Emerging Anti-Mitotic Activities and Other Bioactivities of Sesquiterpene Compounds upon Human Cells

An anti-mitotic compound, (+)-6-tuliposide A, isolated from the Canadian glacier lily, Erythronium grandiflorum

The Canadian prairie ecosystem is subjected to abiotic and biotic conditions that induce plants to produce secondary metabolites that affect mammalian physiology. Extracts prepared from certain plant species native to Canadian prairie and montane cordillera ecosystems have previously been shown to have anti-mitotic activity on human cancer cell lines. In this study, we investigated the glacier lily, Erythronium grandiflorum (Liliaceae), in which the species was the most phylogenetically distant from Asteraceae and had anti-mitotic activity. When added to cell lines, E. grandiflorum extracts induced rounded cell morphology and arrested cells in the G2/M phase of the cell cycle. Of the cells that displayed a rounded phenotype, all were positive for phospho-histone H3 and contained a distorted mitotic spindle. This anti-mitotic activity was distinct from that of the compound colchicine, which has been previously isolated from the Liliaceae family. By biology-guided fractionation, we isolated the natural product (+)-6-tuliposide A and are the first to report its anti-mitotic activity. These results reveal a chemical motif in secondary metabolites and expand the range of Canadian prairie plants with anti-mitotic activity that can become new scientific tools or used in the development of anti-proliferative medicines.

Effects of Sesquiterpene Lactones on Primary Cilia Formation (Ciliogenesis)

Sesquiterpene lactones (SLs), plant-derived metabolites with broad spectra of biological effects, including anti-tumor and anti-inflammatory, hold promise for drug development. Primary cilia, organelles extending from cell surfaces, are crucial for sensing and transducing extracellular signals essential for cell differentiation and proliferation. Their life cycle is linked to the cell cycle, as cilia assemble in non-dividing cells of G0/G1 phases and disassemble before entering mitosis. Abnormalities in both primary cilia (non-motile cilia) and motile cilia structure or function are associated with developmental disorders (ciliopathies), heart disease, and cancer. However, the impact of SLs on primary cilia remains unknown. This study evaluated the effects of selected SLs (grosheimin, costunolide, and three cyclocostunolides) on primary cilia biogenesis and stability in human retinal pigment epithelial (RPE) cells. Confocal fluorescence microscopy was employed to analyze the effects on primary cilia formation (ciliogenesis), primary cilia length, and stability. The effects on cell proliferation were evaluated by flow cytometry. All SLs disrupted primary cilia formation in the early stages of ciliogenesis, irrespective of starvation conditions or cytochalasin-D treatment, with no effect on cilia length or cell cycle progression. Interestingly, grosheimin stabilized and promoted primary cilia formation under cilia homeostasis and elongation treatment conditions. Thus, SLs have potential as novel drugs for ciliopathies and tumor treatment.

Aroma Difference Analysis of Partridge Tea (Mallotus oblongifolius) with Different Drying Treatments Based on HS-SPME-GC-MS Technique

Partridge tea has high medicinal value due to its rich content of terpenoids, phenols, flavonoids, and other related bioactive components. In order to study the best drying method for partridge tea, four treatments, including outdoor sun drying (OD), indoor shade drying (ID), hot-air drying (HAD), and low-temperature freeze-drying (LTD), were performed. The results showed that the OD and HAD treatments favored the retention of the red color of their products, while the ID and LTD treatments were more favorable for the retention of the green color. The HS-SPME-GC-MS results showed that a total of 82 compounds were identified in the four drying treatments of partridge tea, and the most abundant compounds were terpenoids (88.34-89.92%). The HAD-treated tea had the highest terpenoid content (89.92%) and high levels of flavor compounds typical of partridge tea (52.28%). OPLS-DA and PCA showed that α-copaene, β-bourbonene, caryophyllene, α-guaiene, and δ-cadinene could be considered candidate marker compounds for judging the aroma quality of partridge tea with different drying treatments. This study will not only provide a basis for processing and flavor quality control but also for spice and seasoning product development in partridge tea.

An In Vitro and In Vivo Assessment of Antitumor Activity of Extracts Derived from Three Well-Known Plant Species

One of the objectives of this study consists of the assessment of the antitumor activity of several extracts from three selected plant species: Xanthium spinosum L., Trifolium pratense L., and Coffea arabica L. and also a comparative study of this biological activity, with the aim of establishing a superior herbal extract for antitumor benefits. The phytochemical profile of the extracts was established by HPLC-MS analysis. Further, the selected extracts were screened in vitro for their antitumor activity and antioxidant potential on two cancer cell lines: A549-human lung adenocarcinoma and T47D-KBluc-human breast carcinoma and on normal cells. One extract per plant was selected for in vivo assessment of antitumor activity in an Ehrlich ascites mouse model. The extracts presented high content of antitumor compounds such as caffeoylquinic acids in the case of X. spinosum L. (7.22 µg/mL-xanthatin, 4.611 µg/mL-4-O-caffeoylquinic acid) and green coffee beans (10.008 µg/mL-cafestol, 265.507 µg/mL-4-O-caffeoylquinic acid), as well as isoflavones in the case of T. pratense L. (6806.60 ng/mL-ononin, 102.78 µg/mL-biochanin A). Concerning the in vitro results, the X. spinosum L. extracts presented the strongest anticancerous and antioxidant effects. In vivo, ascites cell viability decreased after T. pratense L. and green coffee bean extracts administration, whereas the oxidative stress reduction potential was important in tumor samples after T. pratense L. Cell viability was also decreased after administration of cyclophosphamide associated with X. spinosum L. and T. pratense L. extracts, respectively. These results suggested that T. pratense L. or X. spinosum L. extracts in combination with chemotherapy can induce lipid peroxidation in tumor cells and decrease the tumor viability especially, T. pratense L. extract.

Influences of Different Extraction Techniques and Their Respective Parameters on the Phytochemical Profile and Biological Activities of Xanthium spinosum L. Extracts

The aim of this study was to identify possible influences of extraction methods as well as extraction parameters on the phytochemical and biological profiles of Xanthium spinosum L. extracts. Extraction methods were chosen as follows: classical methods, maceration and Soxhlet extraction; innovative extraction methods, turboextraction, ultrasound-assisted extraction, and a combination of the latter two. Extracts were subjected to total polyphenolic and flavonoid content spectrophotometric analysis. The phytochemical profile was determined for the best-yielding extracts using HPLC-MS analysis. Following the newly acquired data, another sorting of the extracts was performed. Biological activities such as antimicrobial and anti-inflammatory actions were evaluated, as well as oxidative stress reduction potential, on a Wistar rats inflammation model. Comparable results were achieved with Soxhlet extraction and ultrasound-assisted extraction, both surpassing all other tested methods in terms of yields. Bioactive compound concentrations tended to increase with the increase in extraction time and temperature. These maximal values lowered once the degradation points of the bioactive compounds were reached. Extracts demonstrated good protection against Gram-negative bacteria. Additionally, they provided good cellular protection and increased the antioxidant defense in the analyzed rat plantar tissue.

Anticancer mechanism of 7-α-hydroxyfrullanolide on microtubules and computational prediction of its target binding in triple-negative breast cancer cells

Background

Triple-negative breast cancer (TNBC) responds poorly to the available drugs; thus, the mortality rate associated with TNBC remains high. 7-α-Hydroxyfrullanolide (7HF) possesses anticancer properties and arrests cells in the G2/M-phase via modulation of several proteins involved in the G2/M-phase transition, as well as the mitotic checkpoint in MDA-MB-468 (TNBC) cells. Microtubules (MTs) dynamically regulate cell division in the G2/M phase and are related to cancer cell stress response. However, antimitotic drug cytotoxicity to multiple cancer resistance developed in response to drugs are obstacles faced to date. Here, the activity and mechanism via which 7HF controls MTs dynamics was investigated in MDA-MB-468 cells.

Methods

7HF uptake by MDA-MB-468 cells was assessed using spectrophotometry. The drug-like properties of 7HF were predicted using the Swiss-absorption, distribution, metabolism, and excretion (ADME) webtool. Then, the effect of 7HF treatment (6, 12, and 24 µM) on the dynamic arrangement of MTs was assessed for 1, 12, and 24 h using indirect immunofluorescence. Polymerization of α- and β-tubulin was assessed using different 7HF concentrations in a cell-free system for 1 h. Cell proliferation assay with bromodeoxyuridine plus propidium iodide staining and flow cytometry was performed at different 7HF concentrations and time points. The mechanism of action was assessed by detecting the expression of proteins, including Bub3, cyclin B1, p-Cdk1 (Tyr15), Rb, p-Rb (Ser780), Chk1, p-Chk1 (Ser345), Chk2, p-Chk2 (Ser516), and p-H2AX (Ser139), using western blotting. Molecular docking was used to predict the molecular interactions between 7HF and tubulins in MTs.

Results

We observed that 7HF was able to enter the MDA-MB-468 cells. The ADME webtool analysis predicted that it possesses the high passive permeation and gastrointestinal absorption properties of drugs. Various concentrations of 7HF disrupted the dynamic arrangement of spindle MTs by causing radial spindle array shrinkage and expansion of fibrous spindle density and radial array lengths in a time-dependent manner. 7HF reduced polymerization of α-, β-tubulin in dose-dependent manner. 7HF also triggered DNA damage response by inducing G2/M and G1 phase arrests in a concentration and time-dependent manner, which occurred due to the upregulation of Bub3, Chk1, p-Chk1 (Ser345), p-Cdk1 (Tyr15), and cyclin B1. According to molecular docking analysis, 7HF preferred to bind to β-tubulin over α-tubulin. The lactone, ketone, and hydroxyl groups of 7HF supported the 7HF-tubulin interactions. Hydrogen bonding with a hydrocarbon ring and salt bridge attractive forces were responsible for the binding versatility of 7HF.

Conclusions

This is the first study to investigate the molecular mechanism, MTs interacting sites, and the internalization and drug-like properties of 7HF in TNBC cells. The findings will be useful for developing 7HF-based treatment for patients with TNBC.

Pulchelloid A, a sesquiterpene lactone from the Canadian prairie plant Gaillardia aristata inhibits mitosis in human cells

BACKGROUND

The Canadian prairie ecosystem presents a rich source of natural products from plants that are subjected to herbivory by grazing mammals. This type of ecological competition may contribute to the production of natural products of interest in cell biology and medical research. We provide the first biological description of the sesquiterpene lactone, pulchelloid A, which we isolated from the prairie plant, Gaillardia aristata (Asteraceae) and report that it inhibits mitosis in human cells.

METHODS AND RESULTS

We found that G. aristata (Blanket flower) extracts were cytotoxic to human cell lines and used phenotypic assays to characterize the bioactivity of extracts. Before dying, cells were characterized by a rounded morphology, phospho-histone H3 signals, mitotic spindles, and active Cdk1. By biology-guided fractionation of Gaillardia extracts, we isolated a sesquiterpene lactone named pulchelloid A. We used immunofluorescence microscopy and observed that cells treated with pulchelloid A have phospho-histone H3 positive chromosomes and a mitotic spindle, confirming that they were in mitosis. Treated cells arrest with an unusual phenotype; they enter a prolonged mitotic arrest in which the spindles become multipolar and the chromosomes acquire histone γH2AX foci, a hallmark of damaged DNA.

CONCLUSIONS

We propose that pulchelloid A, a natural product present in the prairie plant Gaillardia aristata, delays cells in mitosis. There is a growing body of evidence that a small number of members of the sesquiterpene lactone chemical family may target proteins that regulate mitosis.

Isolation of a natural product with anti-mitotic activity from a toxic Canadian prairie plant

We are investigating plants from the prairie ecological zone of Canada to identify natural products that inhibit mitosis in cancer cells. Investigation of plant parts from the Canadian plant species Hymenoxys richardsonii (Asteraceae) revealed that leaf extracts (PP-360A) had anti-mitotic activity on human cancer cell lines. Cells treated with leaf extracts acquired a rounded morphology, similar to that of cells in mitosis. We demonstrated that the rounded cells contained mitotic spindles and phospho-histone H3 using the techniques of immunofluorescence microscopy. By biology-guided fractionation of H. richardsonii leaves, we isolated a sesquiterpene lactone named hymenoratin, which had not been previously assigned a biological activity. Cells treated with hymenoratin have phospho-histone H3 positive chromosomes, a mitotic spindle, and enter a prolonged mitotic arrest in which the spindles become distorted. By Western blot analysis, hymenoratin treated cells acquire high levels of cyclin B and dephosphorylated Cdk1. There is a growing body of evidence that select members of the sesquiterpene lactone chemical family have anti-mitotic activity.

Cyathus striatus Extract Induces Apoptosis in Human Pancreatic Cancer Cells and Inhibits Xenograft Tumor Growth In Vivo

Simple Summary

The main aim of the present study is to test the effect of Cyathus striatus extract on the cell growth of human pancreatic cancer cells in vitro and in vivo. In addition, the effect of the extract on the gene expression was detected. The results indicated that Cyathus striatus extract significantly inhibited the cell viability and induced apoptosis. The treatment of xenograft mice harboring human pancreatic cancer cells significantly inhibited tumor growth through the induction of apoptosis. RNAseq experiments revealed the involvement of the MAPK and P53 signaling pathways and pointed toward endoplasmic reticulum stress induced apoptosis. These results may suggest that Cyathus striatus extract may contain pro-apoptotic factors that can be identified and used for the treatment of human cancer.

Abstract

Pancreatic cancer is a highly lethal disease with limited options for effective therapy and the lowest survival rate of all cancer forms. Therefore, a new, effective strategy for cancer treatment is in need. Previously, we found that a culture liquid extract of Cyathus striatus (CS) has a potent antitumor activity. In the present study, we aimed to investigate the effects of Cyathus striatus extract (CSE) on the growth of pancreatic cancer cells, both in vitro and in vivo. The proliferation assay (XTT), cell cycle analysis, Annexin/PI staining and TUNEL assay confirmed the inhibition of cell growth and induction of apoptosis by CSE. A Western blot analysis demonstrated the involvement of both the extrinsic and intrinsic apoptosis pathways. In addition, a RNAseq analysis revealed the involvement of the MAPK and P53 signaling pathways and pointed toward endoplasmic reticulum stress induced apoptosis. The anticancer activity of the CSE was also demonstrated in mice harboring pancreatic cancer cell line-derived tumor xenografts when CSE was given for 5 weeks by weekly IV injections. Our findings suggest that CSE could potentially be useful as a new strategy for treating pancreatic cancer.

Cytotoxic Activity of Germacrane-Type Sesquiterpene Lactones from Dimerostemma aspilioides

The need for effective candidates as cytotoxic drugs that at the same time challenge cancer multidrug resistance encouraged a search for these in plants of central Argentina. Bioassay-guided fractionation of the cytotoxic extract from Dimerostemma aspilioides led to the isolation of the germacranolide tomenphantin A (1), along with three new analogues (2-4). These efficiently inhibited the proliferation of the leukemia cell lines K562 and CCRF-CEM and their resistant variants, Lucena 1 and CEM/ADR5000, respectively, with IC₅₀ values ranging from 0.40 to 7.7 μM. The structures and relative configurations of compounds 1-4 were elucidated by analysis of the spectroscopic data, in particular NMR spectroscopy. The most active among these was compound 1 (IC₅₀ = 0.40-5.1 μM), and, therefore, this was selected as a model for a mechanistic study, which revealed that its antiproliferative effect was mediated by cell cycle arrest in the G₂/M phase followed by apoptosis. The activity of compound 1 was selective, given the absence of cytotoxicity toward peripheral blood mononuclear cells. The results show the potential of these compounds, and in particular of compound 1, as leads for the development of drug candidates to fight sensitive and resistant leukemia cells.

Applications of Sesquiterpene Lactones: A Review of Some Potential Success Cases

Sesquiterpene lactones, a vast range of terpenoids isolated from Asteraceae species, exhibit a broad spectrum of biological effects and several of them are already commercially available, such as artemisinin. Here the most recent and impactful results of in vivo, preclinical and clinical studies involving a selection of ten sesquiterpene lactones (alantolactone, arglabin, costunolide, cynaropicrin, helenalin, inuviscolide, lactucin, parthenolide, thapsigargin and tomentosin) are presented and discussed, along with some of their derivatives. In the authors’ opinion, these compounds have been neglected compared to others, although they could be of great use in developing important new pharmaceutical products. The selected sesquiterpenes show promising anticancer and anti-inflammatory effects, acting on various targets. Moreover, they exhibit antifungal, anxiolytic, analgesic, and antitrypanosomal activities. Several studies discussed here clearly show the potential that some of them have in combination therapy, as sensitizing agents to facilitate and enhance the action of drugs in clinical use. The derivatives show greater pharmacological value since they have better pharmacokinetics, stability, potency, and/or selectivity. All these natural terpenoids and their derivatives exhibit properties that invite further research by the scientific community.

Tricarabrols A–C, three anti-inflammatory sesquiterpene lactone trimers featuring a methylene-tethered linkage from Carpesium faberi

Three anti-inflammatory trimeric compounds constructed from carabrol-type sesquiterpenoids through a methylene-tethered linkage were characterized from Carpesium faberi.

MCC1019, a selective inhibitor of the Polo-box domain of Polo-like kinase 1 as novel, potent anticancer candidate

Polo-like kinase (PLK1) has been identified as a potential target for cancer treatment. Although a number of small molecules have been investigated as PLK1 inhibitors, many of which showed limited selectivity. PLK1 harbors a regulatory domain, the Polo box domain (PBD), which has a key regulatory function for kinase activity and substrate recognition. We report on 3-bromomethyl-benzofuran-2-carboxylic acid ethyl ester (designated: MCC1019) as selective PLK1 inhibitor targeting PLK1 PBD. Cytotoxicity and fluorescence polarization-based screening were applied to a library of 1162 drug-like compounds to identify potential inhibitors of PLK1 PBD. The activity of compound MC1019 against the PLK1 PBD was confirmed using fluorescence polarization and microscale thermophoresis. This compound exerted specificity towards PLK1 over PLK2 and PLK3. MCC1019 showed cytotoxic activity in a panel of different cancer cell lines. Mechanistic investigations in A549 lung adenocarcinoma cells revealed that MCC1019 induced cell growth inhibition through inactivation of AKT signaling pathway, it also induced prolonged mitotic arrest—a phenomenon known as mitotic catastrophe, which is followed by immediate cell death via apoptosis and necroptosis. MCC1019 significantly inhibited tumor growth in vivo in a murine lung cancer model without affecting body weight or vital organ size, and reduced the growth of metastatic lesions in the lung. We propose MCC1019 as promising anti-cancer drug candidate.

Isolation of a New Sesquiterpene Lactone From Vernonia Zeylanica (L) Less and its Anti-Proliferative Effects in Breast Cancer Cell Lines

Background/Objective:

Vernonia zeylanica (L) less is an endemic plant to Sri Lanka. The present study was designed to isolate potential cytotoxic compound/s from chloroform and ethyl acetate extracts of V. zeylanica by bio-activity guided isolation and to evaluate its anti-proliferative effects in three breast cancer phenotypes (MCF -7, MDA-MB-231, SKBR-3).

Methods:

Combined chloroform and ethyl acetate extracts were subjected to chromatographic separations to isolate a compound (1) and the structure of the isolated compound was elucidated using 1H, 13C and mass spectroscopic techniques. Cytotoxic effects of the compound were evaluated by the sulforhodamine B (SRB) and the MTT (3- (4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assays. Effects of the compound on apoptosis were evaluated by fluorescent microscopy, caspase 3/7 activation, DNA fragmentation and real time PCR. Effects of the compound on the expression of heat shock protein complex were also evaluated by real time PCR and immunofluorescence.

Results:

Isolated compound was identified as a new sesquiterpene lactone (vernolactone). The compound mediated significant cytotoxic effects in SKBR-3 and MDA-MB-231 breast cancer cells, with little effect in MCF-7 and normal mammary epithelial MCF-10A cells. Morphological changes, DNA fragmentation, increased caspase 3/7 activities and up-regulation of p53, Bax and down regulation of Survivin confirmed the proapoptotic effects of the compound. Significant inhibition of HSP complex related genes were also observed in SKBR-3 and MDA-MB-231 breast cancer cells.

Conclusion:

Overall results indicate that vernolactone can mediate its cytotoxic effects via apoptosis and modulating the HSP complex.

Brevilin A Induces Cell Cycle Arrest and Apoptosis in Nasopharyngeal Carcinoma

Nasopharyngeal carcinoma (NPC) is one of the most common malignant cancers in Southeast Asia and Southern China. Centipeda minima extract (CME) had previously demonstrated anti-cancer effects in human NPC. Brevilin A, a sesquiterpene lactone isolated from C. minima, has been reported to exhibit biological activities. In this study, we investigated its anti-NPC effect and further explored its molecular mechanisms. The effects of brevilin A were tested in the NPC cell lines CNE-1, CNE-2, SUNE-1, HONE1, and C666-1. Effects of brevilin A on cell viability were determined by MTT assay, and cell cycle and apoptosis were detected by flow cytometry. The molecular mechanism of cell cycle regulation and apoptosis were investigated via Western blot. Results showed that brevilin A inhibited NPC cell viability in a concentration- and time-dependent manner. Brevilin A induced cell cycle arrest at G2/M and induced apoptosis. Western blot results demonstrated that brevilin A could down-regulate cyclin D3, cdc2, p-PI3K, p-AKT, p-mTOR, and p-STAT3, while up-regulating cleaved PARP, cleaved caspase 9, and Bax. Regulation of cyclin B1, cdk6, and Bcl-2 expression by brevilin A showed dynamic changes according to dose and time. In the tumor xenograft model, brevilin A could reduce tumor growth, at a similar magnitude to cisplatin. However, notably, whereas cisplatin treatment led to significant weight loss in treated mice, treatment with brevilin A did not, indicating its relative lack of toxicity. Taken together, brevilin A regulated cell cycle, activated the caspase signaling pathway, and inhibited PI3K/AKT/mTOR and STAT3 signaling pathways in vitro, and exhibited similar efficacy to the common chemotherapeutic cisplatin in vivo, without its associated toxicity. These findings provide a framework for the preclinical development of brevilin A as a chemotherapeutic for NPC.

Arnicolide D, from the herb Centipeda minima, Is a Therapeutic Candidate against Nasopharyngeal Carcinoma

Nasopharyngeal carcinoma (NPC) is a high morbidity and mortality cancer with an obvious racial and geographic bias, particularly endemic to Southeast China. Our previous studies demonstrated that Centipeda minima extract (CME) exhibited anti-cancer effects in human NPC cell lines. Arnicolide C and arnicolide D are sesquiterpene lactones isolated from Centipeda minima. In this study, for the first time, we investigated their anti-NPC effects and further explored the related molecular mechanisms. The effects of both arnicolide C and arnicolide D were tested in NPC cells CNE-1, CNE-2, SUNE-1, HONE1, and C666-1. The results showed that the two compounds inhibited NPC cell viability in a concentration- and time-dependent manner. As the inhibitory effect of arnicolide D was the more pronounced of the two, our following studies focused on this compound. Arnicolide D could induce cell cycle arrest at G₂/M, and induce cell apoptosis. The molecular mechanism of cell cycle regulation and apoptosis induction was investigated, and the results showed that arnicolide D could downregulate cyclin D3, cdc2, p-PI3K, p-AKT, p-mTOR, and p-STAT3, and upregulate cleaved PARP, cleaved caspase 9, and Bax. Regulation of cyclin B1, cdk6, and Bcl-2 expression by arnicolide D showed dynamic changes according to dose and time. Taken together, arnicolide D modulated the cell cycle, activated the caspase signaling pathway, and inhibited the PI3K/AKT/mTOR and STAT3 signaling pathways. These findings provide a solid base of evidence for arnicolide D as a lead compound for further development, and act as proof for the viability of drug development from traditional Chinese medicines.

Uncovering the pharmacological response of novel sesquiterpene derivatives that differentially alter gene expression and modulate the cell cycle in cancer cells

The present study aimed to assess the pharmacological anticancer profile of three natural and five synthetic sesquiterpenes developed by total chemical synthesis. To this end, their properties at the cellular and molecular level were evaluated in a panel of normal and cancer cell lines. The results obtained by performing cytotoxicity assays and gene expression analysis by reverse transcription-quantitative polymerase chain reaction showed that: i) Among the sesquiterpene derivatives analyzed, VDS58 exhibited a notable anticancer profile within attached (U-87 MG and MCF-7) and suspension (K562 and MEL-745) cancer cell cultures; however, U-87 MG cells were able to recover their proliferation capacity rapidly after 48 h of exposure; ii) gene expression profiling of U-87 MG cells, in contrast to K562 cells, showed a transient induction of cyclin-dependent kinase inhibitor 1A (CDKN1) expression; iii) the expression levels of transforming growth factor β1 (TGFB1) increased after 12 h of exposure of U-87 MG cells to VDS58 and were maintained at this level throughout the treatment period; iv) in K562 cells exposed to VDS58, TGFB1 expression levels were upregulated for 48 h and decrease afterwards; and v) the re-addition of VDS58 in U-87 MG cultures pretreated with VDS58 resulted in a notable increase in the expression of caspases (CASP3 and CASP9), BCL2‑associated agonist of cell death (BAD), cyclin D1, CDK6, CDKN1, MYC proto-oncogene bHLH transcription factor (MYC), TGFB1 and tumor suppressor protein p53. This upregulation persisted only for 24 h for the majority of genes, as afterwards, only the expression of TGFB1 and MYC was maintained at high levels. Through bioinformatic pathway analysis of RNA-Seq data of parental U-87 MG and K562 cells, substantial variation was reported in the expression profiles of the genes involved in the regulation of the cell cycle. This was associated with the differential pharmacological profiles observed in the same cells exposed to VDS58. Overall, the data presented in this study provide novel insights into the molecular mechanisms of action of sesquiterpene derivatives by dysregulating the expression levels of genes associated with the cell cycle of cancer cells.

β-Bourbonene attenuates proliferation and induces apoptosis of prostate cancer cells

Sesquiterpenes have antitumor, anti-inflammation, and anti-fungal effects. β-bourbonene is a kind of sesquiterpene, but its pharmacological effect has not been studied. The present study was conducted in order to investigate the potential anticancer effects of β-bourbonene on human prostate cancer PC-3M cells. PC-3M cells were incubated with 0, 25, 50, 100 µg/ml of β-bourbonene. Cell Counting Kit-8 (CCK-8) detection showed that compared with the control group, β-bourbonene inhibited the growth of PC-3M cells in a dose-dependent manner. G0/G1 phase arrest was observed by β-bourbonene by using flow cytometry. TUNEL staining and Annexin V/PI dual-staining method revealed that apoptosis was found in cells with β-bourbonene treatment, and the quantity of apoptotic cells was increased with the elevation in concentration. The mRNA and protein expression levels of Fas and FasL in the drug-treatment group were significantly elevated. Furthermore, the western blot assay also indicated that with an increase in the concentration of β-bourbonene, the protein expression of Bax in the drug-treatment group was significantly elevated, while a decrease was identified in the protein expression of Bcl-2. Taken together, β-bourbonene can inhibit the proliferation and simultaneously, induce apoptosis and G0/G1 arrest of prostate cancer PC-3M cells, which may be realized by upregulation of mRNA expression of Fas and FasL, increase of Bax protein expression and decrease of Bcl-2 protein expression.

Application of sesquiterpene lactone: A new promising way for cancer therapy based on anticancer activity

Cancer is one of the most dangerous diseases that are rapidly increasing globally. After heart disease, it is the second leading cause of death, accounting for seven million deaths each year. Chemotherapy is the use of cytotoxic drugs on cancer cells. But the use of common chemotherapy drugs poses a problem due their high side effects and low efficacy. As a result, efforts are on to find new potent compounds with low side effects. The compounds extracted from plants have been studied in this regard due to their prevalence. Sesquiterpene lactones are a group of natural compounds that were first detected in Asteraceae dark plants. These compounds exercise their effects by reacting with functional groups available on proteins and enzymes, especially the thiol group. Owing to the high side effects as an antitumor synthetic drugs, efforts are being made to find drugs with high efficiency and low side effects. Their high structural ranges have attracted the attention of many researchers as a potential source of new anticancer drugs.

Pseudoguaianolides: Recent Advances in Synthesis and Applications

Pseudoguaianolides belong to the class of sesquiterpene lactones and are characterized by the lactone ring cis or trans-anellated (in 6,7- or 7,8- position) to fused seven- and five-membered rings; they differ from guaianolides for the position of the methyl group in 5. The unusual tricyclic fused core 5/7/5 was a challenge and inspired new synthetic methodologies to install substituents with proper stereochemistry. Despite their potential of application in different fields, their exploitation is so far very limited. Because of this, with this review we wanted to give perspectives in terms of availability and resupply of the most active compounds of the class.