Underlying Mechanisms of Thrombosis Associated with Cancer and Anticancer Therapies.

OPINION STATEMENT: Cancer-associated thrombosis (CAT) has been identified as the second most prevalent cause of death after cancer itself. Moreover, the risk of thrombotic events in cancer patients increases due to anticancer drugs, such as tyrosine kinase inhibitors (TKIs). Venous thromboembolism (VTE) as well as arterial thromboembolic (ATE) events are present in CAT. Although VTE occurs more frequently, ATE events are very significant and in some cases are more dangerous than VTE. Guidelines for preventing thrombosis refer mainly VTE as well as the contribution of ATE events. Several factors are involved in thrombosis related to cancer, but the whole pathomechanism of thrombosis is not clear and may differ between patients. The activation of the coagulation system and the interaction of cancer cells with other cells including platelets, endothelial cells, monocytes, and neutrophils are promoted by a hypercoagulable state caused by cancer. We present an update on the pathomechanisms of CAT and the effect of anticancer drugs, mainly targeted therapies with a focus on TKIs. Considering the risk of bleeding associated with anticoagulation in each cancer patient, the anticoagulation strategy may involve the use of FXIa inhibitors, direct oral anticoagulants, and low-molecular-weight heparin. Further research would be valuable in developing strategies for reducing CAT.

Synthesis of Novel Nilotinib Analogues and Biological Evaluation of Their Antiplatelet Activity and Functionality towards Cancer Cell Proliferation In Vitro.

Nilotinib, a second-generation tyrosine kinase inhibitor for the treatment of chronic myelogenous leukemia (CML), inhibits Bcr-Abl tyrosine kinase activity and proliferation of Bcr-Abl-expressing cells, as well as other malignancies. In the present study, new nilotinib analogues were synthesized and fully characterized. A platelet aggregation assay was performed, and the expression of P-selectin and PAC-1, as well as the effect on the proliferation of healthy endothelial cells, were evaluated. The expression and antimetastatic effects of E-cadherin and N-cadherin were assessed. The analogues inhibited platelet aggregation in a statistically significant manner compared to nilotinib, while they exhibited a strong inhibitory effect on P-selectin and PAC-1 expression when activated by AA. All three analogues caused arrest in the mitosis phase of the HepG2 cell cycle, while analogue-1 exhibited the most potent apoptotic effect compared to nilotinib. Interestingly, none of them promoted apoptosis in HUVECs. All the analogues reduced the expression of E- and N-cadherin in different amounts, while the analogues-1 and -3 exhibited similar antimigratory effects on HepG2 cells. The results of this study reveal considerable potential to develop new tyrosine kinase inhibitors with improved antiplatelet and antitumor properties.

Molecular Requirements for the Expression of Antiplatelet Effects by Synthetic Structural Optimized Analogues of the Anticancer Drugs Imatinib and Nilotinib.

BACKGROUND: Platelets play important roles in cancer progression and metastasis, as well as in cancer-associated thrombosis (CAT). Tyrosine kinases are implicated in several intracellular signaling pathways involved in tumor biology, thus tyrosine kinase inhibitors (TKIs) represent an important class of anticancer drugs, based on the concept of targeted therapy. PURPOSE: The objective of this study is the design and synthesis of analogues of the TKIs imatinib and nilotinib in order to develop tyrosine kinase inhibitors, by investigating their molecular requirements, which would express antiplatelet properties. METHODS: Based on a recently described by us improved approach in the preparation of imatinib and/or nilotinib analogues, we designed and synthesized in five-step reaction sequences, 8 analogues of imatinib (I-IV), nilotinib (V, VI) and imatinib/nilotinib (VII, VIII). Their inhibitory effects on platelet aggregation and P-selectin membrane expression induced by arachidonic acid (AA), adenosine diphosphate (ADP) and thrombin receptor activating peptide-6 (TRAP-6), in vitro, were studied. Molecular docking studies and calculations were also performed. RESULTS: The novel analogues V-VIII were well established with the aid of spectroscopic methods. Imatinib and nilotinib inhibited AA-induced platelet aggregation, exhibiting IC50 values of 13.30 µΜ and 3.91 µΜ, respectively. Analogues I and II exhibited an improved inhibitory activity compared with imatinib. Among the nilotinib analogues, V exhibited a 9-fold higher activity than nilotinib. All compounds were less efficient in inhibiting platelet aggregation towards ADP and TRAP-6. Similar results were obtained for the membrane expression of P-selectin. Molecular docking studies showed that the improved antiplatelet activity of nilotinib analogue V is primarily attributed to the number and the strength of hydrogen bonds. CONCLUSION: Our results show that there is considerable potential to develop synthetic analogues of imatinib and nilotinib, as TKIs with antiplatelet properties and therefore being suitable to target cancer progression and metastasis, as well as CAT by inhibiting platelet activation.

NMR-Based Μetabolomics of the Lipid Fraction of Organic and Conventional Bovine Milk.

Origin and quality identification in dairy products is an important issue and also an extremely challenging and complex experimental procedure. The objective of the present work was to compare the metabolite profile of the lipid fraction of organic and conventional bovine milk using NMR metabolomics analysis. ¹H-NMR and 1D TOCSY NMR methods of analysis were performed on extracted lipid fraction of lyophilized milk. For this purpose, 14 organic and 16 conventional retail milk samples were collected monthly, and 64 bulk-tank (58 conventional and 6 organics) milk samples were collected over a 14-month longitudinal study in Cyprus. Data were treated with multivariate methods (PCA, PLS-DA). Minor components were identified and quantified, and modification of the currently used equations is proposed. A significantly increased % content of conjugated (9-cis, 11-trans)18:2 linoleic acid (CLA), α-linolenic acid, linoleic acid, allylic protons and total unsaturated fatty acids (UFA) and decreased % content for caproleic acid were observed in the organic samples compared to the conventional ones. The present work confirms that lipid profile is affected by contrasting management system (organic vs. conventional), and supports the potential of NMR-based metabolomics for the rapid analysis and authentication of the milk from its lipid profile.

Selective One-Dimensional Total Correlation Spectroscopy Nuclear Magnetic Resonance Experiments for a Rapid Identification of Minor Components in the Lipid Fraction of Milk and Dairy Products: Toward Spin Chromatography?

We report a rapid, direct, and unequivocal spin-chromatographic separation and identification of minor components in the lipid fraction of milk and common dairy products with the use of selective one-dimensional (1D) total correlation spectroscopy (TOCSY) nuclear magnetic resonance (NMR) experiments. The method allows for the complete backbone spin-coupling network to be elucidated even in strongly overlapped regions and in the presence of major components from 4 × 10(2) to 3 × 10(3) stronger NMR signal intensities. The proposed spin-chromatography method does not require any derivatization steps for the lipid fraction, is selective with excellent resolution, is sensitive with quantitation capability, and compares favorably to two-dimensional (2D) TOCSY and gas chromatography-mass spectrometry (GC-MS) methods of analysis. The results of the present study demonstrated that the 1D TOCSY NMR spin-chromatography method can become a procedure of primary interest in food analysis and generally in complex mixture analysis.

Synthetic methodologies in organic chemistry involving incorporation of [¹7O] and [¹8O] isotopes.

This review is a critical survey of the literature that aims to highlight the most significant developments on synthetic strategies involving stable oxygen isotopes ([(17)O] and [(18)O]). The labeling methodologies are categorized in groups, according to the oxygen-containing functional group.