Amentoflavone Promotes Apoptosis in Non-Small-Cell Lung Cancer by Modulating Cancerous Inhibitor of PP2A

Natural Flavonoid Apigenin, an Effective Agent Against Nervous System Cancers

Cancer is a serious public health concern worldwide, and nervous system (NS) cancers are among the most life-threatening malignancies. Efforts have been devoted to introduce natural anticancer agents with minimal side effects. Apigenin is an edible flavonoid that is abundantly found in many vegetables and fruits. Various pharmaceutical activities, including anti-inflammatory, antioxidative, antimicrobial, and anticancer effects have been reported for apigenin. This review provides insights into the therapeutic effects of apigenin and flavonoids with similar structure on glioblastoma and neuroblastoma. Current evidence indicates that apigenin has the unique ability to cross the blood-brain barrier, and its antioxidative, anti-inflammatory, neurogenic, and neuroprotective effects have made this flavonoid a great option for the treatment of neurodegenerative disorders. Meanwhile, apigenin has low toxicity on normal neuronal cells, while induces cytotoxicity on NS cancer cells via triggering several signal pathways and molecular targets. Anticancer effects of apigenin have been contributed to various mechanisms such as induction of cell cycle arrest and apoptosis, and inhibition of migration, invasion, and angiogenesis. Although apigenin is a promising pharmaceutical agent, its low bioavailability is an important issue that must be solved before introducing to clinic. Recently, nano-delivery of apigenin by liposomes and poly lactic-co-glycolide nanoparticles has greatly improved functionality of this agent. Hence, investigating pharmaceutical effects of apigenin-loaded nanocarriers on NS cancer cell lines and animal models is recommended for future studies.

Amentoflavone reverses epithelial-mesenchymal transition in hepatocellular carcinoma cells by targeting p53 signalling pathway axis

Epithelial-mesenchymal transition (EMT) and its reversal process are important potential mechanisms in the development of HCC. Selaginella doederleinii Hieron is widely used in Traditional Chinese Medicine for the treatment of various tumours and Amentoflavone is its main active ingredient. This study investigates the mechanism of action of Amentoflavone on EMT in hepatocellular carcinoma from the perspective of bioinformatics and network pharmacology. Bioinformatics was used to screen Amentoflavone-regulated EMT genes that are closely related to the prognosis of HCC, and a molecular prediction model was established to assess the prognosis of HCC. The network pharmacology was used to predict the pathway axis regulated by Amentoflavone. Molecular docking of Amentoflavone with corresponding targets was performed. Detection and evaluation of the effects of Amentoflavone on cell proliferation, migration, invasion and apoptosis by CCK-8 kit, wound healing assay, Transwell assay and annexin V-FITC/propidium iodide staining. Eventually three core genes were screened, inculding NR1I2, CDK1 and CHEK1. A total of 590 GO enrichment entries were obtained, and five enrichment results were obtained by KEGG pathway analysis. Genes were mainly enriched in the p53 signalling pathway. The outcomes derived from both the wound healing assay and Transwell assay demonstrated significant inhibition of migration and invasion in HCC cells upon exposure to different concentrations of Amentoflavone. The results of Annexin V-FITC/PI staining assay showed that different concentrations of Amentoflavone induces apoptosis in HCC cells. This study revealed that the mechanism of Amentoflavone reverses EMT in hepatocellular carcinoma, possibly by inhibiting the expression of core genes and blocking the p53 signalling pathway axis to inhibit the migration and invasion of HCC cells.

Insights Into Amentoflavone: A Natural Multifunctional Biflavonoid

Amentoflavone is an active phenolic compound isolated from Selaginella tamariscina over 40 years. Amentoflavone has been extensively recorded as a molecule which displays multifunctional biological activities. Especially, amentoflavone involves in anti-cancer activity by mediating various signaling pathways such as extracellular signal-regulated kinase (ERK), nuclear factor kappa-B (NF-κB) and phosphoinositide 3-kinase/protein kinase B (PI3K/Akt), and emerges anti-SARS-CoV-2 effect via binding towards the main protease (Mpro/3CLpro), spike protein receptor binding domain (RBD) and RNA-dependent RNA polymerase (RdRp) of SARS-CoV-2. Therefore, amentoflavone is considered to be a promising therapeutic agent for clinical research. Considering the multifunction of amentoflavone, the current review comprehensively discuss the chemistry, the progress in its diverse biological activities, including anti-inflammatory, anti-oxidation, anti-microorganism, metabolism regulation, neuroprotection, radioprotection, musculoskeletal protection and antidepressant, specially the fascinating role against various types of cancers. In addition, the bioavailability and drug delivery of amentoflavone, the molecular mechanisms underlying the activities of amentoflavone, the molecular docking simulation of amentoflavone through in silico approach and anti-SARS-CoV-2 effect of amentoflavone are discussed.

The traditional and modern uses of Selaginella tamariscina (P.Beauv.) Spring, in medicine and cosmetic: Applications and bioactive ingredients

ETHNOPHARMACOLOGICAL RELEVANCE

Extracts of the plant Selaginella tamariscina (P.Beauv.) Spring (spike moss) are used for a long time in Asia, for the treatment of multiple diseases and conditions. Aqueous and alcoholic leave extracts are used by local communities. In China, the plant (Juan bai) is listed on the Pharmacopoeia. In South Korea, the use of this plant (Kwon Baek) is mentioned in the book Dongui-Bogam (Heo Jun 1613), at the origin of the Hyungsang medicine. S. tamariscina is traditionally used in Vietnam (mong lung rong), Thailand (dok hin), Philippines (pakong-tulog) and other Asian countries.

AIM OF THE STUDY

To provide an analysis of the multiple traditional and current uses of S. tamariscina extracts (STE) in the field of medicine and cosmetic. The review is also intended at identifying the main natural products at the origin of the many pharmacological properties reported with these extracts (anti-inflammatory, antioxidant, antidiabetic, antibacterial, antiallergic, anticancer effects).

METHODS

Extensive database retrieval, such as SciFinder and PubMed, was performed by using keywords like " Selaginella tamariscina", "spike moss", "Selaginellaceae ". Relevant textbooks, patents, reviews, and digital documents were consulted to collate all available scientific literature and to provide a complete science-based survey of the topic.

RESULTS

Different solvents and methods are used to prepare STE. The process can largely modify the natural product content and properties of the extracts. STE display a range of pharmacological effects, useful to treat metabolic disorders, several inflammatory diseases and various cancers. A specific carbonized extract (S. tamariscina carbonisatus) has shown hemostatic effects, whereas standard STE can promote blood circulation. Many patented STE-containing cosmetic preparations are reviewed here. Several biflavonoids (chiefly amentoflavone) and phenolic compounds (selaginellin derivatives) are primarily responsible for the observed pharmacological properties. Potent inhibitors of protein tyrosine phosphatase 1 B (PTP1B), phosphodiesterase-4 (PDE4), and repressor of pro-inflammatory cytokines expression have been identified from STE.

CONCLUSION

The traditional use of STE supports the research performed with this plant. There are robust experimental data, based on in vitro and in vivo models, documenting the use of STE to treat type 2 diabetes, several inflammatory diseases, and some cancers (in combination with standard chemotherapy). Selaginella tamariscina (P.Beauv.) is a prime reservoir for amentoflavone, and many other bioactive natural products. The interest of the plant in medicine and cosmetic is amply justified.

Constitutive Cell Proliferation Regulating Inhibitor of Protein Phosphatase 2A (CIP2A) Mediates Drug Resistance to Erlotinib in an EGFR Activating Mutated NSCLC Cell Line

Exploring mechanisms of drug resistance to targeted small molecule drugs is critical for an extended clinical benefit in the treatment of non-small cell lung cancer (NSCLC) patients carrying activating epidermal growth factor receptor (EGFR) mutations. Here, we identified constitutive cell proliferation regulating inhibitor of protein phosphatase 2A (CIP2A) in the HCC4006rErlo0.5 NSCLC cell line adapted to erlotinib as a model of acquired drug resistance. Constitutive CIP2A resulted in a constitutive activation of Akt signaling. The proteasome inhibitor bortezomib was able to reduce CIP2A levels, which resulted in an activation of protein phosphatase 2A and deactivation of Akt. Combination experiments with erlotinib and bortezomib revealed a lack of interaction between the two drugs. However, the effect size of bortezomib was higher in HCC4006rErlo0.5, compared to the erlotinib-sensitive HCC4006 cells, as indicated by an increase in Emax (0.911 (95%CI 0.867-0.954) vs. 0.585 (95%CI 0.568-0.622), respectively) and decrease in EC50 (52.4 µM (95%CI 46.1-58.8 µM) vs. 73.0 µM (95%CI 60.4-111 µM), respectively) in the concentration-effect model, an earlier onset of cell death induction, and a reduced colony surviving fraction (0.38 ± 0.18 vs. 0.95 ± 0.25, respectively, n = 3, p < 0.05). Therefore, modulation of CIP2A with bortezomib could be an interesting approach to overcome drug resistance to erlotinib treatment in NSCLC.

Ultrasonic-Assisted Ionic Liquid Extraction of Two Biflavonoids from Selaginella tamariscina

Selaginella tamariscina, a traditional Chinese medicine, contains a variety of bioactive components, among which biflavonoids are the main active ingredients and have antioxidant, antitumor, and anti-inflammatory properties. In this study, ultrasonic-assisted ionic liquid extraction (UAILE) is used for the first time to extract two main biflavonoids (amentoflavone (AME) and hinokiflavone (HIN)) from S. tamariscina. A high-performance liquid chromatography method is used for the simultaneous determination of AME and HIN in S. tamariscina. Then, three novel ILs are synthesized for the first time by a one-step method using benzoxazole and three acids or acid salts as raw materials, and the structures of the synthesized ILs are characterized by elemental analysis, infrared spectroscopy, and NMR spectroscopy, as well as the thermal stability of the ILs is evaluated by thermogravimetric analysis. After screening the extraction effects of three benzoxazole ILs, three pyridine ILs, and three imidazole ILs, it is found that [Bpy]BF4 is the best and therefore selected as the extractant. The optimal extraction process is explored in terms of the yields of AME and HIN from S. tamariscina by a single-factor experiments and response surface analysis. Under the optimal level of each influencing factor (IL concentration of 0.15 mol/L, solid-liquid ratio of 1:12 g/mL, ultrasonic power of 280 W, ultrasonic time of 30 min, and three extraction cycles), the extraction rates of AME and HIN from S. tamariscina are 13.51 and 6.74 mg/g, respectively. Moreover, the recovery experiment of [Bpy]BF4 on the extraction of biflavonoids shows that the recovered IL can repeatedly extract targets six times and the extraction rate is about 90%, which indicates that the IL can be effectively reused. UAILE can effectively and selectively extract AME and HIN, laying the foundation for the application of S. tamariscina.

PP2A and tumor radiotherapy

Protein phosphatase 2A (PP2A) is a serine/threonine phosphatase that serves as a key regulator of cellular physiology in the context of apoptosis, mitosis, and DNA damage responses. Canonically, PP2A functions as a tumor suppressor gene. However, recent evidence suggests that inhibiting PP2A activity in tumor cells may represent a viable approach to enhancing tumor sensitivity to chemoradiotherapy as such inhibition can cause cells to enter a disordered mitotic state that renders them more susceptible to cell death. Indeed, there is evidence that inhibiting PP2A can slow tumor growth following radiotherapy in a range of cancer types including ovarian cancer, liver cancer, malignant glioma, pancreatic cancer, and nasopharyngeal carcinoma. In the present review, we discuss current understanding of the role of PP2A in tumor radiotherapy and the potential mechanisms whereby it may influence this process.