Discovery and synthesis of novel Wogonin derivatives with potent antitumor activity in vitro

Inducing ubiquitination and degradation of TrxR1 protein by LW-216 promotes apoptosis in non-small cell lung cancer via triggering ROS production

Thioredoxin reductases are frequently overexpressed in various solid tumors as a protective mechanism against heightened oxidative stress. Inhibitors of this system, such as Auranofin, are effective in eradicating cancer cells. However, the clinical significance of thioredoxin reductase 1 (TrxR1) in lung cancer, as well as the potential for its antagonist as a treatment option, necessitated further experimental validation. In this study, we observed significant upregulation of TrxR1 specifically in non-small cell lung cancer (NSCLC), rather than small cell lung cancer. Moreover, TrxR1 expression exhibited associations with survival rate, tumor volume, and histological classification. We developed a novel TrxR1 inhibitor named LW-216 and assessed its antitumor efficacy in NSCLC. Our results revealed that LW-216 is effectively bound with intracellular TrxR1 at sites R371 and G442, facilitating TrxR1 ubiquitination and suppressing TrxR1 expression, while not affecting TrxR2 expression. Treatment of LW-216-induced DNA damage and cell apoptosis in NSCLC cells through the generation of reactive oxygen species (ROS). Importantly, supplementation with N-acetylcysteine (NAC) or ectopic TrxR1 expression reversed LW-216-induced apoptosis. Furthermore, LW-216 displayed potent tumor growth inhibition in NSCLC cell-implanted mice, reducing TrxR1 expression in xenografts. Remarkably, LW-216 exhibited superior antitumor activity compared to Auranofin in vivo. Collectively, our research provides compelling evidence supporting the potential of targeting TrxR1 by LW-216 as a promising therapeutic strategy for NSCLC.

Wogonin inhibits latent HIV-1 reactivation by downregulating histone crotonylation

BACKGROUND

Wogonin, a flavone isolated from Scutellaria baicalensis Georgi, is a commonly used phytochemical with anti-inflammatory and antitumor properties. However, the antiviral activity of wogonin against human immunodeficiency virus type 1 (HIV-1) has not been reported.

PURPOSE

The current study aimed to explore whether wogonin can suppress latent HIV-1 reactivation and the mechanism of wogonin in inhibiting proviral HIV-1 transcription.

METHODS

We assessed the effects of wogonin on HIV-1 reactivation using flow cytometry, cytotoxicity assay, quantitative PCR (qPCR), viral quality assurance (VQA), and western blot analysis.

RESULTS

Wogonin, a flavone isolated from S. baicalensis, significantly inhibited the reactivation of latent HIV-1 in cellular models and in primary CD4+ T cells from antiretroviral therapy (ART)-suppressed individuals ex vivo. Wogonin exhibited low cytotoxicity and long-lasting inhibition of HIV-1 transcription. Triptolide is a latency-promoting agent (LPA) that inhibits HIV-1 transcription and replication; wogonin had a stronger ability to inhibit HIV-1 latent reactivation than triptolide. Mechanistically, wogonin inhibited the reactivation of latent HIV-1 by inhibiting the expression of p300, a histone acetyltransferase, and decreasing the crotonylation of histone H3/H4 in the HIV-1 promoter region.

CONCLUSION

Our study found that wogonin is a novel LPA that can inhibit HIV-1 transcription by HIV-1 epigenetic silencing, which could bear promising significance for future applications of HIV-1 functional cure.

Wogonin, as a potent anticancer compound: From chemistry to cellular interactions

Chinese native medicine Scutellaria baicalensis Georgi, also referred to as Chinese skullcap or Huang-Qin, is frequently used to treat cancer, viral infections, and seizures. This plant's abundance of flavones (wogonoside) and their related aglycones (wogonin) is responsible for many of its pharmacologic effects. A significant ingredient in S. baicalensis that has been the subject of the most research is wogonin. Numerous preclinical investigations revealed that wogonin suppresses tumor growth by cell cycle arrest, stimulating cell death and preventing metastasis. This review focuses on a complete overview of published reports that suggest chemopreventive action of wogonin and the mechanistic insights behind these neoplastic activities. It also emphasizes the synergistic improvements made by wogonin in chemoprevention. The factual data in this mini-review stimulate additional research on chemistry and toxicological profile of wogonin to confirm its safety issues. This review will encourage researchers to generalize the merits of wogonin to be used as potential compound for cancer treatment.

Discovery of novel and bioavailable histone deacetylases and cyclin-dependent kinases dual inhibitor to impair the stemness of leukemia cells

Acute myeloid leukemia (AML) has been confirmed as one of the most lethal heterogeneous clonal diseases. In addition to being essential for the development and progression of leukemia, leukemic stem cells (LSCs), a subpopulation of leukemia cells with stem cell characteristics, are also primarily responsible for the development of leukemia relapse and drug resistance. Elimination of stemness and induction of AML cell differentiation would become a promising and effective therapeutic strategy. In the present study, a novel class of HDACs/CDKs dual inhibitors was prepared and optimized. An active compound 33a has been identified, which exhibited potent and selective inhibition of CDK9, CDK12, CDK13, HDAC1, HDAC2 and HDAC3 at low nanomolar concentrations and significantly induced differentiation of leukemic stem-like cells and inhibited AML proliferation. Furthermore, the lead compound has relatively adequate oral bioavailability, suggesting that it might be used as a novel strategy to reduce the burden of LSCs and improve the prognosis for AML.

Protein-Targeted Degradation Agents Based on Natural Products

Natural products are an important source of drug lead compounds, and natural products with significant biological activity are constantly being discovered and used in clinical practice. At present, natural products play an important role in the targeted therapy of cancer, cardiovascular and cerebrovascular diseases, nervous system diseases, and autoimmune diseases. Meanwhile, in recent years, the rise of protein-targeted degradation technologies, such as proteolysis-targeting chimeras (PROTACs) and molecular glues, has provided a new solution for drug resistance caused by clinical molecular-targeting drugs. It is noteworthy that natural products and their derivatives, as important components of PROTACs and molecular glues, play an important role in the development of protein-targeting drugs. Hence, this review summarized the protein-targeted degradation agents based on natural products, such as PROTACs and molecular glues. More natural products with the potential to be used in the development of PROTACs and molecular glues as targeted protein degradation agents are still being investigated.

Targeting cyclin-dependent kinase 9 in cancer therapy

Cyclin-dependent kinase (CDK) 9 associates mainly with cyclin T1 and forms the positive transcription elongation factor b (p-TEFb) complex responsible for transcriptional regulation. It has been shown that CDK9 modulates the expression and activity of oncogenes, such as MYC and murine double minute 4 (MDM4), and it also plays an important role in development and/or maintenance of the malignant cell phenotype. Malfunction of CDK9 is frequently observed in numerous cancers. Recent studies have highlighted the function of CDK9 through a variety of mechanisms in cancers, including the formation of new complexes and epigenetic alterations. Due to the importance of CDK9 activation in cancer cells, CDK9 inhibitors have emerged as promising candidates for cancer therapy. Natural product-derived and chemically synthesized CDK9 inhibitors are being examined in preclinical and clinical research. In this review, we summarize the current knowledge on the role of CDK9 in transcriptional regulation, epigenetic regulation, and different cellular factor interactions, focusing on new advances. We show the importance of CDK9 in mediating tumorigenesis and tumor progression. Then, we provide an overview of some CDK9 inhibitors supported by multiple oncologic preclinical and clinical investigations. Finally, we discuss the perspective and challenge of CDK9 modulation in cancer.

Recent Development of Flavonoids with Various Activities

Flavonoids, a series of compounds with C6-C3-C6 structure, mostly originate from plant metabolism. Flavonoids have shown beneficial effects on many aspects of human physiology and health. Recently, many flavonoids with various activities have been discovered, which has led to more and more studies focusing on their physiological and pharmacodynamic activities. The anti-cancer and anti-viral activities especially have attracted the attention of many researchers. Therefore, the discovery and development of flavonoids as anti-disease drugs has great potential and may make significant contribution to fighting diseases. This review focus on the discovery and development of flavonoids in medicinal chemistry in recent years.

Structure-guided design and development of novel N-phenylpyrimidin-2-amine derivatives as potential c-Met inhibitors

The HGF/Met signaling pathway is over-expressed in many types of cancers and closely related to oncogenesis and metastasis. Thus, we developed novel N-phenylpyrimidin-2-amine derivatives to test their inhibitory activities towards c-Met kinase, and most of the compounds (15a-i, 15o-r, 20 and 34a-c) could inhibit the target with IC₅₀ values from 550.8 nM to 15.0 nM. Subsequently, compound 15b, 15d, 15f, 15i, 15o, 15r, 20, 34a and 34b also showed high antiproliferative activities in c-Met sensitive tumor cell lines (PC-3, Panc-1, HepG2, HCT116 and Caki-1) with IC₅₀ values from 0.53 to 1.37 μM. The lead compound 34a displayed outstanding c-Met inhibitory activity (IC₅₀: 15.0 nM) and antiproliferative activities. Furthermore, 34a also performed favorable pharmacokinetic properties in mice (F%: 59.3) and an acceptable safety profile in preclinical studies. Further docking studies showed a common interaction of 34a with c-Met at the ATP-binding site, which indicated that 34a could be a potential candidate for c-Met inhibitors.

Identification of novel androgen receptor degrading agents to treat advanced prostate cancer

Prostate cancer (PCa) is one of the most common malignancies affecting men worldwide. Androgen receptor (AR) has been a target of PCa treatment for nearly six decades. AR antagonists/degraders can effectively treat PCa caused by increased AR overexpression. However, all approved AR antagonists have similar chemical structures and exhibit the same mode of action on the protein. Although initially effective, resistance to these AR antagonists usually develops. Therefore, this calls for the identification of novel chemical structures of AR antagonists to overcome the resistance. Herein, we employed the synergetic combination of virtual and experimental screening to identify a flavonoid compound which not only effectively inhibits AR transcriptional activity, but also induces the degradation of the protein. Based on this compound, we designed and synthesized a series of derivatives. We discovered that the most potent compound 10e could effectively inhibit AR transcriptional activity, and possessed a profound ability to cause degradation of both full length- and ARv7 truncated forms of human AR. Notably, 10e efficiently inhibited the growth of ARv7 dependent prostate cancer cell-lines, which are completely resistant to all current anti-androgens. Compound 10e also showed strong antitumor activity in the LNCaP (androgen dependent prostate cancer cell line) in vivo xenograft model. These results provide a foundation for the development of a new class of AR antagonists.

Fluorine-Containing Chrysin Derivatives

Chrysin, a flavonoid, has played a great role in the fields of anticancer, antibacterial, and antiviral drug discovery. A large number of chrysin derivatives have been synthesized recently. The fluorine atom represents an important substituent group for a great number of natural products and pharmaceuticals. Taking into account the importance of both chrysin and the fluorine atom in medicinal chemistry, the synthesis of fluorine-containing chrysin derivatives has gained great interest. Chemically, the synthetic methods for these new chrysin derivatives have also been developed rapidly. In recent years, research on their synthesis has been focused on speeding up the reaction process by changing the catalyst. Biologically, the purpose of introducing fluorine into chrysin was to improve its lipophilicity, but today it is mainly focused on the enhancement and improvement of either its anticancer or antimicrobial activities by incorporating the special properties of fluorine atoms. In this review, synthetic methods for the introduction of fluorine atoms into chrysin are summarized, and their anticancer, antibacterial, antiviral, and hypoglycemic effects are discussed.

Design of wogonin-inspired selective cyclin-dependent kinase 9 (CDK9) inhibitors with potent in vitro and in vivo antitumor activity

Wogonin, a natural product isolated from the plant Scutellaria baicalensis, has been shown to be a potent and selective inhibitor of CDK9. With the purpose of investigating the activity and selectivity of this chemical scaffold, several series of wogonin derivatives were prepared and screened for CDK9 inhibition and cellular antiproliferative activity. Among these compounds, the drug-like compound 51 showed potent activity against CDK9 (IC₅₀ = 19.9 nM) and MV4-11 cell growth (IC₅₀ = 20 nM). In addition, compound 51 showed much improved physicochemical properties, such as water solubility, compared with the parent compound wogonin. The follow-up studies showed that the compound 51 is selective toward CDK9-overexpressing cancer cells over normal cells. Preliminary mechanism studies on the anticancer effect indicated that 51 inhibited the proliferation of MV4-11 cells via caspase-dependent apoptosis. In addition, highlighted compound 51 showed significant antitumor activity in mouse acute myeloid leukemia (AML) models without producing apparent toxic effects in vivo, which gave us a new tool for further investigation of CDK9-targeted inhibitor as a potential antitumor drug especially for AML.

Hydrogen sulfide donating ent-kaurane and spirolactone-type 6,7-seco-ent-kaurane derivatives: Design, synthesis and antiproliferative properties

Motivated by our interest in hydrogen sulfide bio-chemistry and ent-kaurane diterpenoid chemistry, 14 hydrogen sulfide donating derivatives (9, 11a-c, 12a-c, 13, 14, 16a-c and 17a-b) of ent-kaurane and spirolactone-type 6,7-seco-ent-kaurane were designed and synthesized. Four human cancer cell lines (K562, Bel-7402, SGC-7901 and A549) and two normal cell lines (L-02 and PBMC) were selected for antiproliferative assay. Most derivatives showed more potent activities than the lead ent-kaurane oridonin. Among them, compound 12b exhibited the most potent antiproliferative activities, with IC₅₀ values of 1.01, 0.88, 4.36 and 5.21 μM against above human cancer cell lines, respectively. Further apoptosis-related mechanism study indicated that 12b could arrest Bel-7402 cell cycle at G1 phase and induce apoptosis through mitochondria related pathway. Through Western blot assay, 12b was shown to influence the intrinsic pathway by increasing the expression of Bax, cleaved caspase-3, cytochrome c and cleaved PARP, meanwhile suppressing procaspase-3, Bcl-2, Bcl-xL and PARP.