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This study aimed to report the first single-photon emission computed tomographic (SPECT) imaging of articular cartilage in mice using 99mTc-NTP 15-5 radiotracer. Mice intravenously injected with 99mTc-NTP 15-5 were submitted to ( 1 ) dynamic planar imaging, (2) static planar imaging, (3) 1 mm pinhole SPECT acquisition, and ( 4 ) dissection. Tomographic reconstruction of SPECT data was performed with a three-dimensional ordered subset expectation maximization algorithm, and slices were reconstructed in three axes. 99mTc-NTP 15-5 rapidly accumulated in the joint, with ape lk of radioactivity being reached from 5 minutes postinjection and maintained for at least 90 minutes. Given that bone and muscle did not show any accumulation of the tracer, highly contrasted joint imaging was obtained from 15 minutes postinjecticn. When I mm pinhole SPECT acquisition was focused on the knee, the medial and lateral compartments of both the femora condyle and tihial plateau were highly delineated, allowing a separate quantitation of tracer accumulation within each component of the femorotibial joint. A good correlation was found between tracer uptake determined by region of interest analysis of both planar and SPECT scans and dissection. This new approach to imaging of cartilage in mice provides joint functionality assessment in vivo, giving a unique opportunity to achieve a greater understanding of cartilage physiology in health and disease. [ABSTRACT FROM AUTHOR]

This study in the meniscectomised guinea pig aimed to demonstrate that the radiotracer 99mTc-NTP 15-5 would have pathophysiological validity for in vivo osteoarthritis imaging. The specificity of 99mTc-NTP 15-5 for cartilage was determined in healthy animals ( n = 13), by tissue radioactivity counting, joint autoradiography and scintigraphy. 99mTc-NTP 15-5 scintigraphy was performed at 20, 50, 80, 115, 130, 150 and 180 days after medial meniscectomy ( n = 10 MNX) or sham operation ( n = 5), and scintigraphic ratios (operated/contralateral) were calculated for femoral (F) and tibial (T) areas. F and T ratios were compared with those of 99mTc-MDP bone scintigraphy. At the study end-point, autoradiographic analysis of joint 99mTc-NTP 15-5 distribution and macroscopic scoring of cartilage integrity were performed. The high and specific accumulation of 99mTc-NTP 15-5 in normal cartilage (about 5.5 ± 1.7 % of injected dose/g of tissue), which permitted joint imaging with high contrast, was affected by osteoarthritis. In the MNX group, 99mTc-NTP 15-5 accumulation in cartilage within the operated joint, relative to the contralateral joint, was observed to change in the same animals as pathology progressed. Although F and T ratios were significantly higher in MNX (F = 1.7 ± 0.2; T = 1.6 ± 0.1) than in shams (F = 1.0 ± 0.1; T = 1.0 ± 0.1) at day 50, they were significantly lower in MNX (F = 0.6 ± 0.1; T = 0.7 ± 0.1) than in shams (F = 1.0 ± 0.1; T = 0.9 ± 0.1) at day 180. No change in 99mTc-MDP uptake was observed over 6 months. Macroscopic analysis confirmed features of osteoarthritis only in MNX knees. These results in MNX guinea pigs provide additional support for the use of 99mTc-NTP 15-5 for in vivo imaging of osteoarthritis. [ABSTRACT FROM AUTHOR]

Study Objectives: In regard to nuclear medicine literature reporting lung uptake of colloidal radiopharmaceuticals in patients with liver diseases, it has been hypothesized that liver abnormalities could trigger induction of pulmonary intravascular macrophages (PIMs) in humans normally lacking them. Recently, experimental induction of PIMs in rats in which they are not normally prevalent has been demonstrated to be at the origin of pulmonary hemodynamic alterations with an increased susceptibility to ARDS. If such induction may occur in humans, the risk of pulmonary hemodynamic alterations has to be considered and detected. This study demonstrates in a rodent model of biliary cirrhosis that scintigraphy of phagocytic function as commonly used for liver exploration is a suitable strategy for staging PIM development.Design: Sixty rats were randomized as follows: bile duct section (n = 40), sham operation (n = 10), and no operation (n = 10). The rats were submitted to scintigraphy of phagocytic function every 5 days over 35 days for the assessment of radiocolloid uptake within lung and liver. At day 35, radioactivity of blood was counted and immunohistochemistry was performed on lung specimens.Results: As disease progressed, radiopharmaceutical uptake decreased within the liver, while increasing considerably in the lung. At day 35, lung uptake averaged about 66% as compared to 3% before surgery. Lung histologic findings revealed numerous intravascular mononuclear cells closely related to the monocyte-macrophage lineage.Conclusion: Scintigraphy of phagocytic function commonly used for liver scanning could be a suitable strategy for the diagnosis of the induction of PIMs under pathologic situations. [ABSTRACT FROM AUTHOR]

The development of 64Cu-based immuno-PET radiotracers requires the use of copper-specific bifunctional chelators (BFCs) that contain functional groups allowing both convenient bioconjugation and stable copper complexes to limit in vivo bioreduction, transmetallation and/or transchelation. The excellent in vivo kinetic inertness of the pentaazamacrocyclic [64Cu]Cu-15-5 complex prompted us to investigate its potential for the 64Cu-labelling of monoclonal antibodies (mAbs), compared with the well-known NODAGA and DOTA chelators. To this end, three NODAGA, DOTA and 15-5-derived BFCs, containing a pendant azadibenzocyclooctyne moiety, were synthesised and a robust methodology was determined to form covalent bonds between them and azide-functionalised trastuzumab, an anti-HER2 mAb, using strain-promoted azide-alkyne cycloaddition. Unlike the DOTA derivative, the NODAGA- and 15-5-mAb conjugates were radiolabelled with 64Cu, obtaining excellent radiochemical yields, under mild conditions. Although all the radioimmunoconjugates showed excellent stability in PBS or mouse serum, [64Cu]Cu-15-5- and [64Cu]Cu-NODAGA-trastuzumab presented higher resistance to transchelation when challenged by EDTA. Finally, the immunoreactive fraction of the radioimmunoconjugates (88–94%) was determined in HER-2 positive BT474 human breast cancer cells, confirming that the bioconjugation and radiolabelling processes implemented had no significant impact on antigen recognition. [ABSTRACT FROM AUTHOR]

Abstract: Several bone conditions, eg, bone cancer, osteoporosis, and rheumatoid arthritis (RA), are associated with a risk of developing persistent pain. Increased osteoclast activity is often the hallmark of these bony pathologies and not only leads to bone remodeling but is also a source of pronociceptive factors that sensitize the bone-innervating nociceptors. Although historically bone loss in RA has been believed to be a consequence of inflammation, both bone erosion and pain can occur years before the symptom onset. Here, we have addressed the disconnection between inflammation, pain, and bone erosion by using a combination of 2 monoclonal antibodies isolated from B cells of patients with RA. We have found that mice injected with B02/B09 monoclonal antibodies (mAbs) developed a long-lasting mechanical hypersensitivity that was accompanied by bone erosion in the absence of joint edema or synovitis. Intriguingly, we have noted a lack of analgesic effect of naproxen and a moderate elevation of few inflammatory factors in the ankle joints suggesting that B02/B09-induced pain-like behavior does not depend on inflammatory processes. By contrast, we found that inhibiting osteoclast activity and acid-sensing ion channel 3 signaling prevented the development of B02/B09-mediated mechanical hypersensitivity. Moreover, we have identified secretory phospholipase A2 and lysophosphatidylcholine 16:0 as critical components of B02/B09-induced pain-like behavior and shown that treatment with a secretory phospholipase A2 inhibitor reversed B02/B09-induced mechanical hypersensitivity and bone erosion. Taken together, our study suggests a potential link between bone erosion and pain in a state of subclinical inflammation and offers a step forward in understanding the mechanisms of bone pain in diseases such as RA. [ABSTRACT FROM AUTHOR]

Abstract: Rheumatoid arthritis is frequently associated with chronic pain that still remains difficult to treat. Targeting nerve growth factor (NGF) seems very effective to reduce pain in at least osteoarthritis and chronic low back pain but leads to some potential adverse events. Our aim was to better understand the involvement of the intracellular signalling pathways activated by NGF through its specific tyrosine kinase type A (TrkA) receptor in the pathophysiology of rheumatoid arthritis using the complete Freund adjuvant model in our knock-in TrkA/C mice. Our multimodal study demonstrated that knock-in TrkA/C mice exhibited a specific decrease of mechanical allodynia, weight-bearing deficit, peptidergic (CGRP+) and sympathetic (TH+) peripheral nerve sprouting in the joints, a reduction in osteoclast activity and bone resorption markers, and a decrease of CD68-positive cells in the joint with no apparent changes in joint inflammation compared with wild-type mice after arthritis. Finally, transcriptomic analysis shows several differences in dorsal root ganglion mRNA expression of putative mechanotransducers, such as acid-sensing ionic channel 3 and TWIK-related arachidonic acid activated K+ channel, as well as intracellular pathways, such as c-Jun, in the joint or dorsal root ganglia. These results suggest that TrkA-specific intracellular signalling pathways are specifically involved in mechanical hypersensitivity and bone alterations after arthritis using TrkA/C mice. [ABSTRACT FROM AUTHOR]

Isocitrate dehydrogenases (IDHs) are metabolic enzymes commonly mutated in human cancers (glioma, acute myeloid leukaemia, chondrosarcoma, and intrahepatic cholangiocarcinoma). These mutated variants of IDH (mIDH) acquire a neomorphic activity, namely, conversion of α-ketoglutarate to the oncometabolite D-2-hydroxyglutarate involved in tumourigenesis. Thus, mIDHs have emerged as highly promising therapeutic targets, and several mIDH specific inhibitors have been developed. However, the evaluation of mIDH status, currently performed by biopsy, is essential for patient stratification and thus treatment and follow-up. We report herein the development of new radioiodinated and radiofluorinated analogues of olutasidenib (FT-2102) as tools for noninvasive single photon emission computed tomography (SPECT) or positron emission tomography (PET) imaging of mIDH1 up- and dysregulation in tumours. Nonradiolabelled derivatives 2 and 3 halogenated at position 6 of the quinolinone scaffold were synthesised and tested in vitro for their inhibitory potencies and selectivities in comparison with the lead compound FT-2102. Using a common organotin precursor, (S)-[125I]2 and (S)-[18F]3 were efficiently synthesised by radio-iododemetallation and copper-mediated radiofluorination, respectively. Both radiotracers were stable at room temperature in saline or DPBS solution and at 37 °C in mouse serum, allowing future planning of their in vitro and in vivo evaluations in glioma and chondrosarcoma models. [ABSTRACT FROM AUTHOR]

With the emergence of disease modifying osteoarthritis drugs (DMOAD), imaging methods to quantitatively demonstrate their efficacy and to monitor osteoarthritis progression at the functional level are urgently needed. Our group showed that articular cartilage can be quantitatively assessed in nuclear medicine imaging by our radiotracer 99mTc-NTP 15-5 targeting cartilage proteoglycans. In this work, surgically induced DMM mice were treated with sprifermin or saline. We investigated cartilage remodelling in the mice knees by 99mTc-NTP 15-5 SPECT-CT imaging over 24 weeks after surgery, as wells as proteoglycan biochemical assays. OA alterations were scored by histology according to OARSI guidelines. A specific accumulation of 99mTc-NTP 15-5 in cartilage joints was evidenced in vivo by SPECT-CT imaging as early as 30 min post-iv injection. In DMM, 99mTc-NTP 15-5 accumulation in cartilage within the operated joints, relative to contralateral ones, was observed to initially increase then decrease as pathology progressed. Under sprifermin, 99mTc-NTP 15-5 uptake in pathological knees was significantly increased compared to controls, at 7-, 12- and 24-weeks, and consistent with proteoglycan increase measured 5 weeks post-surgery, as a sign of cartilage matrix remodelling. Our work highlights the potential of 99mTc-NTP 15-5 as an imaging-based companion to monitor cartilage remodelling in OA and DMOAD response. [ABSTRACT FROM AUTHOR]

Background: Benzamide-based radioligands targeting melanin were first developed for imaging melanoma and then for therapeutic purpose with targeted radionuclide therapy (TRT). [131I]ICF01012 presents a highly favorable pharmacokinetics profile in vivo for therapy. Tumour growth reduction and increase survival have been established in preclinical models of melanoma. According the these preclinical results, we initiate a first-in-human study aimed to determine the recommended dose of [131I]ICF01012 to administer for the treatment of patients with pigmented metastatic melanoma.Methods: The MELRIV-1 trial is an open-label, multicentric, dose-escalation phase I trial. The study is divided in 2 steps, a selection part with an IV injection of low activity of [131I]ICF01012 (185 MBq at D0) to select patients who might benefit from [131I]ICF01012 TRT in therapeutic part, i.e. patient presenting at least one tumour lesion with [131I]ICF01012 uptake and an acceptable personalized dosimetry to critical organs (liver, kidney, lung and retina). According to dose escalation scheme driven by a Continual Reassessment Method (CRM) design, a single therapeutic injection of 800 MBq/m2, or 1600 MBq/m2, or 2700 MBq/m2 or 4000 MBq/m2 of [131I]ICF01012 will be administered at D11 (± 4 days). The primary endpoint is the recommended therapeutic dose of [131I]ICF01012, with DLT defined as any grade 3-4 NCI-CT toxicity during the 6 weeks following therapeutic dose. Safety, pharmacokinetic, biodistribution (using planar whole body and SPECT-CT acquisitions), sensitivity / specificity of [131I]ICF01012, and therapeutic efficacy will be assessed as secondary objectives. Patients who received therapeutic injection will be followed until 3 months after TRT. Since 6 to 18 patients are needed for the therapeutic part, up to 36 patients will be enrolled in the selection part.Discussion: This study is a first-in-human trial evaluating the [131I]ICF01012 TRT in metastatic malignant melanomas with a diagnostic dose of the [131I]ICF01012 to select the patients who may benefit from a therapeutic dose of [131I]ICF01012, with at least one tumor lesion with [131I]ICF01012 uptake and an acceptable AD to healthy organ.Trial Registration: Clinicaltrials.gov : NCT03784625 . Registered on December 24, 2018. Identifier in French National Agency for the Safety of Medicines and Health Products (ANSM): N°EudraCT 2016-002444-17. [ABSTRACT FROM AUTHOR]

Purpose: This study aims to perform dosimetry for [99mTc]NTP15‐5 radiotracer used in imaging of articular cartilage in rabbits and humans. The radiotracer (covered by a world patent WO 01/00621 A1) has been proposed in the previous years for the study of cartilage in osteoarthritis diseases. A sensitive imaging approach is essential to quantify osteoarthritis progression and monitor response to new therapies. [99mTc]NTP15‐5 binds to cartilage proteoglycans whose decreased content is associated to a loss of biomedical function of cartilage. We have implemented the whole dosimetry study concerning this new radiotracer for rabbits and humans using the GATE Monte Carlo platform. Materials and methods: Absorbed doses to critical organs are determined using the MIRD formalism. Biodistribution data are obtained by organ sampling, measuring the activity in organs for three rabbits sacrificed at various times postadministration, and by SPECT/CT imaging at different times after injection. Most important sources are cartilages (in knees and intervertebral discs), due to localization together with the liver and kidneys due to excretion of the agent. S‐values are calculated from rabbit's CT scan and human CT scan using the GATE v8.0 Monte Carlo platform. Cumulated activity in humans is extrapolated from animals using the %kg‐dose/g method. Particular attention is given to dose calculation in bones, bone marrow and organs at risk. Results: The dosimetry performed in rabbits shows highest absorbed doses for liver and kidneys with respectively 22.5 and 43.8 µGy per MBq of injected activity. In humans, we found absorbed doses for a maximum injected activity of 15 MBq/kg, that is, 1050 MBq for an adult of 70 kgs of 9.03 mGy for kidneys and 4.16 mGy for knee cartilages. Effective dose is 2.69 µSv/MBq. Conclusions: The dosimetry profile of [99mTc]NTP15‐5 in the context of preclinical trials is of major importance in order to make sure that organs at risk are not overexposed. GATE provides all the capability needed to calculate dose profiles for internal dosimetry. The extrapolation of the dose for a human model is a first step towards clinical trials. [ABSTRACT FROM AUTHOR]

Purpose: Pathological complete response to the neoadjuvant therapy (NAT) for triple negative breast cancer (TNBC) is predictive of prolonged patient survival. Methods for early evaluation of NAT efficiency are still needed, in order to rapidly adjust the therapeutic strategy in case of initial non-response. One option for this is molecular imaging of apoptosis induced by chemotherapy. Therefore, we investigated the capacity of [18F]ML-10 PET imaging, an apoptosis radiotracer, to detect tumor cell apoptosis and early predict the therapeutic response of human TNBC. Results: Initially, the induction of apoptosis by different therapies was quantified. We confirmed, in vitro, that paclitaxel or epirubicin, the fundamental cytotoxic drugs for breast cancer, induce apoptosis in TNBC cell lines. Exposure of TNBC models MDA-MB-231 and MDA-MB-468 to these drugs induced a significant increase (p < 0.01) of the apoptotic hallmarks: DNA fragmentation, membrane phospholipid scrambling, and PARP activation. Secondarily, apoptotic fraction was compared to the intracellular accumulation of the radiotracer. [18F]ML-10 accumulated in the apoptotic cells after 72 h of treatment by paclitaxel in vitro; this accumulation positively correlated with the apoptotic fraction. In vivo, [18F]ML-10 was rapidly cleared from the nontarget organs and mainly eliminated by the kidneys. Comparison of the in vivo [18F]FDG, [18F]FMISO, and [18F]ML-10 uptakes revealed that the tumor accumulation of [18F]ML-10 was directly related to the tumor hypoxia level. Finally, after the in vivo treatment of TNBC murine xenografts by paclitaxel, apoptosis was well induced, as demonstrated by the cleaved caspase-3 levels; however, no significant increase of [18F]ML-10 accumulation in the tumors was observed, either on day 3 or day 6 after the end of the treatment. Conclusions: These results highlighted that PET imaging using [18F]ML-10 allows the visualization of apoptotic cells in TNBC models. Nevertheless, the increase of the chemotherapy-induced apoptotic response when using paclitaxel could not be assessed using this radiotracer in our mouse model. [ABSTRACT FROM AUTHOR]

As evidenced by the number of publications and patents published in the last years, the radiosynthesis of 6‐[18F]fluoro‐3,4‐dihydroxy‐L‐phenylalanine ([18F]FDOPA) using the nucleophilic [18F]F‐ process remains currently a challenge for the radiochemists scientific community even if promising methods for the radiofluorination of electron‐rich aromatic structures were recently developed from arylboronate, arylstannane or iodonium salt precursors. In such context, based on the use of an iodonium triflate salt precursor, we optimized a fast and efficient radiofluorination route fully automated and free from any base, cryptand or metal catalyst for the radiosynthesis of [18F]FDOPA. Using this method, this clinically relevant radiotracer was produced in 64 min, 27–38 % RCY d.c. (n = 5), >99 % RCP, >99 % ee., and high Am 170–230 GBq/µmol. In addition, this optimization study clearly highlighted the important role of a triflate‐hydrogen carbonate counterion exchange during the radiolabeling process to achieve high fluorine‐18 incorporation yields. [18F]FDOPA challenge: A new radiosynthetic route to [18F]FDOPA was developed and fully automated from a key iodonium triflate salt precursor. This radiotracer was produced via a "minimalist approach" (see figure) involving nucleophilic [18F]F– process, without any use of base, cryptand or metal catalyst, in 64 min, 27–38 % RCY, >99 % RCP, > 99 % ee., and high Am 170–230 GBq.µmol–1 (n = 5). [ABSTRACT FROM AUTHOR]

Purpose: Dosimetry for melanoma‐targeted radionuclide therapy (TRT) with [131I]ICF01012, a melanin ligand, has been previously evaluated in mice bearing melanomas. In this study, activity distribution and dosimetry are performed on healthy rabbits (Fauve de Bourgogne) using SPECT‐CT imaging and ex vivo measurements. Material and Methods: Ex vivo biodistribution (i.v. injection: 370 kBq/kg, n = 2 per point) is performed on blood, eyes, brain, lung, liver, kidneys, heart, stomach, and spleen. Dosimetry calculations follow the MIRD formalism: S values are calculated from CT images using the GATE Monte Carlo platform and activity distributions are obtained from SPECT‐CT imaging (i.v. injection: 37 MBq/kg n = 3 per point). A specific study is presented to assess dose to human retina. Results: Time‐integrated activities based on SPECT‐CT are in accordance with ex vivo measurements except for spleen. Doses to liver and eyes are the most significant, with respectively, 6.38 ± 0.50 Gy/GBq (evaluated through SPECT‐CT imaging) and 45.8 ± 7.9 Gy/GBq (evaluated through ex vivo measurements). Characterization of ocular [131I]ICF01012 biodistribution in rabbits and quantification of melanin allowed to assess a dose of 3.07 ± 0.70 Gy/GBq to human retina. Conclusion: This study sustains [131I]ICF01012 as a good candidate for melanoma TRT and open perspectives for personalized dosimetry calculation during phase I clinical transfer. [ABSTRACT FROM AUTHOR]

Abstract Due to an abundant chondrogenic, poorly vascularized and particularly hypoxic extracellular matrix, chondrosarcoma, a malignant cartilaginous tumour, is chemo- and radio-resistant. Surgical resection with wide margins remains the mainstay of treatment. To address the lack of therapy, our strategy aims to increase anticancer drugs targeting and delivery in the tumour, by leveraging specific chondrosarcoma hallmarks: an extensive cartilaginous extracellular matrix, namely the high negative fixed charge density and severe chronic hypoxia. A dual targeted therapy for chondrosarcoma was investigated by conjugation of a hypoxia-activated prodrug (HAP) to quaternary ammonium (QA) functions which exhibit a high affinity for polyanionic sites of proteoglycans (PGs), the major components of the chondrosarcoma extracellular matrix. Based on preclinical results, an imidazole prodrug, ICF05016 , was identified and provided the basis for a lead optimization study. A series of 27 QA-phosphoramide mustard conjugates, differing by the type of QA function and the length of the alkyl linker, was yielded by a common multi-step sequence involving phosphorylation of a key 2-nitroimidazole alcohol. Then, a screening was realized by surface plasmon resonance technology to assess biomolecular interactions between QA derivatives and aggrecan, the most abundant PG in chondrosarcoma. Results revealed that affinity depends more on the type of QA function, than on the linker length. Moreover, the presence of a benzyl group enhanced affinity to aggrecan. Twelve compounds were shortlisted and evaluated for antiproliferative activity (i.e., growth inhibiting concentration 50), under normoxic and hypoxic conditions using the human extraskeletal myeloid chondrosarcoma cell line (HEMC-SS). For all prodrugs, hypoxic selectivity was maintained and even increased, compared with the lead. From this study, compound 31f emerged as the most effective PG-targeted HAPs with a dissociation constant of 2.10 μM in the SPR experiment, a hypoxia cytotoxicity ratio of 24 and an efficient reductive cleavage under chemical and enzymatic conditions. Graphical abstract Hypoxia-activated prodrug with a quaternary ammonium function as proteoglycan-targeting ligand for a better management of chondrosarcoma: synthesis, Surface Plasmon Resonance screening, in vitro hypoxic selectivity and reductive activation. Image 1 Highlights • Proteoglycan-targeting applied to hypoxia-activated prodrug in chondrosarcoma. • A series of hypoxia-activated prodrugs was synthesized. • Screening by surface plasmon resonance technology to assess affinity to aggrecan. • Hypoxic selectivity was maintained and even increased, compared with the lead. • Positive impact of benzyle derivatives on affinity to aggrecan and hypoxic selectivity. [ABSTRACT FROM AUTHOR]

Nitrogen mustards, such as chlorambucil (CLB), can cause adverse side-effects due to ubiquitous distribution in non-target organs. To minimize this toxicity, strategies of tumor-targeting drug delivery have been developed, where a cytotoxic warhead is linked to a tumor-cell-specific small ligand. Malignant cells exhibit marked glucose avidity and an accelerated metabolism by aerobic glycolysis, known as the Warburg effect, and recognized as a hallmark of cancer. A targeting approach exploiting the Warburg effect by conjugation of CLB to 2-fluoro-2-deoxyglucose (FDG) was previously reported and identified two peracetylated glucoconjugates 2 and 3 with promising antitumor activities in vivo . These results prompted us to investigate the importance of the spacer in this tumor-targeting glucose-based conjugates. Here we report the chemical synthesis and an in vitro cytotoxicity evaluation, using a 5-member panel of human tumor cell lines and human fibroblasts, of 16 new CLB glucoconjugates in which the alkylating drug is attached to the C-1 position of FDG via different linkages. We studied the structure-activity relationships in the linker, and evidenced the positive impact of an aromatic linker on in vitro cytotoxicity: compound 51 proved to be the most active FDG-CLB glucoside, characterized by a bis-aromatic spacer tethered to CLB through an amide function. [ABSTRACT FROM AUTHOR]

Purpose: This study was conducted during the development of innovative treatment targeting the microenvironment of chondrosarcoma. In this context, MMP inhibitors were conjugated with a quaternary ammonium (QA) function as a targeting ligand to proteoglycans of chondrosarcoma extracellular matrix. Here we report the proof of concept of this strategy applied to the MMP13 inhibitor, doxycycline (Dox).Methods: A quaternary ammonium derivative of the MMP13 inhibitor doxycycline (QA-Dox) was synthesized, and its anticancer activity was evaluated in the Swarm rat chondrosarcoma (SRC) model compared with the parent drug doxycycline, in vitro and in vivo. In vivo, dox and QA-Dox efficiency was assessed at equimolar doses according to a q4dx4 schedule by monitoring tumour volume by MRI and PG-targeted scintigraphy. Molecular mechanism (MMP13 expression, proteoglycan level) and histology studies were performed on tumours.Results: The link of QA targeting function to Dox maintained the MMP13 inhibitory activity in vitro. Interestingly, the bacteriostatic activity was lost. SRC cells incubated with both drugs were blocked in S and G2 M phases. Tumour growth inhibition (confirmed by histology) was observed for both Dox and QA-Dox. Undesirable blood effects (leukocyte decrease) were reduced when Dox was targeted to tumour tissue using the QA function.Conclusions: In the SRC model, the MMP13 inhibitor Dox and its QA derivative are promising as adjuvant therapies for chondrosarcoma management. [ABSTRACT FROM AUTHOR]

PURPOSE: This work reports, in melanoma models, the theranostic potential of ICF15002 as a single fluorinated and iodinatedmelanin-targeting compound.METHODS: Studieswere conducted in themurine syngeneic B16BL6 model and in the A375 and SK-MEL-3 human xenografts. ICF15002 was radiolabeled with fluorine-18 for positron emission tomography (PET) imaging and biodistribution, with iodine-125 for metabolism study, and iodine-131 for targeted radionuclide therapy (TRT). TRT efficacywas assessed by tumor volume measurement, withmechanistics and dosimetry parameters being determined in the B16BL6model. Intracellular localization of ICF15002 was characterized by secondary ion mass spectrometry (SIMS). RESULTS: PET imaging with [18F]ICF15002 evidenced tumoral uptake of 14.33 ± 2.11%ID/g and 4.87 ± 0.93%ID/g in pigmented B16BL6 and SK-MEL-3 models, respectively, at 1 hour post inoculation. No accumulation was observed in the unpigmented A375 melanoma. SIMS demonstrated colocalization of ICF15002 signal with melanin polymers in melanosomes of the B16BL6 tumors. TRT with two doses of 20 MBq [131I]ICF15002 delivered an absorbed dose of 102.3 Gy to B16BL6 tumors, leading to a significant tumor growth inhibition [doubling time (DT) of 2.9 ± 0.5 days in treated vs 1.8 ± 0.3 in controls] and a prolonged median survival (27 days vs 21 in controls). P53S15 phosphorylation and P21 induction were associated with a G2/M blockage, suggesting mitotic catastrophe. In the human SK-MEL-3 model, three doses of 25 MBq led also to a DT increase (26.5 ± 7.8 days vs 11.0 ± 3.8 in controls) and improved median survival (111 days vs 74 in controls). CONCLUSION: Results demonstrate that ICF15002 fulfills suitable properties for bimodal imaging/TRT management of patients with pigmented melanoma. [ABSTRACT FROM AUTHOR]

Here we report the synthesis and radiolabelling with iodine-125 of a melanoma-selective prodrug ( 17a* ) and its parent drug IUdR . The in vivo and ex vivo biodistributions of [ 125 I]( 17a* ) and [ 125 I] IUdR were evaluated in a model of melanoma B16F0-bearing mice. The pharmacokinetic profile of [ 125 I]( 17a* ) suggests rapid release of the active drug [ 125 I] IUdR after i.v. administration of [ 125 I]( 17a* ). Preliminary metabolism studies in dedicated compartments (i.e. blood, urine and tumour) yielded results consistent with this hypothesis. [ABSTRACT FROM AUTHOR]

The cartilage-targeting strategy is based on the strong affinity of quaternary ammonium (QA) functions for cartilage proteoglycans. We use a bifunctional agent containing QA moiety and a polyazamacrocycle structure able to complex technetium-99m. 99m Tc-NTP 15-5 was selected for its high stability and its high affinity for proteoglycans in vivo . Labeling conditions of NTP 15-5 were optimized, and a lyophilized kit was developed for radiolabeling of 99m Tc-NTP 15-5 (radiochemical yields 94.6±1.8%). 99m Tc-NTP 15-5 was stable and resulted in favorable biological evaluations. [ABSTRACT FROM AUTHOR]

Melanin pigment represents an attractive target to address specific treatment to melanoma cells, such as cytotoxic radionuclides. However, less than half of the patients have pigmented metastases. Hence, specific marker is required to stratify this patient population before proceeding with melanin-targeted radionuclide therapy. In such a context, we developed fluorinated analogues of a previously studied melanin-targeting ligand, N -(2-diethylaminoethyl)-6-iodoquinoxaline-2-carboxamide ( ICF01012 ). These latter can be labeled either with 18 F or 131 I/ 125 I for positron emission tomography imaging (melanin-positive patient selection) and targeted radionuclide therapy purposes. Here we describe the syntheses, radiosyntheses and preclinical evaluations on melanoma-bearing mice model of several iodo- and fluoro(hetero)aromatic derivatives of the ICF01012 scaffold. After preliminary planar gamma scintigraphic and positron emission tomography imaging evaluations, [ 125 I]- and [ 18 F]- N -[2-(diethylamino)ethyl]-4-fluoro-3-iodobenzamides ([ 125 I] 4 , [ 18 F] 4 ) were found to be chemically and biologically stable with quite similar tumor uptakes at 1 h p.i. (9.7 ± 2.6% ID/g and 6.8 ± 1.9% ID/g, respectively). [ABSTRACT FROM AUTHOR]

Purpose: Recently, nutritional and pharmaceutical benefits of pomegranate (PG) have raised a growing scientific interest. Since PG is endowed with anti-inflammatory and antioxidant activities, we hypothesized that it may have beneficial effects on osteoporosis. Methods: We used ovariectomized (OVX) mice as a well-described model of postmenopausal osteoporosis to study the influence of PG consumption on bone health. Mice were divided into five groups as following: two control groups sham-operated and ovariectomized (OVX CT) mice fed a standard diet, versus three treated groups OVX mice given a modified diet from the AIN-93G diet, containing 5.7 % of PG lyophilized mashed totum (OVX PGt), or 9.6 % of PG fresh juice (OVX PGj) or 2.9 % of PG lyophilized mashed peel (OVX PGp). Results: As expected, ovariectomy was associated with a decreased femoral bone mineral density (BMD) and impaired bone micro-architecture parameters. Consumption of PGj, PGp, or PGt induced bone-sparing effects in those OVX mice, both on femoral BMD and bone micro-architecture parameters. In addition, PG (whatever the part) up-regulated osteoblast activity and decreased the expression of osteoclast markers, when compared to what was observed in OVX CT animals. Consistent with the data related to bone parameters, PG consumption elicited a lower expression of pro-inflammatory makers and of enzymes involved in ROS generation, whereas the expression of anti-inflammatory markers and anti-oxidant actors was enhanced. Conclusion: These results indicate that all PG parts are effective in preventing the development of bone loss induced by ovariectomy in mice. Such an effect could be partially explained by an improved inflammatory and oxidative status. [ABSTRACT FROM AUTHOR]

Ourproject deals with a multimodal approach using a single fluorinatedand iodinated melanin-targeting structure and offering both imaging(positron emission tomography (PET)/fluorine-18) and treatment (targetedradionuclide therapy/iodine-131) of melanoma. Six 6-iodoquinoxaline-2-carboxamidederivatives with various side chains bearing fluorine were synthesizedand radiofluorinated, and their in vivobiodistributionwas studied by PET imaging in B16Bl6 primary melanoma-bearing mice.Among this series, [18F]8emerged as the mostpromising compound. [18F]8was obtained bya fully automated radiosynthesis process within 57 min with an overallradiochemical yield of 21%, decay-corrected. PET imaging of [18F]8demonstrated very encouraging results asearly as 1 h postinjection with high tumor uptake (14.33% ± 2.11%ID/g), high contrast (11.04 ± 2.87 tumor-to-muscle ratio), andfavorable clearance properties. These results, associated with thepreviously reported pharmacokinetic properties and dosimetry of 8, make it a potential agent for both PET imaging and targetedradionuclide therapy of melanoma. [ABSTRACT FROM AUTHOR]

Abstract: In the current context of longer life expectancy, the prevalence of osteoporosis is increasingly important. This is why development of new strategies of prevention is highly suitable. Pomegranate seed oil (PSO) and its major component, punicic acid (a conjugated linolenic acid), have potent anti-inflammatory and anti-oxidative properties both in vitro and in vivo, two processes strongly involved in osteoporosis establishment. In this study, we demonstrated that PSO consumption (5% of the diet) improved significantly bone mineral density (240.24±11.85 vs. 203.04±34.19 mg/cm3) and prevented trabecular microarchitecture impairment in ovariectomized (OVX) mice C57BL/6J, compared to OVX control animals. Those findings are associated with transcriptional changes in bone tissue, suggesting involvement of both osteoclastogenesis inhibition and osteoblastogenesis improvement. In addition, thanks to an ex vivo experiment, we provided evidence that serum from mice fed PSO (5% by gavage) had the ability to significantly down-regulate the expression of specific osteoclast differentiation markers and RANK-RANKL downstream signaling targets in osteoclast-like cells (RAW264.7) (RANK: negative 0.49-fold vs. control conditions). Moreover, in osteoblast-like cells (MC3T3-E1), it elicited significant increase in alkaline phosphatase activity (+159% at day 7), matrix mineralization (+271% on day 21) and transcriptional levels of major osteoblast lineage markers involving the Wnt/β-catenin signaling pathways. Our data also reveal that PSO inhibited pro-inflammatory factors expression while stimulating anti-inflammatory ones. These results demonstrate that PSO is highly relevant regarding osteoporosis. Indeed, it offers promising alternatives in the design of new strategies in nutritional management of age-related bone complications. [Copyright &y& Elsevier]

Tumor hypoxia is a characteristic of cancer cell growth and invasion, promoting angiogenesis, which facilitates metastasis. Oxygen delivery remains impaired because tumor vessels are anarchic and leaky, contributing to tumor cell dissemination. Counteracting hypoxia by normalizing tumor vessels in order to improve drug and radio therapy efficacy and avoid cancer stem-like cell selection is a highly challenging issue. We show here that inositol trispyrophosphate (ITPP) treatment stably increases oxygen tension and blood flow in melanoma and breast cancer syngeneic models. It suppresses hypoxia-inducible factors (HIFs) and proangiogenic/glycolysis genes and proteins cascade. It selectively activates the tumor suppressor phosphatase and tensin homolog (PTEN) in vitro and in vivo at the endothelial cell (EC) level thus inhibiting PI3K and reducing tumor AKT phosphorylation. These mechanisms normalize tumor vessels by EC reorganization, maturation, pericytes attraction, and lowering progenitor cells recruitment in the tumor. It strongly reduces vascular leakage, tumor growth, drug resistance, and metastasis. ITPP treatment avoids cancer stem-like cell selection, multidrug resistance (MDR) activation and efficiently enhances chemotherapeutic drugs activity. These data show that counteracting tumor hypoxia by stably restoring healthy vasculature is achieved by ITPP treatment, which opens new therapeutic options overcoming hypoxia-related limitations of antiangiogenesis-restricted therapies. By achieving long-term vessels normalization, ITPP should provide the adjuvant treatment required in order to overcome the subtle definition of therapeutic windows for in vivo treatments aimed by the current strategies against angiogenesis-dependent tumors. [ABSTRACT FROM AUTHOR]

Osteoporosis is a bone pathology leading to increase fractures risk and challenging quality of life. Since current treatments could exhibit deleterious side effects, the use of food compounds derived from plants represents a promising innovative alternative due to their potential therapeutic and preventive activities against human diseases. In this study, we investigated the ability of the polyphenol fisetin to counter osteoporosis and analyzed the cellular and molecular mechanisms involved. In vivo, fisetin consumption significantly prevented bone loss in estrogen deficiency and inflammation mice osteoporosis models. Indeed, bone mineral density, micro-architecture parameters and bone markers were positively modulated by fisetin. Consistent with in vivo results, we showed that fisetin represses RANKL-induced osteoclast differentiation and activity as demonstrated by an inhibition of multinucleated cells formation, TRAP activity and differentiation genes expression. The signaling pathways NF-κB, p38 MAPK, JNK and the key transcription factors c-Fos and NFATc1 expressions induced by RANKL, were negatively regulated by fisetin. We further showed that fisetin inhibits the constitutive proteasomal degradation of MKP-1, the phosphatase that deactivates p38 and JNK. Consistently, using shRNA stable cell lines, we demonstrated that impairment of MKP-1 decreases fisetin potency. Taken together, these results strongly support that fisetin should be further considered as a bone protective agent. [ABSTRACT FROM AUTHOR]

Abstract: In order to develop new iodinated and fluorinated matched-pair radiotracers for Single-Photon Emission Computed Tomography (SPECT)/Positron Emission Tomography (PET) imaging and targeted radionuclide therapy of melanoma, we successfully synthesized and radiolabelled with iodine-125 seven new derivatives, starting from our previously described lead structure 3. The relevance of these radiotracers for gamma scintigraphic imaging of melanoma in rodent was assessed. The tumoural radioactivity uptake was most often high and specific even at early time points (12.1–18.3% ID/g at 3 h p.i. for [125I]39–42) and a fast clearance from the non-target organs was observed. Also, calculated effective doses that could be delivered to tumours when using corresponding [131I]-labelled analogues were generally higher than 100 cGy/MBq injected (98.9–150.5 cGy/MBq for [131I]39–42). These results make compounds 39–42 suitable candidates for (i) PET imaging of melanoma after labelling with fluorine-18 and (ii) targeted radionuclide therapy of disseminated melanoma after labelling with iodine-131. [Copyright &y& Elsevier]

The mechanisms linking fat intake to bone loss remain unclear. By demonstrating the expression of the free fatty acid receptor G-coupled protein receptor 40 (GPR40) in bone cells, we hypothesized that this receptor may play a role in mediating the effects of fatty acids on bone remodeling. Using micro-CT analysis, we showed that GPR40-/- mice exhibit osteoporotic features suggesting a positive role of GPR40 on bone density. In primary cultures of bone marrow, we showed that GW9508, a GRP40 agonist, abolished bone-resorbing cell differentiation. This alteration of the receptor activator of NF-κB ligand (RANKL)-induced osteoclast differentiation occurred via the inhibition of the nuclear factor κB (NF-κB) signaling pathway as demonstrated by decrease in gene reporter activity, inhibitor of κB kinase (IKKα/β) activation, inhibitor of κB (IkBα) phosphorylation, and nuclear factor of activated T cells 1 (NFATc1) expression. The GPR40-dependent effect of GW9508 was confirmed using shRNA interference in osteoclast precursors and GPR40-/- primary cell cultures. In addition, in vivo administration of GW9508 counteracted ovariectomy-induced bone loss in wild-type but not GPR40-/- mice, enlightening the obligatory role of the GPR40 receptor. Then, in a context of growing prevalence of metabolic and age-related bone disorders, our results demonstrate for the first time in translational approaches that GPR40 is a relevant target for the design of new nutritional and therapeutic strategies to counter bone complications. [ABSTRACT FROM AUTHOR]

Abstract: A multi-proxy approach using trench sediment analysis on the southwestern coast of Spain (Los Lances Bay, Andalusia) provides a high-resolution record of the 1755 Lisbon tsunami and offers new means to interpret tsunami deposits. A combination of sedimentological (grain size, sorting, AMS), micromorphological (X-ray tomography and radiography, thin sections) and geochemical analyses (X-ray microfluorescence, ICP-AES) combines to provide a comprehensive reconstruction of the different phases of tsunami deposition and flow dynamics. Vertical variations in sediment texture, fabric and composition of the 1755 tsunami deposits in Los Lances are then discussed with reference to existing literature on diagnostic criteria commonly used for identifying and interpreting tsunami deposits. Finally possible leads for future investigation are proposed. [Copyright &y& Elsevier]

Purpose: Here, we report a new and rapid radiosynthesis of F- N-[2-(diethylamino)ethyl]-6-fluoro-pyridine-3-carboxamide ([F]ICF01006), a molecule with a high specificity for melanotic tissue, and its evaluation in a murine model for early specific detection of pigmented primary and disseminated melanoma. Methods: [F]ICF01006 was synthesized using a new one-step bromine-for-fluorine nucleophilic heteroaromatic substitution. Melanoma models were induced by subcutaneous (primary tumour) or intravenous ( lung colonies) injection of B16BL6 melanoma cells in C57BL/6J mice. The relevance and sensitivity of positron emission tomography (PET) imaging using [F]ICF01006 were evaluated at different stages of tumoural growth and compared to F-fluorodeoxyglucose ([F]FDG). Results: The fully automated radiosynthesis of [F]ICF01006 led to a radiochemical yield of 61 % and a radiochemical purity >99 % (specific activity 70-80 GBq/μmol; total synthesis time 42 min). Tumours were visualized before they were palpable as early as 1 h post-injection with [F]ICF01006 tumoural uptake of 1.64 ± 0.57, 3.40 ± 1.47 and 11.44 ± 2.67 percentage of injected dose per gram of tissue (%ID/g) at days 3, 5 and 14, respectively. [F]ICF01006 PET imaging also allowed detection of melanoma pulmonary colonies from day 9 after tumour cell inoculation, with a lung radiotracer accumulation correlated with melanoma invasion. At day 21, radioactivity uptake in lungs reached a value of 5.23 ± 2.08 %ID/g (versus 0.41 ± 0.90 %ID/g in control mice). In the two models, comparison with [F]FDG showed that both radiotracers were able to detect melanoma lesions, but [F]ICF01006 was superior in terms of contrast and specificity. Conclusion: Our promising results provide further preclinical data, reinforcing the excellent potential of [F]ICF01006 PET imaging for early specific diagnosis and follow-up of melanin-positive disseminated melanoma. [ABSTRACT FROM AUTHOR]

Introduction: Osteosarcoma (OS) management requires a better understanding of tumor/bone interactions in vivo during disease progression. Using [(18)F]-FDG and [(99m)Tc]-HMDP imaging, we assessed a methodology for an in vivo quantitative characterization of an orthotopic model of osteolytic OS on the basis of (1) tumor proliferation, (2) tumor and bone metabolic activities, and (3) bone remodeling. Methods: POS-1 tumor bearing mice were monitored in vivo over a 26-day period, with tumor and bone metabolic volumes (TMV and BMV, respectively) being determined from [(18)F]-FDG, bone remodeling from [(99m)Tc]-HMDP, and tumoral volume from micro- computed tomography scans. Results: From day 10, [(18)F]-FDG strongly accumulated within POS-1 tumor, with a tumor/muscle ratio of 3.7 ± 0.8. TMV and BMV increased as pathology progressed: TMV increased at early stage of pathology (from 56%) whereas BMV strongly increased (from 113%) during late stage. From [(99m)Tc]-HMDP imaging, bone remodeling features were evidenced within the distal region of tibia bearing the tumor, with a mean scintigraphic ratio of 1.36 ± 0.11 at day 12, that reached value of 2.53 ± 0.19 at day 26. Conclusions: Our results validated the POS-1 orthotopic model as "OS imaging model," that could serve for evaluating in vivo therapies targeting tumor proliferation and/or bone remodeling in OS. [ABSTRACT FROM AUTHOR]

Abstract: Fats are prevalent in western diets; they have known deleterious effects on muscle insulin resistance and may contribute to bone loss. However, relationships between fatty acids and locomotor system dysfunctions in elderly population remain controversial. The aim of this study was to analyze the impact of fatty acid quality on the age related evolution of the locomotor system and to understand which aging mechanisms are involved. In order to analyze age related complications, the SAMP8 mouse strain was chosen as a progeria model as compared to the SAMR1 control strain. Then, two months old mice were divided in different groups and subjected to the following diets : (1) standard “growth” diet — (2) “sunflower” diet (high ω6/ω3 ratio) — (3) “borage” diet (high γ-linolenic acid) — (4) “fish” diet (high in long chain ω3). Mice were fed ad libitum through the whole protocol. At 12months old, the mice were sacrificed and tissues were harvested for bone studies, fat and muscle mass measures, inflammation parameters and bone cell marker expression. We demonstrated for the first time that borage and fish diets restored inflammation and bone parameters using an original model of senile osteoporosis that mimics clinical features of aging in humans. Therefore, our study strongly encourages nutritional approaches as relevant and promising strategies for preventing aged-related locomotor dysfunctions. This article is part of a Special Issue entitled: Interactions Between Bone, Adipose Tissue and Metabolism. [Copyright &y& Elsevier]

Abstract: The proteasome is a promising target in cancer therapy. However, it is ubiquitous and its inhibitors cause side effects. To target melanoma cells we synthesized new peptide aldehyde and vinylsulfone inhibitors of the proteasome conjugated to the melanin-targeting ligand (MTL) derived from radiotracer [123I]-N-(2-diethylaminoethyl)benzamide ([123I]BZA) or [125I]-N-(4-dipropylaminobutyl)-4-iodobenzamide ([125I]BZ18). Influence on the cytotoxicity of the benzamide alkyl side chain length and the composition of the amino acid sequence was assessed. Among the conjugates evaluated, compound 16 and 22 presented the highest cytotoxicity (IC50, 0.71 and 0.64 μM respectively), which persisted in the presence of an MTL derived from N-(dialkylaminoalkylenyl)benzamide residue. [Copyright &y& Elsevier]

Purpose: Preclinical data pointed to Tc-NTP 15-5 as a good candidate for single photon emission computed tomography (SPECT) imaging of cartilaginous disease. We set out to investigate and quantify Tc-NTP 15-5 ex vivo uptake by human articular cartilage relative to bone Tc-hydroxymethylene diphosphonate (HMDP) radiotracer. Methods: Three osteoarthritic human tibial plateaux and four tibiofemoral joints were incubated with Tc-NTP 15-5 and Tc-HMDP for 2 h. Affinity of tracers for cartilage was determined by visual analysis of SPECT/CT acquisitions and measurement of cartilage to cortical bone uptake ratios. Results: Cartilage to cortical bone uptake ratios were 3.90 ± 2.35 and 0.76 ± 0.24, respectively, for Tc-NTP 15-5 and Tc-HMDP radiotracers. Visual analysis of fused SPECT/CT slices showed selective, intense Tc-NTP 15-5 accumulation in articular cartilage, whereas Tc-HMDP binding was low. Interestingly, a cartilage defect visualized on CT was clearly associated with focal decreased uptake of Tc-NTP 15-5. Conclusion: The tracer Tc-NTP 15-5 is of major interest for human cartilage molecular imaging and could find clinical applications in osteoarthritis staging and monitoring. [ABSTRACT FROM AUTHOR]

Abstract: The cyclization of anticancer drugs into active intermediates has been reported mainly for DNA alkylating molecules including nitrosoureas. We previously defined the original cytotoxic mechanism of anticancerous N-phenyl-N′-(2-chloroethyl)ureas (CEUs) that involves their reactivity towards cellular proteins and not against DNA; two CEU subsets have been shown to alkylate β-tubulin and prohibitin leading to inhibition of cell proliferation by G2/M or G1/S cell cycle arrest. In this study, we demonstrated that cyclic derivatives of CEUs, N-phenyl-4,5-dihydrooxazol-2-amines (Oxas) are two- to threefold more active than CEUs and share the same cytotoxic properties in B16F0 melanoma cells. Moreover, the CEU original covalent binding by an ester linkage on β-tubulin Glu198 and prohibitin Asp40 was maintained with Oxas. Surprisingly, we observed that Oxas were spontaneously formed from CEUs in the cell culture medium and were also detected within the cells. Our results suggest that the intramolecular cyclization of CEUs leads to active Oxas that should then be considered as the key intermediates for protein alkylation. These results will be useful for the design of new prodrugs for cancer chemotherapy. [Copyright &y& Elsevier]

Introduction: The use of radiolabeled molecules allows the study of in vivo biodistribution, target organs, and kinetic profile after systemic administration by 1) radioactive organ counting and 2) quantitative autoradiographic analysis of whole-body slices (WBA). However, these techniques are time- and animal consuming for several times studied. So, in vivo scintigraphic imaging should appear of interest for a first screening of compounds, as it is able to rapidly demonstrate tumoral uptake and kinetics by serial examinations in the same mice. Materials and Methods: In this study, the tumoral distribution and kinetics of six molecules considered as potential melanoma tracers radiolabeled with (125)I were analyzed by gamma-scintigraphy comparatively to the results obtained by WBA. Tumoral uptake has been quantified and expressed by: 1) tumor-to-background ratios and 2) standardized tumoral uptake (STU) in percent injected dose per gram, with tumor weight being extrapolated from the measurement of the two diameters. Results: Results from STU analysis showed good agreement (correlation coefficient = 0.92) with those of WBA, and the same classification of compounds (on the basis of their melanoma affinity) was obtained, with two compounds (of six) being rejected. Conclusions: [(125)I] scintigraphic imaging appeared as a relevant, easy-going method for a first pharmacologic selection in mice. [ABSTRACT FROM AUTHOR]

The use of radiolabeled non-natural amino acids can provide high contrast SPECT/PET metabolic imaging of solid tumors. Among them, radiohalogenated tyrosine analogs (i.e., [123I]IMT, [18F]FET, [18F]FDOPA, [123I]8-iodo-L-TIC(OH), etc.) are of particular interest. While radioiodinated derivatives, such as [123I]IMT, are easily available via electrophilic aromatic substitutions, the production of radiofluorinated aryl tyrosine analogs was a long-standing challenge for radiochemists before the development of innovative radiofluorination processes using arylboronate, arylstannane or iodoniums salts as precursors. Surprisingly, despite these methodological advances, no radiofluorinated analogs have been reported for [123I]8-iodo-L-TIC(OH), a very promising radiotracer for SPECT imaging of prostatic tumors. This work describes a convenient synthetic pathway to obtain new radioiodinated and radiofluorinated derivatives of TIC(OH), as well as their non-radiolabeled counterparts. Using organotin compounds as key intermediates, [125I]5-iodo-L-TIC(OH), [125I]6-iodo-L-TIC(OH) and [125I]8-iodo-L-TIC(OH) were efficiently prepared with good radiochemical yield (RCY, 51–78%), high radiochemical purity (RCP, >98%), molar activity (Am, >1.5–2.9 GBq/µmol) and enantiomeric excess (e.e. >99%). The corresponding [18F]fluoro-L-TIC(OH) derivatives were also successfully obtained by radiofluorination of the organotin precursors in the presence of tetrakis(pyridine)copper(II) triflate and nucleophilic [18F]F− with 19–28% RCY d.c., high RCP (>98.9%), Am (20–107 GBq/µmol) and e.e. (>99%). [ABSTRACT FROM AUTHOR]

Oxaliplatin, the first-line chemotherapeutic agent against colorectal cancer (CRC), induces peripheral neuropathies, which can lead to dose limitation and treatment discontinuation. Downregulation of potassium channels, which involves histone deacetylase (HDAC) activity, has been identified as an important tuner of acute oxaliplatin-induced hypersensitivity. MS-275, a class I histone deacetylase inhibitor (HDACi), prevents acute oxaliplatin-induced peripheral neuropathy (OIPN). Moreover, MS-275 exerts anti-tumor activity in several types of cancers, including CRC. We thus hypothesized that MS-275 could exert both a preventive effect against OIPN and potentially a synergistic effect combined with oxaliplatin against CRC development. We first used RNAseq to assess transcriptional changes occurring in DRG neurons from mice treated by repeated injection of oxaliplatin. Moreover, we assessed the effects of MS-275 on chronic oxaliplatin-induced peripheral neuropathy development in vivo on APCMin/+ mice and on cancer progression when combined with oxaliplatin, both in vivo on APCMin/+ mice and in a mouse model of an orthotopic allograft of the CT26 cell line as well as in vitro in T84 and HT29 human CRC cell lines. We found 741 differentially expressed genes (DEGs) between oxaliplatin- and vehicle-treated animals. While acute OIPN is known as a channelopathy involving HDAC activity, chronic OIPN exerts weak ion channel transcriptional changes and no HDAC expression changes in peripheral neurons from OIPN mice. However, MS-275 prevents the development of sensory neuropathic symptoms induced by repeated oxaliplatin administration in APCMin/+ mice. Moreover, combined with oxaliplatin, MS-275 also exerts synergistic antiproliferative and increased survival effects in CT26-bearing mice. Consistently, combined drug associations exert synergic apoptotic and cell death effects in both T84 and HT29 human CRC cell lines. Our results strongly suggest combining oxaliplatin and MS-275 administration in CRC patients in order to potentiate the antiproliferative action of chemotherapy, while preventing its neurotoxic effect. [ABSTRACT FROM AUTHOR]

Abstract: N-(2-diethylaminoethyl)-6-iodoquinoxaline-2-carbamide (ICF 01012) is a new melanoma imaging agent showing promising properties for application in internal radionuclide therapy. We developed an analytical protocol for detection of ICF 01012 in biological samples using HPLC. The proposed method was first validated using standard of ICF 01012 and four potent metabolites of this compound and then applied to follow the metabolic fate of [125I]ICF 01012 after injection in melanoma-bearing mice. The results demonstrate that this method exhibits a good linearity (r 2 =0.9947), specificity and acceptable accuracy. This simple method appears convenient and sufficient for pharmacokinetic studies on [125I]ICF 01012. [Copyright &y& Elsevier]

Abstract: N-(2-diethylaminoethyl)-2-iodobenzamide (BZA2) has been singled out as the most efficacious melanoma scintigraphy imaging agent. Our work was designed to assess the mechanisms of the specific affinity of the radioiodinated iodobenzamide for melanoma tissue. We studied the cellular uptake and retention of [125I]-BZA2 on various cell lines. In vitro, cellular [125I]-BZA2 uptake was related to the pigmentation status of the cells: higher in pigmented melanoma cell lines (M4 Beu, IPC 227, B 16) than in a nonpigmented one (M3 Dau) and nonmelanoma cell lines (MCF 7 and L 929). Two mechanisms were assessed: binding of the tracer to melanin or to sigma receptors of melanoma cells. First, the uptake of [125I]-BZA2 after melanogenesis stimulation by α-melanocyte-stimulating hormone and l-tyrosine increased in the B 16 melanoma cell line both in vitro and in vivo according to melanin concentration. Moreover, the binding of [125I]-BZA2 to synthetic melanin was dependent on melanin concentration and could be saturated. Second, no competition was evidenced on M4 Beu cells between [125I]-BZA2 and haloperidol, a sigma ligand, at concentrations ≤10−6 M. We show that the specificity and sensibility of BZA2 as a melanoma scintigraphic imaging agent are mostly due to interactions with melanic pigments. [Copyright &y& Elsevier]

The antibody pretargeting approach for radioimmunotherapy (RIT) using inverse electron demand Diels-Alder cycloaddition (IEDDA) constitutes an emerging theranostic approach for solid cancers. However, IEDDA pretargeting has not reached clinical trial. The major limitation of the IEDDA strategy depends largely on trans-cyclooctene (TCO) stability. Indeed, TCO may isomerize into the more stable but unreactive cis-cyclooctene (CCO), leading to a drastic decrease of IEDDA efficiency. We have thus developed both efficient and reproducible synthetic pathways and analytical follow up for (PEGylated) TCO derivatives, providing high TCO isomeric purity for antibody modification. We have set up an original process to limit the isomerization of TCO to CCO before the mAbs' functionalization to allow high TCO/tetrazine cycloaddition. Image 1 • Optimized method to synthesize PEGylated aminoacid with oligomeric lengths (4, 8, 12). • An optimized one-pot two-step synthesis process to obtain PEGylated aminoacids. • The HPLC monitoring process controls the isomerization of TCO precursors. • Optimization of TCO precursors for immunopretargeting approach. [ABSTRACT FROM AUTHOR]

Part 2. Hypoxia-activated prodrug with a quaternary ammonium function as proteoglycan-targeting ligand for a better management of chondrosarcoma: synthesis, reduction-mediated cleavage (chemical and enzymatic) and in vitro hypoxic selectivity. • Proteoglycan-targeting applied to hypoxia-activated prodrug in chondrosarcoma. • Nitro-aromatics containing phosphoramide prodrugs were designed and synthesized. • Access to (2-nitro-1 H -imidazo-5-yl)methanol functionalized at the N -1 and C -4 positions. • Preliminary screening for reduction-mediated cleavage and specific hypoxia cytotoxity. The tumor microenvironment in chondrosarcoma (CHS), a chemo- and radio-resistant cancer provides unique hallmarks for developing a chondrosarcoma targeted drug‐delivery system. Tumor targeting could be achieved using a quaternary ammonium function (QA) as a ligand for aggrecan, the main high negative charged proteoglycan of the extracellular matrix of CHS, and a 2-nitroimidazole as trigger that enables hypoxia‐responsive drug release. In a previous work, ICF05016 was identified as efficient proteoglycan-targeting hypoxia-activated prodrug in a human extraskeletal myxoid chondrosarcoma model in mice and a first study of the structure-activity relationship of the QA function and the alkyl linker length was conducted. Here, we report the second part of the study, namely the modification of the nitro-aromatic trigger and the position of the proteoglycan-targeting ligand at the aromatic ring as well as the nature of the alkylating mustard. Synthetic approaches have been established to functionalize the 2-nitroimidazole ring at the N -1 and C -4 positions with a terminal tertiary alkyl amine, and to perform the phosphorylation step namely through the use of an amine borane complex, leading to phosphoramide and isophosphoramide mustards and also to a phosphoramide mustard bearing four 2-chloroethyl chains. In a preliminary study using a reductive chemical activation, QA-conjugates, except the 4-nitrobenzyl one, were showed to undergo efficient cleavage with release of the corresponding mustard. However N,N,N -trimethylpropylaminium tethered to the N -1 or C -4 positions of the imidazole seemed to hamper the enzymatic reduction of the prodrugs and all tested compounds featured moderate selectivity toward hypoxic cells, likely not sufficient for application as hypoxia-activated prodrugs. [ABSTRACT FROM AUTHOR]