Selective transcription and cellular proliferation induced by PDGF require histone deacetylase activity

Histone deacetylases (HDACs) are key regulatory enzymes involved in the control of gene expression and their inhibition by specific drugs has been widely correlated to cell cycle arrest, terminal differentiation, and apoptosis. Here, we investigated whether HDAC activ- ity was required for PDGF-dependent signal transduction and cellular proliferation. Exposure of PDGF-stimulated NIH3T3 fibroblasts to the HDAC inhibitor trichostatin A (TSA) potently repressed the expression of a group of genes correlated to PDGF-dependent cel- lular growth and pro-survival activity. Moreover, we show that TSA interfered with STAT3-dependent transcriptional activity induced by PDGF. Still, neither phosphorylation nor nuclear translocation and DNA-binding in vitro and in vivo of STAT3 were affected by using TSA to interfere with PDGF stimulation. Finally, TSA treatment resulted in the suppression of PDGF-dependent cellular prolif- eration without affecting cellular survival of NIH3T3 cells. Our data indicate that inhibition of HDAC activity antagonizes the mitogenic effect of PDGF, suggesting that these drugs may specifically act on the expression of STAT-dependent, PDGF-responsive genes

Extracellular signal-regulated kinase 8 (Erk8) controls estrogen-related receptor alpha cellular localization and inhibits its transcriptional activity.

Erk8 (MAPK15) is a large MAP kinase already implicated in the regulation of the functions of different nuclear receptors and in cellular proliferation and transformation. Here, we identify ERRα as a novel Erk8-interacting protein. As a consequence of such interaction, Erk8 induces Crm1-dependent translocation of ERRα to the cytoplasm and inhibits its transcriptional activity. Also, we identify in Erk8 two LXXLL motifs, typical of agonist-bound nuclear receptor corepressors, as necessary features for this MAP kinase to interact with ERRα and to regulate its cellular localization and transcriptional activity. Ultimately, based on the well-established positive role of ERRα in mammary carcinogenesis, we demonstrate that Erk8 is able to counteract, in immortalized human mammary cells, ERRα activation induced by the EGF receptor pathway, often deregulated in breast cancer. Altogether, these results reveal a novel function for Erk8 as a bona fide ERRα corepressor, involved in the control of its cellular localization by nuclear exclusion, and suggest a key role for this MAP kinase in the biological activities of this nuclear receptor

Activation of the Erk8 Mitogen-activated Protein (MAP) Kinase by RET/PTC3, a Constitutively Active Form of the RET Proto-oncogene

Mitogen-activated protein (MAP) kinases have a central role in several biological functions, including cell adhesion and spreading, chemotaxis, cell cycle progression, differentiation, and apoptosis. Extracellular signal-regulated kinase 8 (Erk8) is a large MAP kinase whose activity is controlled by serum and the c-Src non-receptor tyrosine kinase. Here, we show that RET/PTC3, an activated form of the RET proto-oncogene, was able to activate Erk8, and we demon- strate that such MAP kinase participated in RET/PTC3-dependent stimulation of the c-jun promoter. By using RET/PTC3 molecules mutated in specific tyrosine autophosphorylation sites, we charac- terized Tyr981, a known binding site for c-Src, as a major determi- nant of RET/PTC3-induced Erk8 activation, although, surprisingly, the underlying mechanism did not strictly depend on the activity of Src. In contrast, we present evidence that RET/PTC3 acts on Erk8 through Tyr981-mediated activation of c-Abl. Furthermore, we localized the region responsible for the modulation of Erk8 activity by the RET/PTC3 and Abl oncogenes in the Erk8 C-terminal domain. Altogether, these results support a role for Erk8 as a novel effector of RET/PTC3 and, therefore, RET biological functions

MAPK15/ERK8 stimulates autophagy by interacting with LC3 and GABARAP proteins

Macroautophagy (hereafter referred to as autophagy) is an evolutionarily conserved catabolic process necessary for normal recycling of cellular constituents and for appropriate response to cellular stress. Although several genes belonging to the core molecular machinery involved in autophagosome formation have been discovered, relatively little is known about the nature of signaling networks controlling autophagy upon intracellular or extracellular stimuli. We discovered ATG8-like proteins (MAP1LC3B, GABARAP and GABARAPL1) as novel interactors of MAPK15/ERK8, a MAP kinase involved in cell proliferation and transformation. Based on the role of these proteins in the autophagic process, we demonstrated that MAPK15 is indeed localized to autophagic compartments and increased, in a kinase-dependent fashion, ATG8- like proteins lipidation, autophagosome formation and SQSTM1 degradation, while decreasing LC3B inhibitory phosphorylation. Interestingly, we also identified a conserved LC3-interacting region (LIR) in MAPK15 responsible for its interaction with ATG8-like proteins, for its localization to autophagic structures and, consequently, for stimulation of the formation of these compartments. Furthermore, we reveal that MAPK15 activity was induced in response to serum and amino-acid starvation and that this stimulus, in turn, required endogenous MAPK15 expression to induce the autophagic process. Altogether, these results suggested a new function for MAPK15 as a regulator of autophagy, acting through interaction with ATG8 family proteins. Also, based on the key role of this process in several human diseases, these results supported the use of this MAP kinase as a potential novel therapeutic target

The Platelet-derived Growth Factor Controls c-myc Expression through a JNK- and AP-1-dependent Signaling Pathway *

Pro-inflammatory cytokines, environmental stresses, as well as receptor tyrosine kinases regulate the activity of JNK. In turn, JNK phosphorylates Jun members of the AP-1 family of transcription factors, thereby controlling processes as different as cell growth, differentiation, and apoptosis. Still, very few targets of the JNK-Jun pathway have been identified. Here we show that JNK is required for the induction of c-myc expression by PDGF. Furthermore, we identify a phylogenetically conserved AP-1-responsive element in the promoter of the c-myc proto-oncogene that recruits in vivo the c-Jun and JunD AP-1 family members and controls the PDGF-dependent transactivation of the c-myc promoter. These findings suggest the existence of a novel biochemical route linking tyrosine kinase receptors, such as those for PDGF, and c-myc expression through JNK activation of AP-1 transcription factors. They also provide a novel potential mechanism by which both JNK and Jun proteins may exert either their proliferative or apoptotic potential by stimulating the expression of the c-myc proto-oncogene

Characterization of Cystatin B Interactome in Saliva from Healthy Elderly and Alzheimer's Disease Patients

Cystatin B is a small, multifunctional protein involved in the regulation of inflammation, innate immune response, and neuronal protection and found highly abundant in the brains of patients with Alzheimer's disease (AD). Recently, our study demonstrated a significant association between the level of salivary cystatin B and AD. Since the protein is able to establish protein-protein interaction (PPI) in different contexts and aggregation-prone proteins and the PPI networks are relevant for AD pathogenesis, and due to the relevance of finding new AD markers in peripheral biofluids, we thought it was interesting to study the possible involvement of cystatin B in PPIs in saliva and to evaluate differences and similarities between AD and age-matched elderly healthy controls (HC). For this purpose, we applied a co-immunoprecipitation procedure and a bottom-up proteomics analysis to purify, identify, and quantify cystatin B interactors. Results demonstrated for the first time the existence of a salivary cystatin B-linked multi-protein complex composed by 82 interactors and largely expressed in the body. Interactors are involved in neutrophil activation, antimicrobial activity, modulation of the cytoskeleton and extra-cellular matrix (ECM), and glucose metabolism. Preliminary quantitative data showed significantly lower levels of triosophosphate isomerase 1 and higher levels of mucin 7, BPI, and matrix Gla protein in AD with respect to HC, suggesting implications associated with AD of altered glucose metabolism, antibacterial activities, and calcification-associated processes. Data are available via ProteomeXchange with identifiers PXD039286 and PXD030679

A top-down proteomic approach reveals a salivary protein profile able to classify Parkinson's disease with respect to Alzheimer's disease patients and to healthy controls

Parkinson's disease (PD) is a complex neurodegenerative disease with motor and non-motor symptoms. Diagnosis is complicated by lack of reliable biomarkers. To individuate peptides and/or proteins with diagnostic potential for early diagnosis, severity and discrimination from similar pathologies, the salivary proteome in 36 PD patients was investigated in comparison with 36 healthy controls (HC) and 35 Alzheimer's disease (AD) patients. A top-down platform based on HPLC-ESI-IT-MS allowed characterizing and quantifying intact peptides, small proteins and their PTMs (overall 51). The three groups showed significantly different protein profiles, PD showed the highest levels of cystatin SA and antileukoproteinase and the lowest of cystatin SN and some statherin proteoforms. HC exhibited the lowest abundance of thymosin & beta;4, short S100A9, cystatin A, and dimeric cystatin B. AD patients showed the highest abundance of & alpha;-defensins and short oxidized S100A9. Moreover, different proteoforms of the same protein, as S-cysteinylated and S-glutathionylated cystatin B, showed opposite trends in the two pathological groups. Statherin, cystatins SA and SN classified accurately PD from HC and AD subjects. & alpha;-defensins, histatin 1, oxidized S100A9, and P-B fragments were the best classifying factors between PD and AD patients. Interestingly statherin and thymosin & beta;4 correlated with defective olfactory functions in PD patients. All these outcomes highlighted implications of specific proteoforms involved in the innate-immune response and inflammation regulation at oral and systemic level, suggesting a possible panel of molecular and clinical markers suitable to recognize subjects affected by PD

Oncological outcomes in fertility-sparing treatment in stage IA-G2 endometrial cancer

BACKGROUND: The gold standard treatment for early-stage endometrial cancer (EC) is hysterectomy with bilateral salpingo-oophorectomy (BSO) with lymphadenectomy. In selected patients desiring pregnancy, fertility-sparing treatment (FST) can be adopted. Our review aims to collect the most incisive studies about the possibility of conservative management for patients with grade 2, stage IA EC. Different approaches can be considered beyond demolition surgery, such as local treatment with levonorgestrel-releasing intra-uterine device (LNG-IUD) plus systemic therapy with progestins. STUDY DESIGN: Our systematic review was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. PubMed, EMBASE, and Scopus databases were consulted, and five studies were chosen based on the following criteria: patients with a histological diagnosis of EC stage IA G2 in reproductive age desiring pregnancy and at least one oncological outcome evaluated. Search imputes were “endometrial cancer” AND “fertility sparing” AND “oncologic outcomes” AND “G2 or stage IA”. RESULTS: A total of 103 patients were included and treated with a combination of LNG-IUD plus megestrol acetate (MA) or medroxyprogesterone acetate (MPA), gonadotrophin-releasing hormone (GnRH) plus MPA/MA, hysteroscopic resectoscope (HR), and dilation and curettage (D&C). There is evidence of 70% to 85% complete response after second-round therapy prolongation to 12 months. CONCLUSIONS: Conservative measures must be considered temporary to allow pregnancy and subsequently perform specific counseling to adopt surgery. Fertility-sparing management is not the current standard of care for young women with EC. It can be employed for patients with early-stage diseases motivated to maintain reproductive function. Indeed, the results are encouraging, but the sample size must be increased

Computer-aided cognitive training in patients with neurocognitive vascular impairment: effects on cognition, depression and behavior

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