Angelmarin, a novel anti-cancer agent able to eliminate the tolerance of cancer cells to nutrient starvation

Phytochemicals for the prevention and treatment of pancreatic cancer: Current progress and future prospects

Pancreatic cancer is the third leading cause of cancer-related deaths in the United States, owing to its aggressive nature and suboptimal treatment options, emphasizing the need for novel therapeutic approaches. Emerging studies have exhibited promising results regarding the therapeutic utility of plant-derived compounds (phytochemicals) in pancreatic cancer. The purpose of this review is to evaluate the potential of phytochemicals in the treatment and prevention of pancreatic cancer. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses was applied to collect articles for this review. Scholarly databases, including PubMed, Scopus and ScienceDirect, were queried for relevant studies using the following keywords: phytochemicals, phenolics, terpenoids, alkaloids, sulfur-containing compounds, in vitro, in vivo, clinical studies, pancreatic cancer, tumour, treatment and prevention. Aggregate results pooled from qualified studies indicate phytochemicals can inhibit pancreatic cancer cell growth or decrease tumour size and volume in animal models. These effects have been attributed to various mechanisms, such as increasing proapoptotic factors, decreasing antiapoptotic factors, or inducing cell death and cell cycle arrest. Notable signalling pathways modulated by phytochemicals include the rat sarcoma/mitogen activated protein kinase, wingless-related integration site/β-catenin and phosphoinositide 3-kinase/protein kinase B/mammalian target of rapamycin signal transduction pathways. Clinically, phytochemicals have been found to increase survival while being well-tolerated and safe, though research is scarce. While these promising results have produced great interest in this field, further in-depth studies are required to characterize the anticancer activities of phytochemicals before they can be utilized to prevent or treat pancreatic cancer in clinical practice.

Piper longum Constituents Induce PANC-1 Human Pancreatic Cancer Cell Death under Nutrition Starvation

Pancreatic cancer is a highly aggressive form of cancer with a poor prognosis, partly due to 'austerity', a phenomenon of tolerance to nutrient deprivation and survival in its hypovascular tumor microenvironment. Anti-austerity agents which preferentially diminish the survival of cancer cells under nutrition starvation is regarded as new generation anti-cancer agents. This study investigated the potential of Piper longum constituents as anti-austerity agents. The ethanolic extract of Piper longum was found to have preferential cytotoxicity towards PANC-1 human pancreatic cancer cells in a nutrient-deprived medium (NDM). Further investigation led to the identification of pipernonaline (3) as the lead compound with the strongest anti-austerity activity, inducing cell death and inhibiting migration in a normal nutrient medium, as well as strongly inhibiting the Akt/mTOR/autophagy pathway. Therefore, pipernonaline (3) holds promise as a novel antiausterity agent for the treatment of pancreatic cancer.

Arctigenin: pharmacology, total synthesis, and progress in structure modification

Arctium lappa L. is a prevalent medicinal herb and a health supplement that is commonly used in Asia. Over the last few decades, the bioactive component arctigenin has attracted the attention of researchers because of its anti-inflammatory, antioxidant, immunomodulatory, multiple sclerosis fighting, antitumor, and anti-leukemia properties. After summarising the research and literature on arctigenin, this study outlines the current status of research on pharmacological activity, total synthesis, and structural modification of arctigenin. The purpose of this study is to assist academics in obtaining a more comprehensive understanding of the research progress on arctigenin and to provide constructive suggestions for further investigation of this useful molecule.

Chemical Constituents of Callistemon subulatus and Their Anti-Pancreatic Cancer Activity against Human PANC-1 Cell Line

An n-hexane extract of Callistemon subulatus was found to exhibit potent cytotoxicity against PANC-1 human pancreatic cancer cells, preferentially under nutrition starvation conditions, with a PC₅₀ value of 6.2 µg/mL. Phytochemical investigation of this bioactive extract resulted in the isolation of fifteen compounds (1–15), including a new compound, subulatone A (–). The structure of compound 1 was elucidated using HRFABMS and NMR spectroscopic analyses. The isolated compounds were tested for their preferential cytotoxicity against the PANC-1 human pancreatic cancer cell line, using an anti-austerity strategy. Among these, myrtucommulone A (2) showed highly potent preferential cytotoxicity, with a PC₅₀ value of 0.28 µM. Myrtucommulone A (2) was found to alter PANC-1 cell morphology, inhibit cell migration, and downregulate the PI3K/Akt/mTOR and autophagy signaling pathways in nutrient-deprived media, leading to cancer cell death. Therefore, myrtucommulone A (2) is a lead compound for anticancer drug development based on an anti-austerity strategy.

Coumarins as Fungal Metabolites with Potential Medicinal Properties

Coumarins are a structurally varied set of 2H-chromen-2-one compounds categorized also as members of the benzopyrone group of secondary metabolites. Coumarin derivatives attract interest owing to their wide practical application and the unique reactivity of fused benzene and pyrone ring systems in molecular structure. Coumarins have their own specific fingerprints as antiviral, antimicrobial, antioxidant, anti-inflammatory, antiadipogenic, cytotoxic, apoptosis, antitumor, antitubercular, and cytotoxicity agents. Natural products have played an essential role in filling the pharmaceutical pipeline for thousands of years. Biological effects of natural coumarins have laid the basis of low-toxic and highly effective drugs. Presently, more than 1300 coumarins have been identified in plants, bacteria, and fungi. Fungi as cultivated microbes have provided many of the nature-inspired syntheses of chemically diverse drugs. Endophytic fungi bioactivities attract interest, with applications in fields as diverse as cancer and neuronal injury or degeneration, microbial and parasitic infections, and others. Fungal mycelia produce several classes of bioactive molecules, including a wide group of coumarins. Of promise are further studies of conditions and products of the natural and synthetic coumarins’ biotransformation by the fungal cultures, aimed at solving the urgent problem of searching for materials for biomedical engineering. The present review evaluates the fungal coumarins, their structure-related peculiarities, and their future therapeutic potential. Special emphasis has been placed on the coumarins successfully bioprospected from fungi, whereas an industry demand for the same coumarins earlier found in plants has faced hurdles. Considerable attention has also been paid to some aspects of the molecular mechanisms underlying the coumarins’ biological activity. The compounds are selected and grouped according to their cytotoxic, anticancer, antibacterial, antifungal, and miscellaneous effects.

Abietane diterpenes from Abies spectabilis and their anti-pancreatic cancer activity against the MIA PaCa-2 cell line

An ethanolic extract of the stem of Abies spectabilis exhibited strong cytotoxicity against MIA PaCa-2 human pancreatic cancer cells preferentially under nutrient-deprived conditions. Therefore, phytochemical investigation of this bioactive extract was carried out, and that led the isolation of ten compounds (1-10) including a new abietane-type diterpene (1). The structure of the new compound (1) was elucidated by combined spectroscopic techniques, including HRFABMS, NMR and quantum ECD calculation. All the isolated compounds were evaluated for their efficacy against MIA PaCa-2 human pancreatic cancer cell line by employing an anti-austerity strategy. Among the tested compounds, dehydroabietinol (5) displayed the most potent activity with a PC50 value of 6.6 μM. Dehydroabietinol (5) was also found to retard the MIA PaCa-2 cell migration under normal nutrient-rich conditions displaying its anti-metastatic potential. Investigation on the mechanism suggested that dehydroabietinol (5) is an inhibitor of the key cancer cell survival Akt/mTOR/autophagy signaling pathway.

Dihydrochalcones as antitumor agents

Dihydrochalcones are a class of secondary metabolites, possessing several biological properties such as antitumor, antioxidant, antibacterial, antidiabetic, estrogenic, anti-inflammatory, antithrombotic, antiviral, neuroprotective and immunomodulator properties; therefore, they are currently considered promising candidates in the drug discovery process. This review intend to debate their pharmacological actions with a particular attention to their antitumor activity against a panel of cancer cell-lines and to the description of the inhibition mechanisms of cell proliferation such as the regulation of angiogenesis, apoptosis, etc etc.

Structure-activity relationship and mechanistic study on guggulsterone derivatives; Discovery of new anti-pancreatic cancer candidate

Pancreatic cancer is one of the deadliest types of malignancies. A new intervention aiming to combat pancreatic cancer is targeting its extra-ordinary ability to tolerate nutrition starvation, a phenomenon known as "Austerity". As a part of a research program aiming to develop a new-generation of anticancer agents, known as "anti-austerity agents", guggulsterone derivatives (GSDs) were identified as unique anti-austerity agents in terms of potency and selectivity. These agents are able to exert preferential cytotoxic activity only under nutrient-deprived conditions with little or no toxicity under normal conditions. In the present study, a library of 14 GSDs was synthesized and screened against PANC-1 human pancreatic cells. Among tested compounds, GSD-11 showed the most potent activity with PC₅₀ a value of 0.72 μM. It also inhibited pancreatic cancer cell migration and colony formation in a concentration-dependent manner. A mechanistic study revealed that this compound can inhibit the activation of the Akt/mTOR signaling pathway. Therefore, GSD-11 could be a promising lead compound for the anticancer drug discovery against pancreatic cancer.

GDP Induces PANC-1 Human Pancreatic Cancer Cell Death Preferentially under Nutrient Starvation by Inhibiting PI3K/Akt/mTOR/Autophagy Signaling Pathway

Pancreatic tumors are hypovascular, which leads to a poor nutrient supply to support the aggressively proliferating tumor cells. However, human pancreatic cancer cells have extreme resistance to nutrition starvation, which enables them to survive under severe metabolic stress conditions within the tumor microenvironment, a phenomenon known as "austerity" in cancer biology. Discovering agents which can preferentially inhibit the cancer cells' ability to tolerate starvation conditions represents a new generation of anticancer agents. In this study, geranyl 2,4-dihydroxy-6-phenethylbenzoate (GDP), isolated from Boesenbergia pandurata rhizomes, exhibited potent preferential cytotoxicity against PANC-1 human pancreatic cancer cells under nutrition starvation conditions. GDP also possessed PANC-1 cell migration and colony formation inhibitory activities under normal nutrient-rich conditions. Mechanistically, GDP inhibited PI3K/Akt/mTOR/autophagy survival signaling pathway, leading to selective PANC-1 cancer cell death under the nutrition starvation condition. Therefore, GDP is a promising anti-austerity agent for drug development against pancreatic cancer.

Benzophenones from Betula alnoides with Antiausterity Activities against the PANC-1 Human Pancreatic Cancer Cell Line

The antiausterity strategy is a promising approach for the discovery of lead compounds with unprecedented anticancer activities by targeting the tolerance of cancer cells to nutrition starvation. These agents are selectively cytotoxic under the tumor microenvironment-mimicking condition of nutrition starvation, without apparent toxicity in the normal nutrient-rich condition. In this study, an ethanol extract of Betula alnoides showed antiausterity activity against PANC-1 human pancreatic cancer cells under nutrient-deprived conditions, with a PC₅₀ value of 13.2 μg/mL. Phytochemical investigation of this active extract led to the isolation of eight benzophenones (1-8), including six new compounds, named betuphenones A-F (2-7), and three known xanthones (9-11). The structure elucidation of the new compounds was achieved by HRFABMS, NMR, and ECD spectroscopic analyses. A plausible biogenetic pathway of the new compounds was proposed. Compounds 1-7 displayed antiausterity activity with PC₅₀ values of 4.9-8.4 μM. Moreover, compounds 2 and 7 induced alterations in PANC-1 cell morphology under nutrient-deprived conditions and also inhibited PANC-1 colony formation under nutrient-rich conditions.

Benzylisoquinoline alkaloids from Nelumbo nucifera Gaertn. petals with antiausterity activities against the HeLa human cervical cancer cell line

Ethanolic extract of Nelumbo nucifera petals showed preferential cytotoxic activity against HeLa human cervical cancer cell line with a PC₅₀ value of 10.4 μg/mL. This active extract was subjected to a phytochemical investigation study which led to the isolation of nine benzylisoquinoline alkaloids (1-9). The isolated compounds exhibited potent antiausterity activities. Moreover, under nutrient-deprived conditions, (-)-lirinidine (8) induced remarkable alterations in HeLa cell morphology including cell shrinkage and plasma blebbing leading to total cell death within 10 h. Mechanistically, 8 was found to inhibit Akt/mTOR signaling pathway. It also induced apoptosis by promoting caspase-3 activation and inhibiting Bcl-2 expression. Therefore, benzylisoquinoline alkaloids skeleton can be considered as a promising scaffold for the anticancer drug development against cervical cancer.

Chemical constituents of Thai Piper ribesoides and their antiausterity activities against the PANC-1 human pancreatic cancer cell line

A methanolic extract of Thai Piper ribesoides showed preferential cytotoxicity against PANC-1 human pancreatic cancer cells under a nutrient-deprived condition, with a PC₅₀ value of 24 μg/mL. Phytochemical investigation of this bio-active extract led to the isolation of six compounds (1-6), including two new polyoxygenated cyclohexane derivatives, named ribesoidones A and B (1 and 2). The structural elucidation of the new compounds was achieved by a combination of HREIMS, NMR, and circular dichroism spectroscopic analyses. Isolated compounds were tested for their antiausterity activity against PANC-1 human pancreatic cancer cell line. Among these, compounds 1, 3, and 4 displayed potent preferential cytotoxic activity with PC₅₀ values of 5.5-7.2 μM. Ribesoidone A (1) was also found to inhibit PANC-1 colony formation under normal nutrient-rich conditions.

Panduratins Q-Y, dimeric metabolites from Boesenbergia rotunda and their antiausterity activities against the PANC-1 human pancreatic cancer cell line

A methanolic extract of the rhizomes of Boesenbergia rotunda showed potent preferential cytotoxicity against PANC-1 human pancreatic cancer cells under nutrient deficiency conditions with a PC₅₀ value of 6.6 μg/mL. Bioactivity-guided phytochemical investigation of the rhizomes of B. rotunda led to the isolation of nine undescribed dimeric metabolites, panduratins Q-Y. Their structures were elucidated based on NMR, MS, and ECD spectroscopic data interpretation. Panduratins Q-S and U-W exhibited potent cytotoxicity towards PANC-1 cell line with the PC₅₀ values ranging from 0.8 to 6.3 μM. Panduratin W, which possessed a cyclohexenylchalcone-linked flavanone skeleton, showed the most cytotoxicity with a PC₅₀ value of 0.8 μM under nutrient-deprived medium.

Highly Potent Antiausterity Agents from Callistemon citrinus and Their Mechanism of Action against the PANC-1 Human Pancreatic Cancer Cell Line

Human pancreatic cancer cells display remarkable tolerance to nutrition starvation that help them to survive in a hypovascular tumor microenvironment, a phenomenon known as "austerity". The elucidation of agents countering this tolerance is an established antiausterity strategy in anticancer drug discovery. In this study, a Callistemon citrinus leaf extract inhibited the viability of PANC-1 human pancreatic cancer cells preferentially under nutrient-deprived medium (NDM) with a PC₅₀ value of 7.4 μg/mL. Workup of this extract resulted in the isolation of three new meroterpenoids, callistrilones L-N (1-3), together with 14 known compounds (4-17). The structure elucidation of the new compounds was achieved by HRFABMS and by NMR and ECD spectroscopic analysis. The new compounds showed highly potent preferential cytotoxicity against PANC-1 cells with PC₅₀ values ranging from 10 to 65 nM in NDM. Of these, callistrilone L (1) inhibited PANC-1 cell migration and colony formation in a normal nutrient-rich condition. Callistrilone L (1) also strongly suppressed the migration of PANC-1 cells in real time. Mechanistically, 1 was found to inhibit the Akt/mTOR and autophagy activation pathway. Callistrilone L (1) and related meroterpenoids are promising leads for anticancer drug development based on the antiausterity strategy used in this work.

Effect of glucose deprivation on the expression of genes encoding glucocorticoid receptor and some related factors in ERN1-knockdown U87 glioma cells

OBJECTIVE

The aim of the present study was to examine the effect of glucose deprivation on the expression of genes encoded glucocorticoid receptor (NR3C1) and some related proteins (NR3C2, AHR, NRIP1, NNT, ARHGAP35, SGK1, and SGK3) in U87 glioma cells in response to inhibition of endoplasmic reticulum stress signaling mediated by ERN1/IRE1 (endoplasmic reticulum to nucleus signaling 1/inositol requiring enzyme 1) for evaluation of their possible significance in the control of glioma growth through endoplasmic reticulum stress signaling mediated by IRE1 and glucose deprivation.

METHODS

The expression of NR3C1, NR3C2, AHR, NRIP1, NNT, ARHGAP35, SGK1, and SGK3 genes in U87 glioma cells transfected by empty vector pcDNA3.1 (control cells) and cells without ERN1 signaling enzyme function (transfected by dnERN1) under glucose deprivation was studied by real time quantitative polymerase chain reaction.

RESULTS

It was shown that the expression level of NR3C2, AHR, SGK1, SGK3, and NNT genes was up-regulated in control U87 glioma cells under glucose deprivation condition in comparison with the control cells growing with glucose. At the same time, the expression of NRIP1 gene is down-regulated in these glioma cells under glucose deprivation, but NR3C1 and ARHGAP35 genes was resistant to this experimental condition. We also showed that inhibition of ERN1 signaling enzyme function significantly modified the response of most studied gene expressions to glucose deprivation condition. Thus, effect of glucose deprivation on the expression level of NR3C2, AHR, and SGK1 genes was significantly stronger in ERN1 knockdown U87 glioma cells since the expression of NNT gene was resistant to glucose deprivation condition. Moreover, the inhibition of ERN1 enzymatic activities in U87 glioma cells led to up-regulation of ARHGAP35 gene expression and significant down-regulation of the expression of SGK3 gene in response to glucose deprivation condition.

CONCLUSIONS

Results of this study demonstrated that glucose deprivation did not change the expression level of NR3C1 gene but it significantly affected the expression of NR3C2, AHR, NRIP, SGK1, SGK3, and NNT genes in vector-transfected U87 glioma cells in gene specific manner and possibly contributed to the control of glioma growth since the expression of most studied genes in glucose deprivation condition was significantly dependent on the functional activity of IRE1 signaling enzyme.

Traditional Chinese Medicine of Angelicae Pubescentis Radix: A Review of Phytochemistry, Pharmacology and Pharmacokinetics

Angelicae Pubescentis Radix (APR) is a widely used antirheumatic Chinese medicinal herb known as "Duhuo" in China. It has the effects of dispelling wind and removing dampness, diffusing impediment, and relieving pain, and is mainly indicated for rheumatic arthritis with pain in the lower back and knees, and headache. To the best of our knowledge, an attempt is made to provide an up-to-date review on these aspects based on published materials, including ancient and modern books; Master's and doctoral theses; monographs on medicinal plants; the pharmacopoeia of different countries, websites for publication of patent and electronic databases, such as SCI finder, PubMed, Web of Science, ACS, Science Direct, Wiley, Springer, Taylor, CNKI, and Google Scholar. APR, which has a good clinical effect, has been used for traditional Chinese medicine more than 2000 years. Since 1957, a variety of chemical constituents have been reported from the medicinal plants of this herb, mostly coumarins and volatile oil. In the past 30 years, numerous studies have shown that the extracts and compounds isolated from APR showed effective analgesic and anti-inflammatory actions, also showing well effects on central nervous system, effects on cardiovascular system and deworming activity. In addition, we also present and discuss the botany, traditional medicinal use, pharmacokinetics, toxicity, quality control, future trends and prospects of APR. All this information suggest that future research of APR should be supplemented in the area of pharmacology and toxicology to provide further insight on the clinical use and quality control.

Chemical Constituents of Anneslea fragrans and Their Antiausterity Activity against the PANC-1 Human Pancreatic Cancer Cell Line

An ethanolic extract of Anneslea fragrans leaves showed potent preferential cytotoxicity against PANC-1 human pancreatic cancer cells under a nutrient-deprived condition, with a PC₅₀ value of 9.6 μg/mL. Phytochemical investigation of this active extract led to the isolation of two new secondary metabolites, fragranones A (1) and B (2), along with 15 previously reported compounds. The structure elucidation of the new compounds was achieved by HRFABMS, acid hydrolysis, NMR, and ECD spectroscopic analysis. Fragranone A (1) is the first example of a rare natural product bearing an acetonide glucose moiety. Fragranone B (2) is representative of a rare class of natural products with a threonolactone unit linked to a chalcone through an ether linkage. The isolated compounds exhibited antiausterity activity against PANC-1 cells under nutrient-deprived conditions, and betulin (14) was found to be the most potent compound tested, with a PC₅₀ value of 8.4 μM. In addition, fragranone A (1) was found to suppress PANC-1 cancer cell migration in real time.

Natural Products and Synthetic Analogs as a Source of Antitumor Drugs

Cancer is a heterogeneous disease and one of the major issues of health concern, especially for the public health system globally. Nature is a source of anticancer drugs with abundant pool of diverse chemicals and pharmacologically active compounds. In recent decade, some natural products and synthetic analogs have been investigated for the cancer treatment. This article presents the utilization of natural products as a source of antitumor drugs.

The ethnopharmacology, phytochemistry and pharmacology of Angelica biserrata - A review

ETHNOPHARMACOLOGICAL RELEVANCE

Angelica biserrata (R.H. Shan & C.Q. Yuan) C.Q. Yuan & R.H. Shan (Angelica pubescens Maxim. f. biserrata Shan et Yuan) (A.biserrata) is a widely used traditional Chinese medicine; its roots known as 'Duhuo' in China. The herb is used for expelling wind, eliminating dampness, and terminating pain. Moreover, it is used for treating the onset of anemofrigid-damp arthralgia, pain of the waist and knee and headache caused by latent wind pathogenic factor or damp-cold pathogenic factor. A.biserrata is slightly warm, bitter and pungent in taste, and it is well distributed in regions such as Sichuan and Hubei Provinces.

AIM OF THE STUDY

This review aims to provide critical summary of the current evidence on A.biserrata. In particular, the progress of studies in the fields of botany, ethnopharmacology, phytochemistry, pharmacology and toxicity are discussed. Possible directions for future research are also briefly proposed.

MATERIALS AND METHODS

Information on A.biserrata was collected from the internet database PubMed, Elsevier, China Knowledge Resource Integrated databases, ResearchGate, Web of Science, Wiley Online Library and Europe PMC using a combination of various relevant keywords. Other published books providing an overview of extant literature studies were considered for reference if they are related to the taxonomy, traditional knowledge, phytochemistry, pharmacology and toxicity of the plant.

RESULTS

A substantial proportion of the isolated and identified compounds of the herb were reported to be coumarins and volatile oils. Biological effects, such as neuroprotective, anti-tumor, anti-arthritis, anti-inflammatory, and sedative, were also validated in In vitro and in vivo studies. Therapeutic effects are attributed to the bioactivities of the naturally occurring compounds in this herb.

CONCLUSIONS

A.biserrata has been proven as a valuable medicinal sources from traditional herb. Some conventional uses has been evaluated by pharmacological investigation. Although the crude extracts of A.biserrata has been emerged to possess more pharmacological activities, it is now time to isolate and identify more active chemical constituents by Bioactivity-Guided and elucidate their structure-activity relationship. More designed investigations are need to focus on understanding the multi-target network pharmacology, clarity the molecular mechanism of action and efficacy as well as identifying the effective doses of A.biserrata. In addition, A.biserrata is not fully assessed regarding its safety. Further studies are essential to investigate its toxicity on human. It's useful to provide identify its underlying therapeutic remedy and economic value of developing new medicine in the future.

Chemical Constituents of Thai Citrus hystrix and Their Antiausterity Activity against the PANC-1 Human Pancreatic Cancer Cell Line

Human pancreatic cancer cells have an extreme tolerance to nutrition starvation, enabling them to survive in a hypovascular tumor microenvironment. Searching for agents that preferentially inhibit cancer cell viability under nutrition starvation conditions is a novel antiausterity strategy in anticancer drug discovery. In the present study, a hexane extract of the peels of Citrus hystrix fruits showed preferential cytotoxicity against PANC-1 human pancreatic cancer cells using a nutrient-deprived medium. Phytochemical investigation of this bioactive extract led to the isolation of 10 coumarins (1-10) including a new furanocoumarin (1). The isolated compounds were tested for their preferential cytotoxic activity against three different human pancreatic cancer cell lines [PANC-1, MIA PaCa-2, and PSN-1]. Among these, bergamottin (7) was identified as the most active constituent. In real-time live imaging, 7 was found to induce cell shrinkage, membrane blebbing, and disintegration of organelles in PANC-1 cells. Bergamottin (7) was also found to inhibit PANC-1 cell migration and colony formation. Mechanistically, 7 inhibited key survival proteins in the Akt/mTOR signaling pathway. Bergamottin (7) and related compounds are potential antiausterity candidates for drug development against pancreatic cancer.

Michellamines A6 and A7, and further mono- and dimeric naphthylisoquinoline alkaloids from a Congolese Ancistrocladus liana and their antiausterity activities against pancreatic cancer cells

Michellamines A₆ (1) and A₇ (2) are the first dimers of 5,8′-coupled naphthylisoquinoline alkaloids with cis-configured stereocenters in both tetrahydroisoquinoline subunits. They were isolated from the leaves of a recently discovered, yet unidentified Congolese Ancistrocladus liana that shares some morphological characteristics with Ancistrocladus likoko. Two further new dimeric analogs, michellamines B₄ (3) and B₅ (4), were obtained, along with two previously likewise unknown monomers, ancistrobonsolines A₁ (5) and A₂ (6), which, besides one single known other example, are the only naphthyldihydroisoquinolines with an M-configured biaryl axis and R-configuration at C-3. Moreover, five compounds earlier reported from other Ancistrocladus species were identified, ancistroealaine C (7), korupensamines A (8a) and B (8b), and michellamines A₂ (9) and E (10). Their complete structural elucidation succeeded due to the fruitful interplay of spectroscopic, chemical, and chiroptical methods. Chemotaxonomically, the stereostructures of the metabolites clearly delineate this Congolese Ancistrocladus liana from all known related species, showing that it might be a new taxon. Ancistrobonsolines A₁ (5) and A₂ (6) exhibited strong preferential cytotoxicities against human PANC-1 pancreatic cancer cells under nutrient-deprived conditions, without displaying toxicity in normal, nutrient-rich medium. Against cervical HeLa cancer cells, the dimeric alkaloids michellamines A₆ (1) and E (10) displayed the highest cytotoxic activities, comparable to that of the standard agent, 5-fluorouracil. Furthermore, ancistrobonsolines A₁ (5) and A₂ (6) showed weak-to-moderate antiprotozoal activities.

The first dimers of 5,8′-coupled naphthylisoquinolines with two 1,3-cis-configured tetrahydroisoquinoline portions and their cytotoxicities against cancer cells are described.

Phosphorylated Akt Protein at Ser473 Enables HeLa Cells to Tolerate Nutrient-Deprived Conditions

Background:

Despite angiogenesis, many tumours remain hypovascular and starved of nutrients while continuing to grow rapidly. The specific biochemical mechanisms associated with starvation resistance, austerity, may be new biological characters of cancer that are critical for cancer progression.

Objective:

This study aim was to investigate the effect of nutrient starvation on HeLa cells and the possible mechanism by which the cells are able to tolerate nutrient-deprived conditions.

Methods:

Nutrient starvation was achieved by culturing HeLa cells in nutrient-deprived medium (NDM) and cell survival was estimated by using cell counting kit-8. The effect of starvation on cell cycle distribution and the quantitative analysis of apoptotic cells were investigated by flow cytometry using propidium iodide staining. Western blotting was used to detect the expression levels of Akt and phosphorylated Akt at Ser473 (Ser⁴⁷³p-Akt) proteins.

Results:

HeLa cells displayed extremely long survival when cultured in NDM. The percentage of apoptotic HeLa cells was significantly increased by starvation in a time-dependent manner. A significant increase in the expression of Ser⁴⁷³p-Akt protein after starvation was also observed. Furthermore, it was found that Akt inhibitor III molecule inhibited the cells proliferation in a concentration- and time-dependent manner.

Conclusion:

Results of the present study provide evidence that Akt activation may be implicated in the tolerance of HeLa cells for nutrient starvation and may help to suggest new therapeutic strategies designed to prevent austerity of cervical cancer cells through inhibition of Akt activation.

An Efficient Synthesis of Angelmarin and its Analogs

Angelmarin, a naturally occurring coumarin, exhibited highly anti-austerity potency towards human pancreatic carcinoma cell line PANC-1. In this paper, an efficient and eco-friendly synthesis of angelmarin and its analogs from columbianetin has been developed via a ZnO mediated esterification and a Wittig reaction.

Chemical Constituents of Propolis from Vietnamese Trigona minor and Their Antiausterity Activity against the PANC-1 Human Pancreatic Cancer Cell Line

The ethanol extract of propolis from the Vietnamese stingless bee Trigona minor possessed potent preferential cytotoxicity against PANC-1 human pancreatic cancer cells in nutrient-deprived medium, with a PC₅₀ value of 14.0 μg/mL. Chemical investigation of this extract led to the isolation of 15 cycloartane-type triterpenoids, including five new compounds (1-5), and a lanostane-type triterpenoid. The structures of the new compounds were elucidated on the basis of NMR spectroscopic analysis. Among the isolated compounds, 23-hydroxyisomangiferolic acid B (5) and 27-hydroxyisomangiferolic acid (13) exhibited the most potent preferential cytotoxicity against PANC-1 human pancreatic cancer cells under nutrition-deprived conditions, with PC₅₀ values of 4.3 and 3.7 μM, respectively.

Constituents of the Rhizomes of Boesenbergia pandurata and Their Antiausterity Activities against the PANC-1 Human Pancreatic Cancer Line

Human pancreatic cancer cell lines have a remarkable tolerance to nutrition starvation, which enables them to survive under a tumor microenvironment. The search for agents that preferentially inhibit the survival of cancer cells under low nutrient conditions represents a novel antiausterity strategy in anticancer drug discovery. In this investigation, a methanol extract of the rhizomes of Boesenbergia pandurata showed potent preferential cytotoxicity against PANC-1 human pancreatic cancer cells under nutrient-deprived conditions, with a PC₅₀ value of 6.6 μg/mL. Phytochemical investigation of this extract led to the isolation of 15 compounds, including eight new cyclohexene chalcones (1-8). The structures of the new compounds were elucidated by NMR spectroscopic data analysis. Among the isolated compounds obtained, isopanduratin A1 (14) and nicolaioidesin C (15) exhibited potent preferential cytotoxicity against PANC-1 human pancreatic cancer cells under nutrition-deprived conditions, with PC₅₀ values of 1.0 and 0.84 μM, respectively.

N-Methylniphatyne A, a New 3-Alkylpyridine Alkaloid as an Inhibitor of the Cancer Cells Adapted to Nutrient Starvation, from an Indonesian Marine Sponge of Xestospongia sp

In the course of searching for selective growth inhibitors of the cancer cells adapted to nutrient starvation, a new 3-alkylpyridine alkaloid named N-methylniphatyne A (1) was isolated from an Indonesian marine sponge of Xestospongia sp. The chemical structure of 1 was determined on the basis of the spectroscopic analysis and comparison with the synthesized 1 and its analogues. Compound 1 showed the cytotoxic activity against PANC-1 cells under the condition of glucose starvation with IC50 value of 16 µM, whereas no growth-inhibition was observed up to 100 µM under the general culture conditions.

Chemical Constituents of Mangifera indica and Their Antiausterity Activity against the PANC-1 Human Pancreatic Cancer Cell Line

Human pancreatic cancer cell lines such as PANC-1 have an altered metabolism, enabiling them to tolerate and survive under extreme conditions of nutrient starvation. The search for candidates that inhibit their viability during nutrition starvation represents a novel antiausterity strategy in anticancer drug discovery. A methanol extract of the bark of Mangifera indica was found to inhibit the survival of PANC-1 human pancreatic cancer cells preferentially under nutrient-deprived conditions with a PC50 value of 15.5 μg/mL, without apparent toxicity, in normal nutrient-rich conditions. Chemical investigation on this bioactive extract led to the isolation of 19 compounds (1-19), including two new cycloartane-type triterpenes, mangiferolate A (1) and mangiferolate B (2). The structures of 1 and 2 were determined by NMR spectroscopic analysis. Among the isolated compounds, mangiferolate B (2) and isoambolic acid (12) exhibited potent preferential cytotoxicity against PANC-1 human pancreatic cancer cells under the nutrition-deprived condition with PC50 values of 11.0 and 4.8 μM, respectively.

Cassane diterpenes from the seed kernels of Caesalpinia sappan

Eight structurally diverse cassane diterpenes named tomocins A-H were isolated from the seed kernels of Vietnamese Caesalpinia sappan Linn. Their structures were determined by extensive NMR and CD spectroscopic analysis. Among the isolated compounds, tomocin A, phanginin A, F, and H exhibited mild preferential cytotoxicity against PANC-1 human pancreatic cancer cells under nutrition-deprived condition without causing toxicity in normal nutrient-rich conditions.

Evaluation of synthetic coumarins for antiausterity cytotoxicity against pancreatic cancers

A series of functionalized coumarins were synthesized and evaluated for their capacity to inhibit the resistance to starvation of pancreatic cancer cells. This form of cytotoxicity, termed 'antiausterity' activity, was evaluated using a preferential cytotoxicity assay that compared cell survival in nutrient poor and nutrient rich conditions. Six of the seventeen compounds showed weak antiausterity activity against PANC-1. Compound 34 was active against PANC-1, MIA PaCa-2, and Capan-1 cancer cell lines. All of the compounds tested were simplified structural analogs of previously reported natural product leads. Six of the compounds, including 34, contain functionalized triazoles as novel potential bioisosteres of the side chain of the natural product angelmarin. Overall, the analogs were found to have low antiausterity activity relative to the corresponding natural products.

Identification of the Factors Responsible for the Selective in vitro Cytotoxic Activity of Isoprenylated Coumarin Derivatives under Nutrient-deprived Conditions

Pancreatic cancer is one of the most devastating forms of human cancer. The lack of effective clinical treatments for pancreatic cancer has led to one of the lowest five-year survival rates among all cancers. Recently, our laboratory has developed a novel series of isoprenylated coumarin derivatives that have exhibited anti-pancreatic cancer activity exclusively under nutrient-deprived conditions. In this study, we report the effect of the various cell culture medium components on the preferential cytotoxicity of our lead isoprenylated coumarin compound against the pancreatic adenocarcinoma cell line PANC-1. In particular, our findings show a clear link between observed cytotoxicity and glucose deprivation, suggesting that our compound targets a salvage pathway when glycolysis is no longer an option for cancer cell survival. The cytotoxicity of our lead compound was also examined in vitro against two other pancreatic cancer cell lines, BxPC-3 and Capan-2 under both nutrient-rich and nutrient-deprived conditions.

Preferentially Cytotoxic Constituents of Andrographis paniculata and their Preferential Cytotoxicity against Human Pancreatic Cancer Cell Lines

In the course of our search for anticancer agents based on a novel anti-austerity strategy, we found that the 70% EtOH extract of the crude drug Andrographis Herba (aerial parts of Andrographis paniculata), used in Japanese Kampo medicines, killed PANC-1 human pancreatic cancer cells preferentially in nutrient-deprived medium (NDM). Phytochemical investigation of the 70% EtOH extract led to the isolation of 21 known compounds consisting of six labdane-type diterpenes (11, 15, 17-19, 21), six flavones (5, 7, 10, 12, 14, 20), three flavanones (2, 6, 16), two sterols (3, 8), a fatty acid (1), a phthalate (4), a triterpene (9), and a monoterpene (13). Among them, 14-deoxy-11,12-didehydroandrographolide (17) displayed the most potent preferential cytotoxicity against PANC-1 and PSN-1 cells with PC50 values of 10.0 μM and 9.27 μM, respectively. Microscopical observation, double staining with ethidium bromide (EB) and acridine orange (AO), and flow cytometry with propidium iodide/annexin V double staining indicated that 14-deoxy-11,12-didehydroandrographolide (17) triggered apoptosis-like cell death in NDM with an amino acids and/or serum-sensitive mode.

Anti-austeritic Constituents of the Congolese Medicinal Plant Aframomum melegueta

In the course of our search for anticancer agents based on a novel anti-austerity strategy, we found that the CHCl3 extract of the roots of Aflamomum melegueta (Zingiberaceae), collected in the Democratic Republic of Congo, killed PANC-1 human pancreatic cancer cells preferentially in nutrient-deprived medium (NDM). Phytochemical investigation of the CHCl3 extract led to the isolation of seven known compounds [(-)-buplerol (1), (-)-arctigenin (2), ( E)-14-hydroxy-15-norlabda-8(17),12-dien-16-al (3), labda-8(17),12-dien-15,16-dial (4), 16-oxo-8(17),12( E)-labdadien-15-oic acid (5), 5-hydroxy-7-methoxyflavone (6), and apigenin (7)]. In addition to the previously reported preferentially cytotoxic compound, (-)-arctigenin (2, PC50 0.5 μM), (-)-buplerol (1) also displayed potent preferential cytotoxicity with a PC50 value of 8.42 pM and triggered apoptosis-like PANC-1 cell death in NDM.

Synthesis and biological evaluation of isoprenylated coumarins as potential anti-pancreatic cancer agents

A series of isoprenylated coumarins has been designed, synthesized, and evaluated against human pancreatic adenocarcinoma cell line PANC-1 under nutrient-rich and nutrient-deprived conditions. The compounds described investigate the effect of isoprenyl chain length and positioning on cell growth inhibition. The majority of these compounds displayed cytotoxicity against PANC-1 cells selectively in the absence of essential amino acids, glucose, and serum, and showed no cytotoxicity under nutrient-rich conditions. In this study, compound 6 exhibited the highest cytotoxic activity with an LC50 value of 4μM and induced apoptosis-like morphological changes in PANC-1 cells after a 24-h incubation. The evaluated structure-activity relationships show that substitution at the 6-position and the presence of a farnesyl isoprenyl tail are important structural features for enhanced preferential cytotoxicity. These findings provide important information to designing other structural analogues for potential application as novel pancreatic antitumor agents.