A Near-Infrared, Wavelength-Shiftable, Turn-on Fluorescent Probe for the Detection and Imaging of Cancer Tumor Cells

Abstract

Fast, selective, and noninvasive reporting of intracellular cancer-associated events and species will lead to a better understanding of tumorigenesis at the molecular level and development of precision medicine approaches in oncology. Overexpressed reductase presence in solid tumor cells is key to cancer progression and protection of those diseased cells from the oxidative effects of therapeutics meant to kill them. Human NAD(P)H:quinone oxidoreductase isozyme I (hNQO1), a cytoprotective 2-electron-specific reductase found at unusually high activity levels in cancer cells of multiple origins, has attracted significant attention due to its major role in metastatic pathways and its link to low survival rates in patients, as well as its ability to effectively activate quinone-based, anticancer drugs. Accurate assessment of hNQO1 activities in living tumor models and ready differentiation of metastases from healthy tissue by fluorescent light-based protocols requires creation of hNQO1-responsive, near-infrared probes that offer deep tissue penetration and low background fluorescence. Herein, we disclose a quinone-trigger-based, near-infrared probe whose fluorescence is effectively turned on several hundred-fold through highly selective reduction of the quinone trigger group by hNQO1, with unprecedented, catalytically efficient formation of a fluorescent reporter. hNQO1 activity-specific production of a fluorescence signal in two-dimensional cultures of respiring human cancer cells that harbor the reductase enzyme allows for their quick (30 min) high-integrity recognition. The characteristics of the near-infrared probe make possible the imaging of clinically relevant three-dimensional colorectal tumor models possessing spatially heterogeneous hNQO1 activities and provide for fluorescence-assisted identification of submillimeter dimension metastases in a preclinical mouse model of human ovarian serous adenocarcinoma.

Enzyme-Activated Fluorogenic Probes for Live-Cell and in Vivo Imaging

“…More recently, a cyanine-based probe with a similar masking group strategy was applied to three-dimensional tumor spheroids and ovarian cancer mouse models. 34 …”

Trimethyl Lock: A Multifunctional Molecular Tool for Drug Delivery, Cellular Imaging, and Stimuli‐Responsive Materials

“…[153] Compound 117 can be synthesized from heptaindocyanine-Cy7d ye 118 and has been proven to label NQO1overexpressing cancer cells selectively in classical two-dimensional cell-based assays and in clinically relevant three-dimensional colorectal tumor models in vitro. [153] Compound 117 can be synthesized from heptaindocyanine-Cy7d ye 118 and has been proven to label NQO1overexpressing cancer cells selectively in classical two-dimensional cell-based assays and in clinically relevant three-dimensional colorectal tumor models in vitro.…”

“…Another successful example of aN QO1-sensitive latent NIRfluorescent probe was recently reported by McCarley and coworkers. [153] Compound 117 can be synthesized from heptaindocyanine-Cy7d ye 118 and has been proven to label NQO1overexpressing cancer cells selectively in classical two-dimensional cell-based assays and in clinically relevant three-dimensional colorectal tumor models in vitro. In additional studies, the authorss how ah igh sensitivity of probe 117 for the detection of peritoneal ovarian cancer metastases in an in vivo xenograft murine model.…”

An Activatable Photosensitizer Targeting Human NAD(P)H: Quinone Oxidoreductase 1

“…Rather, its high level has been mainly exploited for diagnostics and alternative therapeutic applications. For example, an array of fluorescent chemosensors have been developed to differentiate cancer cells from healthy cells, and in some instances identify metastases in animal models . Several groups have also developed hNQO1‐bioactivated anticancer agents (e.g., prodrugs) to enhance the cancer selectivity of DNA alkylators or other chemotherapeutic agents .…”

“…Rather,i ts high level has been mainlye xploited for diagnostics and alternative therapeutic applications.F or example, an array of fluorescent chemosensors have been developed to differentiate cancer cells from healthy cells, and in some instances identify metastases in animal models. [13][14][15][16][17][18][19][20][21][22][23][24][25] Severalg roupsh avea lso developed hNQO1-bioactivated anticancera gents(e.g.,p rodrugs) to enhancet he cancers electivity of DNA alkylators or other chemotherapeutic agents. [9,[26][27][28][29][30] Lastly,t heranostic prodrugs providingb oth real-time hNQO1 activity monitoring and anticancer drug release in as ingle molecule have also been reported.…”