Synthesis and vasorelaxant evaluation of novel 7-methoxyl-2,3-disubstituted-quinoxaline derivatives

Modulation of Abnormal Vasoconstriction Through 2-Hydroxyisobutyrylation of Tropomyosin 3 Lys141: Targeting Histone Deacetylase 3 as a Key Approach

BACKGROUND

TPM3 (tropomyosin 3) is an actin-binding protein in vascular smooth muscle cells, where posttranslational modifications critically regulate its actin affinity, influencing cardiovascular function. Emerging evidence suggests that Khib (2-hydroxyisobutyrylation) plays a significant role in the cardiovascular system. Histone deacetylase 3 (HDAC3) serves as an "eraser" of Khib marks. However, the impact of TPM3 de-2-hydroxyisobutyrylation on vascular contraction remains unclear.

METHODS AND RESULTS

In this study, we employed mouse models and in vitro experiments to elucidate the mechanism by which phenylephrine-induced HDAC3 activation drives vasoconstriction via de-2-hydroxyisobutyrylation of TPM3. Our findings demonstrate that phenylephrine triggers HDAC3 nuclear export and promotes its interaction with TPM3, resulting in decreased Khib modification and enhanced vasoconstriction. Coimmunoprecipitation experiments confirmed that phenylephrine reduces Khib levels on TPM3 in mouse aorta. Additionally, ex vivo vascular tension assays using mouse aortic rings revealed that treatment with the Khib donor, ethyl 2-hydroxyisobutyrate, induces endothelium-independent vasodilation and ameliorates hypertensive vascular dysfunction. Molecular docking and kinetic simulations identified Lys141 of TPM3 as the primary site targeted by HDAC3-mediated de-2-hydroxyisobutyrylation. This was further validated by adenoviral transfection of isolated blood vessels with a Lys141-mutated TPM3 construct, which abolished the effects of HDAC3 on TPM3 Khib modification and vascular contractility.

CONCLUSIONS

These findings underscore the critical role of TPM3 de-2-hydroxyisobutyrylation in vasoconstriction and suggest that modulating this posttranslational modification could provide a novel therapeutic strategy for hypertensive vascular dysfunction.

Annulation of 2-Aroyl D-A Cyclopropanes via Selectively Ring-Opening Process with o-Benzenediamines to Access Quinoxaline Derivatives

An annulation reaction of 2-aroyl D-A cyclopropanes with o-benzenediamines via selective cleavage of C-C bonds of cyclopropane in the presence of DBU/Sc(OTf)3 reaction systems was developed for the direct preparation of 2-aryl-3-benzylquinoxalines. This synthetic approach tolerated a wide range of readily available aroyl-substituted D-A cyclopropanes with diverse functional groups and had operationally simple and mild reaction conditions.

The hydroxamic acid derivative YPX-C-05 alleviates hypertension and vascular dysfunction through the PI3K/Akt/eNOS pathway

BACKGROUND

Hypertension is a prevalent cardiovascular disease characterized by elevated blood pressure and increased vascular resistance. HDAC inhibitors have emerged as potential therapeutic agents due to their ability to modulate gene expression and cellular processes. YPX-C-05, a novel hydroxamic acid-based HDAC inhibitor, shows promise in its vasodilatory effects and potential targets for hypertension treatment. In this study, we aimed to elucidate the mechanisms underlying YPX-C-05's vasodilatory effects and explore its therapeutic potential in hypertension.

METHODS

To determine the ex vivo vasodilatory effects of YPX-C-05, isolated aortic rings precontracted with phenylephrine were used. We assessed YPX-C-05's inhibitory effects on HDACs and its impact on histone H4 deacetylation levels in endothelial cells. Network pharmacology analysis was employed to predict putative targets of YPX-C-05 for hypertension treatment. To investigate the involvement of the PI3K/Akt/eNOS pathway, we employed enzyme-linked immunosorbent assay and to assess the levels of NO, ET-1, BH2, and BH4 in human umbilical vein endothelial cells. And we also analyzed the mRNA expression of eNOS and ET-1. Furthermore, Western blotting was conducted to quantify the phosphorylated and total Akt and eNOS levels in human umbilical vein endothelial cell lysates following treatment with YPX-C-05. In order to elucidate the vasodilatory mechanism of YPX-C-05, we employed pharmacological inhibitors for evaluation purposes. Furthermore, we evaluated the chronic antihypertensive effects of YPX-C-05 on N-omega-nitro-L-arginine-induced hypertensive mice in an in vivo model. Vascular remodeling was assessed through histological analysis.

RESULTS

Our findings demonstrated that YPX-C-05 exerts significant vasodilatory effects in isolated aortic rings precontracted with phenylephrine. Furthermore, YPX-C-05 exhibited inhibitory effects on HDACs and increased histone H4 acetylation in endothelial cells. Network pharmacology analysis predicted YPX-C-05 might activate endothelial eNOS via PI3K/Akt signaling pathway. Inhibition of the PI3K/Akt/eNOS pathway attenuated the vasodilatory effects of YPX-C-05, as evidenced by reduced levels of phosphorylated Akt and eNOS in human umbilical vein endothelial cell lysates. The chronic administration of YPX-C-05 in N-omega-nitro-L-arginine-induced hypertensive mice resulted in significant antihypertensive effects. Histological analysis demonstrated a reduction in vascular remodeling, further supporting the therapeutic potential of YPX-C-05 in hypertension.

CONCLUSION

This study demonstrates for the first time that the novel hydroxamic acid-based HDAC inhibitor YPX-C-05 produces significant antihypertensive and vasodilatory effects through the PI3K/Akt/eNOS pathway. Our findings support the developing prospect of YPX-C-05 as a novel antihypertensive drug.

New Series of VEGFR-2 Inhibitors and Apoptosis Enhancers: Design, Synthesis and Biological Evaluation

Background

Cancer is still a major world health threat, causing a high rate of mortality. VEGFR-2 inhibitor anticancer agents are of great significance. However, they showed some serious side effects.

Purpose

To discover new effective and safer anticancer agents, a new series of piperazinylquinoxaline-based derivatives was designed and synthesized on the basis of the pharmacophoric features of VEGFR-2 inhibitor drugs.

Methods

The new candidates were evaluated against A549 lung cancer cells, HepG-2 hepatoma cells, Caco-2 colon cancer cells, MDA breast cancer cells, and VEGFR-2 kinase. Moreover, cell cycle kinetics and apoptosis rates were studied in HepG-2 cells treated with compound 11, which was the most promising candidate.

Results

The new derivatives revealed better antitumor results (IC₅₀ from 6.48 to 38.58 µM) against the aforementioned cancer cell lines than sorafenib. Also, the new candidates showed VEGFR-2 inhibition with IC₅₀ values ranging from 0.19 to 0.60 µM compared to 0.08 µM for sorafenib. Compound 11, meanwhile, showed IC₅₀ values equal to 10.61, 9.52, 12.45, 11.52, and 0.19 µM against the cancer cell lines and VEGFR-2, respectively. Moreover, compound 11 raised the apoptosis rate in HepG-2 cells from 5% to 44% and caused 4, 2.3, and 3-fold increases in BAX/Bcl-2 ratio, caspase-3 level, and P53 expression, respectively, compared to control untreated cells. Finally, the new derivatives displayed the correct binding mode into VEGFR-2 kinase pocket, giving interactions with the essential residues.

Conclusion

This work suggests that compound 11 is a very significant anticancer candidate, and piperazinylquinoxaline is an important scaffold in the development of new potential effective and safer VEGFR-2 inhibitor agents.

New styrylquinoxaline: synthesis, structural, biological evaluation, ADMET prediction and molecular docking investigations

The organic compound (E)-3-(4-methylstyryl)quinoxalin-2(1H)-one (SQO) with molecular formula C₁₇H₁₄N₂O was synthesized and analyzed using single crystal X-ray diffraction, ¹H, ¹³C NMR and FTIR spectroscopic techniques. The geometric parameters of the molecule was optimized by density-functional theory (DFT) choosing B3LYP with 6-31++G(d,p) basis set. For compatibility, the theoretical structure and experimental structure were overlapped with each other. Frontier molecular orbitals of the title compound were made, and energy gap between HOMO and LUMO was calculated. Molecular electrostatic potential map was generated finding electrophilic and nucleophilic attack centers using DFT method. Hirshfeld surface analysis (HSA) confirms active regions at the circumference of N1 atoms and O1 atoms that form intermolecular N1-H1···O1 hydrogen bond. The acute oral toxicity study was carried out according to OECD guideline, which approve that the compound SQO was non-toxic. In addition, this quinoxaline derivative was evaluated for its in vitro antidiabetic activity against α-glucosidase and α-amylase enzymes and for antioxidant activity by utilizing several tests as 1,1-diphenyl-2-picryl hydrazyl, (2,2'-azino-bis(3-ethyl benzthiazoline-6-sulfonicacid), reducing power test (FRAP) and hydrogen peroxide activity H₂O₂. The molecular docking studies were performed to investigate the antidiabetic activity of SQO and compared with the experimental results. SQO is a potent antidiabetic from both the experimental and molecular docking results. Finally, the physicochemical, pharmacokinetic and toxicological properties of SQO have been evaluated by using in silico absorption, distribution, metabolism, excretion and toxicity analysis prediction.