Hypoxia imaging in cells and tumor tissues using a highly selective fluorescent nitroreductase probe

Abstract

Hypoxia is a characteristic of locally advanced solid tumors, resulting from an imbalance between oxygen consumption and supply. In hypoxic solid tumors, an increased expression of nitroreductase (NTR) is detected, therefore, the development of NTR-targeted fluorescent probes to selectively and efficiently detect hypoxia in vivo is of utmost importance. In this study, a probe (1) has been designed and tested for effective optical detection of NTR in vitro and in vivo. The reduction of probe (1), catalyzed by NTR, resulted in changes of the electron-withdrawn nitrogen group into an electron-donation amino group. In addition, breakage of the O-C bond ensured selective fluorescence enhancement. The in vitro response towards exogenous NTR, from rat liver microsomes, resulted in the optical enhancement during the detection process. In vivo imaging of caerorhabditis elegans (C.elegan) further confirmed the detection of NTR by probe (1). Moreover, probe (1) was successfully used for the detection of hypoxia in both HI5 cells, and a murine tumor model, which demonstrates the potential of probe (1) for application in fluorescence bioimaging studies, and tumor hypoxia diagnosis.

Directly observing intracellular nanoparticle formation with nanocomputed tomography

“…S15 and S16). NTR is known existing in the cytoplasm of a mammalian cell (34,35). EM image of the NBC-Iod-CBT-treated hypoxic HeLa cells showed the existence of Iod-CBT-NPs with an average diameter of 53.3 ± 2.8 nm in the cytoplasm of the cells (Fig.…”

Novel designed azo substituted semi-cyanine fluorescent probe for cytochrome P450 reductase detection and hypoxia imaging in cancer cells

“…Here, the new designed probe has a signicant difference in chemical structure, as shown in Scheme 1, to most of the reported probes, where the functional group was connected to the electron-donating end of the uorophore molecule. 9,16,19,23 Here, the azo group of the probe AZO-Cy connected to the electron-withdrawing end which is a rst report.…”

“…[13][14][15] Because it is non-invasive, and has high sensitivity and high spatiotemporal resolution, uorescence imaging is still an ideal method for hypoxia detection. [16][17][18][19][20] As a metabolism enzyme, cytochrome P450 reductase plays a key role in the reduction of nitro functional compounds and has higher activity in cancerous cells than in normal cells, especially in a hypoxic environment. Several studies have proved that azo aromatic compounds are good substrates for cytochrome P450 reductase.…”

Activation of HIF-1α by δ-Opioid Receptors Induces COX-2 Expression in Breast Cancer Cells and Leads to Paracrine Activation of Vascular Endothelial Cells

“…Studies have shown that findings from two-dimensional (2D, monolayer) cultured tumor cells differ from in vivo observations (Horman, 2016). Especially drug-induced regulation of HIF-1a observed in cell culture experiments has to be considered critical as solid tumors are often exposed to hypoxia and thus already feature HIF-1a overexpression (Zhong et al, 1999;Yang et al, 2017). To assess the biologic relevance of in vitro data, testing drug effects in 3D-cultured cells is state-of-the-art in cancer research, because 3D-cultured cells have similar characteristics as in vivo and are considered in vitro microtumor models (Ivascu and Kubbies, 2006).…”