Anatoly Pinchuk

Beyond the margins: real-time detection of cancer using targeted fluorophores

Over the past two decades, synergistic innovations in imaging technology have resulted in a revolution in which a range of biomedical applications are now benefiting from fluorescence imaging. Specifically, advances in fluorophore chemistry and imaging hardware, and the identification of targetable biomarkers have now positioned intraoperative fluorescence as a highly specific real-time detection modality for surgeons in oncology. In particular, the deeper tissue penetration and limited autofluorescence of near-infrared (NIR) fluorescence imaging improves the translational potential of this modality over visible-light fluorescence imaging. Rapid developments in fluorophores with improved characteristics, detection instrumentation, and targeting strategies led to the clinical testing in the early 2010s of the first targeted NIR fluorophores for intraoperative cancer detection. The foundations for the advances that underline this technology continue to be nurtured by the multidisciplinary collaboration of chemists, biologists, engineers, and clinicians. In this Review, we highlight the latest developments in NIR fluorophores, cancer-targeting strategies, and detection instrumentation for intraoperative cancer detection, and consider the unique challenges associated with their effective application in clinical settings.

[(E)-γ-(Dimethylphenylsilyl)allyl]diisopinocampheylborane: a highly enantioselective reagent for the synthesis of anti-β-hydroxyallylsilanes ☆

Abstract anti -β-Hydroxyallylsilanes are prepared with 88–95% e.e. via the asymmetric allylboration reactions of aldehydes and [( E )-γ-(dimethylphenylsilyl)allyl]diisopinocampheylborane ( 7 ).

Quantification of CLR1401, a novel alkylphosphocholine anticancer agent, in rat plasma by hydrophilic interaction liquid chromatography-tandem mass spectrometric detection

A rapid and specific LC-MS/MS based bioanalytical method was developed and validated for the determination of 18-(p-iodophenyl)octadecyl phosphocholine (CLR1401), a novel phosphocholine drug candidate, in rat plasma. The optimal chromatographic behavior of CLR1401 was achieved on a Kromasil silica column (50 mm x 3 mm, 5 microm) under hydrophilic interaction chromatography. The total LC analysis time per injection was 2.8 min with a flow rate of 1.5 mL/min under gradient elution. Liquid-liquid extraction in a 96-well format using ethyl acetate was developed and applied for method validation and sample analysis. The method validation was conducted over the curve range of 2.00-1000 ng/mL using 0.0500 mL of plasma sample. The intra- and inter-day precision and accuracy of the quality control samples at low, medium, and high concentration levels showed < or = 5.9% relative standard deviation (RSD) and -10.8 to -1.4% relative error (RE). The method was successfully applied to determine the toxicokinetics of CLR1401 in rats from three dose groups of 0.4, 4.0, and 10.0 mg/kg/day via intravenous administration.

Synthesis and biological evaluation of radioiodinated phospholipid ether analogs

Previous work has shown that radioiodinated phospholipid ether analogs with the iodine-125 substituted on the meta position of the aromatic ring readily localized in a variety of animal tumors. In an effort to ascertain the importance of such meta substitution, three phospholipid ether analogs with the iodine-125 in the para position were synthesized for evaluation as potential tumor-localizing imaging agents. 12-(p-Iodophenyl)dodecyl phosphocholine, 1-O-[12-(p-iodophenyl)dodecyl]-1,3-propanediol-3-phosphocholine, and 1-O-[12-(p-iodophenyl)dodecyl]-2-O-methyl-3-rac-glycerophosphocholine were synthesized and labeled with iodine-125 via an isotope exchange procedure. Similar to previous results with the meta substituted analogs, tissue distribution studies with the three para analogs demonstrated tumor localization and retention of radioactivity at 24 h after i.v. injection. In all three cases, the para isomers showed greater tumor avidity than the meta isomers and clearance of the radiotracer from the tumor was much slower than the clearance from nontarget tissue. 12-(p-Iodophenyl)dodecyl phosphocholine afforded the greatest tumor-to-nontarget tissue ratio. For example, the tumor-to-blood and tumor-to-liver ratios at 24 h were 10.96 and 1.85, respectively. As a result of such selective tumor retention, it was possible to clearly delineate the tumor using gamma-camera scintigraphy.

364 Creation of a Dual-Labeled Cancer-Targeting Alkylphosphocholine Analog for Dual Modality Quantitative Positron Emission Tomography and Intraoperative Tumor Visualization.

INTRODUCTION Near-infrared fluorescence (NIRF) imaging is a promising noninvasive, real-time, sensitive, high-resolution modality for cancer detection due to high tissue penetrance and low background autofluorescence. However, accurate fluorescence quantitation is problematic due to photon scattering by tissues, photon absorption by pigments and water, and static quenching of close-proximity fluorophores. CLR1502 is a NIRF-labeled cancer-specific alkylphosphocholine analog with selective uptake and retention in over 60 preclinical cancer models (including glioblastoma cancer stem cell and brain met models), and approaching clinical trials. To address many of NIRF limitations, we synthesized Iodo-1502, a novel dual-labeled (DL) positron emission tomography (PET) NIRF agent by adding radiolabeled iodine to CLR1502, enabling simultaneous whole-body cancer staging and intraoperative tumor illumination with a single agent. Initial preclinical in vivo studies of Iodo-1502 will be presented. METHODS Standard organic synthetic chemistry and biology methods. Multiple human cancer lines were implanted for tumor xenografts in athymic nude mice. Once tumors reached 3 mm diameter, IV injection of dual-labeled Iodo-1502 and animal imaging up to 120 hours with IVIS Spectrum (excitation = 745 nm, emission = 800 nm) or small-animal Siemens Inveon Hybrid PET/CT scanner was done. Tumors were then removed for similar ex vivo quantitative IVIS and PET studies. RESULTS Like the NIRF CLR1502 predecessor, the new dual-labeled Iodo-1502 showed striking tumor selectivity and retention for at least 6 days postinjection in xenograft models. Moreover, ex vivo quantitation showed excellent correlation of fluorescence and PET imaging. CONCLUSION This new agent overcomes many NIRF limitations, and enables broad-spectrum cancer-specific intraoperative tumor margin illumination and whole-body quantitative PET imaging.