Near Infrared Molecular Imaging of Breast Cancer Cell Lines Using a Novel ER Targeted Fluorescent Dye

Abstract Hormone-targeted contrast agents bind with functional groups associated with the physiology of breast cancer leading to improved prognosis. We have synthesized a novel estrogen receptor (ER) targeted near-infrared fluorescent dye referred to as Novel Dye Conjugate (nDC). It is a conjugate of 17β-estradiol with a derivative of indocyanine green dye, bis-1,1-(4-sulfobutyl) indotricarbocyanine-5-carboxylic acid, sodium salt. Structural and photophysical characterizations of nDC followed with breast cancer cell lines (MCF-7 and MDA MB 231) stained with novel dye were carried out. The target, MCF-7 cells (ER-positive) showed specific high-affinity binding sites of novel dye onto the nucleus and membrane of ER-positive cells, in contrast, the control, MDA MB 231 (ER-negative) showed only plasma membrane staining. Similar results were obtained when ER expressing cancerous tissues (viz. Non-Invasive Ductal Carcinoma, Non-Invasive Lobular Carcinoma, Non-Invasive Adenocarcinoma, and Non-Invasive Medullary Carcinoma) were stained with novel dye. Approximately 70% of breast cancer cases are ER-positive, therefore nDC being ER binding properties can unambiguously improve the specificity and sensitivity of breast cancer imaging.