Na Ye

Therapeutic potential of spirooxindoles as antiviral agents

Antiviral therapeutics with profiles of high potency, low resistance, panserotype, and low toxicity remain challenging, and obtaining such agents continues to be an active area of therapeutic development. Due to their unique three-dimensional structural features, spirooxindoles have been identified as privileged chemotypes for antiviral drug development. Among them, spiro-pyrazolopyridone oxindoles have been recently reported as potent inhibitors of dengue virus NS4B, leading to the discovery of an orally bioavailable preclinical candidate (R)-44 with excellent in vivo efficacy in a dengue viremia mouse model. This review highlights recent advances in the development of biologically active spirooxindoles for their antiviral potential, primarily focusing on the structure-activity relationships (SARs) and modes of action, as well as future directions to achieve more potent analogues toward a viable antiviral therapy.

Biochemical and Pharmacological Characterizations of ESI-09 Based EPAC Inhibitors: Defining the ESI-09 “Therapeutic Window”

The cAMP signaling cascade is one of the most frequently targeted pathways for the development of pharmaceutics. A plethora of recent genetic and pharmacological studies suggest that exchange proteins directly activated by cAMP (EPACs) are implicated in multiple pathologies. Selective EPAC inhibitors have been recently developed. One specific inhibitor, ESI-09, has been shown to block EPAC activity and functions, as well as to recapitulate genetic phenotypes of EPAC knockout mice when applied in vivo. However, a recent study raised concern that ESI-09 might act as a non-specific protein denaturant. Herein, we present a detailed biochemical and pharmacological characterization, as well as a structure-activity relationship (SAR) analysis of ESI-09. Our studies show that ESI-09 dose-dependently inhibits activity of both EPAC1 and EPAC2 with apparent IC50 values well below the concentrations shown to induce “protein denaturation”. Moreover, the ESI-09s action towards EPAC proteins is highly sensitive to minor modifications of the 3-chlorophenyl moiety. Taken together, these results demonstrate that ESI-09 indeed acts as an EPAC specific antagonist and does not significantly destabilize/denature proteins at pharmacological effective concentrations. This conclusion is further supported by NMR data showing that ESI-09 induces residue-dependent chemical shift changes at low concentrations, while preserving well dispersed peaks.

Oridonin Ring A-Based Diverse Constructions of Enone Functionality: Identification of Novel Dienone Analogues Effective for Highly Aggressive Breast Cancer by Inducing Apoptosis

Oridonin (1) has attracted considerable attention in recent years because of its unique and safe anticancer pharmacological profile. Nevertheless, it exhibits moderate to poor effects against highly aggressive cancers including triple-negative and drug-resistant breast cancer cells. Herein, we report the rational design and synthesis of novel dienone derivatives with an additional α,β-unsaturated ketone system diversely installed in the A-ring based on this class of natural scaffold that features dense functionalities and stereochemistry-rich frameworks. Efficient and regioselective enone construction strategies have been established. Meanwhile, a unique 3,7-rearrangement reaction was identified to furnish an unprecedented dienone scaffold. Intriguingly, these new analogues have been demonstrated to significantly induce apoptosis and inhibit colony formation with superior antitumor effects against aggressive and drug-resistant breast cancer cells in vitro and in vivo while also exhibiting comparable or lower toxicity to normal human mammary epithelial cells in comparison with 1.

Design, Synthesis, and Biological Evaluation of a Series of Benzo(de)(1,7)naphthyridin-7(8H)‑ones Bearing a Functionalized Longer Chain Appendage as Novel PARP1 Inhibitors

A series of benzo[de][1,7]naphthyridin-7(8H)-ones possessing a functionalized long-chain appendage have been designed and evaluated as novel PARP1 inhibitors. The initial effort led to the first-generation PARP1 inhibitor 26 bearing a terminal phthalazin-1(2H)-one framework and showing remarkably high PARP1 inhibitory activity (0.31 nM) but only moderate potency in the cell. Further effort generated the second-generation lead 41, showing high potency against both the PARP1 enzyme and BRCA-deficient cells, especially for the BRCA1-deficient MDA-MB-436 cells (CC50 < 0.26 nM). Mechanistic studies revealed that the new PARP1 inhibitors significantly inhibited H2O2-triggered PARylation in SKOV3 cells, induced cellular accumulation of DNA double-strand breaks, and impaired cell-cycle progression in BRCA2-deficient cells. Significant potentiation on the cytotoxicity of Temozolomide was also observed. The unique structural character and exceptionally high potency of 41 made it stand out as a promising drug candidate worthy for further evaluation.

Small Molecule InhibitorsTargeting Activator Protein1 (AP-1): Miniperspective

Activator protein 1 (AP-1) is a pivotal transcription factor that regulates a wide range of cellular processes including proliferation, apoptosis, differentiation, survival, cell migration, and transformation. Accumulating evidence supports that AP-1 plays an important role in several severe disorders including cancer, fibrosis, and organ injury, as well as inflammatory disorders such as asthma, psoriasis, and rheumatoid arthritis. AP-1 has emerged as an actively pursued drug discovery target over the past decade. Excitingly, a selective AP-1 inhibitor T-5224 (51) has been investigated in phase II human clinical trials. Nevertheless, no effective AP-1 inhibitors have yet been approved for clinical use. Despite significant advances achieved in understanding AP-1 biology and function, as well as the identification of small molecules modulating AP-1 associated signaling pathways, medicinal chemistry efforts remain an urgent need to yield selective and efficacious AP-1 inhibitors as a viable therapeutic strategy for human diseases.

Synthesis of Dihydrofuroaporphine Derivatives: Identification of a Potent and Selective Serotonin 5-HT1A Receptor Agonist

A series of new aporphine analogues were synthesized and pharmacologically evaluated. 11-Allyloxy-(17), 11-propargyloxy-(20), and dihydrofuro-(19) aporphines displayed the highest affinity at the 5-HT(1A) receptor with K(i) values of 12.0, 14.0, and 6.7 nM, respectively. The high binding potential of the diastereomeric mixture of aporphine 19 was found residing in the cis-diastereomer (cis-19). [(35)S]GTP gamma S function assays on 5-HT(1A) receptor indicated that aporphines 17 and 20 were partial agonists, while trans-19 behaved as a high efficacy full antagonist and cis-19 was a full agonist. The agonistic property of cis-19 at the 5-HT(1A) receptor was further confirmed in vitro and in vivo. This compound may be useful as a potential treatment for anxiety.

Discovery and development of natural product oridonin-inspired anticancer agents

Natural products have historically been, and continue to be, an invaluable source for the discovery of various therapeutic agents. Oridonin, a natural diterpenoid widely applied in traditional Chinese medicines, exhibits a broad range of biological effects including anticancer and anti-inflammatory activities. To further improve its potency, aqueous solubility and bioavailability, the oridonin template serves as an exciting platform for drug discovery to yield better candidates with unique targets and enhanced drug properties. A number of oridonin derivatives (e.g. HAO472) have been designed and synthesized, and have contributed to substantial progress in the identification of new agents and relevant molecular mechanistic studies toward the treatment of human cancers and other diseases. This review summarizes the recent advances in medicinal chemistry on the explorations of novel oridonin analogues as potential anticancer therapeutics, and provides a detailed discussion of future directions for the development and progression of this class of molecules into the clinic.

Small molecule inhibitors targeting activator protein 1 (AP-1).

Activator protein 1 (AP-1) is a pivotal transcription factor that regulates a wide range of cellular processes including proliferation, apoptosis, differentiation, survival, cell migration, and transformation. Accumulating evidence supports that AP-1 plays an important role in several severe disorders including cancer, fibrosis, and organ injury, as well as inflammatory disorders such as asthma, psoriasis, and rheumatoid arthritis. AP-1 has emerged as an actively pursued drug discovery target over the past decade. Excitingly, a selective AP-1 inhibitor T-5224 (51) has been investigated in phase II human clinical trials. Nevertheless, no effective AP-1 inhibitors have yet been approved for clinical use. Despite significant advances achieved in understanding AP-1 biology and function, as well as the identification of small molecules modulating AP-1 associated signaling pathways, medicinal chemistry efforts remain an urgent need to yield selective and efficacious AP-1 inhibitors as a viable therapeutic strategy for human diseases.

Identification of N-Propylnoraporphin-11-yl 5-(1,2-Dithiolan-3-yl)pentanoate as a New Anti-Parkinson's Agent Possessing a Dopamine D2 and Serotonin 5-HT1A Dual-Agonist Profile

A series of new aporphine analogues (aporlogues) were synthesized bearing a C-, N-, or O-linkage at the C11 position. Lipoic ester (-)-15 was identified as a full agonist at the dopamine D(2) and serotonin 5-HT(1A) receptors with K(i) values of 174 and 66 nM, respectively. It elicited antiparkinsonian action on Parkinsins disease (PD) rats with minor dyskinesia. Chronic use of (-)-15 reduced L-DOPA-induced dyskinesia (LID) without attenuating the antiparkinsonian effect. These results suggest that 5-HT(1A) and D(2) dual-receptor agonist (-)-15 may present a novel candidate drug in the treatment of PD and LID.

Direct Activation of Bax Protein for Cancer Therapy

Bax, a central cell death regulator, is an indispensable gateway to mitochondrial dysfunction and a major proapoptotic member of the B‐cell lymphoma 2 (Bcl‐2) family proteins that control apoptosis in normal and cancer cells. Dysfunction of apoptosis renders the cancer cell resistant to treatment as well as promotes tumorigenesis. Bax activation induces mitochondrial membrane permeabilization, thereby leading to the release of apoptotic factor cytochrome c and consequently cancer cell death. A number of drugs in clinical use are known to indirectly activate Bax. Intriguingly, recent efforts demonstrate that Bax can serve as a promising direct target for small‐molecule drug discovery. Several direct Bax activators have been identified to hold promise for cancer therapy with the advantages of specificity and the potential of overcoming chemo‐ and radioresistance. Further investigation of this new class of drug candidates will be needed to advance them into the clinic as a novel means to treat cancer.