Design, Synthesis, Biological Evaluation and Molecular Docking of Novel F-18-Labeled Focal Adhesion Kinase Inhibitors as Potential Tumor Radiotracers.

Tumor diagnosis, especially at the early stages, holds immense significance. Focal adhesion kinase (FAK) is often highly expressed across various types of tumors, making it a promising target for both therapy and diagnosis. In this study, seven novel inhibitors were designed and synthesized. The inhibitory activity of these compounds against FAK was notably potent, with an IC50 range of 1.27-1968 nM. In particular, compounds 7a and 7c, with IC50 values of 5.59 nM and 1.27 nM, respectively, were radiolabeled with F-18 and then evaluated with S-180 tumor-bearing mice. Subsequently, they exhibited moderate-to-high tumor uptake values, with [18F]7a showing 1.39 ± 0.30%ID/g at 60 min post injection and [18F]7c demonstrating 6.58 ± 0.46%ID/g at 30 min post injection. In addition, the results from docking studies revealed the binding specifics of the studied compounds. Overall, these findings hold the potential to offer valuable guidance for enhancing the development of radiotracers and enzyme inhibitors.

Preparation and Preliminary Evaluation of a Promising 99mTc-Labeled Isonitrile-Containing 6-Thia-Fatty Acid Derivative for Myocardial Metabolism Imaging.

For over 40 years, none of the previous 99mTc-labeled fatty acids for myocardial imaging has potential clinical use. 99mTc-(C10-6-thia-CO2H)(MIBI)5 is the first 99mTc-labeled fatty acid to exhibit good myocardial uptake (2.06 ± 0.06%ID/g) at 60 min post injection, high heart-to-liver ratio (6.43 ± 1.85 and 9.68 ± 0.76), high heart-to-lung ratio (9.48 ± 1.39 and 11.02 ± 0.89), and high heart-to-blood ratio (164.01 ± 43.51 and 197.36 ± 32.29) at 60 and 120 min in Sprague-Dawley (SD) rats, respectively. It also demonstrated excellent myocardial imaging quality. The above target-to-nontarget ratios exceeded those of [123I]BMIPP and were higher than or close to those of 99mTc-MIBI at 60 and 120 min. Most of 99mTc-(C10-6-thia-CO2H)(MIBI)5 was partially ß-oxidized to protein-bound metabolites in myocardium. Administration of trimetazidine dihydrochloride (TMZ, a fatty acid ß-oxidation inhibitor) to rats caused 51% reduction in the myocardial uptake of 99mTc-(C10-6-thia-CO2H)(MIBI)5 and 61% reduction in the distribution of 99mTc-radioactivity in a residual tissue pellet at 60 min, indicating its considerable sensitivity to myocardial fatty acid ß-oxidation.

Design, Synthesis, and Biological Evaluation of 4-Arylamino Pyrimidine Derivatives as FAK Inhibitors and Tumor Radiotracers.

Focal adhesion kinase (FAK) is considered a promising target for the diagnosis and treatment of cancer. In this work, a series of N,N'-(4-((5-bromo-2-(phenylamino)pyrimidin-4-yl)amino)-1,3-phenylene)diacetamide derivatives were synthesized and evaluated as FAK inhibitors and radiotracers. The studied compounds, possessing the same phenylene-diacetamide chain, exhibited high to moderate enzyme inhibition values (IC50) ranging from 3.7 to 108.0 nM. Compound 13a, which exhibits high FAK enzyme inhibition with an IC50 value of 3.7, could effectively suppress the tumor growth. Furthermore, three compounds were radiolabeled with F-18. Among them, a higher tumor uptake value was observed for [18F]17 (3.73 ± 0.10% ID/g) and [18F]13a (3.66 ± 0.02% ID/g). Compound [18F]18 displayed the highest tumor/blood (35.75) value at 120 min postinjection. In addition, the results from docking studies revealed the binding mechanism of the studied compounds. The findings of this study may provide useful guidance to improve the development of radiotracers and enzyme inhibitors.

The Availability of the α7-Nicotinic Acetylcholine Receptor in Early Identification of Vulnerable Atherosclerotic Plaques: A Study Using a Novel 18F-Label Radioligand PET.

Background: It has been confirmed that the α7-nicotinic acetylcholine receptor (α7nAChR) is an important target for identifying vulnerable atherosclerotic plaques. Previously, we successfully designed and synthesized a series of 18F-labeled PET molecular probes targeting α7nAChR, which are mainly used in the diagnosis of Alzheimer's disease. Based on the characteristics of α7nAChR in blood vessels, we have firstly screened for a suitable novel 18F-labeled PET molecular probe ([18F]YLF-DW), with high selectivity for α7nAChR over α4ß2nAChR and a good effect for the imaging of atherosclerotic animal models, to effectively identify vulnerable atherosclerotic plaques at an early stage. Meanwhile, we compared it with the "gold standard" pathological examination of atherosclerosis, to verify the reliability of [18F]YLF-DW in early diagnosis of atherosclerosis. Methods: The vulnerable atherosclerotic plaques model of ApoE-/-mice were successfully established. Then based on the methods of 3D-QSAR and molecular docking, we designed oxazolo[4,5-b] pyridines and fluorenone compounds, which are targeted at α7nAChR. Through further screening, a novel alpha7 nicotinic acetylcholine receptor radioligand ([18F]YLF-DW) was synthesized and automatically 18F-labeled using a Stynthra RNplus module. Subsequently, we employed [18F]YLF-DW for the targeting of α7nAChR in atherosclerotic plaques and control group, using a micro-PET/CT respectively. After imaging, the mice were sacrificed by air embolism and the carotid arteries taken out for making circular sections. The paraffin embedded specimens were sectioned with 5 µm thickness and stained with oil red. After staining, immunohistochemistry experiment was carried out to verify the effect of micro-PET/CT imaging. Results: The micro-PET/CT imaging successfully identified the vulnerable atherosclerotic plaques in the carotid arteries of ApoE-/-mice; whereas, no signal was observed in normal control mice. In addition, compared with the traditional imaging agent [18F]FDG, [18F]YLF-DW had a significant effect on the early plaques imaging of carotid atherosclerosis. The results of oil red staining and immunohistochemistry also showed early formations of carotid plaques in ApoE-/-mice and provided pathological bases for the evaluation of imaging effect. Conclusion: We innovated to apply the novel molecular probe ([18F]YLF-DW) to the identification of vulnerable atherosclerotic plaques in carotid arteries, to detect atherosclerosis early inflammatory response and provide powerful input for the early diagnosis of atherosclerotic lesions, which may play an early warning role in cardiovascular acute events.

Design, Synthesis, Biological Evaluation, and Molecular Docking of 2,4-Diaminopyrimidine Derivatives Targeting Focal Adhesion Kinase as Tumor Radiotracers.

There are two important topics in the field of cancer research: one is targeted molecular therapy and the other is tumor molecular imaging. Focal adhesion kinase (FAK) is considered as an attractive target for oncologic diagnosis and therapy. A series of 2,4-diaminopyrimidine derivatives were labeled with 18F to study their biological properties and their potential as positron emission tomography tumor imaging agents. They inhibited the activity of FAK with IC50 values in the wide range of 0.6-2164 nM, among which the IC50 of Q6 was 3.2 nM. For the biodistribution in S180-bearing mice, the corresponding [18F]Q6 was relatively good, with the highest uptake of 3.35 ± 0.32 % ID/g at 30 min postinjection, with a tumor/muscle ratio of 2.08 and a tumor/bone ratio of 2.48. Accordingly, [18F]Q6 was considered as a potential PET imaging agent for tumor diagnosis.

Nonlinear Method to Predict the Distribution of Structurally Diverse Compounds between Blood and Tissue.

In this work, methods for predicting the distribution of compounds between blood and tissue were investigated using nonlinear regression analysis. For the tissue/blood partition coefficient, 282 compounds and 810 activity data for seven tissues were selected. Twenty-four parameters were studied for each state of the compound. A study set with the most compounds and activity data in similar studies was established, and a model with good prediction ability was obtained. A total of 773 data points were randomly divided into two data sets: the training set contained 623 data points (n = 623, r = 0.822, s = 0.438, F = 142.2, and Q = 0.814) and the test set contained 150 data points (n = 150, r = 0.814, and s = 0.334). Furthermore, individual tissue/blood distribution coefficients were also studied in depth to obtain separate models for predicting the distribution coefficient of a drug between blood and a tissue. By applying these models, not only can the tissue/blood distribution coefficient or single tissue/blood distribution coefficient of the seven tissues and organs of the human body be predicted, but the distribution of the drug molecules in different states (neutral, cation, and anion) in the three tissue components can also be predicted.

Design, synthesis, and biological evaluation of F-18-labelled 2, 4-diaminopyrimidine-type FAK-targeted inhibitors as potential tumour imaging agents.

As a type of intracellular nonreceptor tyrosine kinase, focal adhesion kinase (FAK) can be highly expressed in most types of tumours and is thus regarded as a promising antitumour target. In this study, a series of novel 2,4-diaminopyrimidine FAK-targeted inhibitors were designed, synthesized and characterized by 1H NMR, 13C HNMR, and HRMS spectra. These compounds, with an IC50 range of 5.0-205.1 nM, showed superior inhibitory activity against FAK. Two compounds, [18F]Q-2 and [18F]Q-4, with respective IC50 values of 5.0 nM and 21.6 nM, were labelled by 18F, accompanied by evaluation of their biodistributions. For [18F]Q-2, at 30 min post-injection, promising target-to-nontarget ratios were observed, associated with tumour/blood, tumour/muscle, and tumour/bone ratios of 1.17, 2.99 and 2.19, respectively. The results indicated that [18F]Q-2 is a potential PET tracer for tumour diagnosis.

Synthesis and biological evaluation of 9-fluorenone derivatives for SPECT imaging of α7-nicotinic acetylcholine receptor.

The α7-nicotinic acetylcholine receptor (α7-nAChR) subtype, is found to have a connection with the pathogenesis of a variety of psychiatric and neurological disorders. Herein, we report the development of radioiodinated 9-fluorenone derivatives as single-photon emission computed tomography (SPECT) imaging tracers for α7-nAChRs. Among the derivatives, the best member of the series 10 (Ki = 2.23 nM) were radiolabeled with 125I for in vitro and in vivo studies. The radiotracer [125I]10 exhibited robust brain uptake and specifically labeled α7-nAChRs with a peak uptake value of 9.49 ±â€¯0.87%ID/g in brain. Blocking studies demonstrated that the tracer was highly specific toward α7-nAChR. Furthermore, ex vivo autoradiography and micro-SPECT/CT dynamic imaging in mice confirmed the excellent imaging properties. In addition, molecular docking was also performed to rationalize the potency of the chosen compounds towards α7-nAChRs. To conclude, compound 10 could serve as a promising radiotracer for the α7-nAChRs.

Radioiodinated 9-fluorenone derivatives for imaging α7-nicotinic acetylcholine receptors.

A series of 9H-fluoren-9-one substituents were synthesized and evaluated for imaging cerebral α7-nAChRs. Meta-iodine substituted 9-fluorenone 5 with high binding affinity (K i = 9.3 nM) and selectivity was radiolabeled with 125I. Fully in vitro and in vivo studies of [125I]5 have been performed. [125I]5 exhibited well brain uptake with a peak concentration of 7.5 ± 0.9% ID/g in mice brains. Moreover, ex vivo autoradiography studies and micro single-photon emission computed tomography (micro-SPECT/CT) dynamic imaging in mice confirmed its in vivo imaging properties. Besides, molecular docking and MD studies were also performed to interpret the binding mechanisms of the two series of ligands towards α7-nAChRs. To conclude, the meta-iodine substituted 9-fluorenone [125I]5 could be a promising tracer for imaging α7-nAChRs.

Transcriptomic Insight into Terpenoid Biosynthesis and Functional Characterization of Three Diterpene Synthases in Scutellaria barbata.

Scutellaria barbata (Lamiaceae) is an important medicinal herb widely used in China, Korea, India, and other Asian countries. Neo-clerodane diterpenoids are the largest known group of Scutellaria diterpenoids and show promising cytotoxic activity against several cancer cell lines. Here, Illumina-based deep transcriptome analysis of flowers, the aerial parts (leaf and stem), and roots of S. barbata was used to explore terpenoid-related genes. In total, 121,958,564 clean RNA-sequence reads were assembled into 88,980 transcripts, with an average length of 1370 nt and N50 length of 2144 nt, indicating high assembly quality. We identified nearly all known terpenoid-related genes (33 genes) involved in biosynthesis of the terpenoid backbone and 14 terpene synthase genes which generate skeletons for different terpenoids. Three full length diterpene synthase genes were functionally identified using an in vitro assay. SbTPS8 and SbTPS9 were identified as normal-CPP and ent-CPP synthase, respectively. SbTPS12 reacts with SbTPS8 to produce miltiradiene. Furthermore, SbTPS12 was proven to be a less promiscuous class I diterpene synthase. These results give a comprehensive understanding of the terpenoid biosynthesis in S. barbata and provide useful information for enhancing the production of bioactive neo-clerodane diterpenoids through genetic engineering.

A Method for Synthesis of 3-Hydroxy-1-indanones via Cu-Catalyzed Intramolecular Annulation Reactions.

We report a facile and highly efficient method that copper-catalyzed intramolecular annulation to synthesize 3-hydroxy-1-indanones employing simple 2-ethynylbenzaldehyde as starting materials was achieved successfully. This protocol provided a simple synthetic approach to afford 3-hydroxy-1-indanones under mild conditions in good to excellent yields.

Design, synthesis and biological evaluation of 1,4-Diazobicylco[3.2.2]nonane derivatives as α7-Nicotinic acetylcholine receptor PET/CT imaging agents and agonists for Alzheimer's disease.

α7-Nicotinic acetylcholine receptor (α7-nAChR) agonists are promising therapeutic drug candidates for treating the cognitive impairment associated with Alzheimer's disease (AD). Thus, a novel class of derivatives of 1,4-diazobicylco[3.2.2]nonane has been synthesized and evaluated as α7-nAChR ligands. Five of them displayed high binding affinity (Ki = 0.001-25 nM). In particular, the Ki of 14 was 0.0069 nM, which is superior to that of the most potent ligand that was previously reported by an order of magnitude. Four of them had high selectivity for α7-nAChRs over α4ß2-nAChRs and no significant hERG (human ether-a-go-go-related gene) inhibition. Their agonist activity was also discussed preliminarily. One of the compounds, 15 (Ki = 2.98 ±â€¯1.41 nM), was further radiolabeled with 18F to afford [18F]15 for PET imaging, which exhibited high initial brain uptake (11.60 ±â€¯0.14%ID/g at 15 min post injection), brain/blood value (9.57 at 30 min post injection), specific labeling of α7-nAChRs and fast clearance from the brain. Blocking studies demonstrated that [18F]15 was α7-nAChR selective. In addition, micro-PET/CT imaging in normal rats further indicated that [18F]15 had obvious accumulation in the brain. Therefore, [18F]15 was proved to be a potential PET radiotracer for α7-nAChR imaging.

Synthesis and evaluation of novel 18 F-labeled quinazoline derivatives with low lipophilicity for tumor PET imaging.

Four novel 18 F-labeled quinazoline derivatives with low lipophilicity, [18 F]4-(2-fluoroethoxy)-6,7-dimethoxyquinazoline ([18 F]I), [18 F]4-(3-((4-(2-fluoroethoxy)-7-methoxyquinazolin-6-yl)oxy)propyl)morpholine ([18 F]II), [18 F]4-(2-fluoroethoxy)-7-methoxy-6-(2-methoxyethoxy)quinazoline ([18 F]III), and [18 F]4-(2-fluoroethoxy)-6,7-bis(2-methoxyethoxy)quinazoline ([18 F]IV), were synthesized via a 2-step radiosynthesis procedure with an overall radiochemical yield of 10% to 38% (without decay correction) and radiochemical purities of >98%. The lipophilicity and stability of labeled compounds were tested in vitro. The log P values of the 4 radiotracers ranged from 0.52 to 1.07. We then performed ELISA to measure their affinities to EGFR-TK; ELISA assay results indicated that each inhibitor was specifically bounded to EGFR-TK in a dose-dependent manner. The EGFR-TK autophosphorylation IC50 values of [18 F]I, [18 F]II, [18 F]III, and [18 F]IV were 7.732, 0.4698, 0.1174, and 0.1176 µM, respectively. All labeled compounds were evaluated via cellular uptake and blocking studies in HepG2 cell lines in vitro. Cellular uptake and blocking experiment results indicated that [18 F]I and [18 F]III had excellent cellular uptake at 120-minute postinjection in HepG2 carcinoma cells (51.80 ± 3.42%ID/mg protein and 27.31 ± 1.94%ID/mg protein, respectively). Additionally, biodistribution experiments in S180 tumor-bearing mice in vivo indicated that [18 F]I had a very fast clearance in blood and a relatively high uptake ratio of tumor to blood (4.76) and tumor to muscle (1.82) at 60-minute postinjection. [18 F]III had a quick clearance in plasma, and its highest uptake ratio of tumor to muscle was 2.55 at 15-minute postinjection. These experimental results and experiences were valuable for the further exploration of novel radiotracers of quinazoline derivatives.

Preparation, in vitro and in vivo evaluation, and molecular dynamics (MD) simulation studies of novel F-18 labeled tumor imaging agents targeting focal adhesion kinase (FAK).

Focal adhesion kinase (FAK) has been identified as a promising target in the early diagnosis and therapy of tumor. In this work, we obtained and evaluated another two novel pyrimidine-based F-18 labeled tumor imaging agents targeting FAK. Among them, the corresponding F-19 standards [19F]2, displayed inhibition of FAK with IC50 values of 57.1 nM (better than the results in our published work) and showed an good selectivity profile against some other kinds of cancer-related kinases. [18F]2 also had relatively good results in the in vivo biodistribution in S180-tumor-bearing mice, with tumor uptake of 5.40 ± 0.12 and 5.96 ± 0.09 % ID per g at 15 and 30 min post-injection, respectively. What's more, [18F]2 could be accumulated in tumor at 30 min post-injection, which could be observed from the coronal micro-PET images of mice bearing S180 tumor. In addition, the blocking study for the [18F]2 with PF-562271 (one of the well-known best selective FAK inhibitor), displayed distinct reduction in the uptake of the radiotracer in tumor at 30 min post-injection in mice, suggesting that the uptake of [18F]2 in tumor was due to FAK over-expression or high expression in tumor. And the results of the molecular dynamics (MD) simulations and the docking studies were in consistent with the changing trends of the interaction between the F-19 standards and the FAK. Finally, in order to further increase the uptake of the F-18 labeled tracer in tumor, the following points should arouse attention, which could also be considered as the new findings and contributions of this study to the field of the tumor imaging agents: (1) the F-18 labeled tumor radiotracers which have closer interaction with the FAK, should be further designed, via building of models such as 3D-QSAR model to make reasonable guidance to our drug design and consideration of some functional groups which have hydrogen-bonding or salt-bridge interactions with key residues in the kinase domain of FAK; (2) the F-18 radiotracers with better pharmacokinetic properties should be designed, via building of dynamic drug absorption and distribution model in different tissues, to predict whether the molecules have ideal absorption in tumor and low uptake in non-target tissues. The relevant study is being undertaken.

A highly potent CDK4/6 inhibitor was rationally designed to overcome blood brain barrier in gliobastoma therapy.

Glioblastoma multiforme (GBM) is the most common and deadliest of malignant brain tumors in adults. Disease development is associated with dysregulation of the cyclin D-CDK4/6-INK4-Rb pathway, resulting in increased proliferation; thus, CDK4/6 kinase inhibitors are promising candidates for GBM treatment. The recently developed CDK4/6 inhibitors, palbociclib, ribociclib, and abemaciclib, are effective in subcutaneous glioma models, but their blood-brain barrier (BBB) permeability is poor, limiting drug delivery to the central nervous system. Here, we designed and synthesized a series of novel CDK4/6 inhibitors with favorable BBB permeability for the treatment of GBM. Compound 11 exhibited a favorable pharmacological profile and significant penetration of the BBB with the Kp value of 4.10 and the Kp,uu value of 0.23 in mice after an oral dose of 10 mg/kg. IC50 values for CDK4/cyclin D1 and CDK6/cyclin D3 were 3 nM and 1 nM, respectively. In vivo studies with an orthotopic xenograft mouse model of GBM showed that 11 had tumor growth inhibition values ranging from 62% to 99% for doses ranging from 3.125 to 50 mg/kg, and no significant body weight loss was observed. The increase in life span based on the median survival time of vehicle-treated animals in mice administered a dose of 50 mg/kg was significant at 162% (p < 0.0001). These results suggest that compound 11 is a promising candidate for further investigation as an effective drug for the treatment of GBM.

Development of a series of novel 4-anlinoquinazoline derivatives possessing quinazoline skeleton: Design, synthesis, EGFR kinase inhibitory efficacy, and evaluation of anticancer activities in vitro.

4-anilinoquinazoline-based derivatives represent an attractive scaffold for small molecular EGFR-TKIs in the field of medicinal chemistry. A series of novel heterocyclic substituted derivatives have been designed, synthesized and evaluated their antitumor bioactivities as potential EGFR-TKIs. Most of the new compounds exhibited certain efficient inhibition potency for proliferation of a panel of five human cancer cells with IC50 values at the low micromolar level, and some of them possessed good broad-spectrum inhibition activities, compared to Gefitinib. Especially, the IC50 values of compound 21 against HepG2, A549, MCF-7, DU145 and SH-SY5Y cells were 4.61, 9.50, 9.80, 6.79 and 7.77 µM, respectively, which were much lower than those of Gefitinb. Furthermore, the highlighting compound 21 demonstrated excellent inhibition activity against EGFR-TK with the IC50 value of 3.62 nM, similar to that of Gefitinib(2.21 nM). The results of LDH release assay proved that compound 21 was anti-proliferative rather than cytotoxicity on HepG2 cells. Compound 21 were able to cause HepG2 cells to block in S phase and induce cell death mainly by apoptosis through a mitochondrial dependent pathway. Moreover, the assessment of MMP, the determination of intracellular free Ca2+ concentration, the production of ROS, and the effects on the activity of caspase-3 in a dose-dependent manner demonstrated that compound 21 induced cell apoptosis in HepG2 cells through the Ca2+/ROS-mediated mitochondria/caspase-dependent apoptosis pathway largely. These preliminary results evidenced that compound 21 could be a potential antitumor agent deserving further study.

Functional Diversification of Kaurene Synthase-Like Genes in Isodon rubescens.

Ent-kaurene diterpenoids are the largest group of known Isodon diterpenoids. Among them, oridonin is accumulated in the leaves, and is the most frequently studied compound because of its antitumor and antibacterial activities. We have identified five copalyl diphosphate synthase (CPS) and six kaurene synthase-like (KSL) genes by transcriptome profiling of Isodon rubescens leaves. An in vitro assay assigns ten of them to five different diterpene biosynthesis pathways, except IrCPS3 that has a mutation in the catalytic motif. The Lamiaceae-specific clade genes (IrCPS1 and IrCPS2) synthesize the intermediate copalyl diphosphate (normal-CPP), while IrCPS4 and IrCPS5 synthesize the intermediate ent-copalyl diphosphate (ent-CPP). IrKSL2, IrKSL4, and IrKSL5 react with ent-CPP to produce an ent-isopimaradiene-like compound, ent-atiserene and ent-kaurene, respectively. Correspondingly, the Lamiaceae-specific clade genes IrKSL1 or IrKSL3 combined with normal-CPP led to the formation of miltiradiene. The compound then underwent aromatization and oxidization with a cytochrome P450 forming two related compounds, abietatriene and ferruginol, which were detected in the root bark. IrKSL6 reacts with normal-CPP to produce isopimaradiene. IrKSL3 and IrKSL6 have the γßα tridomain structure, as these proteins tend to possess the bidomain structure of IrKSL1, highlighting the evolutionary history of KSL gene domain loss and further elucidating chemical diversity evolution from a macroevolutionary stance in Lamiaceae.

Initial evaluation of 99m Tc-tricarbonyl-cyclopentadienyl fatty acids derivatives as SPECT tracers for myocardium.

Fatty acids are myocardial metabolic agent for detecting myocardial ischemia and infraction. However, no 99m Tc-labeled fatty acids had potential use in clinical practice. In this study, 99m Tc-CpTT-10-oxo-para-PPA (1d), 99m Tc-CpTT-11-oxo-para-PPA (2d), 99m Tc-CpTT-12-oxo-para-PPA (3d), 99m Tc-CpTT-11-oxo-ortho-PPA (4d), and 99m Tc-CpTT-11-oxo-meta-PPA (5d) were synthesized by a double ligand transfer reaction, and their biological behaviors were investigated. Compound 2d achieved good heart to blood ratio (3.39 at 5 min after intravenous), and 2d showed high-heart uptake of 6.20% ID/g at 5 minutes after injection. Compound 3d displayed a prolonged retention in the myocardium (1.43% ID/g at 60 min after injection). Radioactivity accumulation in the lungs, spleen, and blood was eliminated rapidly. In vivo, metabolite analysis presented that compound 6d may be metabolite of 2d through ß-oxidation in tissue. Unfortunately, the biodistribution studies of 1d, 2d, 3d, 4d, and 5d showed fast heart clearance and poor heart to liver ratios, which suggested that the 5 99m Tc-labeled fatty acid analogues cannot be used for diagnosis.

Synthesis, biological evaluation, and molecular dynamics (MD) simulation studies of three novel F-18 labeled and focal adhesion kinase (FAK) targeted 5-bromo pyrimidines as radiotracers for tumor.

Focal adhesion kinase (FAK) is considered as an attractive target for oncology. A series of F-18 labeled 5-bromo-N2-(4-(2-fluoro-pegylated (FPEG))-3,5-dimethoxyphenyl)-N4-(4-methoxyphenyl)pyrimidine-2,4-diamine derivatives were prepared and evaluated as the FAK targeted radiotracers for the early diagnoses of tumor. For the study of the FAK targeted drug molecules, this was the first attempt to develop the tumor diagnostic imaging agents on the radiopharmaceutical level. They inhibited the activity of FAK with IC50 in the range of 91.4-425.7 nM, and among which the result of the [19F]2 was relatively good and had a modest IC50 of 91.4 nM. The [19F]2 was also profiled in vitro against some other kinds of cancer-related kinases (including two kinds of non-receptor tyrosine kinase: PYK2 and JAK2, and three kinds of receptor tyrosine kinase: IGF-1R, EGFR and PDGFRß). It displayed 25.2 folds selectivity against PYK2, 35.1 folds selectivity against EGFR, and more than 100 folds selectivity against IGF-1R, JAK2 and PDGFRß. For the biodistribution in S180 bearing mice, the corresponding [18F]2 were also relatively good, with modest tumor uptake of 5.47 ± 0.19 and 5.80 ± 0.06 %ID/g at 15 and 30 min post-injection, respectively. Furthermore, its tumor/muscle, tumor/bone and tumor/blood ratio at 15 min post-injection were 3.16, 2.53 and 4.52, respectively. And its tumor/muscle, tumor/bone and tumor/blood ratio at 30 min post-injection were 3.14, 2.76 and 4.43, respectively. In addition, coronal micro-PET/CT images of a mouse bearing S180 tumor clearly confirmed that [18F]2 could be accumulated in tumor, especially at 30 min post-injection. Besides, for the [18F]2, both the biodistribution data and the micro-PET/CT imaging study showed significantly reduced uptake of the radiotracer in the tumor tissue at 30 min post-injection in mice that received PF-562,271 (one of the reported best selective FAK inhibitor which was developed by Pfitzer Inc. and inhibited the activity of FAK with IC50 value of 1.5 nM) at 1 h before the injection of radiotracer. In combination with the above kinase profiling assay, it could be indicated that the uptake of [18F]2 in tumor of the mouse model was due to FAK expression, and that [18F]2 might be a kind of selectively FAK targeted tumor imaging agents. What's more, the results of the MD (molecular dynamics) simulations were in agreement with the changing trends of the interaction between the different F-19 standards and the FAK (expressed as the in vitro inhibitory abilities of enzymatic activities of FAK in this article), which was also in agreement with and had great effect on the changing trends of the uptake of the corresponding F-18 labeled tracers in tumor and some of theirs target/non-target ratios.

Design and synthesis of novel pyrazolo[1,5-a]pyrimidine derivatives bearing nitrogen mustard moiety and evaluation of their antitumor activity in vitro and in vivo.

A series of novel pyrazolo[1,5-a]pyrimidine derivatives bearing nitrogen mustard moiety were designed, synthesized and evaluated for their antiproliferative activities against five human cancer cell lines (A549, SH-SY5Y, HepG2, MCF-7 and DU145) in vitro. Among these compounds, 13b exhibited potent inhibitory effect on the proliferation of the five tumor cells and was able to inhibit cell cycle arrest at G1 phase and induce cell apoptosis. In HepG2 HCC xenograft compound 13b was selected for evaluating the antitumor activity in vivo which exhibited significant cancer growth inhibition with low host toxicity in vivo.