XenoLight RediJect COX-2 probe on the ASK


Cyclooxygenase (COX) is an enzyme responsible for the formation of prostanoids which are involved in inflammation responses. COX enzymes catalyze the conversion of the free essential fatty acids to prostanoids. Inhibition of COX can provide relief from the symptoms of inflammation and pain. One of the isoenzymes, COX-2, is undetectable in most normal tissues. It is an inducible enzyme that is abundant at sites of inflammation. In addition, it has been shown to be upregulated in various carcinomas and has a central role in tumorigenesis.

XenoLight RediJect COX-2 is a novel fluorescent imaging probe for pre-clinical research that specifically detects the cyclooxygenase-2 (COX-2) biomarker noninvasively in vivo. It consists of a fluorescent dye and a COX-2 binding domain. It provides the ability to non-invasively detect COX-2 in early-stage cancer cells, with a level of sensitivity and accuracy not attainable by conventional methods. The probe is very specific, with good signal to background ratios, in targeting tumors that only over express the COX-2 biomarker.

Figure 1: The structure of the RediJect COX-2 probe. The fluorescent 5-ROX dye is highlighted in red and the COX-2 binding domain is shown in black.

Products and catalog numbers

ProductCatalog NumberEx/Em wavelength (nm)Validated ExperimentsApplicationsStorage and Stability
RediJect COX-2 Probe133314581/605In vivo/Ex vivo
In vitro microscopy
Technical Data Sheet

Using RediJect COX-2 Probe in vivo/ex vivo

ProductRoute of InjectionMouse Dose (25 g)Optimal imaging timeRoute of Metabolism/ background tissueFMT and IVIS settings
RediJect COX-2 ProbeIP100 µL3 hKidney, liverIVIS 570/620
Figure 2: Nu/Nu mice were subcutaneously injected with 2x106 of HCT116 (left flank) and HT29 (right flank) tumor cells. At day 16, most of tumors were approximately 100 mm3. Mice were injected with either RediJect COX-2 probe (2 mg/kg intraperitoneally), or the control 5-ROX dye. Mice were imaged at 3, 6 and 24 hours after injection with IVIS Spectrum (Ex 570, Em 640). Images shown were taken at 3 hours (Upper panel). Cox-2 positive HT29 tumor showed preferential labeling by the RediJect COX-2 probe whereas the Cox2 negative HCT116 showed very little binding. Quantification of RediJect COX-2 probe fluorescence is shown by blue bars and 5-ROX control dye quantification is shown by red bars (Lower panels). Quantification of fluorescence signal from the tumors showed a steady decrease of the fluorescence signal at the 6 and 24 hour imaging time points. A 2-fold difference between the Cox2 positive HT29 and Cox2 negative HCT116 was observed in RediJect COX-2 probe injected mice at 3 and 6 hours.

Using RediJect COX-2 Probe in vitro

Figure 3: In vitro binding specificity of RediJect COX-2 probe to COX-2 positive HT29 cells. No targeting is seen in COX-2 negative HCT116 cells using Nuance FX multispectral imaging system.


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