Retracted : Ailanthone exerts an antitumor function on the development of human lung cancer by upregulating microRNA‐195

Ailanthone Inhibits Cell Proliferation in Tongue Squamous Cell Carcinoma via PI3K/AKT Pathway

Tongue squamous cell carcinoma (TSCC) is the most widespread and invasive subtype of oral cancer with high recurrence rates. Ailanthone (AIL) is an active ingredient in the plant extracts of Ailanthus altissima (Mill.) Swingle. Here, we showed that AIL inhibited the proliferation of human TSCC, the cell viability of Cal-27 and Tca8113 was significantly decreased after AIL treatment for 24 h. Hoechst 33258 staining demonstrated apoptotic characteristics (such as chromatin aggregation) after AIL treatment. The ratio of early- and late-apoptotic cells in AIL-treated Cal-27 and TCA8113 cells increased remarkably when compared with the control group. Bcl-2/Bax ratio and the levels of PARP1, caspase-9, and caspase-3 decreased after AIL treatment, accompanied by significant increase of cleaved PARP1, cleaved caspase-9, and caspase-3 in Cal-27 and TCA8113 cells. Meanwhile, AIL led to Cal-27 cell cycle arrest at G2/M phase. Western blot implied decreased levels of CDK1 and cyclin B1 after AIL treatment. The level of phospho-PI3K p55 subunit and p-Akt were significantly downregulated by AIL in both Cal-27 and TCA8113 cells. These findings implied the potential applications of AIL in the treatment of human TSCC.

Polyphenols as Lung Cancer Chemopreventive Agents by Targeting microRNAs

Lung cancer is the second leading cause of cancer-related death worldwide. In recent decades, investigators have found that microRNAs, a group of non-coding RNAs, are abnormally expressed in lung cancer, and play important roles in the initiation and progression of lung cancer. These microRNAs have been used as biomarkers and potential therapeutic targets of lung cancer. Polyphenols are natural and bioactive chemicals that are synthesized by plants, and have promising anticancer effects against several kinds of cancer, including lung cancer. Recent studies identified that polyphenols exert their anticancer effects by regulating the expression levels of microRNAs in lung cancer. Targeting microRNAs using polyphenols may provide a novel strategy for the prevention and treatment of lung cancer. In this review, we reviewed the effects of polyphenols on oncogenic and tumor-suppressive microRNAs in lung cancer. We also reviewed and discussed the potential clinical application of polyphenol-regulated microRNAs in lung cancer treatment.

Creation of Value Chains for the Sustainability of Control and Eradication Actions on Ailanthus altissima (Mill.) Swingle

Actions to control and eradicate Ailanthus altissima (Mill.) Swingle are essential to the prevention of uncontrolled growth and expansion of this species and its competition with native species. This competition leads to biodiversity and productivity losses in forests. The present study evaluated the potential to create value chains to maintain the sustainability of control actions through the energy recovery of collected A. altissima biomass. Other possibilities were also discussed, such as the extraction of allelopathic compounds. For this purpose, and to assess the potential for energy recovery, samples of A. altissima were collected and analyzed in the laboratory to discuss the potential of using extracted compounds in nature-based applications, and a literature review was carried out. It was found that, although there is potential for the use of these biomasses for energy production, the high levels of chlorine and heavy metals pose some obstacles to their large-scale use, mainly due to their corrosive potential. On the other hand, the extraction of allelopathic compounds was shown to be potentially interesting for use in the control of other invasive species. Used in this application, it may be possible to create value chains to sustain, control, and eradicate the actions of this invasive species.

Ailanthone suppresses the activity of human colorectal cancer cells through the STAT3 signaling pathway

Ailanthone (AIL) is a major quassinoid extracted from the Chinese medicinal herb, Ailanthus altissima, which has been reported to exert anti-proliferative effects on various cancer cells. The present study aimed to investigate the anti-tumor effects of AIL on HCT116 and SW620 colon cancer cells, and to analyze the underlying molecular mechanisms. CCK-8 assay was used to detect cell viability. Furthermore, colony formation and Transwell assays, and flow cytometry were used to examine the effects of AIL on cell proliferation, apoptosis and migration. Finally, the expression levels of cell cycle control proteins, and caspase and Bcl-2 family-related proteins involved in the regulation of apoptosis, as well as those of cell migration- and pathway-related proteins were examined using western blot analysis. Reverse transcription-quantitative PCR was used to quantitatively analyze the changes in the JAK and STAT3 gene levels in each group. The in vitro cell function tests revealed that AIL inhibited the proliferation and migration, and induced the apoptosis and cell cycle arrest of HCT116 and SW620 cells. It was further found exerted these effects via the JAK/STAT3 signaling pathway, as well as through caspase and Bcl-2 family proteins. On the whole, the present study demonstrates that AIL suppresses the activity of colon cancer cells via the STAT3 pathway.

Traditional uses, phytochemistry, and pharmacology of Ailanthus altissima (Mill.) Swingle bark: A comprehensive review

ETHNOPHARMACOLOGICAL RELEVANCE

The dried bark of Ailanthus altissima (Mill.) Swingle (BAA), commonly designated as "Chunpi" in Chinese, is extensively used as a common traditional medicine in China, Korea, and India. It has been used to treat multiple ailments, including asthma, epilepsy, spermatorrhea, bleeding, and ophthalmic diseases, for thousands of years.

AIM OF THE REVIEW

To present a comprehensive and constructive review on the phytochemistry, pharmacology, pharmacokinetics, traditional uses, quality control, and toxicology of BAA; to aid the assessment of the therapeutic potential of BAA; to guide researchers working on the development of novel therapeutic agents.

MATERIALS AND METHODS

Information related to BAA (from 1960 to 2020) was retrieved from a wide variety of electronic databases, such as PubMed, Web of Science, China Knowledge Resource Integrated Database, ScienceDirect, SciFinder, and Google Scholar. Additional information and materials were acquired from Chinese Medicine Monographs, the 2020 edition of the Chinese Pharmacopoeia, and several web sources, such as the official website of The Plant List and Flora of China. Additionally, perspectives for future investigations and applications of BAA were extensively explored.

RESULTS

Approximately 221 chemical compounds, including alkaloids, quassinoids, phenylpropanoids, triterpenoids, volatile oils, and other compounds, have been isolated and characterized from BAA; among these, the quassinoid ailanthone is the most typical. The crude extracts and active compounds of BAA have been reported to exert a wide range of pharmacological activities, such as antitumor, anti-inflammatory, antiviral, herbicidal, and insecticidal activities. Although BAA is safe when administered at a conventional dose, at higher doses, it exhibits toxicity due to the presence of quassinoids. Thus, more studies are required to evaluate the efficacy and safety of BAA.

CONCLUSION

Modern pharmacological studies have revealed that BAA, as a valuable medicinal resource, possesses the potential to treat a wide variety of ailments, especially, cancer and gastrointestinal inflammation. These studies present a wide range of perspectives for the development of new drugs related to BAA. However, only a few traditional uses are associated with the reported pharmacological activities of BAA and have been confirmed by preclinical and clinical studies. Moreover, the pharmacokinetics, toxicology, and quality control of BAA should be considered indispensable research topics.

Two Worlds Colliding: The Interplay Between Natural Compounds and Non-Coding Transcripts in Cancer Therapy

Cancer is a devastating disease and has recently become the leading cause of death in western countries, representing an immense public health burden. When it comes to cancer treatment, chemotherapy is one of the main pillars, especially for advanced stage tumors. Over the years, natural compounds have emerged as one of the most valuable resources for new chemotherapies. It is estimated that more than half of the currently used chemotherapeutic agents are derived from natural compounds. Usually, natural compounds are discovered empirically and an important limitation of introducing new anti-cancer natural products is lack of knowledge with regard to their mechanism of action. Recent data has proven that several natural compounds may function via modulating the expression and function of non-coding RNAs (ncRNAs). NcRNAs are a heterogenous class of RNA molecules which are usually not translated into proteins but have an important role in gene expression regulation and are involved in multiple tumorigenic processes, including response/resistance to pharmacotherapy. In this review, we will discuss how natural compounds function via ncRNAs while summarizing the available data regarding their effects on over 15 types of cancer. Moreover, we will critically analyze the current advances and limitations in understanding the way natural compounds exert these health-promoting effects by acting on ncRNAs. Finally, we will propose several hypotheses that may open new avenues and perspectives regarding the interaction between natural compounds and ncRNAs, which could lead to improved natural compound-based therapeutic strategies in cancer.

Ailanthus Altissima-derived Ailanthone enhances Gastric Cancer Cell Apoptosis by Inducing the Repression of Base Excision Repair by Downregulating p23 Expression

Chemotherapy plays an irreplaceable role in the treatment of GC, but currently available chemotherapeutic drugs are not ideal. The application of medicinal plants is an important direction for new drug discovery. Through drug screening of GC organoids, we determined that ailanthone has an anticancer effect on GC cells in vitro and in vivo. We also found that AIL can induce DNA damage and apoptosis in GC cells. Further transcriptome sequencing of PDX tissue indicated that AIL inhibited the expression of XRCC1, which plays an important role in DNA damage repair, and the results were also confirmed by western blotting. In addition, we found that AIL inhibited the expression of P23 and that inhibition of P23 decreased the expression of XRCC1, indicating that AIL can regulate XRCC1 via P23. The results of coimmunoprecipitation showed that AIL can inhibit the binding of P23 and XRCC1 to HSP90. These findings indicate that AIL can induce DNA damage and apoptosis in GC cells. Meanwhile, AIL can decrease XRCC1 activity by downregulating P23 expression to inhibit DNA damage repair. The present study sheds light on the potential application of new drugs isolated from natural medicinal plants for GC therapy.

Analysis of Long Noncoding RNAs in Aila-Induced Non-Small Cell Lung Cancer Inhibition

Non-small cell lung cancer (NSCLC) has the highest morbidity and mortality among all carcinomas. However, it is difficult to diagnose in the early stage, and current therapeutic efficacy is not ideal. Although numerous studies have revealed that Ailanthone (Aila), a natural product, can inhibit multiple cancers by reducing cell proliferation and invasion and inducing apoptosis, the mechanism by which Aila represses NSCLC progression in a time-dependent manner remains unclear. In this study, we observed that most long noncoding RNAs (lncRNAs) were either notably up- or downregulated in NSCLC cells after treatment with Aila. Moreover, alterations in lncRNA expression induced by Aila were crucial for the initiation and metastasis of NSCLC. Furthermore, in our research, expression of DUXAP8 was significantly downregulated in NSCLC cells after treatment with Aila and regulated expression levels of EGR1. In conclusion, our findings demonstrate that Aila is a potent natural suppressor of NSCLC by modulating expression of DUXAP8 and EGR1.

The disruption of protein-protein interactions with co-chaperones and client substrates as a strategy towards Hsp90 inhibition

The 90-kiloDalton (kD) heat shock protein (Hsp90) is a ubiquitous, ATP-dependent molecular chaperone whose primary function is to ensure the proper folding of several hundred client protein substrates. Because many of these clients are overexpressed or become mutated during cancer progression, Hsp90 inhibition has been pursued as a potential strategy for cancer as one can target multiple oncoproteins and signaling pathways simultaneously. The first discovered Hsp90 inhibitors, geldanamycin and radicicol, function by competitively binding to Hsp90's N-terminal binding site and inhibiting its ATPase activity. However, most of these N-terminal inhibitors exhibited detrimental activities during clinical evaluation due to induction of the pro-survival heat shock response as well as poor selectivity amongst the four isoforms. Consequently, alternative approaches to Hsp90 inhibition have been pursued and include C-terminal inhibition, isoform-selective inhibition, and the disruption of Hsp90 protein-protein interactions. Since the Hsp90 protein folding cycle requires the assembly of Hsp90 into a large heteroprotein complex, along with various co-chaperones and immunophilins, the development of small molecules that prevent assembly of the complex offers an alternative method of Hsp90 inhibition.

Nrf2 signaling pathway in cisplatin chemotherapy: Potential involvement in organ protection and chemoresistance

Nuclear factor erythroid 2-related factor 2 (Nrf2) is a vital transcription factor and its induction is of significant importance for protecting against oxidative damage. Increased levels of Reactive Oxygen Species (ROS) stimulate Nrf2 signaling, enhancing the activity of antioxidant enzymes such as catalase, superoxide dismutase and glutathione peroxidase. These enzymes are associated with retarding oxidative stress. On the other hand, Nrf2 activation in cancer cells is responsible for the development of chemoresistance due to disrupting oxidative mediated-cell death by reducing ROS levels. Cisplatin (CP), cis-diamminedichloroplatinum(II), is a potent anti-tumor agent extensively used in cancer therapy, but its frequent application leads to the development of chemoresistance as well. In the present study, association of Nrf2 signaling with chemoresistance to CP and protection against its deleterious effects is discussed. Anti-tumor compounds, mainly phytochemicals, retard chemoresistance by suppressing Nrf2 signaling. Upstream mediators such as microRNAs can regulate Nrf2 expression during CP chemotherapy regimens. Protection against side effects of CP is mediated via activating Nrf2 signaling and its downstream targets activating antioxidant defense system. Protective agents that activate Nrf2 signaling, can ameliorate CP-mediated ototoxicity, nephrotoxicity and neurotoxicity. Reducing ROS levels and preventing cell death are the most important factors involved in alleviating CP toxicity upon Nrf2 activation. As pre-clinical experiments advocate the role of Nrf2 in chemoprotection and CP resistance, translating these findings to the clinic can provide a significant progress in treatment of cancer patients.

miR-195 reduces age-related blood-brain barrier leakage caused by thrombospondin-1-mediated selective autophagy

Blood–brain barrier (BBB) disruption contributes to neurodegenerative diseases. Loss of tight junction (TJ) proteins in cerebral endothelial cells (ECs) is a leading cause of BBB breakdown. We recently reported that miR‐195 provides vasoprotection, which urges us to explore the role of miR‐195 in BBB integrity. Here, we found cerebral miR‐195 levels decreased with age, and BBB leakage was significantly increased in miR‐195 knockout mice. Furthermore, exosomes from miR‐195‐enriched astrocytes increased endothelial TJ proteins and improved BBB integrity. To decipher how miR‐195 promoted BBB integrity, we first demonstrated that TJ proteins were metabolized via autophagic–lysosomal pathway and the autophagic adaptor p62 was necessary to promote TJ protein degradation in cerebral ECs. Next, proteomic analysis of exosomes revealed miR‐195‐suppressed thrombospondin‐1 (TSP1) as a major contributor to BBB disruption. Moreover, TSP1 was demonstrated to activate selective autophagy of TJ proteins by increasing the formation of claudin‐5‐p62 and ZO1‐p62 complexes in cerebral ECs while TSP1 impaired general autophagy. Delivering TSP1 antibody into the circulation showed dose‐dependent reduction of BBB leakage by 20%–40% in 25‐month‐old mice. Intravenous or intracerebroventricular injection of miR‐195 rescued TSP1‐induced BBB leakage. Dementia patients with BBB damage had higher levels of serum TSP1 compared to those without BBB damage (p = 0.0015), while the normal subjects had the lowest TSP1 (p < 0.0001). Taken together, the study implies that TSP1‐regulated selective autophagy facilitates the degradation of TJ proteins and weakens BBB integrity. An adequate level of miR‐195 can suppress the autophagy–lysosome pathway via a reduction of TSP1, which may be important for maintaining BBB function.

Ailanthone: A novel potential drug for treating human cancer

Cancer is the second leading cause of death after cardiovascular disease. In 2015, >8.7 million people died worldwide due to cancer, and by 2030 this figure is expected to increase to ~13.1 million. Tumor chemotherapy drugs have specific toxicity and side effects, and patients can also develop secondary drug resistance. To prevent and treat cancer, scientists have developed novel drugs with improved antitumor effects and decreased toxicity. Ailanthone (AIL) is a quassinoid extract from the traditional Chinese medicine plant Ailanthus altissima, which is known to have anti-inflammatory and antimalarial effects. An increasing number of studies have focused on AIL due to its antitumor activity. AIL can inhibit cell proliferation and induce apoptosis by up- or downregulating cancer-associated molecules, which ultimately leads to cancer cell death. Antitumor effects of AIL have been observed in melanoma, acute myeloid leukemia, bladder, lung, breast, gastric and prostate cancer and vestibular neurilemmoma. To the best of our knowledge, the present study is the first review to describe the antitumor mechanisms of AIL.

Dynamical network analysis reveals key microRNAs in progressive stages of lung cancer

Non-coding RNAs are fundamental to the competing endogenous RNA (CeRNA) hypothesis in oncology. Previous work focused on static CeRNA networks. We construct and analyze CeRNA networks for four sequential stages of lung adenocarcinoma (LUAD) based on multi-omics data of long non-coding RNAs (lncRNAs), microRNAs and mRNAs. We find that the networks possess a two-level bipartite structure: common competing endogenous network (CCEN) composed of an invariant set of microRNAs over all the stages and stage-dependent, unique competing endogenous networks (UCENs). A systematic enrichment analysis of the pathways of the mRNAs in CCEN reveals that they are strongly associated with cancer development. We also find that the microRNA-linked mRNAs from UCENs have a higher enrichment efficiency. A key finding is six microRNAs from CCEN that impact patient survival at all stages, and four microRNAs that affect the survival from a specific stage. The ten microRNAs can then serve as potential biomarkers and prognostic tools for LUAD.

Anticancer properties and mechanism of action of the quassinoid ailanthone

Ailanthone (AIT) is a quassinoid natural product isolated from the worldwide-distributed plant Ailanthus altissima. The drug displays multiple pharmacological properties, in particular significant antitumor effects against a variety of cancer cell lines in vitro. Potent in vivo activities have been evidenced in mice bearing hepatocellular carcinoma, nonsmall cell lung cancer and castration-resistant prostate cancer. This review focusses on the mechanism of action of AIT, notably to highlight the capacity of the drug to activate DNA damage responses, to inhibit the Hsp90 co-chaperone p23 and to modulate the expression of several microRNA. The interconnexion between these effects is discussed. The unique capacity of AIT to downregulate oncogenic miR-21 and to upregulate the tumor suppressor miRNAs miR-126, miR-148a, miR-195, and miR-449a is presented. AIT exploits several microRNAs to exert its anticancer effects in distinct tumor types. AIT is one of the rare antitumor natural products that binds to and strongly inhibits cochaperone p23, opening interesting perspectives to treat cancers. However, the toxicity profile of the molecule may limit its development as an anticancer drug, unless it can be properly formulated to prevent AIT-induced gastro-intestinal damages in particular. The antitumor properties of AIT and analogs are underlined, with the aim to encourage further pharmacological studies with this underexplored natural product and related quassinoids. HIGHLIGHTS: Ailanthone (AIT) is an anticancer quassinoid isolated from Ailanthus altissima It inhibits proliferation and induces cell death of many cancer cell types The drug activates DNA damage response and targets p23 cochaperone Up or downregulation of several microRNA by AIT contributes to the anticancer activity Analogs or specific formulations must be developed to prevent the toxicity of AIT.