Mechanisms underlying the cytotoxic effect of propolis on human laryngeal epidermoid carcinoma cells

Propolis has been used as a traditional remedy for centuries because of its beneficial effects, including anticancer properties. The aim of this study was to compare the cytotoxic mechanism of Cuban red propolis (CP) and Brazilian green propolis (BP) on human laryngeal carcinoma (HEp-2) cells. Cell viability, leakage of lactate dehydrogenase, fluorescence staining, mitochondrial membrane potential (ΔΨm) and the expression of pro/anti-apoptotic genes were assessed. Cell viability and cytotoxic assays suggested a dose-dependent effect of CP and BP extracts with a possible association of intracellular reactive oxygen species production and decreased ΔΨm. Both samples induced apoptosis via activation of TP53, CASP3, BAX, P21 signalling, and downregulation of BCL2 and BCL-XL. CP exerted a higher cytotoxic effect than BP extract. Our findings suggest further investigation of the main components of each propolis sample, what may lead to the development of strategies for the treatment of laryngeal cancer.     

A New Anthraquinone and Two New Tetrahydroanthraquinones from the Roots of Prismatomeris connata

A new anthraquinone, 4‐hydroxy‐1,2,3‐trimethoxy‐6‐methylanthracene‐9,10‐dione ( 1 ), and two novel tetrahydroanthraquinones, prisconnatanones A and B ( 2 and 3 , resp.), together with 15 known anthraquinones, 4 – 18 , were isolated from the roots of Prismatomeris connata. Their structures were elucidated on the basis of spectroscopic data. Compounds 1 – 18 were evaluated for their cytotoxicity against A549 and LAC human cancer cell lines. Compound 2 and the anthraquinones with free OH groups exhibited activity against the test cell lines.     

AMP kinase/cyclooxygenase-2 pathway regulates proliferation and apoptosis of cancer cells treated with quercetin

AMPK (AMP-activated protein kinase) is highly conserved in eukaryotes, where it functions primarily as a sensor of cellular energy status. Recent studies indicate that AMPK activation strongly suppresses cell proliferation in non-malignant cells as well as in tumor cells. In this study, quercetin activated AMPK in MCF breast cancer cell lines and HT-29 colon cancer cells, and this activation of AMPK seemed to be closely related to a decrease in COX-2 expression. The application of a COX-2 inhibitor or cox-2^-/- cells supported the idea that AMPK is an upstream signal of COX-2, and is required for the anti-proliferatory and pro-apoptotic effects of quercetin. The suppressive or growth inhibitory effects of quercetin on COX-2 were abolished by treating cancer cells with an AMPK inhibitor Compound C. These results suggest that AMPK is crucial to the anti-cancer effect of quercetin and that the AMPK-COX-2 signaling pathway is important in quercetin-mediated cancer control.     

Soluble mediators from mesenchymal stem cells suppress T cell proliferation by inducing IL-10

Mesenchymal stem cells (MSCs) can inhibit T cell proliferation; however, the underlying mechanisms are not clear. In this study, we investigated the mechanisms of the immunoregulatory activity of MSCs on T cells. Irradiated MSCs co-cultured with either naïve or pre-activated T cells in a mixed lymphocyte reaction (MLR) significantly suppressed T cell proliferation in a dose-dependent manner, irrespective of allogeneic disparity between responders and MSCs. Transwell assays revealed that the suppressive effect was primarily mediated by soluble factors that induced apoptosis. Splenocytes stimulated with alloantigen in the presence of the MSC culture supernatant (CS) produced a significant amount of IL-10, which was attributed to an increase in the number of IL-10 secreting cells, confirmed by an ELISPOT assay. The blockade of IL-10 and IL-10 receptor interaction by anti-IL-10 or anti-IL-10-receptor antibodies abrogated the suppressive capacity of MSC CS, indicating that IL-10 plays a major role in the suppression of T cell proliferation. The addition of 1-methyl-DL-tryptophan (1-MT), an indoleamine 2,3-dioxygenase (IDO) inhibitor, also restored the proliferative capacity of T cells. In conclusion, we demonstrated that soluble mediators from culture supernatant of MSCs could suppress the proliferation of both naïve and pre-activated T cells in which IL-10 and IDO play important roles.     

Characterization,selenylation, and antineoplastic effects on HepG2 cells in vitro and in vivo of an arabinofuranan from the fruits of Akebia quinata

Akebia quinata is a traditional medicinal plant distributed in East Asia and its fruits are applicated in food and pharmaceutical fields. Herein, a novel polysaccharide (AQP70-2A) with a molecular weight of 1.49 × 10⁴ Da was isolated from the fruits of A. quinata. Results of the chemical and spectroscopic analysis indicated that AQP70-2A was an arabinofuranan with a backbone mainly consisting of → 5)-α-l-Araf-(1→, →3,5)-α-l-Araf-(1→, and → 2,3,5)-α-l-Araf-(1→, and it also contained two types of branch chains. At the cellular level, AQP70-2A did not show significant antitumor properties, while selenylation significantly made the inhibitory effect of this natural macromolecule on HepG2 cells to be increased. Furthermore, the zebrafish xenograft model confirmed that selenized polysaccharide Se-AQP70-2A effectively blocked hepatocellular carcinoma cells invasion and metastasis. Meanwhile, the inhibition of Se-AQP70-2A on development of intersegmental vessels revealed its antiangiogenic activity.     

A new flavonol triglycoside derived from Anoectochilus elwesii on stimulating glucose uptake in insulin-induced human HepG2 cells

A novel flavonol triglycoside (4), isorhamnetin-3-O-β-d-glucopyranosyl (1→2)-α-l-rhamnopyranosyl (1→6)-β-d-glucopyranoside, named elwesoside A, together with six known flavonols (1–3, 5–7) was isolated from Anoectochilus elwesii (Clarke ex Hook. f.) King et Pantl. and its structure was elucidated by extensive spectroscopic methods and comparison with the literature data. All compounds were first reported in this plant and two of them (4 and 5) were the first examples of flavonol triglycosides isolated from Anoectochilus genus. The effects of 1–7 were evaluated on insulin-treated human HepG2 cells under high glucose conditions for stimulating glucose uptake activities. The novel compound (4) displayed highly potent dose-dependent effect on the stimulation of glucose uptake in insulin-resistant human HepG2 cells.     

Perisomalien A,a new cytotoxic scalarane sesterterpene from the fruits of Periploca somaliensis

Abstract

The CHCl₃ fraction of MeOH extract of Periploca somaliensis (family Asclepiadaceae) fruits afforded a new scalarane sesterterpene, namely perisomalien A (1), along with lupeol acetate (2), β-amyrin (3), cycloart-23Z-ene-3β,25-diol (4), and β-sitosterol-3-O-β-D-glucopyranoside (5). Their chemical structures were established by various spectroscopic analyses, in addition to comparison with the formerly reported data. Moreover, the cytotoxic activity of these metabolites was assessed towards MCF-7, HepG2, and HCT-116 tumour cell lines using sulforhodamine B (SRB) assay. Compound 4 showed the most potent cytotoxic profile with IC₅₀ 9.0?µM towards MCF-7, compared to doxorubicin (IC₅₀ 0.18?µM). Also, 1 and 4 possessed the most potent effect towards HepG2 with IC₅₀s 26.7 and 25.9?μM, respectively. In addition, all tested compounds showed cytotoxic effects with IC₅₀ values ranging from 19.9 to 39.3?µM against HCT-116.     

In vitro induction of anterior gradient-2-specific cytotoxic T lymphocytes by dendritic cells transduced with recombinant adenoviruses as a potential therapy for colorectal cancer

Anterior gradient-2 (AGR2) promotes tumor growth, cell migration, and cellular transformation, and is one of the specific mRNA markers for circulating tumor cells in patients with gastrointestinal cancer. We investigated the feasibility of AGR2 as a potent antigen for tumor immunotherapy against colorectal cancer (CRC) cells using dendritic cells (DCs) transduced with a recombinant adenovirus harboring the AGR2 gene (AdAGR2). DCs transduced with a recombinant adenovirus encoding the AGR2 gene (AdAGR2/DCs) were characterized. These genetically-modified DCs expressed AGR2 mRNA as well as AGR2 protein at a multiplicity of infection of 1,000 without any significant alterations in DC viability and cytokine secretion (IL-10 and IL-12p70) compared with unmodified DCs as a control. In addition, AdAGR2 transduction did not impair DC maturation, but enhanced expression of HLA-DR, CD80, and CD86. AdAGR2/DCs augmented the number of IFN-γ-secreting T-cells and elicited potent AGR2-specific cytotoxic T lymphocytes capable of lysing AGR2-expressing CRC cell lines. These results suggest that AGR2 act as a potentially important antigen for immunotherapy against CRC in clinical applications.     

Ajuforrestin A,an Abietane Diterpenoid from Ajuga ovalifolia var. calanthe,Induces A549 Cell Apoptosis by Targeting SHP2

The Src-homology 2 domain-containing phosphatase 2 (SHP2), which is encoded by PTPN11, participates in many cellular signaling pathways and is closely related to various tumorigenesis. Inhibition of the abnormal activity of SHP2 by small molecules is an important part of cancer treatment. Here, three abietane diterpenoids, named compounds 1–3, were isolated from Ajuga ovalifolia var. calantha. Spectroscopic analysis was used to identify the exact structure of the compounds. The enzymatic kinetic experiment and the cellular thermal shift assay showed compound 2 selectively inhibited SHP2 activity in vitro. Molecular docking indicated compound 2 targeted the SHP2 catalytic domain. The predicted pharmacokinetic properties by SwissADME revealed that compound 2 passed the majority of the parameters of common drug discovery rules. Compound 2 restrained A549 proliferation (IC₅₀ = 8.68 ± 0.96 μM), invasion and caused A549 cell apoptosis by inhibiting the SHP2–ERK/AKT signaling pathway. Finally, compound 2 (Ajuforrestin A) is a potent and efficacious SHP2 inhibitor and may be a promising compound for human lung epithelial cancer treatment.     

Selective addition of CXCR3+CCR4-CD4+ Th1 cells enhances generation of cytotoxic T cells by dendritic cells in vitro

Increasing importance is being given to the stimulation of Th1 response in cancer immunotherapy because its presence can shift the direction of adaptive immune responses toward protective immunity. Based on chemokine receptor expression, CXCR3⁺CCR4^-CD4⁺ T cells as Th1-type cells were investigated its capacity in monocyte-derived dendritic cell (DC) maturation and polarization, and induction of antigen specific cytotoxic T lymphocytes (CTL) in vitro. The levels of IL-4, IL-5 and IL-10 were decreased to the basal level compared with high production of IFN-γ, TNF-α, and IL-2 in CXCR3⁺CCR4^-CD4⁺ T cells stimulated with anti-CD3 and anti-CD28 antibodies. Co-incubation of activated CD4⁺ or CXCR3⁺CCR4^-CD4⁺ T cells with DC (CD4⁺/DC or CXCR3⁺CD4⁺/DC, respectively) particularly up-regulated IL-12 and CD80 expression compared with DC matured with TNF-α and LPS (mDC). Although there was no significant difference between the effects of the CXCR3⁺CCR4^-CD4⁺ and CD4⁺ T cells on DC phenotype expression, CXCR3⁺CD4⁺/DC in CTL culture were able to expand number of CD8⁺ T cells and increased frequencies of IFN-γ secreting cells and overall cytolytic activity against tumor antigen WT-1. These results demonstrated that the selective addition of CXCR3⁺CCR4^-CD4⁺ T cells to CTL cultures could enhance the induction of CTLs by DC in vitro, and implicated on a novel strategy for adoptive T cell therapy.     

In vivo evaluation of CYP1A2, CYP2A6, NAT-2 and xanthine oxidase activities in a Greek population sample by the RP-HPLC monitoring of caffeine metabolic ratios

A RP-HPLC method was developed for the assessment of caffeine and its metabolites in urine and was used for the evaluation of the CYP1A2, CYP2A6, xanthine oxidase (XO) and N-acetyl-transferase-2 (NAT-2) in vivo activities in 44 Greek volunteers (21 men, 23 women). Spot urine samples were analyzed 6 h after 200 mg caffeine consumption, following a 30 h methylxantine-free diet. The major urinary caffeine metabolites are 1-methyluric acid (1U), 5-acetylamino-6-formylamino-3-methyluracil (AFMU), 1-methylxanthine (1X), 1,7-dimethyluric acid (17U) and 1,7-dimethylxanthine (17X). CYP1A2, CYP2A6, XO and NAT-2 activities were estimated from the metabolic ratios (AFMU + 1U + 1X)/17U, 17U/17X, 1U/(1X + 1U) and AFMU/(AFMU + 1U + 1X), respectively. Metabolites and internal standard were extracted with chloroform/isopropanol (85:15, v/v) and separated on a C18 column by an isocratic HPLC system using a two-step elution with manual switch from solvent A (0.1% acetic acid-methanol-acetonitrile, 92:4:5 v/v) to solvent B (0.1% acetic acid-methanol, 60:40, v/v), and detected at 280 nm. The method exhibited adequate metabolite separation (resolution factors >1.48), accuracy (94.1-106.3%) and intraday and interday precision <8.02 and <8.78%, respectively (n = 6). Smoking affected only CYP1A2, whereas gender had no effect in any enzyme activity. NAT-2 exhibited bimodal distribution, 63.6% of volunteers being slow acetylators. The developed RP-HPLC method was fully validated and successfully applied for the evaluation of CYP1A2, CYP2A6, XO and NAT-2 activities.     

Pyrazine based Pt(II) bis‐alkynyl organometallic complexes: Synthesis,characterization, and cytotoxic effect on A549 human lung carcinoma cells

A facile and efficient synthesis of a series of five new pyrazine‐based organometallic complexes is being reported. The complexes ( 2 – 6 ) have been fully characterized. Molecules 2 , 3 and 6 were structurally characterized by single crystal X‐ray crystallographic analyses. Additionally, anticancer properties of these organometallic complexes have been studied against A549 human lung carcinoma cells. Biological studies suggest that complex 5 (with pendant pyridine moieties) exhibited maximal growth inhibitory cytotoxic effect even at lower concentration (nearly 0.5–1 μM) whereas the other four compounds ( 2 , 3 , 4 and 6 ) were non‐toxic below 1 μM concentration. Two complexes ( 4 and 6) were effective only at higher doses (approx 30 μM) while the remaining two organometallic complexes ( 2 and 3) were able to inhibit 50% cell growth at slightly lower concentration (nearly 10 μM). As far as IC₅₀ is concerned, 5 exhibited a minimum value ranging between 3–5 μM which is comparable with cisplatin under similar conditions.     

Valtrate from Valeriana jatamansi Jones induces apoptosis and inhibits migration of human breast cancer cells in vitro

Abstract

Valtrate is a principle compound isolated from Valeriana jatamansi Jones, a traditional Chinese folk medicine originally used to treat various nervous disorders. Here, we found that valtrate exhibited significant anti-cancer activity in vitro, especially in human breast cancer cells, while displayed relatively low cytotoxicity to normal human breast epithelial cells (MCF 10A). Valtrate induced cell cycle arrest at G2/M stage and apoptosis in MDA-MB-231 and MCF-7 cells, with reduced expression of p-Akt (Ser 473), cyclin B1 and caspase 8, and increased expression of p21, p-cdc2, cleaved-caspase 3, cleaved-caspase 7 and poly (ADP-ribose) polymerase (PARP). In addition, valtrate inhibited cell migration through down-regulation of MMP-9 and MMP-2 expression. These results demonstrate that valtrate possesses anti-breast cancer activities via cell cycle arrest, apoptosis, and inhibition of cell migration, thus supporting valtrate as a potential antitumor agent.     

Callyptide A,a new cytotoxic peptide from the Red Sea marine sponge Callyspongia species

In the course of our continuing efforts to allocate bioactive secondary metabolites from Red Sea marine invertebrates, we have investigated the sponge Callyspongia species. The cytotoxic dichloromethane fraction of the methanolic extract of the sponge afforded a new cytotoxic peptide named callyptide A (1). Its structure was determined by extensive 1D and 2D NMR (COSY, HSQC and HMBC) studies and high-resolution mass spectral determination. The configuration of the amino acids was determined by Marfey’s analysis. Callyptide A was found to exhibit growth inhibitory activity when tested against different cancer cell lines.     

Accumulation of argpyrimidine, a methylglyoxal-derived advanced glycation end product, increases apoptosis of lens epithelial cells both in vitro and in vivo

The formation of advanced glycation end products (AGEs) has been considered to be a potential causative factor of injury to lens epithelial cells (LECs). Damage of LECs is believed to contribute to cataract formation. The purpose of this study was to investigate the cytotoxic effect of AGEs on LECs both in vitro and in vivo. We examined the accumulation of argpyrimidine, a methylglyoxal-derived AGE, and the expression of apoptosis-related molecules including nuclear factor- kappaB (NF-κB), Bax, and Bcl-2 in the human LEC line HLE-B3 and in cataractous lenses of Zucker diabetic fatty (ZDF) rats, an animal model of type 2 diabetes. In cataractous lenses from twenty-oneweek- old ZDF rats, LEC apoptosis was markedly increased, and the accumulation of argpyrimidine as well as subsequent activation of NF-κB in LECs were significantly enhanced. The ratio of Bax to Bcl-2 protein levels was also increased. In addition, the accumulation of argpyrimidine triggered apoptosis in methylglyoxal- treated HLE-B3 cells. However, the presence of pyridoxamine (an AGEs inhibitor) and pyrrolidine dithiocarbamate (a NF-κB inhibitor) prevented apoptosis in HLE-B3 cells through the inhibition of argpyrimidine formation and the blockage of NF-κB nuclear translocalization, respectively. These results suggest that the cellular accumulation of argpyrimidine in LECs is NF-κB-dependent and pro-apoptotic.     

Thromboxane A2 modulates migration, proliferation, and differentiation of adipose tissue-derived mesenchymal stem cells

Prostanoid metabolites are key mediators in inflammatory responses, and accumulating evidence suggests that mesenchymal stem cells (MSCs) can be recruited to injured or inflamed tissues. In the present study, we investigated whether prostanoid metabolites can regulate migration, proliferation, and differentiation potentials of MSCs. We demonstrated herein that the stable thromboxane A₂ (TxA₂) mimetic U46619 strongly stimulated migration and proliferation of human adipose tissue-derived MSCs (hADSCs). Furthermore, U46619 treatment increased expression of α-smooth muscle actin (α-SMA), a smooth muscle marker, in hADSCs, suggesting differentiation of hADSCs into smooth muscle-like cells. U46619 activated ERK and p38 MAPK, and pretreatment of the cells with the MEK inhibitor U0126 or the p38 MAPK inhibitor SB202190 abrogated the U46619-induced migration, proliferation, and α-SMA expression. These results suggest that TxA₂ plays a key role in the migration, proliferation, and differentiation of hADSCs into smooth muscle-like cells through signaling mechanisms involving ERK and p38 MAPK.     

Stereoselective total synthesis of arenastatin A, a spongean cytotoxic depsipeptide

A highly stereoselective total synthesis of arenastatin A, an extremely potent cytotoxic cyclic depsipeptide from marine sponge, was developed. The desired 7,8-β-epoxide in arenastatin A was constructed by asymmetric sulfur ylide-mediated epoxidation in good yield and highly stereoselective manner.     

Metabolomic profile and in vitro evaluation of the cytotoxic activity of Asphodelus microcarpus against human malignant melanoma cells A375

Melanoma is a huge worldwide health problem that must be handled more effectively with better therapeutic options. As a result, new treatment drugs are required to treat this condition. The goal of this study was to investigate the cytotoxic activity of the anthraquinone-rich fractions obtained from Asphodelus microcarpus against human melanoma cell A375. On these melanoma cell lines; the cytotoxicity of these fractions had never been studied before. Liquid chromatography linked to mass spectrometry (LC-MS-MS) and Nuclear Magnetic Resonance was used to determine the chemical profiles of these fractions. The cytotoxicity of the fractions studied was determined by measuring cell viability and calculating IC₅₀ values. Both ethyl acetate (EtOAC) and the precipitate fractions (PPT) exhibited selective cytotoxicity on human melanoma A 375 cell line with IC₅₀ values of 83 and 65 µg/mL, respectively. The antiproliferative properties of EtOAc fraction and PPT were supported by a noticeable decrease in cell numbers during the G2/M cell cycle arrest. Our findings suggest that the anthraquinone content of A. microcarpus tubers is responsible for its anti-proliferative and apoptotic properties and that further in vivo investigations should be conducted to establish the viability of using them to treat human melanomas.