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Abstract: Notch signaling pathway regulates a wide variety of cellular processes during development and it also plays a crucial role in human diseases. This important link is firmly established in cancer, since a rare T-ALL-associated genetic lesion has been initially reported to result in deletion of Notch1 ectodomain and constitutive activation of its intracellular region. Interestingly, the cellular response to Notch signaling can be extremely variable depending on the cell type and activation context. Notch signaling triggers signals implicated in promoting carcinogenesis and autoimmune diseases, whereas it can also sustain responses that are critical to suppress carcinogenesis and to negatively regulate immune response. However, Notch signaling induces all these effects via an apparently simple signal transduction pathway, diversified into a complex network along evolution from Drosophila to mammals. Indeed, an explanation of this paradox comes from a number of evidences accumulated during the last few years, which dissected the intrinsic canonical and non-canonical components of the Notch pathway as well as several modulatory extrinsic signaling events. The identification of these signals has shed light onto the mechanisms whereby Notch and other pathways collaborate to induce a particular cellular phenotype. In this article, we review the role of Notch signaling in cells as diverse as T lymphocytes and epithelial cells of the epidermis, with the main focus on understanding the mechanisms of Notch versatility. [Copyright &y& Elsevier]

Abstract: Notch signaling plays a key role in cell-fate determination and differentiation in different organisms and cell types. Several reports suggest that Notch signaling may be involved in neoplastic transformation. However, in primary keratinocytes, Notch1 can function as a tumor suppressor. Similarly, in HPV-positive cervical cancer cells, constitutively active Notch1 signaling was found to cause growth suppression. Activated Notch1 in these cells represses viral E6/E7 expression through AP-1 down-modulation, resulting in increased p53 expression and a block of pRb hyperphosphorylation. Here we show that in cervical cancer cell lines in which Notch1 ability to repress AP-1 activity is impaired, Notch1-enforced expression elicits an alternative pathway leading to growth arrest. Indeed, activated Notch1 signaling suppresses activity of the helix–loop–helix transcription factor E47, via ERK1/2 activation, resulting in inhibition of cell cycle progression. Moreover, we found that RBP-Jκ-dependent Notch signaling is specifically repressed in cervical cancer cells and this repression could provide one such mechanism that needs to be activated for cervical carcinogenesis. Finally, we show that inhibition of endogenous Notch1 signaling, although results in a proliferative advantage, sensitizes cervical cancer cell lines to drug-induced apoptosis. Together, our results provide novel molecular insights into Notch1-dependent growth inhibitory effects, counteracting the transforming potential of HPV. [Copyright &y& Elsevier]

The rote of Notch signaling in growth/differentiation control of mammalian epithelial cells is still poorly defined. We show that keratinocyte-specific deletion of the Notch1 gene results in marked epidermal hyperplasia and deregulated expression of multiple differentiation markers. In differentiating primary keratinocytes in vitro endogenous Notch1 is required for induction of p21WAF1/Cip1expression, and activated Notch1 causes growth suppression by inducing p21WAF1/Cip1 expression. Activated Notch1 also induces expression of 'early' differentiation markers, while suppressing the late markers. Induction of p21WAF1/Cip1 expression and early differentiation markers occur through two different mechanisms. The RBP-Jκ protein binds directly to the endogenous p21 promoter and p21 expression is induced specifically by activated Notch1 through RBP-Jκ-dependent transcription. Expression of early differentiation markers is RBP- Jκ-independent and can be induced by both activated Notch1 and Notch2, as well as the highly conserved ankyrin repeat domain of the Notch1 cytoplasmic region. Thus, Notch signaling triggers two distinct pathways leading to keratinocyte growth arrest and differentiation. [ABSTRACT FROM AUTHOR]

The genes coding for white collar-1 and white collar-2 (wc-1 and wc-2 ) have been isolated previously, and their products characterized as Zn-finger transcription factors involved in the control of blue light-induced genes. Here, we show that the PAS dimerization domains present in both proteins enable the WC-1 and WC-2 proteins to dimerize in vitro. Homodimers and heterodimers are formed between the white collar (WC) proteins. A computer analysis of WC-1 reveals a second domain, called LOV, also identified in NPH1, a putative blue light photoreceptor in plants and conserved in redox-sensitive proteins and in the phytochromes. The WC-1 LOV domain does not dimerize with canonical PAS domains, but it is able to self-dimerize. The isolation of three blind wc-1 strains, each with a single amino acid substitution only in the LOV domain, reveals that this region is essential for blue light responses in Neurospora. The demonstration that the WC-1 proteins in these LOV mutants are still able to self-dimerize suggests that this domain plays an additional role, essential in blue light signal transduction. [ABSTRACT FROM AUTHOR]

Simple Summary: We observed that both the proximal GATA sequence in light-responsive elements (LREs) of the albino-3 promoter and the Zinc Finger Domain of WC-1 are involved in the dark-related repressive control mechanism of light-regulated genes. Light influences a wide range of physiological processes from prokaryotes to mammals. Neurospora crassa represents an important model system used for studying this signal pathway. At molecular levels, the WHITE COLLAR Complex (WCC), a heterodimer formed by WC-1 (the blue light photo-sensor) and WC-2 (the transcriptional activator), is the critical positive regulator of light-dependent gene expression. GATN (N indicates any other nucleotide) repeats are consensus sequences within the promoters of light-dependent genes recognized by the WCC. The distal GATN is also known as C-box since it is involved in the circadian clock. However, we know very little about the role of the proximal GATN, and the molecular mechanism that controls the transcription of light-induced genes during the dark/light transition it is still unclear. Here we showed a first indication that mutagenesis of the proximal GATA sequence within the target promoter of the albino-3 gene or deletion of the WC-1 zinc finger domain led to a rise in expression of light-dependent genes already in the dark, effectively decoupling light stimuli and transcriptional activation. This is the first observation of cis-/trans-acting repressive machinery, which is not consistent with the light-dependent regulatory mechanism observed in the eukaryotic world so far. [ABSTRACT FROM AUTHOR]

Hailey‐Hailey disease (HHD) is a rare autosomal dominantly inherited disorder caused by mutations in the ATP2C1 gene that encodes an adenosine triphosphate (ATP)‐powered calcium channel pump. HHD is characterized by impaired epidermal cell‐to‐cell adhesion and defective keratinocyte growth/differentiation. The mechanism by which mutant ATP2C1 causes HHD is unknown and current treatments for affected individuals do not address the underlying defects and are ineffective. Notch signalling is a direct determinant of keratinocyte growth and differentiation. We found that loss of ATP2C1 leads to impaired Notch1 signalling, thus deregulation of the Notch signalling response is therefore likely to contribute to HHD manifestation. NOTCH1 is a transmembrane receptor and upon ligand binding, the intracellular domain (NICD) translocates to the nucleus activating its target genes. In the context of HHD, we found that loss of ATP2C1 function promotes upregulation of the active NOTCH1 protein (NICD‐Val1744). Here, deeply exploring this aspect, we observed that NOTCH1 activation is not associated with the transcriptional enhancement of its targets. Moreover, in agreement with these results, we found a cytoplasmic localization of NICD‐Val1744. We have also observed that ATP2C1‐loss is associated with the degradation of NICD‐Val1744 through the lysosomal/proteasome pathway. These results show that ATP2C1‐loss could promote a mechanism by which NOTCH1 is endocytosed and degraded by the cell membrane. The deregulation of this phenomenon, finely regulated in physiological conditions, could in HHD lead to the deregulation of NOTCH1 with alteration of skin homeostasis and disease manifestation. [ABSTRACT FROM AUTHOR]

Simple Summary: The overall survival rate in T-cell acute lymphoblastic leukemia (T-ALL) patients is relatively high. However, the therapeutic options for refractory and relapsed cases with poor prognosis are still limited. Therefore, novel therapies are required to improve high-risk patient outcomes. Natural products can play a crucial role in developing novel drug candidates. The proven preclinical efficacy of the phytochemical compound curcumin, mediated through modulation of multiple molecular targets, including Notch signaling, is well known. However, limited data are available regarding its anti-cancer effects and its relationship with Notch in T-ALL. Our study provides evidence that curcumin reduces Notch activity and exerts anti-cancer effects in T-ALL cells by favouring DNA damage-dependent cell death. Furthermore, we identified the curcumin derivative CD2066, which is endowed with potentiated anti-growth, anti-Notch, and DNA-damaging activities. Although CD2066 anti-leukemia activity requires further investigation, our study highlights the potential of curcumin-based bioactive agents for Notch-dependent leukemia treatment. T-cell acute lymphoblastic leukemia (T-ALL) is an aggressive hematological malignancy considered curable by modern clinical management. Nevertheless, the prognosis for T-ALL high-risk cases or patients with relapsed and refractory disease is still dismal. Therefore, there is a keen interest in developing more efficient and less toxic therapeutic approaches. T-ALL pathogenesis is associated with Notch signaling alterations, making this pathway a highly promising target in the fight against T-ALL. Here, by exploring the anti-leukemic capacity of the natural polyphenol curcumin and its derivatives, we found that curcumin exposure impacts T-ALL cell line viability and decreases Notch signaling in a dose- and time-dependent fashion. However, our findings indicated that curcumin-mediated cell outcomes did not depend exclusively on Notch signaling inhibition, but might be mainly related to compound-induced DNA-damage-associated cell death. Furthermore, we identified a novel curcumin-based compound named CD2066, endowed with potentiated anti-proliferative activity in T-ALL compared to the parent molecule curcumin. At nanomolar concentrations, CD2066 antagonized Notch signaling, favored DNA damage, and acted synergistically with the CDK1 inhibitor Ro3306 in T-ALL cells, thus representing a promising novel candidate for developing therapeutic agents against Notch-dependent T-ALL. [ABSTRACT FROM AUTHOR]

Deregulated Notch signaling has been extensively linked to T-cell acute lymphoblastic leukemia (T-ALL). Here, we show a direct relationship between Notch3 receptor and Jagged1 ligand in human cell lines and in a mouse model of T-ALL. We provide evidence that Notch-specific ligand Jagged1 is a new Notch3 signaling target gene. This essential event justifies an aberrant Notch3/Jagged1 cis-expression inside the same cell. Moreover, we demonstrate in Notch3-IC-overexpressing T lymphoma cells that Jagged1 undergoes a raft-associated constitutive processing. The proteolytic cleavage allows the Jagged1 intracellular domain to empower Notch signaling activity and to increase the transcriptional activation of Jagged1 itself (autocrine effect).On the other hand, the release of the soluble Jagged1 extracellular domain has a positive impact on activating Notch signaling in adjacent cells (paracrine effect), finally giving rise to a Notch3/Jagged1 auto-sustaining loop that supports the survival, proliferation, and invasion of lymphoma cells and contributes to the development and progression of Notch-dependent T-ALL. These observations are also supported by a study conducted on a cohort of patients in which Jagged1 expression is associated to adverse prognosis. [ABSTRACT FROM AUTHOR]

Embryonic cells are expected to possess high growth/differentiation potential, required for organ morphogenesis and expansion during development. However, little is known about the intrinsic properties of embryonic epithelial cells due to difficulties in their isolation and cultivation. We report here that pure keratinocyte populations from E15.5 mouse embryos commit irreversibly to differentiation much earlier than newborn cells. Notch signaling, which promotes keratinocyte differentiation, is upregulated in embryonic keratinocyte and epidermis, and elevated caspase 3 expression, which we identify as a transcriptional Notch1 target, accounts in part for the high commitment of embryonic keratinocytes to terminal differentiation. In vivo, lack of caspase 3 results in increased proliferation and decreased differentiation of interfollicular embryonic keratinocytes, together with decreased activation of PKC-δ, a caspase 3 substrate which functions as a positive regulator of keratinocyte differentiation. Thus, a Notch1-caspase 3 regulatory mechanism underlies the intrinsically high commitment of embryonic keratinocytes to terminal differentiation. [Copyright &y& Elsevier]

The eukaryotic translation initiation factor 5A (eIF5A) is an essential protein for the viability of the cells whose proposed function is to prevent the stalling of the ribosomes during translation elongation. eIF5A activity requires a unique and functionally essential post-translational modification, the change of a lysine to hypusine. eIF5A is recognized as a promoter of cell proliferation, but it has also been suggested to induce apoptosis. To date, the precise molecular mechanism through which eIF5A affects these processes remains elusive. In the present study, we explored whether eIF5A is involved in controlling the stress-induced expression of the key cellular regulator p53. Our results show that treatment of HCT-116 colon cancer cells with the deoxyhypusine (DHS) inhibitor N1-guanyl-1,7-diamineheptane (GC7) caused both inhibition of eIF5A hypusination and a significant reduction of p53 expression in UV-treated cells, and that eIF5A controls p53 expression at the level of protein synthesis. Furthermore, we show that treatment with GC7 followed by UV-induced stress counteracts the pro-apoptotic process triggered by p53 up-regulation. More in general, the importance of eIF5A in the cellular stress response is illustrated by the finding that exposure to UV light promotes the binding of eIF5A to the ribosomes, whereas UV treatment complemented by the presence of GC7 inhibits such binding, allowing a decrease of de novo synthesis of p53 protein. [ABSTRACT FROM AUTHOR]

The ubiquitin system is a dynamic regulatory pathway controlling the activity, subcellular localization and stability of a myriad of cellular proteins, which in turn affects cellular homeostasis through the regulation of a variety of signaling cascades. Aberrant activity of key components of the ubiquitin system has been functionally linked with numerous human diseases including the initiation and progression of human tumors. In this review, we will contextualize the importance of the two main components of the ubiquitin system, the E3 ubiquitin ligases (E3s) and deubiquitinating enzymes (DUBs), in the etiology of squamous cell carcinomas (SCCs). We will discuss the signaling pathways regulated by these enzymes, emphasizing the genetic and molecular determinants underlying their deregulation in SCCs. [ABSTRACT FROM AUTHOR]

Notch signaling plays a complex role in carcinogenesis, and its signaling pathway has both tumor suppressor and oncogenic components. To identify regulators that might control this dual activity of NOTCH1, we screened a chemical library targeting kinases and identified Polo-like kinase 1 (PLK1) as one of the kinases involved in arsenite-induced NOTCH1 down-modulation. As PLK1 activity drives mitotic entry but also is inhibited after DNA damage, we investigated the PLK1-NOTCH1 interplay in the G2 phase of the cell cycle and in response to DNA damage. Here, we found that PLK1 regulates NOTCH1 expression at G2/M transition. However, when cells in G2 phase are challenged with DNA damage, PLK1 is inhibited to prevent entry into mitosis. Interestingly, we found that the interaction between NOTCH1 and PLK1 is functionally important during the DNA damage response, as we found that whereas PLK1 activity is inhibited, NOTCH1 expression is maintained during DNA damage response. During genotoxic stress, cellular transformation requires that promitotic activity must override DNA damage checkpoint signaling to drive proliferation. Interestingly, we found that arsenite-induced genotoxic stress causes a PLK1-dependent signaling response that antagonizes the involvement of NOTCH1 in the DNA damage checkpoint. Taken together, our data provide evidence that Notch signaling is altered but not abolished in SCC cells. Thus, it is also important to recognize that Notch plasticity might be modulated and could represent a key determinant to switch on/off either the oncogenic or tumor suppressor function of Notch signaling in a single type of tumor. [ABSTRACT FROM AUTHOR]

This study aims at investigating the cytotoxicity of zinc oxide nanorods (ZnO-NR) and microrods (ZnO-MR) in two different human cell lines. The materials were produced by a simple and cost-effective hydrothermal route and induced a slight dose dependent toxic effect on MCF7 and HaCaT cells. Both cell lines showed a very low cytotoxicity when exposed to suspensions containing 1–100 μg/ml of ZnO-NR and ZnO-MR. Moreover, Field-emission scanning electron microscopy (FE-SEM) images of both cell lines exposed to the materials showed no significant effect on cell morphology compared to untreated cells. However, the treatments induced modifications of filopodia, mainly in MCF7 cells exposed to ZnO-NR. In addition, a very slight increase in ROS generation was observed only in ZnO-MR-treated cells. Moreover, an apoptotic effect of ZnO-NR rather than a cell cycle arrest was observed in MCF7 cells after treatment. Overall the cytotoxicity in in vitro systems reflects a biocompatibility of both ZnO-NR and ZnO-MR, representing powerful tools in several applications. [ABSTRACT FROM AUTHOR]

The cross-talk between axon and glial cells during development and in adulthood is mediated by several molecules. Among them are neurotransmitters and their receptors, which are involved in the control of myelinating and non-myelinating glial cell development and physiology. Our previous studies largely demonstrate the functional expression of cholinergic muscarinic receptors in Schwann cells. In particular, the M2 muscarinic receptor subtype, the most abundant cholinergic receptor expressed in Schwann cells, inhibits cell proliferation downregulating proteins expressed in the immature phenotype and triggers promyelinating differentiation genes. In this study, we analysed the in vitro modulation of the Neuregulin-1 (NRG1)/erbB pathway, mediated by the M2 receptor activation, through the selective agonist arecaidine propargyl ester (APE). M2 agonist treatment significantly downregulates NRG1 and erbB receptors expression, both at transcriptional and protein level, and causes the internalization and intracellular accumulation of the erbB2 receptor. Additionally, starting from our previous results concerning the negative modulation of Notch-active fragment NICD by M2 receptor activation, in this work, we clearly demonstrate that the M2 receptor subtype inhibits erbB2 receptors by Notch-1/NICD downregulation. Our data, together with our previous results, demonstrate the existence of a cross-interaction between the M2 receptor and NRG1/erbB pathway-Notch1 mediated, and that it is responsible for the modulation of Schwann cell proliferation/differentiation. [ABSTRACT FROM AUTHOR]

A growing body of evidence indicates that protein factors controlling translation play an important role in tumorigenesis. The protein known as eIF6 is a ribosome anti-association factor that has been implicated in translational initiation and in ribosome synthesis. Over-expression of eIF6 is observed in many natural tumours, and causes developmental and differentiation defects in certain animal models. Here we show that the transcription of the gene encoding eIF6 is modulated by the receptor Notch-1, a protein involved in embryonic development and cell differentiation, as well as in many neoplasms. Inhibition of Notch-1 signalling by γ-secretase inhibitors slowed down cell-cycle progression and reduced the amount of eIF6 in lymphoblastoid and ovarian cancer cell lines. Cultured ovarian cancer cell lines engineered to stably over-expressing eIF6 did not show significant changes in proliferation rate, but displayed an enhanced motility and invasive capacity. Inhibition of Notch-1 signalling in the cells over-expressing eIF6 was effective in slowing down the cell cycle, but did not reduce cell migration and invasion. On the whole, the results suggest that eIF6 is one of the downstream effectors of Notch-1 in the pathway that controls cell motility and invasiveness. [ABSTRACT FROM AUTHOR]

Hailey-Hailey disease (HHD) is an autosomal dominant disorder characterized by suprabasal cutaneous cell separation (acantholysis) leading to the development of erosive and oozing skin lesion. Micro RNAs (miRNAs) are endogenous post-transcriptional modulators of gene expression with critical functions in health and disease. Here, we evaluated whether the expression of specific miRNAs may play a role in the pathogenesis of HHD. Here, we report that miRNAs are expressed in a non-random manner in Hailey-Hailey patients. miR-125b appeared a promising candidate for playing a role in HHD manifestation. Both Notch1 and p63 are part of a regulatory signalling whose function is essential for the control of keratinocyte proliferation and differentiation and of note, the expression of both Notch1 and p63 is downregulated in HHD-derived keratinocytes. We found that both Notch1 and p63 expression is strongly suppressed by miR-125b expression. Additionally, we found that miR-125b expression is increased by an oxidative stress-dependent mechanism. Our data suggest that oxidative stress-mediated induction of miR-125b plays a specific role in the pathogenesis of HHD by regulating the expression of factors playing an important role in keratinocyte proliferation and differentiation. [ABSTRACT FROM AUTHOR]

Simple Summary: The Notch signaling pathway regulates cell proliferation, apoptosis, stem cell self-renewal, and differentiation in a context-dependent fashion both during embryonic development and in adult tissue homeostasis. Consistent with its pleiotropic physiological role, unproper activation of the signaling promotes or counteracts tumor pathogenesis and therapy response in distinct tissues. In the last twenty years, a wide number of studies have highlighted the anti-cancer potential of Notch-modulating agents as single treatment and in combination with the existent therapies. However, most of these strategies have failed in the clinical exploration due to dose-limiting toxicity and low efficacy, encouraging the development of novel agents and the design of more appropriate combinations between Notch signaling inhibitors and chemotherapeutic drugs with improved safety and effectiveness for distinct types of cancer. Notch signaling guides cell fate decisions by affecting proliferation, apoptosis, stem cell self-renewal, and differentiation depending on cell and tissue context. Given its multifaceted function during tissue development, both overactivation and loss of Notch signaling have been linked to tumorigenesis in ways that are either oncogenic or oncosuppressive, but always context-dependent. Notch signaling is critical for several mechanisms of chemoresistance including cancer stem cell maintenance, epithelial-mesenchymal transition, tumor-stroma interaction, and malignant neovascularization that makes its targeting an appealing strategy against tumor growth and recurrence. During the last decades, numerous Notch-interfering agents have been developed, and the abundant preclinical evidence has been transformed in orphan drug approval for few rare diseases. However, the majority of Notch-dependent malignancies remain untargeted, even if the application of Notch inhibitors alone or in combination with common chemotherapeutic drugs is being evaluated in clinical trials. The modest clinical success of current Notch-targeting strategies is mostly due to their limited efficacy and severe on-target toxicity in Notch-controlled healthy tissues. Here, we review the available preclinical and clinical evidence on combinatorial treatment between different Notch signaling inhibitors and existent chemotherapeutic drugs, providing a comprehensive picture of molecular mechanisms explaining the potential or lacking success of these combinations. [ABSTRACT FROM AUTHOR]

HMGA1 is a member of a small family of architectural transcription factors involved in the coordinate assembly of multiprotein complexes referred to as enhanceosomes. In addition to their role in cell proliferation, differentiation, and development, high-mobility group proteins of the A type (HMGA) family members behave as transforming protoncogenes either in vitro or in animal models. Recent reports indicated that HMGA1 might counteract p53 pathway and provided an interesting hint on the mechanisms determining HMGA's transforming potential. HMGA1 expression is deregulated in a very large array of human tumors, including cervical cancer, but very limited information is available on the molecular mechanisms leading to HMGA1 deregulation in cancer cells. Here, we report that HMGA1 expression is sustained by human papilloma virus (HPV) E6/E7 proteins in cervical cancer, as demonstrated by either E6/E7 overexpression or by repression through RNA interference. Knocking down HMGA1 expression by means of RNA interference, we also showed that it is involved in cell proliferation and contributes to p53 inactivation in this type of neoplasia. Finally, we show that HMGA1 is necessary for the full expression of HPV18 E6 and E7 oncoproteins thus establishing a positive autoregulatory loop between HPV E6/E7 and HMGA1 expression. [ABSTRACT FROM AUTHOR]

Constitutive activation of the transmembrane receptor, Notch3, and loss of function of the hematopoietic transcription repressor, Ikaros (IK), play direct roles in T-cell differentiation and leukemogenesis that are dependent on pre-T-cell receptor (pre-TCR) signaling. We demonstrate the occurrence of crosstalk between Notch3 and IK that results in transcriptional regulation of the gene encoding the pTα chain of the pre-TCR. We also show that, in the presence of the pre-TCR, constitutive activation of Notch3 in thymocytes causes increased expression of dominantnegative non-DNA-binding IK isoforms, which are able to restrain the IK inhibition of Notch3's transcriptional activation of pTα. This effect appears to be mediated by Notch3's pre-TCR-dependent upregulation of the RNA-binding protein, HuD. Notch3 signaling thus appears to play a critical role in the diminished IK activity described in several lymphoid leukemias. By exerting transcription-activating and transcription-repressing effects on the pTα promoter, Notch3 and IK cooperate in the fine-tuning of pre-TCR expression and function, which has important implications for the regulation of thymocyte differentiation and proliferation. [ABSTRACT FROM AUTHOR]

Protein kinase (PK)C?is a critical regulator of mature T-cell activation and proliferation, being implicated in TCR-triggered nuclear factor (NF)-?B activation and providing important survival signals to leukemic T cells. We previously showed that overexpression of pTa/pre-TCR and constitutive activation of NF-?B characterize the T-cell leukemia/lymphoma developing in Notch3-IC transgenic mice. We report here that PKC?is a downstream target of Notch3 signaling and that its activation and membrane translocation require a functional pre-TCR in order to trigger NF-?B activation in thymocytes and lymphoma cells of transgenic mice. Furthermore, deletion of PKC?in Notch3-IC transgenic mice reduces the incidence of leukemia, correlating with decreased NF-?B activation. This paper therefore suggests that PKC?mediates the activation of NF-?B by pre-TCR in immature thymocytes and contributes to the development of Notch3-dependent T-cell lymphoma.Oncogene (2005) 24, 992-1000. doi:10.1038/sj.onc.1208302 Published online 13 December 2004 [ABSTRACT FROM AUTHOR]

In the physiopathology of cystic fibrosis (CF), oxidative stress implications are recognized and widely accepted. The cystic fibrosis transmembrane conductance regulator (CFTR) defects disrupt the intracellular redox balance causing CF pathological hallmarks. Therefore, oxidative stress together with aberrant expression levels of detoxification genes and microRNAs (miRNAs/miRs) may be associated with clinical outcome. Using total RNA extracted from epithelial nasal cells, the present study analyzed the expression levels of oxidative stress genes and one miRNA using quantitative PCR in a representative number of patients with CF compared with in healthy individuals. The present pilot study revealed the existence of an association among CFTR, genes involved in the oxidative stress response and miR-125b. The observed downregulation of CFTR gene expression was accompanied by increased expression levels of Nuclear factor erythroid derived-2 like2 and its targets NAD(P)H:Quinone Oxidoreductase and glutathione S-transferase 1. Moreover, the expression levels of heme oxygenase-1 (HO-1) and miR-125b were positively correlated with a forced expiratory volume in 1 sec (FEV1) >60% in patients with CF with chronic Pseudomonas aeruginosa lung infection (r=0.74; P<0.001 and r=0.57; P<0.001, respectively). The present study revealed the activation of an inducible, but not fully functional, oxidative stress response to protect airway cells against reactive oxygen species-dependent injury in CF disease. Additionally, the correlations of HO-1 and miR-125b expression with an improved FEV1 value suggested that these factors may synergistically protect the airway cells from oxidative stress damage, inflammation and apoptosis. Furthermore, HO-1 and miR-125b may be used as prognostic markers explaining the wide CF phenotypic variability as an additional control level over the CFTR gene mutations. [ABSTRACT FROM AUTHOR]

Hailey–Hailey disease (HHD) is a rare, chronic and recurrent blistering disorder, characterized by erosions occurring primarily in intertriginous regions and histologically by suprabasal acantholysis. Mutation of the Golgi Ca2+-ATPase ATP2C1 has been identified as having a causative role in Hailey–Hailey disease. HHD-derived keratinocytes have increased oxidative-stress that is associated with impaired proliferation and differentiation. Additionally, HHD is characterized by skin lesions that do not heal and by recurrent skin infections, indicating that HHD keratinocytes might not respond well to challenges such as wounding or infection. Hypochlorous acid has been demonstrated in vitro and in vivo to possess properties that rescue both oxidative stress and altered wound repair process. Thus, we investigated the potential effects of a stabilized form of hypochlorous acid (APR-TD012) in an in vitro model of HHD. We found that treatment of ATP2C1-defective keratinocytes with APR-TD012 contributed to upregulation of Nrf2 (nuclear factor (erythroid-derived 2)-like 2). Additionally, APR TD012-treatment restored the defective proliferative capability of siATP2C1-treated keratinocytes. We also found that the APR-TD012 treatment might support wound healing process, due to its ability to modulate the expression of wound healing associated cytokines. These observations suggested that the APR-TD012 might be a potential therapeutic agent for HHD-lesions. [ABSTRACT FROM AUTHOR]

DNA is an entity shielded by mechanisms that maintain genomic stability and are essential for living cells; however, DNA is constantly subject to assaults from the environment throughout the cellular life span, making the genome susceptible to mutation and irreparable damage. Cells are prepared to mend such events through cell death as an extrema ratio to solve those threats from a multicellular perspective. However, in cells under various stress conditions, checkpoint mechanisms are activated to allow cells to have enough time to repair the damaged DNA. In yeast, entry into the cell cycle when damage is not completely repaired represents an adaptive mechanism to cope with stressful conditions. In multicellular organisms, entry into cell cycle with damaged DNA is strictly forbidden. However, in cancer development, individual cells undergo checkpoint adaptation, in which most cells die, but some survive acquiring advantageous mutations and selfishly evolve a conflictual behavior. In this review, we focus on how, in cancer development, cells rely on checkpoint adaptation to escape DNA stress and ultimately to cell death. [ABSTRACT FROM AUTHOR]

The term orthodisease defines human disorders in which the pathogenic gene has orthologs in model organism genomes. Yeasts have been instrumental for gaining insights into the molecular basis of many human disorders, particularly those resulting from impaired cellular metabolism. We and others have used yeasts as a model system to study the molecular basis of Hailey-Hailey disease (HHD), a human blistering skin disorder caused by haploinsufficiency of the gene ATP2C1 the orthologous of the yeast gene PMR1. We observed that K. lactis cells defective for PMR1 gene share several biological similarities with HHD derived keratinocytes. Based on the conservation of ATP2C1/PMR1 function from yeast to human, here we used a yeast-based assay to screen for molecules able to influence the pleiotropy associated with PMR1 deletion. We identified six compounds, Kaempferol, Indirubin, Lappaconite, Cyclocytidine, Azomycin and Nalidixic Acid that induced different major shape phenotypes in K. lactis. These include mitochondrial and the cell-wall morphology-related phenotypes. Interestingly, a secondary assay in mammalian cells confirmed activity for Kaempferol. Indeed, this compound was also active on human keratinocytes depleted of ATP2C1 function by siRNA-treatment used as an in-vitro model of HHD. We found that Kaempferol was a potent NRF2 regulator, strongly inducing its expression and its downstream target NQO1. In addition, Kaempferol could decrease oxidative stress of ATP2C1 defective keratinocytes, characterized by reduced NRF2-expression. Our results indicated that the activation of these pathways might provide protection to the HHD-skin cells. As oxidative stress plays pivotal roles in promoting the skin lesions of Hailey-Hailey, the NRF2 pathway could be a viable therapeutic target for HHD. [ABSTRACT FROM AUTHOR]

Glioblastoma (GBM) is the most aggressive human brain tumor. The high growth potential and decreased susceptibility to apoptosis of the glioma cells is mainly dependent on genetic amplifications or mutations of oncogenic or pro-apoptotic genes, respectively. We have previously shown that the activation of the M2 acetylcholine muscarinic receptors inhibited cell proliferation and induced apoptosis in two GBM cell lines and cancer stem cells. The aim of this study was to delve into the molecular mechanisms underlying the M2-mediated cell proliferation arrest. Exploiting U87MG and U251MG cell lines as model systems, we evaluated the ability of M2 receptors to interfere with Notch-1 and EGFR pathways, whose activation promotes GBM proliferation. We demonstrated that the activation of M2 receptors, by agonist treatment, counteracted Notch and EGFR signaling, through different regulatory cascades depending, at least in part, on p53 status. Only in U87MG cells, which mimic p53-wild type GBMs, did M2 activation trigger a molecular circuitry involving p53, Notch-1, and the tumor suppressor mir-34a-5p. This regulatory module negatively controls Notch-1, which affects cell proliferation mainly through the Notch-1/EGFR axis. Our data highlighted, for the first time, a molecular circuitry that is deregulated in the p53 wild type GBM, based on the cross-talk between M2 receptor and the Notch-1/EGFR pathways, mediated by mir-34a-5p. [ABSTRACT FROM AUTHOR]