Synthesis and evaluation of the HIF-1α inhibitory activity of 3(5)-substituted-4-(quinolin-4-yl)- and 4-(2-phenylpyridin-4-yl)pyrazoles as inhibitors of ALK5

Synthesis and antimicrobial activity evaluation of pyrazole derivatives containing imidazothiadiazole moiety

AIM

The purpose of this work was to investigate the antimicrobial activity of pyrazole derivatives (21a - i and 23a - o) synthesized.

MATERIALS & METHODS

The pyrazole derivatives were synthesized, molecular docked and tested for their antimicrobial activity, cytotoxicity, and hemolysis rate.

RESULTS

Most of the target compounds showed high selective inhibitory activity against multi-drug resistance compared with other strains. Of these, compounds 21c (MIC = 0.25 µg/mL) and 23 h (MIC = 0.25 µg/mL) showed the strongest antibacterial activity, which was 4-flods than that of the positive control compound gatifloxacin (MIC = 1 µg/mL). Furthermore, compound 23 h showed no cytotoxicity to human LO2 cells, and did not show hemolysis even at ultra-high concentration.

CONCLUSION

These results prompted that these compounds are valuable for further development as antimicrobial agents.

Synthesis and biological evaluation of sulfonamide derivatives containing imidazole moiety as ALK5 inhibitors

Four series of sulfonamide derivatives (13a-b, 14a-d, 15a-b, and 16a-d) were synthesized and evaluated for their activin receptor-like kinase 5 (ALK5) inhibitory activities. Of these, compounds 13b (IC50 = 0.130 μM) and 15a (IC50 = 0.130 μM) showed the highest inhibitory activities against ALK5 kinase, with activities similar to the positive control LY-2157299. Notably, we discovered that introduction of sulfonamide group at the 2-position of the central imidazole ring significantly increased ALK5 inhibitory activity. Compounds 13b and 15a did not show toxicity in A549 cells up to the maximum concentration of 50 μM, and effectively inhibited TGF-β1-induced Smad-signaling and cell motility in A549 cells. The results indicate that compounds 13b and 15a are worth of further development as anticancer agents.

Synthesis of amide derivatives containing the imidazole moiety and evaluation of their anti-cardiac fibrosis activity

Three series of N-{[4-([1,2,4]triazolo[1,5-α]pyridin-6-yl)-5-(6-methylpyridin-2-yl)-1H-imidazol-2-yl]methyl}acetamides (14a-d, 15a-n, and 16a-f) were synthesized and evaluated for activin receptor-like kinase 5 (ALK5) inhibitory activities in an enzymatic assay. The target compounds showed high ALK5 inhibitory activity and selectivity. The half maximal inhibitory concentration (IC50) for phosphorylation of ALK5 of 16f (9.1 nM), the most potent compound, was 2.7 times that of the clinical candidate EW-7197 (vactosertib) and 14 times that of the clinical candidate LY-2157299. The selectivity index of 16f against p38α mitogen-activated protein kinase was >109, which was much higher than that of positive controls (EW-7197: >41, and LY-2157299: 4). Furthermore, a molecular docking study provided the interaction modes between the target compounds and ALK5. Compounds 14c, 14d, and 16f effectively inhibited the protein expression of α-smooth muscle actin (α-SMA), collagen I, and tissue inhibitor of metalloproteinase 1 (TIMP-1)/matrix metalloproteinase 13 (MMP-13) in transforming growth factor-β-induced human umbilical vein endothelial cells. Compounds 14c and 16f showed especially high activity at low concentrations, which suggests that these compounds could inhibit myocardial cell fibrosis. Compounds 14c, 14d, and 16f are potential preclinical candidates for the treatment of cardiac fibrosis.

Synthesis and Antimicrobial Activity Evaluation of Pyridine Derivatives Containing Imidazo[2,1-b][1,3,4]Thiadiazole Moiety

Four series of novel pyridine derivatives (17 a-i, 18 a-i, 19 a-e, and 20 a-e) were synthesized and their antimicrobial activities were evaluated. Of all the target compounds, almost half target compounds showed moderate or high antibacterial activity. The 4-F substituted compound 17 d (MIC=0.5 μg/mL) showed the highest antibacterial activity, its activity was twice the positive control compound gatifloxacin (MIC=1.0 μg/mL). For fungus ATCC 9763, the activities of compounds 17 a and 17 d are equivalent to the positive control compound fluconazole (MIC=8 μg/mL). Furthermore, compounds 17 a and 17 d showed little cytotoxicity to human LO2 cells, and did not show hemolysis even at ultra-high concentration (200 μM). The results indicate that these compounds are valuable for further development as antibacterial and antifungal agents.

Synthesis and Evaluation of Imidazole Derivatives Bearing Imidazo[2,1-b] [1,3,4]thiadiazole Moiety as Antibacterial Agents

BACKGROUND

Drug-resistant infections kill hundreds of thousands of people globally every year. In previous work, we found that tri-methoxy- and pyridine-substituted imidazoles show strong antibacterial activities.

OBJECTIVE

The aim of this work was to investigate the antibacterial activities and bacterial resistances of imidazoles bearing an aromatic heterocyclic, alkoxy, or polycyclic moiety on the central ring.

METHODS

Three series of 2-cyclopropyl-5-(5-(6-methylpyridin-2-yl)-2-substituted-1H-imidazol-4- yl)-6-phenylimidazo[2,1-b][1,3,4]thiadiazoles (13a-e, 14a-d, and 15a-f) were synthesized and their antibacterial activity was evaluated. The structures were confirmed by their 1H NMR, 13C NMR, and HRMS spectra. All the synthesized compounds were screened against Gram-positive, Gramnegative, and multidrug-resistant bacterial strains.

RESULTS

More than half of the compounds showed moderate or strong antibacterial activity. Among them, compound 13e (MICs = 1-4 μg/mL) showed the strongest activity against Gram-positive and drug-resistant bacteria as well as high selectivity against Gram-negative bacteria. Furthermore, it showed no cytotoxicity against HepG2 cells, even at 100 μM, and no hemolysis at 20 μM.

CONCLUSION

These results indicate that compound 13e is excellent candicate for further study as a potential antibacterial agent.

Recent Advances in Research on Active Compounds Against Hepatic Fibrosis

BACKGROUND

Almost all chronic liver diseases cause fibrosis, which can lead to cirrhosis and eventually liver cancer. Liver fibrosis is now considered to be a reversible pathophysiological process and suppression of fibrosis is necessary to prevent liver cancer. At present, no specific drugs have been found that have hepatic anti-fibrotic activity.

OBJECTIVE

The research progress of anti-hepatic fibrosis compounds in recent ten years was reviewed to provide a reference for the design and development of anti-hepatic fibrosis drugs.

METHODS

According to the structure of the compounds, they are divided into monocyclic compounds, fused-heterocyclic compounds, and acyclic compounds.

RESULTS

In this article, the natural products and synthetic compounds with anti-fibrotic activity in recent ten years were reviewed, with emphasis on their pharmacological activity and structure-activity relationship (SAR).

CONCLUSION

Most of these compounds are natural active products and their derivatives, and there are few researches on synthetic compounds and SAR studies on natural product.

Synthesis and antimicrobial activity evaluation of pyrazole derivatives containing the imidazo[2,1-b][1,3,4]thiadiazole moiety

Four series of novel pyrazole derivatives (compounds 17a-m, 18a-m, 19a-g, and 20a-g) were synthesized, and their antibacterial and antifungal activities were evaluated. Most of the target compounds (17a-m, 18k-m, and 19b-g) showed strong antifungal activity and high selectivity relative to both Gram-positive and Gram-negative bacteria. Among them, compounds 17l (minimum inhibitory concentration [MIC] = 0.25 µg/mL) and 17m (MIC = 0.25 µg/mL) showed the strongest antifungal activity, being 2- and 4-fold more active than the positive controls gatifloxacin and fluconazole, respectively. In particular, compound 17l showed little cytotoxicity against human LO2 cells and did not exhibit hemolysis at ultrahigh concentrations, as did the positive control compounds gatifloxacin and fluconazole. These results indicate that these compounds are valuable for further development as antifungal agents.

Panaxadiol inhibits IL-1β secretion by suppressing zinc finger protein 91-regulated activation of non-canonical caspase-8 inflammasome and MAPKs in macrophages

ETHNOPHARMACOLOGICAL RELEVANCE

The use of Panax ginseng C.A.Mey. in traditional Chinese medicine dates back to about 5000 years ago thanks to its several beneficial and healing properties. Panaxadiol is a triterpenoid sapogenin monomer found in the roots of Panax ginseng C.A.Mey. and has been proven to have various bio-activities such as anti-inflammatory, anti-tumour and neuroprotective effects.

AIM OF THE STUDY

The present study focuses on investigating the inflammation inhibitory effect and mechanism of panaxadiol by regulating zinc finger protein 91-regulated activation of non-canonical caspase-8 inflammasome and MAPKs in macrophages.

MATERIALS AND METHODS

In vitro, the underlying mechanisms by which panaxadiol inhibits ZFP91-regulated IL-1β expression were investigated using molecular docking, western blotting, RT-PCR, ELISA, immunofluorescence, and immunoprecipitation assays. In vivo, colitis was induced by oral administration of DSS in drinking water, and peritonitis was induced by an intraperitoneal injection of alum. Recombinant adeno-associated virus (AAV serotype 9) vector was used to establish ZFP91 knockdown mouse.

RESULTS

We confirmed that panaxadiol inhibited IL-1β secretion by suppressing ZFP91 in macrophages. Further analysis revealed that panaxadiol inhibited IL-1β secretion by suppressing ZFP91-regulated activation of non-canonical caspase-8 inflammasome. Meanwhile, panaxadiol inhibited IL-1β secretion by suppressing ZFP91-regulated activation of MAPKs. In vivo, prominent anti-inflammatory effects of panaxadiol were demonstrated in a DSS induced acute colitis mouse model and in an alum-induced peritonitis model by suppressing ZFP91-regulated secretion of inflammatory mediators, consistent with the results of the AAV-ZFP91 knockdown in mice.

CONCLUSIONS

We report for the first time that panaxadiol inhibited IL-1β secretion by suppressing ZFP91-regulated activation of non-canonical caspase-8 inflammasome and MAPKs, providing evidence for anti-inflammation mechanism of panaxadiol treatment for inflammatory diseases.

Recent contributions of quinolines to antimalarial and anticancer drug discovery research

Quinoline, a privileged scaffold in medicinal chemistry, has always been associated with a multitude of biological activities. Especially in antimalarial and anticancer research, quinoline played (and still plays) a central role, giving rise to the development of an array of quinoline-containing pharmaceuticals in these therapeutic areas. However, both diseases still affect millions of people every year, pointing to the necessity of new therapies. Quinolines have a long-standing history as antimalarial agents, but established quinoline-containing antimalarial drugs are now facing widespread resistance of the Plasmodium parasite. Nevertheless, as evidenced by a massive number of recent literature contributions, they are still of great value for future developments in this field. On the other hand, the number of currently approved anticancer drugs containing a quinoline scaffold are limited, but a strong increase and interest in quinoline compounds as potential anticancer agents can be seen in the last few years. In this review, a literature overview of recent contributions made by quinoline-containing compounds as potent antimalarial or anticancer agents is provided, covering publications between 2018 and 2020.

Synthesis and Evaluation of Chiral Rhodanine Derivatives Bearing Quinoxalinyl Imidazole Moiety as ALK5 Inhibitors

BACKGROUND

TGF-β signaling pathway inhibition is considered an effective way to prevent the development of several diseases. In the design and synthesis of TGF-β inhibitors, a rhodanine compound containing a quinoxalinyl imidazole moiety was found to have strong antimicrobial activity.

OBJECTIVE

The purpose of this work was to investigate the antimicrobial activity of other chiral rhodanine TGF-β inhibitors synthesized.

METHODS

Two series of 3-substituted-5-((5-(6-methylpyridin-2-yl)-4-(quinoxalinyl-6-yl)- 1H-imidazol-2-yl)methylene)-2-thioxothiazolin-4-ones (12a-h and 13a-e) were synthesized and evaluated for their ALK5 inhibitory and antimicrobial activity. The structures were confirmed by their 1H NMR, 13C NMR, and HRMS spectra. All the synthesized compounds were screened against Gram-positive strains, Gram-negative strains, and fungi.

RESULTS

Among the synthesized compounds, compound 12h showed the highest activity (IC50 = 0.416 μM) against ALK5 kinase. Compound 12h exhibited a good selectivity index of > 24 against p38α MAP kinase and was 6.0-fold more selective than the clinical candidate, compound 2 (LY-2157299). Nearly all the compounds displayed high selectivity toward both Gram-positive and Gram-negative bacteria. They also showed similar or 2.0-fold greater antifungal activity (minimum inhibitory concentration [MIC] = 0.5 µg/mL) compared with the positive control compounds Gatifloxacin (MIC = 0.5 µg/mL) and fluconazole (MIC = 1 µg/mL).

CONCLUSION

The findings suggest that the synthesized rhodanine compounds have good ALK5 inhibitory activity and can be used for further research and development as potential antifungal drugs.

Novel HIF-1α inhibitor CDMP-TQZ for cancer therapy

Aim: Tumor cells adapt to hypoxic microenvironments by releasing the key transcription factor HIF-1α, which promotes angiogenesis, glycolytic phenotype, metastasis and erythropoiesis, allowing proliferation amid low oxygen levels. Therefore, therapeutic targeting of HIF-1α represents a viable strategy for cancer therapy. Methods & Results: The authors synthesized a series of novel tetrahydroquinazoline derivatives in six steps and demonstrated that their development had a unique ability to suppress HIF-1α expression through proteasomal degradation. Conclusion: Among these compounds, CDMP-TQZ (8bf) exhibited the highest antiproliferative potency in human cancer cells, in part through downregulation of HIF-1α.

Design, synthesis of novel celastrol derivatives and study on their antitumor growth through HIF-1α pathway

Four series of hypoxia-inducible factor-1 alpha (HIF-1α) functioning derivatives stemming from modifications to the C-29 carboxyl group of celastrol were designed and synthesized, and their anticancer activities were evaluated. To address the structure and activity relationship of each derivative, extensive structural changes were made. HRE luciferase reporter assay demonstrated that 12 modified compounds showed superior HIF-1α inhibitory activity. Among them, compound C6 exhibited the best features: firstly, the strongest HIF-1α inhibitory activity (IC₅₀ = 0.05 μM, 5-fold higher than that of celastrol); secondly, lower cytotoxicity (22-fold lower, C6-16.85 μM vs celastrol-0.76 μM). Thus, the safety factor of C6 was about 112 times higher than that of celastrol. Western blot assay indicated that C6 may inhibit the expression of HIF-1α protein in cells. Additionally, C6 hindered tumor cell cloning, migration and induced cell apoptosis. It is worth mentioning that in the mouse tumor xenograft model, C6 (10 mg/kg) displayed good antitumor activity in vivo, showing a better inhibition rate (74.03%) than the reference compound 5-fluorouracil (inhibition rate, 59.58%). However, the celastrol treatment group experienced collective death after four doses of the drug. Moreover, C6 minimally affected the mouse weight, indicating that its application in vivo has little toxic effect. H&E staining experiments show that it could also exacerbate the degree of tumor cell damage. The results of water solubility experiment show that the solubility of C6 is increased by 1.36 times than that of celastrol. In conclusion, C6 is a promising antitumor agent through HIF-1α pathway.

The Landscape of Interactions between Hypoxia-Inducible Factors and Reactive Oxygen Species in the Gastrointestinal Tract

The gastrointestinal tract (GT) is the major organ involved in digestion, absorption, and immunity, which is prone to oxidative destruction by high levels of reactive oxygen species (ROS) from luminal oxidants, such as food, drugs, and pathogens. Excessive ROS will lead to oxidative stresses and disrupt essential biomolecules, which also act as cellular signaling molecules in response to growth factors, hormones, and oxygen tension changes. Hypoxia-inducible factors (HIFs) are critical regulators mediating responses to cellular oxygen tension changes, which are also involved in energy metabolism, immunity, renewal, and microbial homeostasis in the GT. This review discusses interactions between HIF (mainly HIF-1α) and ROS and relevant diseases in the GT combined with our lab's work. It might help to develop new therapies for gastrointestinal diseases associated with ROS and HIF-1α.