Cytotoxic mechanism of novel compound jiangxienone from Cordyceps jiangxiensis against cancer cells involving DNA damage response pathway

Jiangxienone is a novel compound recently purified from the traditional Chinese medicinal mushroom Cordyceps jiangxiensis and was reported to show potent cytotoxicity against cancer cells. However, its mechanism of action remains unclear. In this work, the underlying mechanism of jiangxienone against human gastric cancer cells HGC-27 was investigated using whole-genome microarray. The results demonstrated that jiangxienone significantly decreased cell population of various human cancer cell lines, while slightly inhibited the colony formation of stromal cells from murine marrow even at a high concentration. Differential gene expression profiling indicated that the cytotoxic action of jiangxienone against HGC-27 is closely related to the DNA damage response pathway, which was evident by the identification of 23 DNA damage response-associated genes, such as XRCC4/5/6, NBS1, RAD51, and BRCA1/2. By using gel retardation assays, UV absorption spectrometry and single-cell gel electrophoresis, it was found that jiangxienone could bind to DNA and inhibit cancer cell growth. The above results indicated that the cytotoxic mechanism of jiangxienone against cancer cells was involved in the DNA damage response pathway. The findings will be helpful to the development of useful cancer chemopreventive compounds from C. jiangxiensis.     

Cannabinoid receptor signaling in progenitor/stem cell proliferation and differentiation

Cannabinoids, the active components of cannabis (Cannabis sativa) extracts, have attracted the attention of human civilizations for centuries, much earlier than the discovery and characterization of their substrate of action, the endocannabinoid system (ECS). The latter is an ensemble of endogenous lipids, their receptors [in particular type-1 (CB₁) and type-2 (CB₂) cannabinoid receptors] and metabolic enzymes. Cannabinoid signaling regulates cell proliferation, differentiation and survival, with different outcomes depending on the molecular targets and cellular context involved. Cannabinoid receptors are expressed and functional from the very early developmental stages, when they regulate embryonic and trophoblast stem cell survival and differentiation, and thus may affect the formation of manifold adult specialized tissues derived from the three different germ layers (ectoderm, mesoderm and endoderm). In the ectoderm-derived nervous system, both CB₁ and CB₂ receptors are present in neural progenitor/stem cells and control their self-renewal, proliferation and differentiation. CB₁ and CB₂ show opposite patterns of expression, the former increasing and the latter decreasing along neuronal differentiation. Recently, endocannabinoid (eCB) signaling has also been shown to regulate proliferation and differentiation of mesoderm-derived hematopoietic and mesenchymal stem cells, with a key role in determining the formation of several cell types in peripheral tissues, including blood cells, adipocytes, osteoblasts/osteoclasts and epithelial cells. Here, we will review these new findings, which unveil the involvement of eCB signaling in the regulation of progenitor/stem cell fate in the nervous system and in the periphery. The developmental regulation of cannabinoid receptor expression and cellular/subcellular localization, together with their role in progenitor/stem cell biology, may have important implications in human health and disease.     

Promising antibacterial agents against multidrug resistant Staphylococcus aureus

Rapid emergence of multidrug resistant Staphylococcus aureus infections has created a critical health menace universally. Resistance to all the available chemotherapeutics has been on rise which led to WHO to stratify Staphylococcus aureus as high tier priorty II pathogen. Hence, discovery and development of new antibacterial agents with new mode of action is crucial to address the multidrug resistant Staphylococcus aureus infections. The egressing understanding of new antibacterials on their biological target provides opportunities for new therapeutic agents. This review underlines on various aspects of drug design, structure activity relationships (SARs) and mechanism of action of various new antibacterial agents and also covers the recent reports on new antibacterial agents with potent activity against multidrug resistant Staphylococcus aureus. This review provides attention on in vitro and in vivo pharmacological activities of new antibacterial agents in the point of view of drug discovery and development.     

Exploring the antimalarial potential of the methoxy-thiazinoquinone scaffold: Identification of a new lead candidate

A small library of antiplasmodial methoxy-thiazinoquinones, rationally designed on the model of the previously identified hit 1, has been prepared by a simple and inexpensive procedure. The synthetic derivatives have been subjected to in vitro pharmacological screening, including antiplasmodial and toxicity assays. These studies afforded a new lead candidate, compound 9, endowed with higher antiplasmodial potency compared to 1, a good selectivity index when tested against a panel of mammalian cells, no toxicity against RBCs, a synergistic antiplasmodial action in combination with dihydroartemisinin, and a promising inhibitory activity on stage V gametocyte growth. Computational studies provided useful insights into the structural requirements needed for the antiplasmodial activity of thiazinoquinone compounds and on their putative mechanism of action.     

Novel quinazolin-4-one derivatives as potentiating agents of doxorubicin cytotoxicity

We report the design, synthesis and biological evaluation of 17 novel 8-aryl-2-morpholino-3,4-dihydroquinazoline derivatives based on the standard model of DNA-PK and PI3K inhibitors. Novel compounds are sub-divided into two series where the second series of five derivatives was designed to have a better solubility profile over the first one. A combination of in vitro and in silico techniques suggested a plausible synergistic effect with doxorubicin of the most potent compound 14d on cell proliferation via DNA-PK and poly(ADP-ribose) polymerase-1 (PARP-1) inhibition, while alone having a negligible effect on cell proliferation.     

3, 9-di-O-substituted coumestrols incorporating basic amine side chains act as novel apoptosis inducers with improved pharmacological selectivity

There is much interest in the use of phytoestrogens such as coumestrol in breast cancer intervention due to their antiestrogenic activity and multiple modes of tumor cell death. However, the clear beneficial effects of naturally occurring estrogen mimetic coumestrol remain controversial due to experimental evidence that it has been shown to stimulate MCF-7 cell proliferation via agonist effect on estrogen receptor at low concentration. Herein, to disconnect the ER interaction and apoptosis-specific mechanism of coumestrol, various 3, 9-di-O-substituted coumestrols (7a-7e) and their furan ring-opened analogs (5a-5e) were synthesized and assessed for antiproliferative properties. Attachment of a dimethylamine-containing side chain to 3-O of coumestrol led to the most promising compound 7e with improved antiproliferative activity (1.7-fold increase) against MCF-7 cells, decreased estrogen activity (>20 times weaker ERα binder) and a novel action to induce apoptosis. Mechanistic studies revealed that 7e is a tubulin polymerization inhibitor, which could arrest cell cycle at G2/M phase and induce apoptosis along with the decrease of mitochondrial membrane potential. In summary, such subtle modifications to the 3, 9-di-hydroxyl groups of coumestrol allow the generation of a novel apoptosis inducer with distinct pharmacological properties, providing an excellent starting point to future development of novel tumor-vascular disrupting agents targeting tubulin.     

Norepinephrine stimulation of alpha1D-adrenoceptor promotes proliferation of pulmonary artery smooth muscle cells via ERK-1/2 signaling

It has been shown that the sympathetic nervous system is activated in pulmonary arterial hypertension (PAH). Norepinephrine (NE) levels are increased by chemoreflex-dependent sympathetic overactivation and involved in pulmonary vascular remodeling. However, the underlying mechanisms of the remodeling induced by NE are poorly understood. In this study, we found that, in vivo, the expression of tyrosine hydroxylase and the concentration of plasma NE were increased in PAH rats compared with normal rats. Increases in ventricular hypertrophy and medial width of the pulmonary arteries were reversed by prazosin, α₁-adrenoceptor (α₁-AR) antagonists, in PAH rats. Elevated expression of α_1D-AR was detected in PAH rats. In addition, prazosin reduced the increasing expression of PCNA, CyclinA and CyclinE induced by hypoxia. In vitro, MTT assay, flow cytometry, Western blotting and immunofluorescence were performed to investigate the effects of NE on proliferation of pulmonary artery smooth muscle cells (PASMCs). We revealed that NE promoted PASMCs viability, increased the expression of PCNA, CyclinA and CyclinE, made more cells from G₀/G₁ phase to G₂/M + S phase and enhanced the microtubule formation. Above NE-induced changes could be suppressed by BMY 7378, an inhibitor of α_1D-AR. Furthermore, ERK-1/2 pathway was activated by NE. U0126, a specific inhibitor for ERK-1/2, attenuated the NE-induced proliferation of PASMCs under normoxia and hypoxia. Taken together, our results suggest that NE which stimulates α_1D-AR promotes proliferation of PASMCs and the effect is, at least in part, mediated via the ERK-1/2 pathway.     

Stochastic exposure to sub-lethal high temperature enhances exopolysaccharides (EPS) excretion and improves Bifidobacterium bifidum cell survival to freeze–drying

Exposure of microbial cells to sub-lethal stresses is known to increase cell robustness. In this work, a two-compartment bioreactor in which microbial cells are stochastically exposed to sub-lethal temperature stresses has been used in order to investigate the response of the stress sensitive Bifidobacterium bifidum THT 0101 to downstream processing operations. A stochastic model validated by residence time distribution experiments has shown that in the heat-shock configuration, a two-compartment bioreactor (TCB) allows the exposure of microbial cells to sub-lethal temperature of 42 °C for a duration comprised between 100 and 300 s. This exposure resulted in a significant increase of cell resistance to freeze–drying by comparison with cells cultivated in conventional bioreactors or in the TCB in the cold shock mode (CS-TCB). The mechanism behind this robustness seems to be related with the coating of microbial cells with exopolysaccharide (EPS), as assessed by the change of the zeta potential and the presence of higher EPS concentration after heat shock. Conditioning of Bifidobacteria on the basis of the heat shock technique is interesting from the practical and economical point of view since this strategy can be directly implemented in the bioreactor during stationary phase preceding cell recovery and freeze–drying.     

Therapeutic utility of the newly discovered properties of interleukin-21

Since its discovery in 2000, interleukin-21 (IL-21) has been shown to display a broad spectrum of pleiotropic actions including the regulation of development, differentiation and function of lymphoid-myeloid cells. More specifically, IL-21 modulates the effector functions of T, B and NK cells, which not only have key roles in antitumoral and antiviral immunity but also in exerting major effects on inflammatory responses promoting the development of autoimmune diseases. Recent studies have unveiled an unexpected role for IL-21 in immune regulation and de novo T-cell development. While highlighting its critical role in immunity, this review will mainly focus on recent advances in IL-21 biology and how such newly discovered properties could potentially be exploited therapeutically in the establishment of future clinical trials.     

Design,synthesis and biological evaluation of benzoylacrylic acid shikonin ester derivatives as irreversible dual inhibitors of tubulin and EGFR

In this study, a series of shikonin derivatives combined with benzoylacrylic had been designed and synthesized, which showed an inhibitory effect on both tubulin and the epidermal growth factor receptor (EGFR). In vitro EGFR and cell growth inhibition assay demonstrated that compound PMMB-317 exhibited the most potent anti-EGFR (IC₅₀ = 22.7 nM) and anti-proliferation activity (IC₅₀ = 4.37 μM) against A549 cell line, which was comparable to that of Afatinib (EGFR, IC₅₀ = 15.4 nM; A549, IC₅₀ = 6.32 μM). Our results on mechanism research suggested that, PMMB-317 could induce the apoptosis of A549 cells in a dose- and time-dependent manner, along with decrease in mitochondrial membrane potential (MMP), production of ROS and alterations in apoptosis-related protein levels. Also, PMMB-317 could arrest cell cycle at G2/M phase to induce cell apoptosis, and inhibit the EGFR activity through blocking the signal transduction downstream of the mitogen-activated protein MAPK pathway and the anti-apoptotic kinase AKT pathway; typically, such results were comparable to those of afatinib. In addition, PMMB-317 could suppress A549 cell migration through the Wnt/β-catenin signaling pathway in a dose-dependent manner. Additionally, molecular docking simulation revealed that, PMMB-317 could simultaneously combine with EGFR protein (5HG8) and tubulin (1SA0) through various forces. Moreover, 3D-QSAR study was also carried out, which could optimize our compound through the structure-activity relationship analysis. Furthermore, the in vitro and in vivo results had collectively confirmed that PMMB-317 might serve as a promising lead compound to further develop the potential therapeutic anticancer agents.     

Mitochondrial free fatty acid β-oxidation supports oxidative phosphorylation and proliferation in cancer cells

Oxidative phosphorylation (OxPhos) is functional and sustains tumor proliferation in several cancer cell types. To establish whether mitochondrial β-oxidation of free fatty acids (FFAs) contributes to cancer OxPhos functioning, its protein contents and enzyme activities, as well as respiratory rates and electrical membrane potential (ΔΨm) driven by FFA oxidation were assessed in rat AS-30D hepatoma and liver (RLM) mitochondria. Higher protein contents (1.4–3 times) of β-oxidation (CPT1, SCAD) as well as proteins and enzyme activities (1.7–13-times) of Krebs cycle (KC: ICD, 2OGDH, PDH, ME, GA), and respiratory chain (RC: COX) were determined in hepatoma mitochondria vs. RLM. Although increased cholesterol content (9-times vs. RLM) was determined in the hepatoma mitochondrial membranes, FFAs and other NAD-linked substrates were oxidized faster (1.6–6.6 times) by hepatoma mitochondria than RLM, maintaining similar ΔΨm values. The contents of β-oxidation, KC and RC enzymes were also assessed in cells. The mitochondrial enzyme levels in human cervix cancer HeLa and AS-30D cells were higher than those observed in rat hepatocytes whereas in human breast cancer biopsies, CPT1 and SCAD contents were lower than in human breast normal tissue. The presence of CPT1 and SCAD in AS-30D mitochondria and HeLa cells correlated with an active FFA utilization in HeLa cells. Furthermore, the β-oxidation inhibitor perhexiline blocked FFA utilization, OxPhos and proliferation in HeLa and other cancer cells. In conclusion, functional mitochondria supported by FFA β-oxidation are essential for the accelerated cancer cell proliferation and hence anti-β-oxidation therapeutics appears as an alternative promising approach to deter malignant tumor growth.     

Negative regulation of the hepatic fibrogenic response by suppressor of cytokine signaling 1

Suppressor of cytokine signaling 1 (SOCS1) is an indispensable regulator of IFNγ signaling and has been implicated in the regulation of liver fibrosis. However, it is not known whether SOCS1 mediates its anti-fibrotic functions in the liver directly, or via modulating IFNγ, which has been implicated in attenuating hepatic fibrosis. Additionally, it is possible that SOCS1 controls liver fibrosis by regulating hepatic stellate cells (HSC), a key player in fibrogenic response. While the activation pathways of HSCs have been well characterized, the regulatory mechanisms are not yet clear. The goals of this study were to dissociate IFNγ-dependent and SOCS1-mediated regulation of hepatic fibrogenic response, and to elucidate the regulatory functions of SOCS1 in HSC activation. Liver fibrosis was induced in Socs1^−/−Ifng^−/− mice with dimethylnitrosamine or carbon tetrachloride. Ifng^−/− and C57BL/6 mice served as controls. Following fibrogenic treatments, Socs1^−/−Ifng^−/− mice showed elevated serum ALT levels and increased liver fibrosis compared to Ifng^−/− mice. The latter group showed higher ALT levels and fibrosis than C57BL/6 controls. The livers of SOCS1-deficient mice showed bridging fibrosis, which was associated with increased accumulation of myofibroblasts and abundant collagen deposition. SOCS1-deficient livers showed increased expression of genes coding for smooth muscle actin, collagen, and enzymes involved in remodeling the extracellular matrix, namely matrix metalloproteinases and tissue inhibitor of metalloproteinases. Primary HSCs from SOCS1-deficient mice showed increased proliferation in response to growth factors such as HGF, EGF and PDGF, and the fibrotic livers of SOCS1-deficient mice showed increased expression of the Pdgfb gene. Taken together, these data indicate that SOCS1 controls liver fibrosis independently of IFNγ and that part of this regulation may occur via regulating HSC proliferation and limiting growth factor availability.     

Chemically induced degradation of CK2 by proteolysis targeting chimeras based on a ubiquitin–proteasome pathway

As a ubiquitous, highly pleiotropic and constitutively active serine/threonine protein kinase, casein kinase 2 (CK2) is closely associated with tumorigenesis by its overexpression in cancer cells. Here we report several proteolysis targeting chimeras (PROTACs) via “click reaction” to connect a CK2 inhibitor (CX-4945) and pomalidomide for degradation of CK2 protein. Among them, compound 2 degraded CK2 in a dose and time-dependent manner, and kept CK2 at a low basal level by recruiting ubiquitin-proteasome system. The degradation of CK2 resulted in the reduced phosphorylation of Akt and the up-regulation of p53. As a CK2 protein degrader, 2 showed the analogous cytotoxicity to CX-4945 but with a quite different mechanism of action from the CK2 inhibitor, hinting that degradation of CK2 proteins by PROTACs is a potential way for cancer treatments.     

A transcriptional target of androgen receptor,miR-421 regulates proliferation and metabolism of prostate cancer cells

Prostate cancer is one of the most common malignancies, and microRNAs have been recognized to be involved in tumorigenesis of various kinds of cancer including prostate cancer (PCa). Androgen receptor (AR) plays a core role in prostate cancer progression and is responsible for regulation of numerous downstream targets including microRNAs. This study identified an AR-repressed microRNA, miR-421, in prostate cancer. Expression of miR-421 was significantly suppressed by androgen treatment, and correlated to AR expression in different prostate cancer cell lines. Furthermore, androgen-activated AR could directly bind to androgen responsive element (ARE) of miR-421, as predicted by bioinformatics resources and demonstrated by ChIP and luciferase reporter assays. In addition, over-expression of miR-421 markedly supressed cell viability, delayed cell cycle, reduced glycolysis and inhibited migration in prostate cancer cells. According to the result of miR-421 target genes searching, we focused on 4 genes NRAS, PRAME, CUL4B and PFKFB2 based on their involvement in cell proliferation, cell cycle progression and metabolism. The expression of these 4 downstream targets were significantly repressed by miR-421, and the binding sites were verified by luciferase assay. Additionally, we explored the expression of miR-421 and its target genes in human prostate cancer tissues, both in shared microarray data and in our own cohort. Significant differential expression and inverse correlation were found in PCa patients.     

In vitro and ex vivo vanadium antitumor activity in (TGF-β)-induced EMT. Synergistic activity with carboplatin and correlation with tumor metastasis in cancer patients

Epithelial to mesenchymal transition (EMT) plays a key role in tumor progression and metastasis as a crucial event for cancer cells to trigger the metastatic niche. Transforming growth factor-β (TGF-β) has been shown to play an important role as an EMT inducer in various stages of carcinogenesis. Previous reports had shown that antitumor vanadium inhibits the metastatic potential of tumor cells by reducing MMP-2 expression and inducing ROS-dependent apoptosis. However, the role of vanadium in (TGF-β)-induced EMT remains unclear. In the present study, we report for the first time on the inhibitory effects of vanadium on (TGF-β)-mediated EMT followed by down-regulation of ex vivo cancer stem cell markers. The results demonstrate blockage of (TGF-β)-mediated EMT by vanadium and reduction in the mitochondrial potential of tumor cells linked to EMT and cancer metabolism. Furthermore, combination of vanadium and carboplatin (a) resulted in synergistic antitumor activity in ex vivo cell cultures, and (b) prompted G₀/G₁ cell cycle arrest and sensitization of tumor cells to carboplatin-induced apoptosis. Overall, the findings highlight the multifaceted antitumor action of vanadium and its synergistic antitumor efficacy with current chemotherapy drugs, knowledge that could be valuable for targeting cancer cell metabolism and cancer stem cell-mediated metastasis in aggressive chemoresistant tumors.     

Anti-malarial drug artesunate protects against cigarette smoke-induced lung injury in mice

Cigarette smoking is the primary cause of chronic obstructive pulmonary disease (COPD), which is mediated by lung infiltration with inflammatory cells, enhanced oxidative stress, and tissue destruction. Anti-malarial drug artesunate has been shown to possess anti-inflammatory and anti-oxidative actions in mouse asthma models. We hypothesized that artesunate can protect against cigarette smoke-induced acute lung injury via its anti-inflammatory and anti-oxidative properties. Artesunate was given by oral gavage to BALB/c mice daily 2 h before 4% cigarette smoke exposure for 1 h over five consecutive days. Bronchoalveolar lavage (BAL) fluid and lungs were collected for analyses of cytokines, oxidative damage and antioxidant activities. Bronchial epithelial cell BEAS-2B was exposed to cigarette smoke extract (CSE) and used to study the mechanisms of action of artesunate. Artesunate suppressed cigarette smoke-induced increases in BAL fluid total and differential cell counts; levels of IL-1β, MCP-1, IP-10 and KC; and levels of oxidative biomarkers 8-isoprostane, 8-OHdG and 3-nitrotyrosine in a dose-dependent manner. Artesunate promoted anti-oxidant catalase activity and reduced NADPH oxidase 2 (NOX2) protein level in the lungs from cigarette smoke-exposed mice. In BEAS-2B cells, artesunate suppressed pro-inflammatory PI3 K/Akt and p44/42 MAPK signaling pathways, and increased nuclear Nrf2 accumulation in response to CSE. Artesunate possesses anti-inflammatory and anti-oxidative properties against cigarette smoke-induced lung injury, probably via inhibition of PI3K and p42/22 MAPK signaling pathways, augmentation of Nrf2 and catalase activities, and reduction of NOX2 level. Our data suggest that artesunate may have therapeutic potential for treating COPD.     

Interaction of nonsteroidal anti-inflammatory drugs with membranes: In vitro assessment and relevance for their biological actions

Nonsteroidal anti-inflammatory drugs (NSAIDs) are among the most commonly used drugs in the world due to their anti-inflammatory, analgesic and antipyretic properties. Nevertheless, the consumption of these drugs is still associated with the occurrence of a wide spectrum of adverse effects. Regarding the major role of membranes in cellular events, the hypothesis that the biological actions of NSAIDs may be related to their effect at the membrane level has triggered the in vitro assessment of NSAIDs-membrane interactions. The use of membrane mimetic models, cell cultures, a wide range of experimental techniques and molecular dynamics simulations has been providing significant information about drugs partition and location within membranes and also about their effect on diverse membrane properties. These studies have indeed been providing evidences that the effect of NSAIDs at membrane level may be an additional mechanism of action and toxicity of NSAIDs. In fact, the pharmacokinetic properties of NSAIDs are closely related to the ability of these drugs to interact and overcome biological membranes. Moreover, the therapeutic actions of NSAIDs may also result from the indirect inhibition of cyclooxygenase due to the disturbing effect of NSAIDs on membrane properties. Furthermore, increasing evidences suggest that the disordering effects of these drugs on membranes may be in the basis of the NSAIDs-induced toxicity in diverse organ systems. Overall, the study of NSAIDs-membrane interactions has proved to be not only important for the better understanding of their pharmacological actions, but also for the rational development of new approaches to overcome NSAIDs adverse effects.     

Effect of piceatannol-rich passion fruit seed extract on human glyoxalase I–mediated cancer cell growth

Passion fruit seed extract (PFSE), a product rich in stilbenes such as piceatannol and scirpusin B, has various physiological effects. It is unclear whether PFSE and its stilbene derivatives inhibit cancer cell proliferation via human glyoxalase I (GLO I), the rate-limiting enzyme for detoxification of methylglyoxal. We examined the anticancer effects of PFSE in two types of human cancer cell lines with different GLO I expression levels, NCI–H522 cells (highly-expressed GLO I) and HCT116 cells (lowly-expressed GLO I). PFSE and its stilbenes inhibited GLO I activity. In addition, PFSE and its stilbenes supressed the cancer cell proliferation of NCI–H522 cells more than HCT116 cells. These observations suggest that PFSE can provide a novel anticancer strategy for prevention and treatment.