed nanovalves that can control release of anticancer drugs from thousands of pores
These nanoparticles are equipped with specially designed nanovalves that can control release of anticancer drugs from thousands of pores, or tiny tubes, which hold molecules of chemotherapy drugs. The ends of the pores are blocked with capping molecules that hold the drug in like a cork in a bottle. The nanovalves contain special molecules that respond to the energy from two-photon light exposure, which opens the pores and releases the anticancer drugs. The operation of the nanoparticles was demonstrated in the laboratory using human breast cancer cells.
Dr Fuyu Tamanoi
Because the effective depth range of the two-photon laser in the infrared red wavelength can reach four centimetres from the skin surface, this delivery system is best for tumours that can be reached within that range, which possibly include breast, stomach, colon, and ovarian cancers.
Another feature of the nanoparticles is that they are fluorescent and thus can be tracked in the body with molecular imaging techniques. This ability to track a therapy to its target is called 'theranostics' in scientific literature.
'We have a wonderful collaboration,' said Zink. 'When the JCCC brings together totally diverse fields, in this case a physical chemist and a cell signalling scientist, we can do things that neither could do alone.'
'Our collaboration with scientists at Charles Gerhardt Institute was important to the success of this two-photon activated technique,' said Tamanoi. 'It provides controls over drug delivery to allow local treatment that dramatically reduces side effects.'
