An image-enhancing tool which could lead to both earlier diagnosis and improvements in monitoring treatment of cancers has been developed by researchers at The University of Texas at Austin College of Engineering and the M.D. Anderson Cancer Center, Cancer Research reported in its May 1 issue.
Dr. Rebecca Richards-Kortum, the Robert M. and Prudie Leibrock Endowed Professor in Engineering at The University of Texas at Austin, and Dr. Konstantin Sokolov, a faculty member at the M.D. Anderson Cancer Center, guided the development of the new, improved contrast agent, a material which, when applied topically to a bio-material, greatly improves the sharpness and resolution obtained when that material is imaged by a camera or other optical device.
The innovative contrast agent couples nano-sized gold particles--about 1/10,000 the width of a hair--with proteins called "monoclonal antibodies." These antibodies seek out and bind with specific types of cancers, which have an overabundance of "epidermal growth factor receptor" (EGFR). Present in all cells to some degree, EGFR is overexpressed on the surface of cancerous and pre-cancerous cells.
"We can deliver the contrast agent to cells overexpressing EGFR throughout the epithelial layer of tissue, where 85 percent of all cancers originate," said Richards-Kortum, a world-renowned authority on medical applications of imaging technology.
Adding the gold nano-particles to the cancer-seeking antibodies gives them an extremely strong light reflectivity, allowing the cells to be imaged with unprecedented precision.
Although biomaterials employing gold-organic bonds have previously been used to improve imaging for non-living organic materials, Richards-Kortum's team is the first to adapt the technology to living tissue in near-real time. Their experiments use sophisticated microscope systems that image reflected red-wavelength light to provide detailed pictures of tissue microanatomy.
"Because of its high resolution," Richards-Kortum said, "the contrast agent we have developed will allow us to make precise, three-dimensional images of the molecular changes of cancer at the earliest possible stages of development. We'll be able to image changes in individual cells throughout a lesion, including whether abnormalities regress under treatment."
The process also has the powerful advantage of being non-invasive, she said.
"We can paint it on the tissue and it binds to the surface of tumor cells," Richards-Kortum said. "Then we can image the tissue to look at the changes associated with cancer. We think it will be quite useful, not only for early detection but to select an appropriate therapy and then determine whether the therapy is working."
The contrast agent may also eliminate the need for laborious thin-sectioning of tissue specimens.
The material has successfully been tested under three in vitro scenarios: tissue cultures, cell suspensions and cervical biopsies. Animal trials are underway.
Other University of Texas at Austin researchers involved in the study were biomedical engineering graduate students Jesse Aaron and Ina Pavlova. Drs. Michele Follen, Anais Malpica, physicians, and Dr. Reuben Lotan, professor of oncology research, composed the M.D. Anderson team. The work was supported by the National Science Foundation.
NOTE TO EDITORS: Photos of the UT Austin team are available at http://www.engr.utexas.edu/news/action_shots/pages/kortum.cfm
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