Roxane Tenta

Oleuropein prevents doxorubicin-induced cardiomyopathy interfering with signaling molecules and cardiomyocyte metabolism

Oleuropein, a natural phenolic compound, prevents acute doxorubicin (DXR)-induced cardiotoxicity but there is no evidence regarding its role in chronic DXR-induced cardiomyopathy (DXR-CM). In the present study, we investigated the role of oleuropein in DXR-CM by addressing cardiac geometry and function (transthoracic echocardiography), cardiac histopathology, nitro-oxidative stress (MDA, PCs, NT), inflammatory cytokines (IL-6, Big ET-1), NO homeostasis (iNOS and eNOS expressions), kinases involved in apoptosis and metabolism (Akt, AMPK) and myocardial metabonomics. Rats were randomly divided into 6 groups: Control, OLEU-1 and OLEU-2 [oleuropein at 1000 and 2000 mg/kg in total, respectively, intraperitoneally (i.p.) for 14 days], DXR (18 mg/kg, i.p. divided into 6 equal doses for 2 weeks), DXR-OLEU-1 and DXR-OLEU-2 (both oleuropein and DXR as previously described). Impaired left ventricular contractility and inflammatory and degenerative pathology lesions were encountered only in the DXR group. The DXR group also had higher MDA, PCs, NT, IL-6 and Big ET-1 levels, higher iNOS and lower eNOS, Akt and AMPK activation compared to controls and the oleuropein-treated groups. Metabonomics depicted significant metabolite alterations in the DXR group suggesting perturbed energy metabolism and protein biosynthesis. The effectiveness of DXR in inhibiting cell proliferation is not compromised when oleuropein is present. We documented an imbalance between iNOS and eNOS expressions and a disturbed protein biosynthesis and metabolism in DXR-CM; these newly recognized pathways in DXR cardiotoxicity may help identifying novel therapeutic targets. Activation of AMPK and suppression of iNOS by oleuropein seem to prevent the structural, functional and histopathological cardiac effects of chronic DXR toxicity.

Activation of AMP-Activated Protein Kinase by Adiponectin Rescues Salivary Gland Epithelial Cells From Spontaneous and Interferon-γ-Induced Apoptosis

OBJECTIVE Primary Sjögrens syndrome (SS) is an autoimmune disease characterized by lymphocytic infiltrates associated with destruction of salivary gland epithelial cells (SGECs) induced mainly by apoptosis. Adiponectin is an immunoregulatory hormone. We have previously shown that SGECs from patients with primary SS as well as from controls differentially express adiponectin. SGECs derived from patients with primary SS constitutively produce and secrete adiponectin in higher quantities. The aim of this study was to investigate the effect of adiponectin on the proliferation and apoptosis of SGECs. METHODS Cultured, non-neoplastic SGECs were treated with recombinant human adiponectin, and the rate of cell proliferation was assessed. Spontaneous and interferon-gamma (IFNgamma)-induced apoptosis was evaluated with a specific single-stranded DNA enzyme-linked immunosorbent assay. The AMP-activated protein kinase (AMPK) inhibitor Compound C was used to test the involvement of AMPK in adiponectin effects. Western blotting was applied to detect the phosphorylation levels of AMPK after adiponectin treatment. RESULTS Adiponectin treatment resulted in a dose-dependent suppression of proliferation of SGECs from patients with primary SS and control donors. Adiponectin protected cells from spontaneous as well as from IFNgamma-induced apoptosis. Furthermore, the antiapoptotic effects of adiponectin were dependent upon AMPK phosphorylation at Thr(172), since pretreatment of SGECs with Compound C abolished the adiponectin protective effect. CONCLUSION Adiponectin exerted antiproliferative effects on SGECs without inducing apoptosis and protected SGECs from spontaneous as well as from IFNgamma-induced apoptosis through an AMPK-dependent pathway. Our observations suggest that adiponectin may protect SGECs in this specific inflammatory milieu, providing a potential pathway through which AMPK may regulate cell survival under energy stress conditions such as autoimmune inflammation.

Endoplasmic reticulum stress causes autophagy and apoptosis leading to cellular redistribution of the autoantigens Ro/Sjögren's syndrome-related antigen A (SSA) and La/SSB in salivary gland epithelial cells

The aim of this study was to examine the levels of endoplasmic reticulum (ER) stress in minor salivary glands, to investigate the interplay between ER stress‐induced autophagy and apoptosis in human salivary gland (HSG) cells and to test the effect of ER stress‐induced apoptosis on the cellular redistribution of the two major Sjögrens syndrome (SS) autoantigens Ro/Sjögrens syndrome‐related antigen A (SSA) and La/Sjögrens syndrome‐related antigen B (SSB). Minor salivary gland biopsies from SS patients and sicca controls were examined by immunohistochemistry for the expression of 78 kDa glucose‐regulated protein/binding immunoglobulin protein (GRP78/BiP) as an indicator of unfolded protein response (UPR). HSG cells were treated with thapsigargin (TG) and cell viability, autophagy and apoptosis were assessed. Immunoblot was applied to detect the conversion of LC3I to LC3II and the protein levels of GRP78/BiP and X‐box binding protein‐1 (XBP‐1). Apoptosis was evaluated by a single‐stranded DNA enzyme‐linked immunosorbent assay (ELISA). Ro/SSA and La/SSB localization was visualized using immunofluorescence. GRP78/BiP was expressed by acinar and ductal epithelial cells in salivary glands of patients and sicca controls. TG treatment induced autophagy, as indicated by enhanced protein expression of LC3II. The protein levels of UPR marker XBP‐1 were increased after TG treatment, while GRP78/BiP levels were decreased. TG treatment resulted in induction of HSG apoptosis. Ro/SSA and La/SSB autoantigens were localized predominantly to the cytoplasm in resting cells, while they were redistributed to cell membrane and blebs in the apoptotic cells. In conclusion, ER stress is activated in minor salivary gland epithelial cells from SS patients and controls. ER stress‐induced apoptosis in HSG cells leads to cell surface and apoptotic blebs relocalization of Ro/SSA and La/SSB autoantigens.

Bioactive natural products against prostate cancer: mechanism of action and autophagic/apoptotic molecular pathways.

Prostate cancer is one of the leading causes of death worldwide for men. There is increasing evidence that diet and lifestyle play a crucial role in prostate cancer biology and tumorigenesis. Due to the fact that conventional chemotherapy is not adequately effective against prostate cancer and has severe side effects, numerous in vitro studies have been conducted in order to identify the potent cytotoxic or chemopreventive activity of naturally occurring compounds and their respective molecular mechanisms of action. In this context, many natural compounds isolated from plants have been found to inhibit cancer growth and to induce cell cycle arrest, suppress angiogenesis, and promote apoptotic or autophagic cell death. Therefore, in this article, the most promising bioactive natural products and their respective mechanisms of action for the prevention or/and treatment of prostate cancer are presented.

Synthesis of New Nebularine Analogues and Their Inhibitory Activity against Adenosine Deaminase

A number of new 2,6-disubstituted-1-deazanebularine analogues as well as two structurally related pyrazole-fused tricyclic nucleosides were prepared. Their synthesis was carried out by the conversion of 6-amino-2-picoline to a suitable 1-deazapurine, followed by a Vorbrüggen type glycosylation and subsequent elaboration of the condensed pyrazole ring. The synthesized nebularine analogues proved to be weak adenosine deaminase inhibitors.

Bone metabolism compensates for the delayed growth in small for gestational age neonates

The goal of the present study is to investigate the relationship between anthropometric and bone metabolism markers in a sample of neonates and their mothers. A sample of 20 SGA (small for the gestational age), AGA (appropriate for the gestational age) and LGA (large for the gestational age) term neonates and their 20 mothers was analyzed at birth and at exit. Elisa method was used to measure the OPG (Osteoprotegerin), RANK (Receptor activator of nuclear factor-kappaB), RANKL (Receptor activator of nuclear factor-kappaB Ligand), IGF-1 (Insulin-like growth factor 1), IGFBP3 (Insulin-like Growth Factor Binding Protein 3) and Leptin levels. Birth weight and length were positively correlated with RANKL, IGF-1 and IGFBP3 and negatively with the ratio OPG/RANKL. SGA neonates presented lower RANKL values and higher OPG/RANKL ratio while LGA neonates had higher RANK levels than AGA neonates. Positive association was shown between neonatal IGFBP3 and maternal IGF-1 values and between neonatal and maternal RANK values at birth and at exit. These results reveal a remarkable upregulation of OPG/RANKL ratio in SGA neonates, pointing out the role of bone turnover in compensating for the delayed neonatal growth.

Hormonal responses following eccentric exercise in humans

OBJECTIVEMechanically overloaded muscle and its subsequent damage are strong stimuli for eliciting acute hormonal changes, while the muscle adaptation which occurs following exercise-induced muscle damage may involve complex hormonal responses before the completion of muscle regeneration. The purpose of this study was to investigate systemic responses of various hormones, as well as secreted proteins that are exercise-regulated and associated with muscle adaptation, for several days after eccentric exercise-induced muscle damage in humans.DESIGNNine young male volunteers performed 50 maximal eccentric muscle actions using the knee extensor muscles of both legs. Blood samples were drawn before and at 6, 48 and 120 hours post exercise and serum levels of growth hormone (GH), insulin-like growth factor binding protein-3 (IGFBP-3), cortisol, prolactin, thyroid-stimulating hormone (TSH), free thyroxine (fT4), irisin, follistatin and sclerostin were measured. Myoglobin (Mb) concentration and lactate dehydrogenase (LDH) activity were also evaluated as indirect markers of muscle damage.RESULTSSignificant alterations in Mb and LDH were observed over time after eccentric exercise (p=0.039–0.001). A late serum increase in fT4 and decrease in irisin levels, along with an early and persistent decrease in IGFBP-3 levels, were observed following the muscle-damaging exercise (p=0.049–0.016). GH, cortisol, prolactin, TSH, follistatin and sclerostin exhibited moderate changes during the recovery period after exercise, though without reaching statistical significance (p>0.05), while correlational analyses revealed significant associations between GH and IGFBP-3, prolactin and sclerostin over time (p=0.049–0.001).CONCLUSIONSThe significant hormonal responses observed in this study may indicate their involvement in the regenerative mechanisms following muscle damage, potentially as part of a regulatory network to support a normal adaptation process after muscle-damaging exercise.

The discovery of new cytotoxic pyrazolopyridine derivatives

A number of new 3,7-disubstituted pyrazolo[3,4-c]pyridines have been designed and synthesized from suitable 2-aminopyridines. The antiproliferative activity of the derivatives was determined against the pancreatic MIA PaCa-2 and ovarian SCOV3 cancer cell-lines. IC50 values of the most promising analogue 46 lie in the submicromolar or low micromolar range. Furthermore, compound 46 shows similar inhibitory activities against DU145, A2058 and PC-3 cancer cells, blocks the cell cycle at the G0/G1 phase and induce apoptosis, as determined by the appearance of apoptotic nuclei.

Association between male Infertility and seminal plasma levels of growth hormone and insulin-like growth factor-1

Growth hormone (GH) and insulin‐like growth factor 1 (IGF‐1) have been proposed to play a pivotal role in male infertility due to their anabolic effects. The aim of this study was to investigate possible associations between seminal plasma levels of GH and IGF‐1 and sperm parameters. Fifty men participated in this study. Semen analysis was performed, while cell‐free seminal plasma was collected following sperm centrifugation. Seminal plasma concentrations of IGF‐1 and GH were determined by enzyme‐linked immunosorbent assay (ELISA). Due to the presence of asthenozoospermia in all participants who presented with abnormal sperm parameters, the participants were further subdivided into normal (group A), asthenozoospermic (group B) and asthenozoospermic plus at least one additional abnormal parameter (group C). A marginally nonsignificant statistical difference (p = 0.063) was revealed between the GH levels corresponding to the asthenozoospermic and the normal group with the latter presenting with higher GH levels. A statistically significant positive correlation (p < 0.05) was noted between levels of GH and IGF‐1 in group C. The above relationship has also been observed in men with low sperm concentration, vitality, volume and abnormal morphology. These novel findings require further investigation in order for the biological significance of those associations to be clarified.

Antiproliferative Effects of Red and White Wine Extracts in PC-3 Prostate Cancer Cells

ABSTRACT Experimental and epidemiological studies have shown that antioxidant polyphenols can act as chemopreventive agents against prostate cancer. Cabernet Sauvignon and Rombola wine were extracted in order to obtain fractions containing different classes of compounds. All extracts inhibited the androgen-insensitive human prostate cancer cells (PC-3) proliferation in a dose-dependent manner. The most potent compounds were selected to be further tested.Treatment of PC-3 cells with the selected wine extracts marginally increased the cell distribution in S phase, while producing a remarkable induction of autophagy. Finally, the levels of glutathione along with the concentration of hydrogen peroxide and nitrogen oxide were modulated in the treated cells. Herein, we show that red and wine extracts have direct effects on the proliferation, survival, oxidative status, and the induction of autophagy of PC-3 cells. Our data may have important implications for the design of a more effective adjuvant treatment for prostate cancer patients.