The synthesis and bioactivities of ROCK2 inhibitors with 1,2-dithiolan-3-yl motif.

Rho-associated coiled-coil containing kinase (ROCK) plays an important role in inflammation. Herein, a series of compounds were designed and synthesized as ROCK inhibitors based on the structure-based drug design (SBDD) strategy and were evaluated for cytotoxicity, antioxidant activity and anti-inflammatory activity. Among them, compound DC24 was identified as the optimal hit in enzymatic screening with an IC50 value of 0.124 µM against ROCK2 and 50-fold selectivity over ROCK1. DC24 has a novel lipid amide scaffold with a bis(4-fluorophenyl)methyl substituent, and DC24 is the first ROCK2 inhibitor interacting with the hinge region of ROCK2 via the 1,2-dithiolan-3-yl motif, which has been confirmed by the binding model of DC24 with ROCK2. In a complete Freund's adjuvant (CFA) induced acute inflammation model, DC24 at a dose of 5 mg kg-1 exhibited an anti-inflammatory effect better than that of belumosudil. Furthermore, DC24 exhibits good safety in vivo.

Synthesis and evaluation of L-quebrachitol derivatives against platelet aggregation.

Thrombosis plays an important role in the occurrence and development of cardiovascular and cerebrovascular diseases that contribute to high mortality and morbidity in patients. L-(-)-Quebrachitol (QCT), a natural product, was first isolated from quebracho bark. It can inhibit PAF receptor and decrease gastric damage induced by indomethacin, as a drug against platelet aggregation. Here, five QCT derivatives were synthesized and investigated for their inhibitory effects on platelet aggregation. Among them, compound 3a showed anticoagulant effects comparable to aspirin, while compound 4b showed dose-independent inhibitory activities in rats that were stronger than aspirin.

DNA Methyltransferase 3A: a Significant Target for the Discovery of Inhibitors as Potent Anticancer Drugs.

DNA methyltransferase (DNMT) is a conserved family of Cytosine methylases, which plays a crucial role in the regulation of Epigenetics. They have been considered promising therapeutic targets for cancer. Among the DNMT family, mutations in the DNMT3A subtype are particularly important in hematologic malignancies. The development of specific DNMT3A subtype inhibitors to validate the therapeutic potential of DNMT3A in certain diseases is a significant task. In this review, we summarized the small molecule inhibitors of DNMT3A discovered in recent years and their inhibitory activities, and classified them based on their inhibitory mechanisms.

Toll-like receptor 4 (TLR4) inhibitors: Current research and prospective.

Toll-like receptor 4 (TLR4), a member of the Toll-like receptor (TLR) family, is involved in innate immunity and mediates inflammatory responses by recognizing lipopolysaccharide (LPS) or bacterial endotoxins. Hyperactivation of TLR4 triggers the production of various inflammatory factors, which are associated with the development of a variety of diseases, such as sepsis, endotoxemia, acute lung injury, rheumatoid arthritis, and cardiovascular diseases. And anti-inflammatory potential of TLR4 inhibitors have been validated. In this review, we discuss TLR4 inhibitors that can bind directly to TLR4 or the TLR4/MD2 complex, and provide a brief introduction to compounds that can downregulate the expression of TLR4. We focused on the possible modes by which the TLR4 inhibitors bind to the TLR4 or TLR4/MD2 complex. Three compounds targeting TLR4 have entered clinical trials, but unfortunately, two of them have been discontinued due to poor efficacy. Therefore, the discovery of effective small molecular compounds is the main research focus for TLR4 inhibitor design. In this review, by summarizing results from molecular dynamics simulation and molecular docking, we found that the Arg241 residue of TLR4 and the Tyr102, Ser120, and Lys122 residues of MD2 are involved in the binding of antagonistic ligands to the TLR4/MD2 complex; this is useful information for structure-based TLR4 inhibitor design.

OAB-14 Effectively Ameliorates the Dysfunction of the Endosomal-Autophagic-Lysosomal Pathway in APP/PS1 Transgenic Mice.

In Alzheimer's disease (AD), damaged Aß clearance contributes to elevated levels of Aß that cause a series of cytotoxic cascade reactions. Thus, targeting Aß clearance has now been considered a valid therapeutic approach for AD. Cellular uptake and degradation are important mechanisms for Aß clearance, which are mainly performed by the endosomal-autophagic-lysosomal (EAL) pathway. Our previous study showed that OAB-14, a novel small molecule designed with bexarotene as the lead compound, treatment for 3 months significantly alleviated cognitive disorders and remarkably reduced the deposition of Aß without affecting its production in APP/PS1 transgenic mice. Here, we further revealed that enhancement of the EAL activity is one of the mechanisms that increases Aß clearance after OAB-14 administration for 3 months. OAB-14 facilitates receptor-mediated endocytosis and restores autophagy flux via the AMPK/mTOR pathway. Meanwhile, OAB-14 enhances the lysosomal activity, and reduced Aß accumulation in lysosomes was observed in OAB-14-treated AD mice. These results suggest that OAB-14 may promote Aß clearance in lysosomes by alleviating the EAL dysfunction in AD mice.

Discovery of memantyl urea derivatives as potent soluble epoxide hydrolase inhibitors against lipopolysaccharide-induced sepsis.

Sepsis, a systemic inflammatory response, caused by pathogenic factors including microorganisms, has high mortality and limited therapeutic approaches. Herein, a new soluble epoxide hydrolase (sEH) inhibitor series comprising a phenyl ring connected to a memantyl moiety via a urea or amide linkage has been designed. A preferential urea pharmacophore that improved the binding properties of the compounds was identified for those series via biochemical assay in vitro and in vivo studies. Molecular docking displayed that 3,5-dimethyl on the adamantyl group in B401 could make van der Waals interactions with residues at a hydrophobic pocket of sEH active site, which might indirectly explain the subnanomolar level activities of memantyl urea derivatives in vitro better than AR-9281. Among them, compound B401 significantly improved the inhibition potency with human and murine sEH IC50 values as 0.4 nM and 0.5 nM, respectively. Although the median survival time of C57BL/6 mice in LPS-induced sepsis model was slightly increased, the survival rate did not reach significant efficacy. Based on safety profile, metabolic stability, pharmacokinetic and in vivo efficacy, B401 demonstrated the proof of potential for this class of memantyl urea-based sEH inhibitors as therapeutic agents in sepsis.

SET Protein in Cancer: A Potential Therapeutic Target.

SET protein is a multi-functional oncoprotein that is ubiquitously expressed in most tumor cells. Dysregulation of SET has been associated with many types of cancer. Due to ever-accumulating evidence of its strong correlation with both poor prognosis and drug resistance, the targeting of SET is starting to be explored. SET is currently regarded as a potential target for cancer therapy, and several inhibitors are being developed for clinical trials. In this review, the physiological and pathological functions of SET, as well as its antagonists, will be discussed along with the prospects and challenges involved with translating SET inhibitors into bona fide therapeutic options.

Targeting HDAC/OAZ1 axis with a novel inhibitor effectively reverses cisplatin resistance in non-small cell lung cancer.

Cisplatin yields significant efficacy and is generally used as a frontline therapy for non-small cell lung cancer (NSCLC). However, acquired resistance strongly limits its application. Here, we identified that a novel histone deacetylase (HDAC) inhibitor S11, with P-glycoprotein inhibitory activity, could obviously suppress cell growth in cisplatin-resistant NSCLC cell lines. In addition, S11 could increase the expression of Ac-H4 and p21, which confirmed its HDAC inhibitory action, suppress colony formation, and block cell migration of cisplatin-resistant NSCLC cells. Notably, co-treatment with S11 and cisplatin exhibited synergistically inhibitory efficacy in cisplatin-resistant NSCLC cells. Gene microarray data showed that OAZ1 was downregulated in resistant cells but upregulated after S11 treatment. Further study indicated that knockdown of OAZ1 by siRNA resulted in the decrease of sensitivity of resistant cells to cisplatin treatment and contributed to the increase of resistant cell migration. Additionally, ChIP assay data demonstrated that HDAC inhibitor S11 could increase the accumulation of Ac-H4 in OAZ1 promoter region, suggesting the direct regulation of OAZ1 by HDAC. Importantly, the combination of S11 and cisplatin overcome resistance through inhibiting HDAC activity and subsequently increasing the OAZ1 expression in preclinical model. Moreover, we observed that positive expression of HDAC1 was associated with the downregulation of OAZ1 in NSCLC patients with platinum-based treatment, and predicted drug resistance and poor prognosis. In summary, we demonstrated a role of HDAC/OAZ1 axis in cisplatin-resistant NSCLC and identified a promising compound to overcome cisplatin resistance.

Design, synthesis and evaluation of N-hydroxypropenamides based on adamantane to overcome resistance in NSCLC.

A series of novel N-hydroxypropenamides containing adamantane moiety were identified and most of them exhibited HDAC inhibitory activity and could reverse the resistance of cisplatin in NSCLC cell lines. In this process, molecular docking was employed to verify the rationality of designing, subsequently, target compounds were synthesized and conducted to enzyme- and cell-based biological evaluation. Most of synthesized compounds could inhibit HDAC activity with the IC50 values lower than 50 nM and result in the increase of Ac-H4 and p21 in A549 cells. Importantly, we assessed the reversal effect of those compounds and found several compounds display an anti-resistant effect in lung cancer cells, especially compound 8f. As compared to belinostat and cisplatin, compound 8f showed improved inhibitory activity against A549/CDDP cell lines with IC50 value of 5.76 µM, and far lower resistance index of 1.24. Moreover, the structure-activity relationships of these compounds were summarized and compound 8f could serve as a research tool for identifying the mechanism of reversing resistance and a template for designing novel compounds to reverse cisplatin resistance.

Insight into the roles of tightly and loosely bound extracellular polymeric substances on a granular sludge in ammonium nitrogen removal.

To explicitly understand the function of extracellular polymeric substances in the treatment of ammonium-nitrogen-rich wastewater using aerobic granular sludge, the three forms of nitrogen (ammonium, nitrite and nitrate nitrogen) contained in tightly and loosely bound extracellular polymeric substances were analyzed. The three forms of nitrogen were monitored in the tightly and loosely bound extracellular polymeric substances in aerobic granular sludge after adsorption. The ammonium nitrogen contained in the extracellular polymeric substances was distributed in both the tightly and loosely bound forms and decreased gradually as the aeration time increased. Ammonium nitrogen remained in the tightly bound extracellular polymeric substances even after aeration was complete. The nitrite and nitrate nitrogen species in the extracellular polymeric substances were mainly present in the loosely bound extracellular polymeric substances. The sources of the three nitrogen forms detected in the extracellular polymeric substances differed relative to the different nitrogen forms.

SYP-5, a novel HIF-1 inhibitor, suppresses tumor cells invasion and angiogenesis.

Hypoxia-inducible factor-1 (HIF-1) plays an essential role in carcinogenesis. The overexpression of HIF-1 induced by hypoxia is closely associated with metastasis, poor prognosis and high mortality. In this study, a novel HIF-1 inhibitor SYP-5 was first observed by the luciferase reporter assay. Western blots results showed SYP-5 inhibited hypoxia-induced upregulation of HIF-1. Moreover, the proteins of vascular endothelial growth factor (VEGF) and matrix metalloproteinases (MMP)-2 that are targets of HIF-1, were down-regulated by SYP-5. Furthermore, in the tube formation assay, SYP-5 suppressed angiogenesis induced by hypoxia and VEGF in vitro. Additionally, using Transwell and RTCA assays, we found that SYP-5 also retarded the Hep3B and Bcap37 cells migration and invasion induced by hypoxia and FBS. Last, we also detected the upstream pathways related to HIF-1 and found both PI3K/AKT and MAPK/ERK were involved in the SYP-5 mediated invasive inhibition of Bcap37 cells. These results indicates that SYP-5 inhibits tumor cell migration and invasion, as well as tumor angiogenesis, which are mediated by suppressing PI3K/AKT- and MAPK/ERK-dependent HIF-1 pathway. It suggests that SYP-5 might be a potential HIF-1 inhibitor as an anticancer agent.

Novel cinnamohydroxamic acid derivatives as HDAC inhibitors with anticancer activity in vitro and in vivo.

A novel series of cinnamohydroxamic acid derivatives were synthesized and their biological activities against HDAC were assessed. Our results showed that the compound with more strong inhibitory activity to HDAC would exhibited more significant anti-proliferative effect on tumor cells. Among these compounds, 7e displayed clearly inhibitory effects on HDAC and tumor cell growth. Furthermore, HDAC isoforms enzyme data indicated that, compared to HDAC pan-inhibitor SAHA, 7e owned an enhanced inhibitory effect on HDAC1, 3 and 6 isoforms. Meanwhile, it also significantly suppressed cell growth of lung cancer cells compared to SAHA, but with lower toxicity in normal cells. Mechanistically, 7e prompted acetylation of histone3 and histone4, led to up-regulation of p21, and then mediated cell cycle arrest and pro-apoptosis. Moreover, the in vivo study indicated that compound 7e could retard tumor growth of A549 xenograft models. These findings support the further investigation on the anti-tumor potential of this class of compounds as HDAC inhibitor.