We combine active targeting, fluorescent imaging, and subsequent photothermal treatment of malignant cells as a viable approach for the treatment of a variety of cancer types that over-express the epidermal growth factor including head and neck, colorectal, ovarian, cervical, breast, bladder, pancreatic, and prostate cancers. In our photothermal therapy experiments, the use of a near infrared (NIR) laser enables us to take advantage of both the plasmon resonance absorption peak of gold nanorods (GNR), ∼785 nm with aspect ratio of ∼ 4, as well as the absorption peak of the fluorescent dye, ∼774 nm. We used a 785 nm NIR laser with fluence of ∼9.5 W/cm2 and a 4 minute exposure time. Anti- epidermal growth factor receptor (EGFR) antibody, which targets the epidermal growth factor receptor over-expressed on malignant head and neck cancer cells, was labeled with a fluorescent dye and conjugated to GNR. We have studied the conjugation parameters for GNR and anti-EGFR antibodies and used nearest neighbor approximations to analyze the nanorod-to-antibody ratio from transmission electron microscope images. The optimal conjugation of dye:antibody:GNR facilitates active targeting of the nanorods to the tumor site. This active targeting is more efficient than previously reported results that rely solely on the enhanced permeability and retention effect. We demonstrate that PEGylating the GNR before conjugation to antibodies improves the quality of the conjugation. We also show that binding ability of the conjugated antibody to the epidermal growth factor receptor has not been affected. In addition, cell death by NIR photothermal therapy and gold nanorods is not compromised following conjugation of gold nanorods to a fluorescently labeled antibody. NIR photothermal treatment with the dye-antibody-nanorod conjugate selectively heated the GNR, excited fluorescence, and was sufficient to kill nearly 90% of tumor cells comparable to photothermal therapy with the GNR alone.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 1972. doi:1538-7445.AM2012-1972

©2012 American Association for Cancer Research
2012