Discovery of novel trimethoxyphenylbenzo[d]oxazoles as dual tubulin/PDE4 inhibitors capable of inducing apoptosis at G2/M phase arrest in glioma and lung cancer cells

Development of indole hybrids for potential lung cancer treatment - part II

Lung cancer has become the most prevalent cancer for the past three decades, and the 5-years survival rate of lung cancer is only ~20% nowadays. Chemotherapy is the mainstay of lung cancer therapy, especially for non-small cell lung cancer. However, drug resistance represents a principal cause of therapeutic failure in non-small cell lung cancer leading to therapeutic insensitivity, tumor recurrence, and disease progression. Indole hybrids have the potential to conquer drug resistance, enhance efficacy, reduce adverse events, and improve pharmacokinetic properties due to their capacity to inhibit multiple targets simultaneously. Moreover, indole hybrids osimertinib, mobocertinib, cediranib, and vizimpro are currently applied in clinics for lung cancer therapy, demonstrating that indole hybrids are valuable scaffolds in the treatment and eradication of lung cancer. This review provides a comprehensive overview of the evolving landscape of indole hybrids with the in vitro and in vivo efficacy against lung cancer, and the structure-activity relationships as well as mechanisms of action are also discussed, covering articles published from 2021 onward.

Oxazole and isoxazole-containing pharmaceuticals: targets, pharmacological activities, and their SAR studies

Oxazole, a five-membered aromatic heterocycle featuring a nitrogen and an oxygen atom separated by a carbon atom, and its isomer isoxazole, with directly attached oxygen and nitrogen atoms, have been pivotal in medicinal chemistry. Over the past few decades, the U.S. Food and Drug Administration (FDA) has approved more than 20 drugs containing these nuclei for various clinical conditions, including Tafamidis and Oxaprozin. Due to their unique physicochemical properties, these drugs often exhibit superior pharmacokinetic profiles and pharmacological effects compared to those with similar heterocycles. This review provides a comprehensive overview of all FDA-approved drugs containing oxazole and isoxazole nuclei, focusing on their pharmacological activities and structure-activity relationships.

Discovery of novel N2-indazole derivatives as phosphodiesterase 4 inhibitors for the treatment of inflammatory bowel disease

Inflammatory bowel disease (IBD) is a chronic and progressive condition with a significant global burden. Currently, available treatments primarily provide symptomatic relief and retard disease progression, yet they do not offer a cure and are frequently associated with adverse effects. Therefore, the discovery of new targets and therapeutic drugs for IBD is crucial. Phosphodiesterase 4 (PDE4) inhibitors have emerged as promising candidates in the search for effective IBD treatments, although dose-dependent side effects hamper their clinical utility. In this study, building upon heterocyclic biaryl derivatives (TPA16), we designed and synthesized a series of N2-substituted indazole-based PDE4D inhibitors, emphasizing improving safety profiles. An enzyme activity screening discovered an optimized compound, LZ-14 (Z21115), which exhibited high PDE4D7 (IC50 = 10.5 nM) inhibitory activity and good selectivity. More interestingly, LZ-14 has demonstrated promising effects in treating IBD in mouse models by improving the inflammatory response and colon injury. Furthermore, LZ-14 displayed low emetogenic potential in ketamine/xylazine anesthesia mice alternative models.

Benzo[d]oxazoles from Anilides by N-Deprotonation-O-SNAr Cyclization

A synthesis of benzo[d]oxazoles by an N-deprotonation-O-SNAr cyclization sequence from anilide precursors is reported. Anilides derived from 2-fluorobenzaldehydes, activated toward SNAr ring closure by C5 electron-withdrawing groups, were prepared and subjected to deprotonation-cyclization using 2 equiv. of K2CO3 in anhydrous DMF. Following deprotonation at nitrogen, the delocalized anion cyclized from the amide oxygen to give high yields of benzo[d]oxazoles. The temperature required for the cyclization of benzanilides correlated with the potency of the C5 activating group on the SNAr acceptor ring with nitro (most potent) reacting at 90 °C (1 h), cyano reacting at 115 °C (1 h), methoxycarbonyl reacting at 120 °C (2 h), and trifluoromethyl (least potent) reacting at 130 °C (3 h). Acetanilides were more difficult to cyclize but generally required 4-6 h at these same temperatures for completion. Product purification was accomplished by recrystallization or chromatography.

Preliminary evaluation of antiproliferative and apoptotic activities of novel indolin-2-one derivatives

Indole-based agents are frequently used in targeted or supportive therapy of several cancers. In this study, we investigated the anticancer properties of originally synthesized novel indolin-2-one derivatives (6a-d) against Malignant Mesothelioma, Breast cancer, and Colon Cancer cells. Our results revealed that all derivatives were effectively delayed cell proliferation by inhibiting the ERK1/2, AKT, and STAT3 signaling pathways in a concentration-dependent manner. Additionally, these variants induced cell cycle arrest in the S phase, accompanied by elevated levels of p21 and p27 expressions. Derivatives also initiated mitochondrial apoptosis through the upregulation of Bax and downregulation of Bcl-2 proteins, leading to the activation of caspase 3 and PARP cleavage in exposed cells. Remarkably, three of the indolin-2-one derivatives displayed significant selectivity towards Breast and Colon Cancer cells, with compound 6d promising as the most potent and wide spectral one for all cancer cell lines.

PDE4 inhibitors for disease therapy: advances and future perspective

The PDE4 enzyme family is specifically responsible for hydrolyzing cAMP and plays a vital role in regulating the balance of second messengers. As a crucial regulator in signal transduction, PDE4 has displayed promising pharmacological targets in a variety of diseases, for which its inhibitors have been used as a therapeutic strategy. This review provides a comprehensive summary of the development of PDE4 inhibitors in the past few years, along with the structure, clinical and research progress of multiple inhibitors of PDE4, focusing on the research and development strategies of PDE4 inhibitors. We hope our analysis will provide a significant reference for the future development of new PDE4 inhibitors.

Potential PDE4B inhibitors as promising candidates against SARS-CoV-2 infection

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) is an RNA virus belonging to the coronavirus family responsible for coronavirus disease 2019 (COVID-19). It primarily affects the pulmonary system, which is the target of chronic obstructive pulmonary disease (COPD), for which many new compounds have been developed. In this study, phosphodiesterase 4 (PDE4) inhibitors are being investigated. The inhibition of PDE4 enzyme produces anti-inflammatory and bronchodilator effects in the lung by inducing an increase in cAMP concentrations. Piclamilast and rolipram are known selective inhibitors of PDE4, which are unfortunately endowed with common side effects, such as nausea and emesis. The selective inhibition of the phosphodiesterase 4B (PDE4B) subtype may represent an intriguing technique for combating this highly contagious disease with fewer side effects. In this article, molecular docking studies for the selective inhibition of the PDE4B enzyme have been carried out on 21 in-house compounds. The compounds were docked into the pocket of the PDE4B catalytic site, and in most cases, they were almost completely superimposed onto piclamilast. Then, in order to enlarge our study, drug-likeness prediction studies were performed on the compounds under study.

Discovery of polymethoxyphenyl-pyridines bearing amino side chains as tubulin colchicine-binding site inhibitors

Nineteen TH03 analogues were designed and synthesized as tubulin colchicine-binding site inhibitors with potent antiproliferative activities. Among these compounds, 3,5-dimethoxyphenylpyridines 8j bearing a 4-methoxybenzyl aniline side-chain displayed the best antiproliferative activities against glioma (U87MG and U251). In addition, the trimethoxyphenylpyridine 8o bearing a 4-methyl-N-methyl aniline side-chain showed the best antiproliferative activities against colon carcinoma and lung cancer with the lowest IC₅₀ value (0.09 µM < IC₅₀ < 0.86 µM). Compared with CA-4, Compounds 8j and 8o displayed lower cytotoxicities toward normal cells but higher antiproliferative activities against RKO (IC₅₀ = 0.15 µM and 0.09 µM respectively), NCI-H1299 (IC₅₀ = 0.73 µM and 0.14 µM respectively), and A549 cells (IC₅₀ = 0.86 µM and 0.37 µM respectively). Further investigations revealed that 8o shows higher tubulin polymerization inhibitory activity (IC₅₀ = 3.1 ± 0.5 µM) than colchicine (IC₅₀ = 8.6 ± 0.2 µM), and induced cell cycle arrest at the G2/M phase and cellular apoptosis through disrupting the microtubule network.

Synergistic Effects of A Combined Treatment of Glioblastoma U251 Cells with An Anti-miR-10b-5p Molecule and An AntiCancer Agent Based on 1-(3',4',5'-Trimethoxyphenyl)-2-Aryl-1H-Imidazole Scaffold

(1) Background: In the development of new and more effective anticancer approaches, combined treatments appear of great interest. Combination therapy could be of importance in the management of glioblastoma (GBM), a lethal malignancy that accounts for 42% of cancer of the central nervous system, with a median survival of 15 months. This study aimed to verify the activity on a glioblastoma cancer cell line of one of the most active compounds of a novel series of tubulin polymerization inhibitors based on the 1-(3′,4′,5′-trimethoxyphenyl)-2-aryl-1H-imidazole scaffold, used in combination with a miRNA inhibitor molecule targeting the oncomiRNA miR-10b-5p. This microRNA was selected in consideration of the role of miR-10b-5p on the onset and progression of glioblastoma. (2) Methods: Apoptosis was analyzed by Annexin-V and Caspase 3/7 assays, efficacy of the anti-miR-10b-5p was assessed by determining the miR-10b-5p content by RT-qPCR. (3) Results: The results obtained show that a “combination therapy” performed by combining the use of an anti-miR-10b-5p and a 1-(3′,4′,5′-trimethoxyphenyl)-2-aryl-1H-imidazole derivative is an encouraging strategy to boost the efficacy of anticancer therapies and at the same time to reduce side effects.

Discovery of Novel 3-Amino-4-alkoxyphenylketones as PDE4 Inhibitors with Improved Oral Bioavailability and Safety against Spatial Memory Impairments

To realize PDE4 inhibitors with good developmental potentiality for the treatment of dementia, structure-based optimizations of lead compound FCPR03 resulted in novel aminophenylketones 9c and 9H with low nanomolar potency, which displayed comparable activity to rolipram, satisfactory bioavailability (F% = 36.92 and 42.96% respectively), and good blood-brain barrier (BBB) permeability switching from the cyclopropyl methoxy group to the cyclopropyl methylamine and the amide group to the corresponding ketone. Emetogenicity evaluation on a combined ketamine/xylazine anesthesia mice alternative model demonstrated that 9H displays no emetogenicity even at an oral dose of 5 mg/kg. In contrast, rolipram and roflumilast displayed emetogenicity at an oral dose of 0.5 mg/kg. In acute toxicological evaluation, 9H showed no obvious toxicological effect on mice when administered at oral doses below 625 mg/kg. Further investigations revealed that 9H improves the memory and cognitive impairment of Alzheimer's disease (AD) model mice induced by Aβ_25-35.