UCLA researchers have developed an innovative technique that can carry chemotherapy medication safely and release it inside cancer cells. As a result, the toxic chemotherapeutic agent does not harm normal cells on its way to its target: a cancer cell. The researchers published their findings on February 20 in the Journal of Polymer Science: Polymer Physics.
Researchers from the cancer nanotechnology and signal transduction and therapeutics programs of UCLA’s Jonsson Comprehensive Cancer Center (JCCC) note that after the chemotherapy medication enters the cancer cell it is triggered by two-photon laser in the infrared red wave length. The investigators note that a light-activated drug delivery system has significant promised because it can control when and where a drug is released. They explain that determining methods to deliver and release anticancer medication in a controlled manner, which only affects the malignant cells can markedly reduce the amount of side-effects from treatment; in addition. It significantly increases the drug’s effectiveness for destroying cancer cells. They not that a major obstacle in treating cancer is due to the difficulty in getting chemotherapeutic agents directly to the cancer cells without damaging healthy tissue. The side-effects that cancer patients experience during chemotherapy is the result of drug exposure to healthy tissues.
The major obstacle that the researchers faced with their development of a light-activated drug delivery was penetration of tissue by the light. Therefore, the researchers collaborated with Dr. Jean-Olivier Durand at University of Montpellier, France to develop a new type of nanoparticle (microscopic particle) that can absorb energy from tissue-penetrating light that releases drugs in cancer cells. The nanoparticles they developed are equipped with specially-designed nanovalves, which can control release of anticancer drugs from thousands of pores (tiny tubes), which contain molecules of chemotherapy drugs. Both ends of the pores are sealed with capping molecules; thus, the drug molecules are sealed inside the pores. The nanovalves contain molecules that respond to the energy from two-photon light exposure; thus, the light opens the pores and releases the chemotherapy drugs. The researchers demonstrated the opening of the nanovalves in the laboratory with human breast cancer cells.
The effective depth range of the two-photon laser in the infrared red wavelength is 4 centimeters (about 1.5 inch) from the skin surface; therefore, the delivery system is best suited for tumors that can be reached within that range; this range may include breast, ovarian, stomach, and colon cancers. Another characteristic of the nanoparticles is that they are fluorescent; thus, molecular imaging techniques can track them in the body. This allows the investigators to track the progress of the nanoparticle into the cancer cell to insure that it is in its target before light activation. This tracking ability has been termed “theranostics”.
“We have a wonderful collaboration,” explained study author Drs. Jeffrey Zink, UCLA professor of chemistry and biochemistry said Zink. He added, “When the JCCC brings together totally diverse fields, in this case a physical chemist and a cell signaling scientist, we can do things that neither one could do alone.” Author Dr. Fuyu Tamanoi, UCLA professor of microbiology, immunology and molecular genetics, added, “Our collaboration with scientists at Charles Gerhardt Institute was important to the success of this two-photon activated technique, which provides controls over drug delivery to allow local treatment that dramatically reduces side effects.”