European Journal of Pharmacology (v.658, #1)

Mycophenolic acid induces adipocyte-like differentiation and reversal of malignancy of breast cancer cells partly through PPARγ by Zhi-Hui Zheng; Yi Yang; Xin-Hua Lu; Hua Zhang; Xiao-Xi Shui; Chen Liu; Xiao-Bo He; Qin Jiang; Bao-Hua Zhao; Shu-Yi Si (1-8).
Mycophenolic acid (MPA) has been known for decades to be an anticancer and immunosuppressive agent and has significant anticancer properties, but its underlying molecular mechanisms are poorly characterized. Peroxisome proliferator-activated receptor gamma (PPARγ) has a central role in adipocyte differentiation, and MPA has been shown to be a potent PPARγ agonist. Whether PPARγ activation has a putative role in the anticancer efficacy of MPA via induction of adipocyte-like differentiation has not been elucidated. In the present study, MPA was demonstrated to dose-dependently activate PPARγ transcription in the GAL4-hPPARγ (LBD) chimeric receptor assay and PPRE-luc reporter gene assay with an EC50 of 5.2–9.3 μM. Treatment of the breast cancer cell lines MDA-MB-231 and MCF-7 with MPA resulted in differentiation of adipose tissue that was characterized by accumulation of intracellular lipids, enlargement of cell volume, and permanent withdrawal from the cell cycle at the G1/G0 stage. At a molecular level, the expression of three adipocyte differentiation markers (PPARγ, adipsin D, and aP2) was remarkably induced in differentiated breast cancer cells. However, RNA interference experiments showed that PPARγ-knockdown cannot completely reverse the differentiated state of MDA-MB-231 cells after MPA treatment. These data suggest that the effects of MPA on adipocyte-like terminal differentiation of breast cancer cells are (at least in part) due to PPARγ activation, which is a novel anticancer mechanism of MPA.
Keywords: Mycophenolic acid; PPARγ; Breast cancer; Adipocyte differentiation; Lipid accumulation; RNAi;

2′,4′,6′-Tris(methoxymethoxy) chalcone induces apoptosis by enhancing Fas-ligand in activated hepatic stellate cells by Sung Hee Lee; Yu-Zhe Zhao; Eun-Jeon Park; Xian-Hua Che; Geom Seog Seo; Dong Hwan Sohn (9-15).
Suppression of hepatic stellate cell (HSC) activation and proliferation, and induction of apoptosis in activated HSCs have been proposed as therapeutic strategies for the treatment and prevention of the hepatic fibrosis. We previously showed that 2′,4′,6′-tris(methoxymethoxy) chalcone (TMMC), a synthesized chalcone derivative, inhibits platelet-derived growth factor-induced HSC proliferation at 5–20 μM. Here, we showed that TMMC induces apoptosis in activated HSCs at higher concentrations (30–50 μM), but is not cytotoxic to primary hepatocytes. Moreover, TMMC induces hyperacetylation of histone by inhibiting histone deacetylase (HDAC) in activated HSCs. Interestingly, TMMC treatment remarkably increased Fas-ligand (FasL) mRNA expression in a dose-dependent manner. Cycloheximide treatment reversed the induction of TMMC on apoptosis, indicating that de novo protein synthesis was required for TMMC-induced apoptosis in activated HSCs. In addition, FasL synthesis by TMMC is closely associated with maximal procaspase-3 proteolytic processing. In vivo, TMMC reduced activated HSCs in CCl4-intoxicated rats during liver injury recovery, as demonstrated by α-smooth muscle actin expression in rat liver. TMMC treatment also resulted in apoptosis, as demonstrated by cleavage of poly(ADP-ribose) polymerase in rat liver. In conclusion, TMMC may have therapeutic potential by inducing HSC apoptosis for the treatment of hepatic fibrosis.
Keywords: 2′,4′,6′-Tris(methoxymethoxy) chalcone; Hepatic stellate cell; Apoptosis; HDAC inhibitor; Fas-ligand; Hepatic fibrosis;

Intraventricular administration of neuropeptide S has reward-like effects by Junran Cao; Luis de Lecea; Satoshi Ikemoto (16-21).
Neuropeptide S (NPS) is an endogenous brain peptide produced by neurons located in the lower brainstem, and functional studies suggest that NPS has arousing effects. Because its receptors are found in reward-associated regions throughout the brain, we evaluated whether intraventricular NPS injections elicit reward-related effects in rats. Rats increased lever presses that led to intraventricular administration of NPS (0.34–34 pmol per infusion) in a dose dependent manner, with a cue-assisted procedure. Cue-assisted self-administration of NPS was decreased by systemic administration of the dopamine receptor antagonist SCH 23390 (0.025 mg/kg, i.p.) or the hypocretin-1 (orexin-1) receptor antagonist SB 334867 (20 mg/kg, i.p.). In addition, intraventricular NPS injections (1000 pmol) induced conditioned place preference, whereas a lower dose (100 pmol) of NPS induced conditioned place aversion. Finally, NPS injections (100–1000 pmol) acutely facilitated locomotor activity, whereas repeated NPS injections did not lead to locomotor sensitization. Our data suggest that intraventricular NPS injections have reward-like effects in that NPS weakly facilitates seeking and induces positive reinforcement. These effects may depend on intact dopamine and hypocretin systems.
Keywords: Self-administration; Place conditioning; Locomotion; Neuropeptide S; SB 334867; SCH 23390;

Inhibition of activated ERK1/2 and JNKs improves vascular function in mouse aortae in the absence of nitric oxide by Indranil Bhattacharya; Marlen Damjanović; Ana Perez Dominguez; Elvira Haas (22-27).
Activation of mitogen-activated protein kinases (MAPKs) is important for vascular contraction. Decreased nitric oxide availability combined with activation of MAPKs contributes to an increase in vascular tone. In this study, we have determined the involvement of extracellular signal-regulated kinases1/2 (ERK1/2) and c-Jun N-terminal kinases (JNKs) in reactivity of mouse aortae in the absence of nitric oxide. Additionally, we have examined the contribution of these kinases to endothelium-dependent and prostaglandin F (PGF)-induced contractions. Precontracted aortic rings were treated with MAPK/ERK kinase1/2 (MEK1/2) inhibitor U0126 or JNKs inhibitor SP600125 to determine reactivity after inhibition of nitric oxide synthase using organ bath chambers. Additionally, rings were pretreated with or without these inhibitors to assess PGF- and acetylcholine-induced, endothelium-dependent contractions. Specificity of the inhibitors was evaluated in each aortic ring by determining the phosphorylation levels of ERK1/2 and c-Jun using Bio-Plex™ phospho-protein detection kit. In the absence of nitric oxide both inhibitors caused relaxation, and the dilator response was increased by 2.5-fold using SP600125 in comparison with U0126. Transient endothelium-dependent contractions were blocked by U0126, whereas SP600125 strongly attenuated sustained PGF-induced contractions. U0126 inhibited only phosphorylation of ERK1/2, while SP600125 at higher concentrations not only inhibited phosphorylation of c-Jun but also ERK1/2 phosphorylation. In conclusion, the present study demonstrates that in aortae inhibition of activated ERK1/2 and JNKs mediates vascular relaxation, even in the absence of nitric oxide. Activation of ERK1/2 contributes predominantly to transient endothelium-dependent contractions while JNKs, possibly synergistically with ERK1/2, leads to sustained PGF-induced contractions.
Keywords: Endothelium-dependent contractions; Mitogen-activated protein kinase; Thoracic aorta; Nitric oxide; Hypertension;

Glutamine treatment attenuates the development of organ injury induced by zymosan administration in mice by Stefania Mondello; Maria Galuppo; Emanuela Mazzon; Domenico Italiano; Patrizia Mondello; Carmela Aloisi; Salvatore Cuzzocrea (28-40).
Glutamine is the most abundant amino acid in the bloodstream. It is important in nucleotide synthesis, is anti-catabolic, has anti-oxidant properties via metabolism to glutathione, may enhance immune responsiveness and possesses immunoregulatory functions. Moreover, it reduces atrophy of intestinal mucosa in animals on total parenteral nutrition and prevents intestinal mucosal injury accompanying small bowel transplantation, chemotherapy and radiation. In the present study, we investigated the effects of glutamine on development of non-septic shock caused by zymosan. Mice received either zymosan (500 mg/kg, administered i.p., as a suspension in saline) or vehicle (saline). Glutamine (1.5 mg/kg i.p.) was administered 1 and 6 h after zymosan administration. Organ failure and systemic inflammation in mice were assessed 18 h after administration of zymosan and/or glutamine. Glutamine-treatment reduced the peritoneal exudation and the migration of polymorphonuclear cells caused by zymosan-injection and also attenuated the pancreatic and gut injury. Inflammatory and apoptotic parameters were evaluated to better investigate the effects of the glutamine-administration. So, by immunohistochemical analysis and in vitro assays, we have clearly showed that glutamine reduces: 1) the histological damage in pancreas and gut; 2) the inducible nitric oxide synthase expression; 3) nitrotyrosine and poly (ADP-ribose) formation; 4) TNF-α and IL-1β tissue and plasma levels; 5) FasL localization; and 6) alteration of the balance between Bax and Bcl-2. In addition, at the end of the observation period (7 days), zymosan causes severe illness in the mice characterized by a systemic toxicity, significant loss of body weight and mortality. Glutamine-treatment significantly reduced all these parameters.
Keywords: Zymosan-induced multiple organ failure; Glutamine; Inflammation; Cytokine; Apoptosis;

Therapeutic utility of bone marrow transplantation in diabetes is an attractive approach. However, the oxidative stress generated by hyperglycemia may hinder β-cell regeneration. The present study was undertaken to investigate the therapeutic potential of curcumin, a dietary spice with antioxidant activity, bone marrow transplantation, and their combined effects in the reversal of experimental diabetes. Diabetes was induced in mice by multiple low doses of streptozotocin. After the onset of diabetes, mice were treated with curcumin (10 mM; 100 μl/mouse, i.p., for 28 days) or received a single bone marrow transplantation (106 un-fractionated bone morrow cells), or both. Parameters of diabetes, integrity of pancreatic islets, pancreatic oxidative stress markers, and serum pro-inflammatory cytokines, were evaluated. Treatment with either curcumin or bone marrow transplantation significantly reversed streptozotocin-induced hyperglycemia/glucose intolerance, hypoinsulinemia, and damage of pancreatic islets. Interestingly, combination of curcumin and bone marrow transplantation elicited the most profound alleviation of such streptozotocin-evoked anomalies; including islet regeneration/insulin secretion. On the other hand, curcumin, either alone or combined with bone marrow transplantation, blunted the pancreatic lipid-peroxidation, up-regulated activities of the antioxidant enzymes, and suppressed serum levels of TNF-α and IL-1β. Curcumin and single bone marrow transplantation proved their therapeutic potential in reversing diabetes when used in combination. Curcumin, via its antioxidant and anti-inflammatory effects, evidently enhanced the ability of bone marrow transplantation to regenerate functional pancreatic islets. Hence, the use of natural antioxidants combined with other therapeutic regimens to induce pancreatic regeneration is a promising strategy in the management of diabetes.
Keywords: Curcumin; Bone marrow transplantation; Diabetes; Antioxidant; Inflammation; Islet regeneration;