Duplicate.or ketoprofen (compounds 124-139). However, conjugation in the celecoxib analog with nile blue or sulforhodamine (e.g., 124 and 125) resulted in selective COX-2 inhibition with moderate to poor potencies. The COX-2 inhibitory activity of indomethacin- or celecoxib-like building blocks (140-152) is delineated in Table 6. Even though the derivatives of indomethacin and celecoxib, for example iodoindomethacin and carboxypropionyl celecoxib, retain the COX-2 inhibitory activity from the parent compound, their fluorescent derivatives have been not usually COX-2 inhibitors. So, unlike the parent indomethacin, conversion of indomethacin- or celecoxib-like molecules into fluorescent amide derivatives doesn’t readily create a family of very selective COX-2 inhibitors. Evaluation of Fluorescent COX-2 Inhibitors in Cell Culture. The potential of fluorescent derivatives to inhibit COX-2 in intact cells was assayed in activated RAW264.7 macrophages or 1483 HNSCC cells making use of previously reported solutions,27 as briefly described in Experimental Procedures. Within this assay, numerous of the structurally diverse fluorescent compounds inhibited COX-2 in LPS-activated RAW264.7 cells with IC50 values within the nanomolar variety (Table 7). As an example, the IC50 values for inhibition of prostaglandin synthesis by 41 and 58, were 0.4-Bromobutoxy-tert-butyl-dimethylsilane Formula 31 and 0.34, M, respectively. In 1483 HNSCC cells, which constitutively express COX-2, compounds 41 and 58 retained their COX-2 inhibitory activity with IC50 values of 0.09 and 0.38 M, respectively. Thus, conjugation of an NSAID, indomethacin, with zwitterionic fluorophores, tethered by means of an n-butydiamide linker afforded fluorescent conjugates that have been capable of passing by way of the cell membrane to inhibit COX-2 proficiently. In Vitro Optical Imaging of Cells. The human head and neck cancer cell line, 1483, which expresses high levels ofCOX-2,28 was treated with compound 58. Just after washout, the cells were imaged by fluorescence microscopy and exhibited sturdy red fluorescence as a result of the accumulation of the rhodamine derivative (Figure 2A). Preincubation with the cells with all the COX inhibitor indomethacin blocked uptake and labeling of 1483 cells by compound 58 (Figure 2B). These outcomes are consistent with these reported previously for compound 41.27 In Vivo Optical Imaging of Tumor Xenografts. We evaluated the capability of compound 58 to target COX-2 in human tumor xenografts. Nude mice bearing 1483 or HCT116 xenograft tumors around the left flank were dosed by intraperitoneal injection with compound 58 (two mg/kg). At 60 min postinjection, no fluorescence was observed inside the tumor.16-Aminohexadecanoic acid Chemscene Signal was detected inside the COX-2 expressing 1483 tumors beginning at three h (Figure 3A).PMID:33660139 In contrast for the selective uptake of 58 into 1483 xenografts, minimal uptake was observed at three h in HCT116 xenografts, a human colon tumor that does not express COX-2.29 An ex vivo imaging was performed to confirm the in vivo imaging results and to confirm the 1483 tumor signal was on account of the tumor uptake of 58, and not from the nearby regular tissues or skin. A vibrant fluorescence signal was detected in the ex vivo 1483 tumor as compared together with the HCT116 tumor (Figure 3C,D). The signal enrichment of 58 within the 1483 tumors compared to HCT116 or contralateral leg muscle was established to be 10:1 (Figure 3E). Further, we performed a COX-2 blocking experiment making use of indomethacin, in which nude mice with 1483 xenografts had been pretreated with either DMSO or indomethacin in DMSO (2 mg/kg, intraperito.