Phytochemicals from Vanda bensonii and Their Bioactivities to Inhibit Growth and Metastasis of Non-Small Cell Lung Cancer Cells

The most prevalent lung cancer is non-small cell lung cancer (NSCLC). This lung cancer type often develops other organ-specific metastases that are critical burdens in the treatment process. Orchid species in the genus Vanda have shown their potential in folkloric medication of diverse diseases but not all its species have been investigated, and little is known about their anticancer activities against NSCLC. Here, we firstly profiled the specialized metabolites of Vanda bensonii and examined their capability to inhibit growth and metastasis of NSCLC using NCI-H460 cells as a study model. Four phytochemicals, including phloretic acid methyl ester (1), cymbinodin-A (2), ephemeranthoquinone B (3), and protocatechuic acid (4), were isolated from the whole plant methanolic extract of V. bensonii. The most distinguished cytotoxic effect on NCI-H460 cells was observed in the treatments with crude methanolic extract and compound 2 with the half maximal inhibitory concentrations of 40.39 µg mL−1 and 50.82 µM, respectively. At non-cytotoxic doses (10 µg mL−1 or 10 µM), only compound 1 could significantly limit NCI-H460 cell proliferation when treated for 48 h, while others excluding compound 4 showed significant reduction in cell proliferation after treating for 72 h. Compound 1 also significantly decreased the migration rate of NCI-H460 cells examined through a wound-healing assay. Additionally, the crude extract and compound 1 strongly affected survival and growth of NCI-H460 cells under anchorage-independent conditions. Our findings proved that natural products from V. bensonii could be promising candidates for the future pharmacotherapy of NSCLC.

Stimulation of adenosine A1 receptor prevents oxidative injury in H9c2 cardiomyoblasts: Role of Gßγ-mediated Akt and ERK1/2 signaling.

Oxidative stress causes cellular injury and damage in the heart primarily through apoptosis resulting in cardiac abnormalities such as heart failure and cardiomyopathy. During oxidative stress, stimulation of adenosine receptor (AR) has been shown to protect against oxidative damage due to their cytoprotective properties. However, the subtype specificity and signal transductions of adenosine A1 receptor (A1R) on cardiac protection during oxidative stress have remained elusive. In this study, we found that stimulation of A1Rs with N6-cyclopentyladenosine (CPA), a specific A1R agonist, attenuated the H2O2-induced intracellular and mitochondrial reactive oxygen species (ROS) production and apoptosis. In addition, A1R stimulation upregulated the synthesis of antioxidant enzymes (catalase and GPx-1), antiapoptotic proteins (Bcl-2 and Bcl-xL), and mitochondria-related markers (UCP2 and UCP3). Blockades of Gßγ subunit of heterotrimeric Gαi protein antagonized A1R-mediated antioxidant and antiapoptotic effects, confirming the potential role of Gßγ subunit-mediated A1R signaling. Additionally, cardioprotective effects of CPA mediated through PI3K/Akt- and ERK1/2-dependent signaling pathways. Thus, we propose that A1R represents a promising therapeutic target for prevention of oxidative injury in the heart.

Cardioprotective Effects of Glucagon-like Peptide-1 (9-36) Against Oxidative Injury in H9c2 Cardiomyoblasts: Potential Role of the PI3K/Akt/NOS Pathway.

ABSTRACT: Glucagon-like peptide (GLP)-1(7-36), a major active form of GLP-1 hormone, is rapidly cleaved by dipeptidyl peptidase-4 to generate a truncated metabolite, GLP-1(9-36) which has a low affinity for GLP-1 receptor (GLP-1R). GLP-1(7-36) has been shown to have protective effects on cardiovascular system through GLP-1R-dependent pathway. Nevertheless, the cardioprotective effects of GLP-1(9-36) have not fully understood. The present study investigated the effects of GLP-1(9-36), including its underlying mechanisms against oxidative stress and apoptosis in H9c2 cells. Here, we reported that GLP-1(9-36) protects H9c2 cardiomyoblasts from hydrogen peroxide (H2O2)-induced oxidative stress by promoting the synthesis of antioxidant enzymes, glutathione peroxidase-1, catalase, and heme oxygenase-1. In addition, treatment with GLP-1(9-36) suppressed H2O2-induced apoptosis by attenuating caspase-3 activity and upregulating antiapoptotic proteins, Bcl-2 and Bcl-xL. These protective effects of GLP-1(9-36) are attenuated by blockade of PI3K-mediated Akt phosphorylation and prevention of nitric oxide synthase-induced nitric oxide production. Thus, GLP-1(9-36) represents the potential therapeutic target for prevention of oxidative stress and apoptosis in the heart via PI3K/Akt/nitric oxide synthase signaling pathway.

Stimulation of GLP-1 Receptor Inhibits Methylglyoxal-Induced Mitochondrial Dysfunctions in H9c2 Cardiomyoblasts: Potential Role of Epac/PI3K/Akt Pathway.

Accumulation of methylglyoxal (MG) contributes to oxidative stress, apoptosis, and mitochondrial dysfunction, leading to the development of type 2 diabetes and cardiovascular diseases. Inhibition of mitochondrial abnormalities induced by MG in the heart may improve and delay the progression of heart failure. Although glucagon-like peptide-1 receptor (GLP-1R) agonists have been used as anti-diabetic drugs and GLP-1R has been detected in the heart, the cardioprotective effects of GLP-1R agonists on the inhibition of MG-induced oxidative stress and mitochondrial abnormalities have not been elucidated. Stimulation of GLP-1Rs leads to cAMP elevation and subsequently activates PKA- and/or Epac-dependent signaling pathway. However, the signaling pathway involved in the prevention of MG-induced mitochondrial dysfunctions in the heart has not been clarified so far. In the present study, we demonstrated that stimulation of GLP-1Rs with exendin-4 inhibited MG-induced intracellular and mitochondrial reactive oxygen species (ROS) production and apoptosis in H9c2 cardiomyoblasts. GLP-1R stimulation also improved the alterations of mitochondrial membrane potential (MMP) and expressions of genes related to mitochondrial functions and dynamics induced by MG. In addition, stimulation of GLP-1R exhibits antioxidant and antiapoptotic effects as well as the improvement of mitochondrial functions through cAMP/Epac/PI3K/Akt signaling pathway in H9c2 cells. Our study is the first work demonstrating a novel signaling pathway for cardioprotective effects of GLP-1R agonist on inhibition of oxidative stress and prevention of mitochondrial dysfunction. Thus, GLP-1R agonist represents a potential therapeutic target for inhibition of oxidative stress and modulation of mitochondrial functions in the heart.

Pharmacological effects of Chatuphalatika in hyperuricemia of gout.

CONTEXT: Chatuphalatika (CTPT), is a Thai herbal formulation mixture of Phyllanthus emblica Linn. (Euphorbiaceae), Terminalia belerica Linn. (Combretaceae), T. chebula and the fruit of T. arjuna (Roxb.) Wight & Arn. CTPT is considered to exert anti-inflammatory and antihyperuricemic effects, but there have been no reports to demonstrate these pharmacological effects in a quantitative manner. OBJECTIVES: To investigate the antioxidative, anti-inflammatory and antihyperuricemic effects of CTPT. MATERIALS AND METHODS: Antioxidant activities of CTPT extracts were measured in vitro by DPPH, ABTS and FRAP assays, and anti-inflammatory effect by measuring inflammatory mediator production induced by lipopolysaccharide (LPS) in RAW264.7 macrophages. The mechanism of the hypouricemic effect was investigated using oxonate-induced hyperuricemic ddY mice treated with oral administrations of CTPT at 250, 500 and 1000 mg/kg. RESULTS: Antioxidant activities of CTPT measured by ABTS and FRAP assays were 1.35 g TEAC/g extract and 10.3 mmol/100 g extract, respectively. IC50 for the inhibition of DPPH radical was 13.8 µg/mL. CTPT (10 µg/mL) significantly downregulated the mRNA expression of TNF-α and iNOS in RAW 264.7 cells. Lineweaver-Burk analysis of the enzyme kinetics showed that CTPT inhibited xanthine oxidase (XOD) activity in a noncompetitive manner with the Ki of 576.9 µg/mL. Oral administration of CTPT (1000 mg/kg) significantly suppressed uric acid production by inhibiting hepatic XOD activity, and decreased plasma uric acid levels in hyperuricemic mice by approximately 40% (p < 0.05). CONCLUSIONS: This study demonstrated for the first time the antioxidative, anti-inflammatory and antihyperuricemic effects of CTPT in vivo and in vitro, suggesting a possibility of using CTPT for the treatment of hyperuricemia in gout.

Sustained ß-AR stimulation induces synthesis and secretion of growth factors in cardiac myocytes that affect on cardiac fibroblast activation.

Paracrine factors, including growth factors and cytokines, released from cardiac myocytes following ß-adrenergic receptor (ß-AR) stimulation regulate cardiac fibroblasts. Activated cardiac fibroblasts have the ability to increase collagen synthesis, cell proliferation and myofibroblast differentiation, leading to cardiac fibrosis. However, it is unknown which ß-AR subtypes and signaling pathways mediate the upregulation of paracrine factors in cardiac myocytes. In this study, we demonstrated that sustained stimulation of ß-ARs significantly induced synthesis and secretion of growth factors, including connective tissue growth factor (CTGF) and vascular endothelial growth factor (VEGF), via the cAMP-dependent and protein kinase A (PKA)-dependent pathways. In addition, isoproterenol (ISO)-mediated synthesis and secretion of CTGF and VEGF through the ß1-AR and ß2-AR subtypes. Paracrine factors released by cardiac myocytes following sustained ß-AR stimulation are necessary for the induction of cell proliferation and synthesis of collagen I, collagen III and α-smooth muscle actin (α-SMA) in cardiac fibroblasts, confirming that ß-AR overstimulation of cardiac myocytes induces cardiac fibrosis by releasing several paracrine factors. These effects can be antagonized by ß-blockers, including atenolol, metoprolol, and propranolol. Thus, the use of ß-blockers may have beneficial effects on the treatment of myocardial fibrosis in patients with heart failure.