Fluorochrome Selection for Imaging Intraoperative Ovarian Cancer Probes

Abstract

The identification and removal of all gross and microscopic tumor to render the patient disease free represents a huge challenge in ovarian cancer treatment. The presence of residual disease is an independent negative prognostic factor. Herein, we describe the synthesis and the “in vitro” evaluation of compounds as cyclooxygenase (COX)-1 inhibitors, the COX-1 isoform being an ovarian cancer biomarker, each bearing fluorochromes with different fluorescence features. Two of these compounds N-[4-(9-dimethylimino-9H-benzo[a]phenoxazin-5-ylamino) butyl]-2-(3,4-bis(4-methoxyphenyl)isoxazol-5-yl)acetamide chloride (RR11) and 3-(6-(4-(2-(3,4-bis(4-methoxyphenyl)isoxazole-5-yl)acetamido)butyl)amino-6-oxohexyl)-2-[7-(1,3-dihydro-1,1-dimethyl-3-ethyl 2H-benz[e]indolin-2-yl-idene)-1,3,5-heptatrienyl]-1,1-dimethyl-3-(6-carboxilato-hexyl)-1H-benz[e]indolium chloride, 23 (MSA14) were found to be potent and selective inhibitors of cyclooxygenase (COX)-1 “in vitro”, and thus were further investigated “in vivo”. The IC50 values were 0.032 and 0.087 µM for RR11 and 23 (MSA 14), respectively, whereas the COX-2 IC50 for RR11 is 2.4 µM while 23 (MSA14) did not inhibit COX-2 even at a 50 µM concentration. Together, this represented selectivity index = 75 and 874, respectively. Structure-based virtual screening (SBVS) performed with the Fingerprints for Ligands and Proteins (FLAP) software allowed both to differentiate highly active compounds from less active and inactive structures and to define their interactions inside the substrate-binding cavity of hCOX1. Fluorescent probes RR11 and 23 (MSA14), were used for preliminary near-infrared (NIR) fluorescent imaging (FLI) in human ovarian cancer (OVCAR-3 and SKOV-3) xenograft models. Surprisingly, a tumor-specific signal was observed for both tested fluorescent probes, even though this signal is not linked to the presence of COX-1.

Olive Mill Wastewater Fermented with Microbial Pools as a New Potential Functional Beverage

“…COX catalyzes the first step in the biosynthesis of prostaglandins (PG), prostacyclin and thromboxane starting from free arachidonic acid (AA) [ 43 ]. Among prostaglandins, PGE 2 is involved in inflammation, angiogenesis and in promoting the growth of several solid tumors, such as breast, ovarian, head and neck cancer, renal cell carcinoma and hematological cancers [ 44 , 45 , 46 ]. COX-1 and COX-2 are of great interest because they are targets of non–steroidal anti–inflammatory drugs (NSAIDs), which, when binding to the active site of COX, prevent the AA from reaching the catalytic pocket and, thus, the biosynthesis of prostaglandins.…”

Genome-Wide Identification and Validation of Gene Expression Biomarkers in the Diagnosis of Ovarian Serous Cystadenocarcinoma

“…The PET radiotracer [ 18 F]-FDG alone has 78% sensitivity and 68% specificity [ 30 , 31 ]. Further studies attempted to identify novel PET radiotracers [ 32 ] and fluorescent probes [ 33 , 34 ] targeting unexplored putative biomarkers.…”

Fluorescent imaging probes for in vivo ovarian cancer targeted detection and surgery

“…Constitutively expressed in many organs, COX-1 may not be specific enough to allow specific in vivo detection of ovarian cancer. 28,29 2.1.2 | MSA14 probe MSA14 (Figure 2) is a NIR fluorescent compound (λ abs1 = 260 nm, λ abs2 = 770 nm; λ em1 = 318 nm, λ em2 = 822 nm) designed and synthesized for targeting in vitro and in vivo COX-1.…”

“…However, further investigation is necessary to identify the real target of the newly prepared compounds, which still maintain great potential as contrast agents for ovarian cancer FGS. 29…”

“…The diffuse fluorescent signals detected among the whole body may be related to mouse and human COX‐1 cross‐reactivity. Constitutively expressed in many organs, COX‐1 may not be specific enough to allow specific in vivo detection of ovarian cancer 28,29 …”