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In human neuroblastoma SH-SY5Y cells, hydrogen peroxide (H2O2, 200μM) rapidly (< 5 min) induced autophagy, as shown by processing and vacuolar relocation of light chain 3(LC3). Accumulation of autophagosome peaked at 30 min of H2O2 exposure. The continuous presence of H2O2 eventually (at > 60 min) caused autophagy-dependent annexin V–positive cell death. However, the cells exposed to H2O2 for 30 min and then cultivated in fresh medium could recover and grow, despite ongoing autophagy. H2O2 rapidly (5 min) triggered the formation of dichlorofluorescein-sensitive HO·-free radicals within mitochondria, whereas the mitochondria-associated oxidoradicals revealed by MitoSox (O2·−) became apparent after 30 min of exposure to H2O2. 3-Methyladenine inhibited autophagy and cell death, but not the generation of HO·. Genetic silencing of beclin-1 prevented bax- and annexin V–positive cell death induced by H2O2, confirming the involvement of canonical autophagy in peroxide toxicity. The lysosomotropic iron chelator deferoxamine (DFO) prevented the mitochondrial generation of both HO. and O2·− and suppressed the induction of autophagy and of cell death by H2O2. Upon exposure to H2O2, Akt was intensely phosphorylated in the first 30 min, concurrently with mammalian target of rapamycin inactivation and autophagy, and it was dephosphorylated at 2 h, when > 50% of the cells were dead. DFO did not impede Akt phosphorylation, which therefore was independent of reactive oxygen species (ROS) generation but inhibited Akt dephosphorylation. In conclusion, exogenous H2O2 triggers two parallel independent pathways, one leading to autophagy and autophagy-dependent apoptosis, the other to transient Akt phosphorylation, and both are inhibited by DFO. The present work establishes HO· as the autophagy-inducing ROS and highlights the need for free lysosomal iron for its production within mitochondria in response to hydrogen peroxide. [ABSTRACT FROM AUTHOR]

Three molecular forms of the proteolytic enzyme Cathepsin D (CD) are found in the cell: the precursor (proCD), the intermediate single-chain and the mature double-chain. ProCD, which is found in the Golgi Complex, is enzymatically inactive, while the intermediate and the mature forms, respectively found in endosomes and lysosomes, are enzymatically active. The latter are involved in autophagy and apoptosis pathways thus playing a crucial role in the control of cell and tissue homeostasis. ProCD can be secreted in the extracellular space and, by interacting with membrane receptors, can promote cell proliferation. At slightly acid pH, secreted proCD undergoes partial maturation and becomes active. In the extracellular space, CD can degrade the protein components of the matrix and free growth factors therein embedded, thus favoring tumor growth, invasion and angiogenesis. Based on the multiple tasks performed by CD inside and outside the cell, it is not irrational to hypothesize its involvement in cancer development and progression and a strict link between its tissue expression and the clinico-pathological features of the tumor. Thus, not surprisingly, as many as 519 articles are found in the database of pubmed with the keywords 'cathepsin D, cancer and marker'. Disappointingly, however, in spite of, or because of, this large number of studies, the scientific community has not reached a general agreement on the prognostic value of CD in cancer progression. Here, we will briefly review the relevant literature and offer a possible explanation for the conflicting data. [ABSTRACT FROM AUTHOR]

Hydrogen peroxide (H2O2) is an extremely reactive oxidoradical that is normally produced as a by-product of the mitochondrial activity and also under several metabolic stress conditions. Autophagy, a lysosomal degradation pathway, is triggered by oxidative stress as a defensive response. How autophagy and death pathways are coordinated in cells subjected to oxidative stress is still poorly understood. In human neuroblastoma SH-SY5Y cells, 200mM H2O2 rapidly induced the formation of LC3-positive autophagic vacuoles and of beclin1-Vps34 double-positive macroaggregates. Vacuolar LC3 and beclin1 aggregates did not form when oxidative stress was performed in cells pretreated with 3-methyladenine (3MA), an inhibitor of Vps34, or infected with a recombinant adenovirus expressing a dominant-negative mutant of Vps34. H2O2 provoked the permeabilization of lysosomes (at 30 min) and of mitochondria, the concomitant oligomerization of bax, and eventually (at 2 h), cell death in about 50% of the cell culture. Inactivation of Vps34-dependent autophagy in oxidativestressed cells abrogated lysosome leakage, bax activation, and caspase-dependent apoptosis and conferred protection for as long as 16 h. Inhibition of caspase activity (by ZVAD-fmk) did not trigger an alternative cell death pathway but rather afforded complete protection from oxidative toxicity, despite the ongoing generation of oxidoradicals and the cellular accumulation of autophagic vacuoles and of leaking lysosomes. On long-term (16 h) exposure to H2O2, signs of necrotic cell death became apparent in LC3-positive cells, which could be prevented by ZVAD-fmk. The present data highlight the pivotal role of autophagy in H2O2- induced cell death in dopaminergic neuroblastoma cells. [ABSTRACT FROM AUTHOR]

Arsenic trioxide (arsenite) was the first chemotherapeutic drug to be described and is now being rediscovered in cancer treatment, including glioblastoma multiforme. Arsenite toxicity triggers autophagy in cancer cells, although final stages of the process involve executive caspases, suggesting an interplay between autophagic and apoptotic pathways that awaits to be explained at a molecular level. We evaluated the contribution of the lysosomal cathepsins (Cat) L and B, which are upregulated in glioblastomas, in the mechanism of arsenite toxicity in human glioblastoma cells. Arsenite treatment induced autophagosome formation and permeabilization of mitochondria, followed by caspase 3/7-mediated apoptosis. The autophagy inhibitor 3-methyladenine protected from arsenite toxicity, whereas bafilomycin A1 did not. Furthermore, arsenite significantly decreased CatB levels and selectively inhibited its cellular and recombinant protein activity, while not affecting CatL. However, downregulation of CatL greatly enhanced apoptosis by arsenite. Our results show that arsenite toxicity involves a complex interplay between autophagy and apoptosis in human glioblastoma cells and is associated with inhibition of CatB, and that this toxicity is highly exacerbated by simultaneous CatL inhibition. The latter points to a synergy that could be used in clinical treatment to lower the therapeutic dose, thus avoiding the toxic side effects of arsenite in glioblastoma management. [ABSTRACT FROM AUTHOR]

Hepatocyte growth factor (HGF), a pleiotropic cytokine with mitogenic, motogenic, morphogenic, and antiapoptotic effects in various cell types, is a cardioprotective growth factor that can counteract the loss of cardiomyocytes usually observed in cardiac diseases. HGF is a quite unstable molecule in its biologically active heterodimeric form. Since all HGF-induced biological responses are mediated by its high-affinity tyrosine kinase receptor (MetJHGF-R) encoded by the Met gene, we asked whether a monoclonal antibody (MAb) that displays receptor full agonist activity could protect cardiac muscle cell lines from hydrogen peroxide-induced apoptosis. We report that the MAb efficiently inhibited hydrogen peroxide-induced cell shrinkage, DNA fragmentation, annexin V positivity, mitochondrial translocation of bax, and caspase activation. The MAb was thus able to counteract apoptosis evaluated by both morphological and biochemical criteria. The agonist activity of the MAb was mediated by Met/HGF-R, since a Met/HGF-R-specific short hairpin RNA (5hRNA) inhibited both activation of transduction pathways and motility triggered by MAb DO-24. The protective antiapoptotic effect of MAb DO-24 was dependent on activation of the ras-MAPK Erk 1/2 and phosphatidylinositol 3-kinase (P13-kinase)-Akt transduction pathways, since it was abrogated by treatments with their specific pharmacological inhibitors, PD-98059 and wortmannin. Moreover, the MAb induced a motogenic, but not mitogenic, response in these cells, mimicking in all aspects the natural ligand HGF but displaying a significant higher stability than HGF in culture. This MAb may thus be a valuable substitute for HGF, being more easily available in a biologically active, highly stable, and purified form. [ABSTRACT FROM AUTHOR]

In this article we provide an overview of the intersection between amyotrophic lateral sclerosis (ALS) and the autophagy pathway and discuss the potential protective effects of lithium through mechanisms that recruit autophagy and other effects. The autophagy pathway is recruited during motor neuron (MN) death both in vitro and in vivo. Despite a few controversial issues concerning the significance (detrimental/protective) of autophagy in ALS, recent findings indicate a protective role. Lithium in low doses is a well-known autophagy inducer that clears misfolded proteins and altered mitochondria from MNs. Moreover, lithium preserves mitochondria and sustains their genesis. This effect is replicated by rapamycin, which is an autophagy inducer but with a different mechanism from lithium. Lithium also increases the number of Renshaw cells that are affected early during the progression of experimental ALS. Again, lithium has been reported to decrease glial proliferation in the ALS spinal cord and induces sprouting in corticospinal fibers. Muscle Nerve 40: 173-194, 2009 [ABSTRACT FROM AUTHOR]

The ovarian cancer cell lines A2780 (wild-type p53) and NIHOVCAR3 (mutated p53) showed, respectively, sensitivity and resistance towards several chemotherapy drugs. We hypothesized that the two cell lines differ in their ability to activate the intrinsic death pathway and have, therefore, dissected the lysosome-mitochondrion signalling pathway by pharmacological inhibition or genetic manipulation of key regulators and executioners. Biochemical and morphological confocal fluorescence studies showed that: (1) In A2780 cells bcl-2 is expressed at an undetectable level, whereas Bax is expressed at a rather high level; by contrast, bcl-2 is highly expressed and Bax is expressed at extremely low levels in NIHOVCAR3 cells; (2) Chemotherapy treatment reduced the expression of bcl-2 in NIHOVCAR3 cells, yet these cells resisted to drug toxicity; (3) Cathepsin D (CD), not cathepsin B or L, mediates the activation of the mitochondrial intrinsic death pathway in A2780 cells; (4) Lysosome leakage and cytosolic relocation of CD occurs in the chemosensitive A2780 cells, not in the chemoresistant NIHOVCAR3 cells; (5) Bax is essential for the permeabilization of both lysosomes and mitochondria in A2780 cells exposed to chemotherapy drugs; (6) CD activity is mandatory for the oligomerization of Bax on both mitochondrial and lysosomal membranes; (7) Bax activation did not occur in the resistant NIHOVCAR3 cells despite their high content in CD. The present data are consistent with a model in which on treatment with a cytotoxic drug the activation of a CD-Bax loop leads to the generalized permeabilization of lysosomes and eventually of mitochondria, thus reaching the point of no return, and culminates with the activation of the caspase cascade. Our data also imply that dysfunctional permeabilization of lysosomes contributes to the development of chemoresistance. [ABSTRACT FROM AUTHOR]

The cyclic regeneration of human endometrium is guaranteed by the proliferative capacity of endometrial mesenchymal stromal cells (E-MSCs). Due to this, the autologous infusion of E-MSCs has been proposed to support endometrial growth in a wide range of gynecological diseases. We aimed to compare two different endometrial sampling methods, surgical curettage and vacuum aspiration biopsy random assay (VABRA), and to validate a novel xeno-free method to culture human E-MSCs. Six E-MSCs cell samples were isolated after mechanical tissue homogenization and cultured using human platelet lysate. E-MSCs were characterized for the colony formation capacity, proliferative potential, and multilineage differentiation. The expression of mesenchymal and stemness markers were tested by FACS analysis and real-time PCR, respectively. Chromosomal alterations were evaluated by karyotype analysis, whereas tumorigenic capacity and invasiveness were tested by soft agar assay. Both endometrial sampling techniques allowed efficient isolation and expansion of E-MSCs using a xeno-free method, preserving their mesenchymal and stemness phenotype, proliferative potential, and limited multi-lineage differentiation ability during the culture. No chromosomal alterations and invasive/tumorigenic capacity were observed. Herein, we report the first evidence of efficient E-MSCs isolation and culture in Good Manufacturing Practice compliance conditions, suggesting VABRA endometrial sampling as alternative to surgical curettage. [ABSTRACT FROM AUTHOR]

Focusing on defining metabolite-based inter-tumoral heterogeneity in ovarian cancer, we investigated the metabolic diversity of a panel of high-grade serous ovarian carcinoma (HGSOC) cell-lines using a metabolomics platform that interrogate 731 compounds. Metabolic fingerprinting followed by 2-dimensional and 3-dimensional principal component analysis established the heterogeneity of the HGSOC cells by clustering them into five distinct metabolic groups compared to the fallopian tube epithelial cell line control. An overall increase in the metabolites associated with aerobic glycolysis and phospholipid metabolism were observed in the majority of the cancer cells. A preponderant increase in the levels of metabolites involved in trans-sulphuration and glutathione synthesis was also observed. More significantly, subsets of HGSOC cells showed an increase in the levels of 5-Hydroxytryptamine, γ-aminobutyrate, or glutamate. Additionally, 5-hydroxytryptamin synthesis inhibitor as well as antagonists of γ-aminobutyrate and glutamate receptors prohibited the proliferation of HGSOC cells, pointing to their potential roles as oncometabolites and ligands for receptor-mediated autocrine signaling in cancer cells. Consistent with this role, 5-Hydroxytryptamine synthesis inhibitor as well as receptor antagonists of γ-aminobutyrate and Glutamate-receptors inhibited the proliferation of HGSOC cells. These antagonists also inhibited the three-dimensional spheroid growth of TYKNU cells, a representative HGSOC cell-line. These results identify 5-HT, GABA, and Glutamate as putative oncometabolites in ovarian cancer metabolic sub-type and point to them as therapeutic targets in a metabolomic fingerprinting-based therapeutic strategy. [ABSTRACT FROM AUTHOR]

Methamphetamine causes nigrostriatal denervation and striatal dopamine loss, while sparing nigral cell bodies. Nigral dopamine neurons feature autophagic vacuoles and cytoplasmic α-synuclein-, ubiquitin- and parkin-positive inclusion-like bodies. On that basis, autophagy was considered essential in methamphetamine-induced neurotoxicity, but its neurotoxic or protective role has never been addressed. Here we review the gap between the descriptive evidence on activation of autophagy and the lack of knowledge about its role during methamphetamine intoxication. Our preliminary findings rule out a detrimental role for autophagy; this represents the first step in understanding the consequence of activation of autophagy in methamphetamine toxicity. [ABSTRACT FROM AUTHOR]

Methamphetamine abuse is toxic to dopaminergic neurons, causing nigrostriatal denervation and striatal dopamine loss. Following methamphetamine exposure, the number of nigral cell bodies is generally preserved, but their cytoplasm features autophagic-like vacuolization and cytoplasmic accumulation of α-synuclein-, ubiquitin- and parkin-positive inclusion-like bodies. Whether autophagy is epiphenomenal or it plays a role in the mechanism of methamphetamine toxicity and, in the latter case, whether its role consists of counteracting or promoting the neurotoxic effect remains obscure. We investigated the signaling pathway and the significance (protective vs . toxic) of autophagy activation and the convergence of the autophagic and the ubiquitin-proteasome pathways at the level of the same intracellular bodies in a simple cell model of methamphetamine toxicity. We show that autophagy is rapidly up-regulated in response to methamphetamine. Confocal fluorescence microscopy and immuno-electron microscopy studies demonstrated the presence of α-synuclein aggregates in autophagy-lysosomal structures in cells exposed to methamphetamine, a condition compatible with cell survival. Inhibition of autophagy either by pharmacologic or genetic manipulation of the class III Phosphatidylinositol-3 kinase-mediated signaling prevented the removal of α-synuclein aggregates and precipitated a bax-mediated mitochondrial apoptosis pathway. [ABSTRACT FROM AUTHOR]

The intracellular assembly of tau aggregates is a pathological hallmark shared by Alzheimer's disease and other neurodegenerative disorders known collectively as tauopathies. To model how tau fibrillogenesis evolves in tauopathies, we previously established transfectant M1C cultures from human neuroblastoma BE(2)-M17D cells that inducibly express human tau. In the present study, these cells were used to determine the role of the autophagic-lysosomal system in the degradation and aggregation of wild-type tau. Tau induction for 5 days led to the accumulation of tau with nominal assembly of tau aggregates within cells. When the lysosomotropic agent, chloroquine (CQ), was added following the termination of tau induction, tau clearance was delayed. Decreased tau truncation and increased levels of intact tau were observed. When present during tau induction, CQ led to tau accumulation and promoted the formation of sarkosyl-insoluble aggregates containing both truncated and full-length tau. CQ treatment significantly decreased the activities of cathepsins D, B and L, and the inhibition of cathepsins B and L mimicked the effect of CQ and increased tau levels in cells. Additionally, exposure of cells to the autophagy inhibitor, 3-methyladenine, led to tau accumulation and aggregation. These results suggest that the autophagic-lysosomal system plays a role in the clearance of tau, and that dysfunction of this system results in the formation of tau oligomers and insoluble aggregates. [ABSTRACT FROM AUTHOR]

ALS is a devastating neurodegenerative disorder with no effective treatment. In the present study, we found that daily doses of lithium, leading to plasma levels ranging from 0.4 to 0.8 mEq/liter, delay disease progression in human patients affected by ALS. None of the patients treated with lithium died during the 15 months of the follow-up, and disease progression was markedly attenuated when compared with age-, disease duration-, and sex-matched control patients treated with riluzole for the same amount of time. In a parallel study on a genetic ALS animal model, the G93A mouse, we found a marked neuroprotection by lithium, which delayed disease onset and duration and augmented the life span. These effects were concomitant with activation of autophagy and an increase in the number of the mitochondria in motor neurons and suppressed reactive astrogliosis. Again, lithium reduced the slow necrosis characterized by mitochondrial vacuolization and increased the number of neurons counted in lamina VII that were severely affected in saline-treated G93A mice. After lithium administration in G93A mice, the number of these neurons was higher even when compared with saline-treated WT. All these mechanisms may contribute to the effects of lithium, and these results offer a promising perspective for the treatment of human patients affected by ALS. [ABSTRACT FROM AUTHOR]

In the corpus luteum (CL), blood vessels develop, stabilize, and regress. This process depends on the ratio of pro- and antiangiogenic factors, which change during the ovarian cycle. The present study focuses on the possible roles of 23,000 (23 K) prolactin (PRL) in the bovine CL and its antiangiogenic NH2-terminal fragments after extracellular cleavage by cathepsin D (Cath D). PRL RNA and protein were demonstrated in the CL tissue, in luteal endothelial cells, and in steroidogenic cells. Cath D was detected in CL tissue, cell extracts, and corresponding cell supernatants. In the intact CL, 23K PRL levels decreased gradually, whereas Cath D levels concomitantly increased between early and late luteal stages. In vitro, PRL cleavage occurred in the presence of acidified homogenates of CL tissue, cells, and corresponding cell supernatants. Similar fragments were obtained with purified Cath D, and their appearance was inhibited by pepstatin A. The aspartic protease specific substrate MOCAc-GKPILF∼FRLK(Dnp)-D-R-NH2 was cleaved b)) CL cell supernatants, providing further evidence for Cath D activity. The 16,000 PRL inhibited proliferation of luteal endothelial cells accompanied by an increase in cleaved caspase-3. In conclusion, 1) the bovine CL is able to produce PRL and to process it into antiangiogenic fragments by Cath D activity and 2) PRL cleavage might mediate angioregression during luteolysis. [ABSTRACT FROM AUTHOR]

Summary: The prognostic significance of microvessel density and proliferative activity of the neoplastic cells, evaluated respectively by CD31 and Ki-67 positivity, and immunohistochemical expression of vascular endothelial growth factor (VEGF) was retrospectively investigated in 105 cases of sinonasal carcinoma (80 surgical specimens and 25 biopsies). The most represented histologic types were intestinal-type adenocarcinoma found in 36 patients (34.3%), squamous cell carcinoma (SCC) in 34 (32.4%), mucinous adenocarcinoma (mainly made up of signet-ring cell patterns) in 15 (14.3%), and adenoid cystic carcinoma in 7 (6.7%). Microvessel density values (in vessels per square millimeter), VEGF, and Ki-67 were not dependent on histologic type but were rather correlated to the histologic grading in SCC. Clinical data were available for 92 (87.6%) of 105 patients, with minimum follow-up of 48 months. Most of the patients (81.5%) were at an advanced stage (T3-T4) at diagnosis. The values of all markers were correlated to tumor stage (P = .03). Multivariate analysis showed that both microvessel density and proliferative activity of the neoplastic cells were independent prognostic parameters (mortality hazard ratio, 1.33 and 1.60, respectively). Although VEGF expression was not correlated to prognosis on the whole series (P = .06), it was a powerful prognostic marker when the analysis was restricted to the group of SCCs (hazard ratio, 3.02; 90% confidence interval, 1.58-5.80). These results show that tumor neoangiogenesis, expressed by microvessel density, together with proliferative activity, is a pathologic marker with a strong prognostic impact in sinonasal carcinomas. Therefore, it may be a useful tool in this field so as to carry out therapeutic protocol planning, which may be further enhanced by the adoption of the more recent antiangiogenic molecules. [Copyright &y& Elsevier]

The present study investigated whether the expression of cellular Fas-associated death domain-like interleukin-1 β-converting enzyme (FLICE) inhibitory protein (cFLIP) conveys prognostic information in non-Hodgkin lymphomas (NHLs). cFLIP expression was quantified by immunohistochemistry and immunofluorescence in biopsy specimens from 86 NHL patients for whom clinical information was available. NHL malignancy was graded as high/intermediate or low according to the World Health Organization Classification of Lymphoid Neoplasms. cFLIP was positive in 23 of 45 high-/intermediate-grade NHLs and in 25 of 41 low-grade NHLs. Negative expression of cFLIP was associated with the presence of apoptotic cells in the tumour mass, regardless of the histotype and of the malignancy grade. In NHLs positive for cFLIP, 11 of 23 (48%) high-/intermediate-grade cases and 18 of 25 (72%) low-grade cases showed a bad outcome. In NHLs negative for cFLIP, only four of 22 (18%) high-/intermediate-grade patients and 12 of 16 (75%) low-grade patients achieved complete remission. All these correlations were statistically significant. The correlation of cFLIP expression with clinical outcome was independent of therapy, whether or not it included anti-CD20 antibody (Rituximab). The present findings strongly indicate that cFLIP is a reliable predictor of tumour progression and clinical prognosis in NHLs of low grade of malignancy. [ABSTRACT FROM AUTHOR]

A short period of hypoxia reduces the cytotoxicity produced by a subsequent prolonged hypoxia in isolated hepatocytes. This phenomenon, termed hypoxic preconditioning, is mediated by the activation of adenosine A2A-receptor and is associated with the attenuation of cellular acidosis and Na+ overload normally occurring during hypoxia. Bafilomycin, an inhibitor of the vacuolar H+/ATPase, reverts the latter effects and abrogates the preconditioning-induced cytoprotection. Here we provide evidence that the acquisition of preconditioning-induced cytoprotection requires the fusion with plasma membrane and exocytosis of endosomal-lysosomal organelles. Poisons of the vesicular traffic, such as wortmannin and 3methyladenine, which inhibit phosphatydilinositol 3kinase, or cytochalasin D, which disassembles the actin cytoskeleton, prevented lysosome exocytosis and also abolished the preconditioning-associated protection from acidosis and necrosis provoked by hypoxia. Preconditioning was associated with the phosphatydilinositol 3-kinase-dependent increase of cytosolic [Ca2+]. Chelation of free cytosolic Ca2+ in preconditioned cells prevented lysosome exocytosis and the acquisition of cytoprotection. We conclude that lysosomeplasma membrane fusion is the mechanism through which hypoxic preconditioning allows hepatocytes to preserve the intracellular pH and survive hypoxic stress. This process is under the control of phosphatydilinositol 3-kinase and requires the integrity of the cytoskeleton and the rise of intracellular free calcium ions. [ABSTRACT FROM AUTHOR]

Background: Ovarian cancer progression and invasiveness are promoted by a range of soluble factors released by cancer cells and stromal cells within the tumor microenvironment. Our previous studies demonstrated that resveratrol (RV), a nutraceutical and caloric restriction mimetic with tumor-suppressive properties, counteracts cancer cell motility induced by stromal IL-6 by upregulating autophagy. Lysophosphatidic acid (LPA), a bioactive phospholipid that shows elevated levels in the tumor microenvironment and the ascites of ovarian cancers, stimulates the growth and tissue invasion of cancer cells. Whether LPA elicits these effects by inhibiting autophagy and through which pathway and whether RV can counteract the same remain obscure. Aims: To investigate the molecular pathways involved in LPA-induced ovarian cancer malignancy, particularly focusing on the role of autophagy, and the ability of RV to counteract LPA activity. Results: LPA stimulated while RV inhibited ovarian cancer cell migration. Transcriptomic and bioinformatic analyses showed an opposite regulation by LPA and RV of genes linked to epithelial-to-mesenchymal transition (EMT) and autophagy with involvement of the PI3K-AKT, JAK-STAT and Hedgehog (Hh) pathways. LPA upregulated the Hh and EMT members GLI1, BMI-1, SNAIL-1 and TWIST1 and inhibited autophagy, while RV did the opposite. Similar to the inhibitors of the Hh pathway, RV inhibited LPA-induced cancer cell migration and 3D growth of ovarian cancer cells. BMI-1 silencing prevented LPA-induced EMT, restored autophagy and hampered cell migration, resembling the effects of RV. TCGA data analyses indicated that patients with low expression of Hh/EMT-related genes together with active autophagy flux tended to have a better prognosis and this correlates with a more effective response to platinum therapy. In in vitro 3D spheroids, LPA upregulated BMI-1, downregulated autophagy and inhibited platinum toxicity while RV and Hh inhibitors restored autophagy and favored BAX-mediated cell death in response to platinum. Conclusions: By inhibiting the Hh pathway and restoration of autophagy, RV counteracts LPA-induced malignancy, supporting its inclusion in the therapy of ovarian cancer for limiting metastasis and chemoresistance. [ABSTRACT FROM AUTHOR]

With the focus on defining the oncogenic network stimulated by lysophosphatidic acid (LPA) in ovarian cancer, the present study sought to interrogate the oncotranscriptome regulated by the LPA-mediated signaling pathway. LPA, LPA-receptor (LPAR) and LPAR-activated G protein 12 α-subunit, encoded by G protein subunit α 12 (GNA12), all serve an important role in ovarian cancer progression. While the general signaling mechanism regulated by LPA/LPAR/GNA12 has previously been characterized, the global transcriptomic network regulated by GNA12 in ovarian cancer pathophysiology remains largely unknown. To define the LPA/LPAR/GNA12-orchestrated oncogenic networks in ovarian cancer, transcriptomic and bioinformatical analyses were conducted using SKOV3 cells, in which the expression of GNA12 was silenced. Array analysis was performed in Agilent SurePrint G3 Human Comparative Genomic Hybridization 8×60 microarray platform. The array results were validated using Kuramochi cells. Gene and functional enrichment analyses were performed using Database for Annotation, Visualization and Integrated Discovery, Search Tool for Retrieval of Interacting Genes and Cytoscape algorithms. The results indicated a paradigm in which GNA12 drove ovarian cancer progression by upregulating a pro-tumorigenic network with AKT1, VEGFA, TGFB1, BCL2L1, STAT3, insulin-like growth factor 1 and growth hormone releasing hormone as critical hub and/or bottleneck nodes. Moreover, GNA12 downregulated a growth-suppressive network involving proteasome 20S subunit (PSM) β6, PSM α6, PSM ATPase 5, ubiquitin conjugating enzyme E2 E1, PSM non-ATPase 10, NDUFA4 mitochondrial complex-associated, NADH:ubiquinone oxidoreductase subunit B8 and anaphase promoting complex subunit 1 as hub or bottleneck nodes. In addition to providing novel insights into the LPA/LPAR/GNA12-regulated oncogenic networks in ovarian cancer, the present study identified several potential nodes in this network that could be assessed for targeted therapy. [ABSTRACT FROM AUTHOR]

Methamphetamine (METH) is a widely abused psychostimulant and a stress-inducing compound, which leads to neurotoxicity for nigrostriatal dopamine (DA) terminals in rodents and primates including humans. In vitro studies indicate that autophagy is a strong modulator of METH toxicity. In detail, suppressing autophagy increases METH toxicity, while stimulating autophagy prevents METH-induced toxicity in cell cultures. In the present study, the role of autophagy was investigated in vivo. In the whole brain, METH alone destroys meso-striatal DA axon terminals, while fairly sparing DA cell bodies within substantia nigra pars compacta (SNpc). No damage to either cell bodies or axons from ventral tegmental area (VTA) is currently documented. According to the hypothesis that ongoing autophagy prevents METH-induced DA toxicity, we tested whether systemic injection of autophagy inhibitors such as asparagine (ASN, 1000 mg/Kg) or glutamine (GLN, 1000 mg/Kg), may extend METH toxicity to DA cell bodies, both within SNpc and VTA, where autophagy was found to be inhibited. When METH (5 mg/Kg × 4, 2 h apart) was administered to C57Bl/6 mice following ASN or GLN, a frank loss of cell bodies takes place within SNpc and a loss of both axons and cell bodies of VTA neurons is documented. These data indicate that, ongoing autophagy protects DA neurons and determines the refractoriness of cell bodies to METH-induced toxicity. [ABSTRACT FROM AUTHOR]

Alzheimer's disease (AD) is implicated in the imbalance of several proteins, including Amyloid-β (Aβ), amyloid precursor protein (APP), and BACE1. APP overexpression interferes with neurite outgrowth, while BACE1 plays a role in Aβ generation. Medicinal herbs with effects on neurite outgrowth stimulation and BACE1 inhibition may benefit AD. This study aimed to investigate the neurite outgrowth stimulatory effect, along with BACE1 inhibition of Caesalpinia mimosoides (CM), using wild-type (Neuro2a) and APP (Swedish mutant)-overexpressing (Neuro2a/APPSwe) neurons. The methanol extract of CM leaves stimulated neurite outgrowth in wild-type and APP-overexpressing cells. After exposure to the extract, the mRNA expression of the neurite outgrowth activation genes growth-associated protein-43 (GAP-43) and teneurin-4 (Ten-4) was increased in both Neuro2a and Neuro2a/APPSwe cells, while the mRNA expression of neurite outgrowth negative regulators Nogo receptor (NgR) and Lingo-1 was reduced. Additionally, the extract suppressed BACE1 activity in the APP-overexpressing neurons. Virtual screening demonstrated that quercetin-3′-glucuronide, quercetin-3-O-glucoside, clausarinol, and theogallin were possible inhibitors of BACE1. ADMET was analyzed to predict drug-likeness properties of CM-constituents. These results suggest that CM extract promotes neurite outgrowth and inhibits BACE1 activity in APP-overexpressing neurons. Thus, CM may serve as a source of drugs for AD treatment. Additional studies for full identification of bioactive constituents and to confirm the neuritogenesis in vivo are needed for translation into clinic of the present findings. [ABSTRACT FROM AUTHOR]

Increased expression of GNAi2, which encodes the α-subunit of G-protein i2, has been correlated with the late-stage progression of ovarian cancer. GNAi2, also referred to as the proto-oncogene gip2, transduces signals from lysophosphatidic acid (LPA)-activated LPA-receptors to oncogenic cellular responses in ovarian cancer cells. To identify the oncogenic program activated by gip2, we carried out micro-array-based transcriptomic and bioinformatic analyses using the ovarian cancer cell-line SKOV3, in which the expression of GNAi2/gip2 was silenced by specific shRNA. A cut-off value of 5-fold change in gene expression (p < 0.05) indicated that a total of 264 genes were dependent upon gip2-expression with 136 genes coding for functional proteins. Functional annotation of the transcriptome indicated the hitherto unknown role of gip2 in stimulating the expression of oncogenic/growth-promoting genes such as KDR/VEGFR2, CCL20, and VIP. The array results were further validated in a panel of High-Grade Serous Ovarian Carcinoma (HGSOC) cell lines that included Kuramochi, OVCAR3, and OVCAR8 cells. Gene set enrichment analyses using DAVID, STRING, and Cytoscape applications indicated the potential role of the gip2-stimulated transcriptomic network involved in the upregulation of cell proliferation, adhesion, migration, cellular metabolism, and therapy resistance. The results unravel a multi-modular network in which the hub and bottleneck nodes are defined by ACKR3/CXCR7, IL6, VEGFA, CYCS, COX5B, UQCRC1, UQCRFS1, and FYN. The identification of these genes as the critical nodes in GNAi2/gip2 orchestrated onco-transcriptome establishes their role in ovarian cancer pathophysiology. In addition, these results also point to these nodes as potential targets for novel therapeutic strategies. [ABSTRACT FROM AUTHOR]

The uncovering ratio of phosphate groups in lysosomal enzymes in defined as the percentage of phosphomonoester groups in the oligosaccharide side chains based on the sum of phosphomonoester and phosphodiester groups. Using a new procedure for the specific and complete hydrolysis on uncovered phosphomonoester groups in denatured immunoprecipates of human cathepsin D, we show that the uncovering ratio varies between different forms of the enzyme and may be used as an indicator of the maturation of its carbohydrate side chains. The uncovering ratio in the total (cellular and secreted) cathepsin D from U937 promonocytes is >95%. It is only slightly decreased in cells incubated in the presence of 1α,25-dihydroxycholecalciferol, in which the rate of synthesis of cathepsin D is several times higher than in the control cells. In U937 cells and also in fibroblasts, the uncovering is nearly complete in intermediate and mature forms of the intracellular cathepsin D but less extensive in the intracellular and secreted precursor. In both cell types, incubation with 10 mN NH4Cl results in a decrease in the uncovering ratio of total cathepsin D. However, the activity of the uncovering enzyme, N-acetylglucosamine-1-phosphodiester α-N-acetylglucosaminidase, as determined with UDP — N-acetylglucosamine is not affected with up to 60 mM NH4Cl. Our results suggest that NH4Cl, in addition to its known effects on the acidic-pH-dependent functions of lysosomal compartments and of mannose-6-phosphte receptors, impairs the processing or transport of lysosomal enzyme precursors at, or proximally to, the site of the uncovering of their mannose 6-phosphate residues. [ABSTRACT FROM AUTHOR]

Enterocyte-like differentiated HT-29 colon carcinoma cells were shown to contain far higher intracellular levels of activity of lysosomal cathepsins B, D, and L than their undifferentiated counterparts. In the latter, inhibition of lysosomal functions by leupeptin or ammonium chloride led to a marked increase in the cell-associated activity of the three cathepsins. High levels of pro-cathepsins B, D, and L were found in the culture media of both HT-29 cell populations. Ammonium chloride and chloroquine, which are known to impair the mannose-6-phosphate-dependent trafficking of lysosomal-targeted proteins, did not increase the secretion of the three cathepsins in either undifferentiated or differentiated cultures of HT-29 cells. Analyses by cell fractionation revealed heterogeneities with regard to the density and the content of lysosomal cathepsins between the two cell populations. Leupeptin induced the accumulation of mature lysosomal cathepsins B and L in light density organelles in undifferentiated HT-29 cells. Altogether, these data demonstrate that (1) the expression and subcellular distribution of cathepsins B, D, and L in HT-29 cells are influenced by their state of enterocytic differentiation, (2) the segregation of lysosomal cathepsins is largely inefficient in this tumor cell line and does not increase upon differentiation, and (3) the mannose-6-phosphate-receptor-dependent pathway plays a minor role in the sorting of the three cathepsins, both in undifferentiated and enterocytic-differentiated HT-29 cells. [ABSTRACT FROM AUTHOR]

Interleukin-10 plays a vital role in maintaining peripheral immunotolerance and favors a regulatory immune milieu through the suppression of T effector cells. Inflammation-induced microvascular loss has been associated with airway epithelial injury, which is a key pathological source of graft malfunctioning and subepithelial fibrosis in rejecting allografts. The regulatory immune phase maneuvers alloimmune inflammation through various regulatory modulators, and thereby promotes graft microvascular repair and suppresses the progression of fibrosis after transplantation. The present study was designed to investigate the therapeutic impact of IL-10 on immunotolerance, in particular, the reparative microenvironment, which negates airway epithelial injury, and fibrosis in a mouse model of airway graft rejection. Here, we depleted and reconstituted IL-10, and serially monitored the phase of immunotolerance, graft microvasculature, inflammatory cytokines, airway epithelium, and subepithelial collagen in rejecting airway transplants. We demonstrated that the IL-10 depletion suppresses FOXP3+ Tregs, tumor necrosis factor-inducible gene 6 protein (TSG-6), graft microvasculature, and establishes a pro-inflammatory phase, which augments airway epithelial injury and subepithelial collagen deposition while the IL-10 reconstitution facilitates FOXP3+ Tregs, TSG-6 deposition, graft microvasculature, and thereby favors airway epithelial repair and subepithelial collagen suppression. These findings establish a potential reparative modulation of IL-10-associated immunotolerance on microvascular, epithelial, and fibrotic remodeling, which could provide a vital therapeutic option to rescue rejecting transplants in clinical settings. [ABSTRACT FROM AUTHOR]

Many invasive cancers emerge through a years-long process of somatic evolution, characterized by an accumulation of heritable genetic and epigenetic changes and the emergence of increasingly aggressive clonal populations. In solid tumors, such as breast ductal carcinoma, the extracellular environment for cells within the nascent tumor is harsh and imposes different types of stress on cells, such as hypoxia, nutrient deprivation, and cytokine inflammation. Acidosis is a constant stressor of most cancer cells due to its production through fermentation of glucose to lactic acid in hypoxic or normoxic regions (Warburg effect). Over a short period of time, acid stress can have a profound effect on the function of lysosomes within the cells exposed to this environment, and after long term exposure, lysosomal function of the cancer cells can become completely dysregulated. Whether this dysregulation is due to an epigenetic change or evolutionary selection has yet to be determined, but understanding the mechanisms behind this dysregulation could identify therapeutic opportunities. [ABSTRACT FROM AUTHOR]

Lysosomes, acidic, membrane-bound organelles, are not only the core of the cellular recycling machinery, but they also serve as signaling hubs regulating various metabolic pathways. Lysosomes maintain energy homeostasis and provide pivotal substrates for anabolic processes, such as DNA replication. Every time the cell divides, its genome needs to be correctly duplicated; therefore, DNA replication requires rigorous regulation. Challenges that negatively affect DNA synthesis, such as nucleotide imbalance, result in replication stress with severe consequences for genome integrity. The lysosomal complex mTORC1 is directly involved in the synthesis of purines and pyrimidines to support DNA replication. Numerous drugs have been shown to target lysosomal function, opening an attractive avenue for new treatment strategies against various pathologies, including cancer. In this review, we focus on the interplay between lysosomal function and DNA replication through nucleic acid degradation and nucleotide biosynthesis and how these could be exploited for therapeutic purposes. [ABSTRACT FROM AUTHOR]

Depending on context and tumor stage, deregulation of autophagy can either suppress tumorigenesis or promote chemoresistance and tumor survival. Histone deacetylases (HDACs) can modulate autophagy; however, the exact mechanisms are not fully understood. Here, we analyze the effects of the broad-spectrum HDAC inhibitors (HDACi) panobinostat and vorinostat on the transcriptional regulation of autophagy with respect to autophagy transcription factor activity (Transcription factor EB—TFEB, forkhead boxO—FOXO) and autophagic flux in neuroblastoma cells. In combination with the late-stage autophagic flux inhibitor bafilomycin A1, HDACis increase the number of autophagic vesicles, indicating an increase in autophagic flux. Both HDACi induce nuclear translocation of the transcription factors FOXO1 and FOXO3a, but not TFEB and promote the expression of pro-autophagic FOXO1/3a target genes. Moreover, FOXO1/3a knockdown experiments impaired HDACi treatment mediated expression of autophagy related genes. Combination of panobinostat with the lysosomal inhibitor chloroquine, which blocks autophagic flux, enhances neuroblastoma cell death in culture and hampers tumor growth in vivo in a neuroblastoma zebrafish xenograft model. In conclusion, our results indicate that pan-HDACi treatment induces autophagy in neuroblastoma at a transcriptional level. Combining HDACis with autophagy modulating drugs suppresses tumor growth of high-risk neuroblastoma cells. These experimental data provide novel insights for optimization of treatment strategies in neuroblastoma. [ABSTRACT FROM AUTHOR]