Enhancement of radiosensitivity by the novel anticancer quinolone derivative vosaroxin in preclinical glioblastoma models

Purpose: Glioblastoma multiforme (GBM) is the most aggressive brain tumor. The activity of vosaroxin, a first-in-class anticancer quinolone derivative that intercalates DNA and inhibits topoisomerase II, was investigated in GBM preclinical models as a single agent and combined with radiotherapy (RT). Results: Vosaroxin showed antitumor activity in clonogenic survival assays, with IC50 of 10-100 nM, and demonstrated radiosensitization. Combined treatments exhibited significantly higher γH2Ax levels compared with controls. In xenograft models, vosaroxin reduced tumor growth and showed enhanced activity with RT; vosaroxin/RT combined was more effective than temozolomide/RT. Vosaroxin/ RT triggered rapid and massive cell death with characteristics of necrosis. A minor proportion of treated cells underwent caspase-dependent apoptosis, in agreement with in vitro results. Vosaroxin/RT inhibited RT-induced autophagy, increasing necrosis. This was associated with increased recruitment of granulocytes, monocytes, and undifferentiated bone marrow-derived lymphoid cells. Pharmacokinetic analyses revealed adequate blood-brain penetration of vosaroxin. Vosaroxin/RT increased disease-free survival (DFS) and overall survival (OS) significantly compared with RT, vosaroxin alone, temozolomide, and temozolomide/RT in the U251-luciferase orthotopic model. Materials and Methods: Cellular, molecular, and antiproliferative effects of vosaroxin alone or combined with RT were evaluated in 13 GBM cell lines. Tumor growth delay was determined in U87MG, U251, and T98G xenograft mouse models. (DFS) and (OS) were assessed in orthotopic intrabrain models using luciferasetransfected U251 cells by bioluminescence and magnetic resonance imaging. Conclusions: Vosaroxin demonstrated significant activity in vitro and in vivo in GBM models, and showed additive/synergistic activity when combined with RT in O6- methylguanine methyltransferase-negative and -positive cell lines

Increased expression and activity of p75NTR are crucial events in azacitidine-induced cell death in prostate cancer

The high affinity nerve growth factor (NGF) NGF receptor, p75NTR, is a member of the tumor necrosis factor (TNF) receptor superfamily that shares a conserved intracellular death domain capable of inducing apoptosis and suppressing growth in prostate epithelial cells. Expression of this receptor is lost as prostate cancer progresses and is minimal in established prostate cancer cell lines. We aimed to verify the role of p75NTR in the azacitidine-mediated antitumor effects on 22Rv1 and PC3 androgen-independent prostate cancer cells. In the present study, we reported that the antiproliferative and pro-apoptotic effects of 5-azacytidine (azacitidine) were more marked in the presence of physiological concentrations of NGF and were reduced when a blocking p75NTR antibody or the selective p75NTR inhibitor, Ro 08-2750, were used. Azacitidine increased the expression of p75NTR without interfering with the expression of the low affinity NGF receptor TrkA and induced caspase 9-dependent caspase 3 activity. Taken together, our results suggest that the NGF network could be a candidate for future pharmacological manipulation in aggressive prostate cancer

The first-in-class alkylating deacetylase inhibitor molecule tinostamustine shows antitumor effects and is synergistic with radiotherapy in preclinical models of glioblastoma

Background: The use of alkylating agents such as temozolomide in association with radiotherapy (RT) is the therapeutic standard of glioblastoma (GBM). This regimen modestly prolongs overall survival, also if, in light of the still dismal prognosis, further improvements are desperately needed, especially in the patients with O6- methylguanine-DNA-methyltransferase (MGMT) unmethylated tumors, in which the benefit of standard treatment is less. Tinostamustine (EDO-S101) is a first-in-class alkylating deacetylase inhibitor (AK-DACi) molecule that fuses the DNA damaging effect of bendamustine with the fully functional pan-histone deacetylase (HDAC) inhibitor, vorinostat, in a completely new chemical entity. Methods: Tinostamustine has been tested in models of GBM by using 13 GBM cell lines and seven patient-derived GBM proliferating/stem cell lines in vitro. U87MG and U251MG (MGMT negative), as well as T98G (MGMT positive), were subcutaneously injected in nude mice, whereas luciferase positive U251MG cells and patient-derived GBM stem cell line (CSCs-5) were evaluated the orthotopic intra-brain in vivo experiments. Results: We demonstrated that tinostamustine possesses stronger antiproliferative and pro-apoptotic effects than those observed for vorinostat and bendamustine alone and similar to their combination and irrespective of MGMT expression. In addition, we observed a stronger radio-sensitization of single treatment and temozolomide used as control due to reduced expression and increased time of disappearance of γH2AX indicative of reduced signal and DNA repair. This was associated with higher caspase-3 activation and reduction of RT-mediated autophagy. In vivo, tinostamustine increased time-to-progression (TTP) and this was additive/synergistic to RT. Tinostamustine had significant therapeutic activity with suppression of tumor growth and prolongation of DFS (disease-free survival) and OS (overall survival) in orthotopic intra-brain models that was superior to bendamustine, RT and temozolomide and showing stronger radio sensitivity. Conclusions: Our data suggest that tinostamustine deserves further investigation in patients with glioblastoma

The small molecule ephrin receptor inhibitor, GLPG1790, Reduces renewal capabilities of cancer stem cells, showing anti-tumour efficacy on preclinical glioblastoma models

Therapies against glioblastoma (GBM) show a high percentage of failure associated with the survival of glioma stem cells (GSCs) that repopulate treated tumours. Forced differentiation of GSCs is a promising new approach in cancer treatment. Erythropoietin-producing hepatocellular (Eph) receptors drive tumourigenicity and stemness in GBM. We tested GLPG1790, a first small molecule with inhibition activity versus inhibitor of various Eph receptor kinases, in preclinical GBM models using in vitro and in vivo assays. GLPG1790 rapidly and persistently inhibited Ephrin-A1-mediated phosphorylation of Tyr588 and Ser897, completely blocking EphA2 receptor signalling. Similarly, this compound blocks the ephrin B2-mediated EphA3 and EphB4 tyrosine phosphorylation. This resulted in anti-glioma effects. GLPG1790 down-modulated the expression of mesenchymal markers CD44, Sox2, nestin, octamer-binding transcription factor 3/4 (Oct3/4), Nanog, CD90, and CD105, and up-regulated that of glial fibrillary acidic protein (GFAP) and pro-neural/neuronal markers, βIII tubulin, and neurofilaments. GLPG1790 reduced tumour growth in vivo. These effects were larger compared to radiation therapy (RT; U251 and T98G xenografts) and smaller than those of temozolomide (TMZ; U251 and U87MG cell models). By contrast, GLPG1790 showed effects that were higher than Radiotherapy (RT) and similar to Temozolomide (TMZ) in orthotopic U87MG and CSCs-5 models in terms of disease-free survival (DFS) and overall survival (OS). Further experiments were necessary to study possible interactions with radio- and chemotherapy. GLPG1790 demonstrated anti-tumor effects regulating both the differentiative status of Glioma Initiating Cells (GICs) and the quality of tumor microenvironment, translating into efficacy in aggressive GBM mouse models. Significant common molecular targets to radio and chemo therapy supported the combination use of GLPG1790 in ameliorative antiglioma therapy

Nanoscale phase separation in the iron chalcogenide superconductor K0.8Fe1.6Se2 as seen via scanning nanofocused x-ray diffraction

Advanced synchrotron radiation focusing down to a size of 300 nm has been used to visualize nanoscale phase separation in the K0.8Fe1.6Se2 superconducting system using scanning nanofocus single-crystal X-ray diffraction. The results show an intrinsic phase separation in K0.8Fe1.6Se2 single crystals at T< 520 K, revealing coexistence of i) a magnetic phase characterized by an expanded lattice with superstructures due to Fe vacancy ordering and ii) a non-magnetic phase with an in-plane compressed lattice. The spatial distribution of the two phases at 300 K shows a frustrated or arrested nature of the phase separation. The space-resolved imaging of the phase separation permitted us to provide a direct evidence of nanophase domains smaller than 300 nm and different micrometer-sized regions with percolating magnetic or nonmagnetic domains forming a multiscale complex network of the two phases.Comment: 5 pages, 4 figure

Kinetic Study of Laboratory Mutants of NDM-1 Metallo-beta-Lactamase and the Importance of an Isoleucine at Position 35.

peer reviewedTwo laboratory mutants of NDM-1 were generated by replacing the isoleucine at position 35 with threonine and serine residues: the NDM-1(I35T)and NDM-1(I35S)enzymes. These mutants were well characterized, and their kinetic parameters were compared with those of the NDM-1 wild type. Thekcat,Km, andkcat/Kmvalues calculated for the two mutants were slightly different from those of the wild-type enzyme. Interestingly, thekcat/Kmof NDM-1(I35S)for loracarbef was about 14-fold higher than that of NDM-1. Far-UV circular dichroism (CD) spectra of NDM-1 and NDM-1(I35T)and NDM-1(I35S)enzymes suggest local structural rearrangements in the secondary structure with a marked reduction of alpha-helix content in the mutants

Pharmacological treatment with inhibitors of nuclear export enhances the antitumor activity of docetaxel in human prostate cancer

Background and aims: Docetaxel (DTX) modestly increases patient survival of metastatic castration-resistant prostate cancer (mCRPC) due to insurgence of pharmacological resistance. Deregulation of Chromosome Region Maintenance (CRM-1)/ exportin-1 (XPO-1)-mediated nuclear export may play a crucial role in this phenomenon. Material and methods: Here, we evaluated the effects of two Selective Inhibitor of Nuclear Export (SINE) compounds, selinexor (KPT-330) and KPT-251, in association with DTX by using 22rv1, PC3 and DU145 cell lines with their. DTX resistant derivatives. Results and conclusions: We show that DTX resistance may involve overexpression of β-III tubulin (TUBB3) and P-glycoprotein as well as increased cytoplasmic accumulation of Foxo3a. Increased levels of XPO-1 were also observed in DTX resistant cells suggesting that SINE compounds may modulate DTX effectiveness in sensitive cells as well as restore the sensitivity to DTX in resistant ones. Pretreatment with SINE compounds, indeed, sensitized to DTX through increased tumor shrinkage and apoptosis by preventing DTX-induced cell cycle arrest. Basally SINE compounds induce FOXO3a activation and nuclear accumulation increasing the expression of FOXO-responsive genes including p21, p27 and Bim causing cell cycle arrest. SINE compounds-catenin and survivin supporting apoptosis. βdown-regulated Cyclin D1, c-myc, Nuclear sequestration of p-Foxo3a was able to reduce ABCB1 and TUBB3 H2AX levels, prolonged γ expression. Selinexor treatment increased DTX-mediated double strand breaks (DSB), and reduced the levels of DNA repairing proteins including DNA PKc and Topo2A. Our results provide supportive evidence for the therapeutic use of SINE compounds in combination with DTX suggesting their clinical use in mCRPC patients

Peirce como leitor & leitura como devaneio

Scientific inquirers in the modern sense, those thinkers with whom C. S. Peirce most deeply identified, “have been successful because they have spent their lives not in their libraries and museums but in their laboratories and in the field” (CP 1.34). But, in fact, Peirce spent countless hours engaged in an activity he appears to slight in this and other passages. Indeed, he seems to have misread his life as a reader. The author offers a portrait of Peirce as a reader, but of even greater importance he draws upon Georges Poulet to sketch a phenomenology of reading and upon Elaine Scarry to offer an account of reading as a form of reverie. In addition, he shows how Peirce’s thought underwrites both of these endeavors, paying close attention to Peirce’s synechistic account of mind, consciousness, and subjectivity, but also consideration to the semeiotic categories of diagram, symbol, and to a less degree icons.Investigadores científicos no sentido moderno, aqueles pensadores com os quais C.S. Peirce identificava-se mais profundamente, “têm sido bem-sucedidos pois eles passaram suas vidas não em suas bibliotecas ou museus, mas em seus laboratórios e no campo” (CP 1.34). De fato, Peirce gastou incontáveis horas envolvido em uma atividade na qual ele parece menosprezar nesta e em outras passagens. Aliás, ele parece ter interpretado incorretamente sua vida como leitor. O autor oferece um retrato de Peirce como leitor, mesmo quando de maior importância ele se vale de Georges Poulet para delinear uma fenomenologia de leitura e sobre Elaine Scarry para oferecer um relato de leitura como uma forma de devaneio. Além, disso, ele mostra como o pensamento de Peirce garante ambos esforços, acompanhando de perto a consideração peirciana sinequista da mente, consciência e subjetividade, mas também, a consideração às categorias semióticas de diagrama, símbolo e para ícones de graus menores.Investigadores científicos no sentido moderno, aqueles pensadores com os quais C.S. Peirce identificava-se mais profundamente, “têm sido bem-sucedidos pois eles passaram suas vidas não em suas bibliotecas ou museus, mas em seus laboratórios e no campo” (CP 1.34). De fato, Peirce gastou incontáveis horas envolvido em uma atividade na qual ele parece menosprezar nesta e em outras passagens. Aliás, ele parece ter interpretado incorretamente sua vida como leitor. O autor oferece um retrato de Peirce como leitor, mesmo quando de maior importância ele se vale de Georges Poulet para delinear uma fenomenologia de leitura e sobre Elaine Scarry para oferecer um relato de leitura como uma forma de devaneio. Além, disso, ele mostra como o pensamento de Peirce garante ambos esforços, acompanhando de perto a consideração peirciana sinequista da mente, consciência e subjetividade, mas também, a consideração às categorias semióticas de diagrama, símbolo e para ícones de graus menores

O retrato pragmatista da racionalidade deliberativa de Peirce

My overarching purpose is to offer a pragmatist sketch of deliberative rationality derived from collated texts in C. S. Peirce’s voluminous corpus. Though in some instances, the formulations are mine, not Peirce’s. But this does not make my effort an instance of ventriloquism (a case of putting my words into his mouth): the position regarding rationality is his, not (in the first instance) mine. My thesis is that, for Peirce, reason is at bottom a more or less integrated set of habits enabling agents to be deliberative. That is, deliberation is for him the heart of rationality. This is fundamentally an agential capacity: it pertains first and foremost to agents, theoretical knowers being a distinctive role played by deliberative agents. What I hope to show in this paper is why this portrait of reason is distinctively pragmatic and truly Peircean. What I also hope to show is how Peirce’s position entails what in contemporary philosophy is identified by Christine Korsgaard as self-constitution, Sabrina Lovibond as self-formation, and other theorists by other designations. Deliberative agents are, in Peirce’s account, radically responsible agents. They are responsible for the very criteria by which reasonableness and responsibility are defined and developed. The question of maturity and the relationship between being moral and being mature are central to Peirce’s account of rationality. His pragmatist portrait of deliberative rationality is, in my judgment, not only a tenable but also a compelling one. Above all, this is what I hope to show in this essay.Meu propósito abrangente é oferecer um esboço pragmatista da racionalidade deliberativa derivada dos textos coligidos no volumoso conjunto de C. S. Peirce. Embora em alguns casos, as formulações sejam minhas, e não de Peirce. Porém, isso não torna meu esforço um caso de ventriloquismo (colocando minhas palavras na boca dele): a posição em relação à racionalidade é dele, e não (no primeiro caso) minha. Minha tese é que, para Peirce, a razão é no fundo, um conjunto mais ou menos integrado de hábitos, possibilitando aos agentes serem deliberativos. Ou seja, para ele, a deliberação é o cerne da racionalidade. Esta é, fundamentalmente, uma capacidade agencial: aplica-se primordialmente a agentes, sendo conhecedores teóricos um papel importante desempenhado por agentes deliberativos. O que espero demonstrar neste trabalho é a razão pela qual este retrato da razão é distintamente pragmático e verdadeiramente peirciano. O que também espero demonstrar é como a posição de Peirce implica o que, na filosofia contemporânea, é identificado por Christine Korsgaard como autoconstituição, por Sabrina Lovibond como autoformação e por outros teóricos com designações outras. Agentes deliberativos são, segundo Peirce, agentes radicalmente responsáveis. São responsáveis pelos verdadeiros critérios nos quais razoabilidade e responsabilidade são definidas e desenvolvidas. A questão de maturidade e a relação entre ser moral e ser maduro são essenciais à explicação de Peirce de racionalidade. Seu retrato pragmatista da racionalidade deliberativa é, a meu ver, não só sustentável quanto convincente. Acima de tudo, isto é o que espero demonstrar neste ensaio

C. S. Peirce e Josiah Royce: Entendimento, entendimento de si e desentendimento de si

There is, at the heart of this paper, a comparison between Peirce’s understanding of inquiry and Royce’s account of interpretation. It is framed by a consideration of self-misunderstanding (a consideration developed in reference to Peirce) and, tied to this discussion of self-misunderstanding, a consideration of understanding itself. For Peirce, in his account of inquiry, and Royce in his meta-interpretation (i.e., his interpretation of the meaning and function of interpretation itself), some form of understanding is at stake. For example, the task of the scientific inquirer is unfinished if it stops at the discovering of the bare facts (simply that something is actually the case—i.e., a body such as a small stone held aloft by a person will fall to the ground if the person lets it go). While for both thinkers, science is not a body of secure knowledge but rather a form of ongoing inquiry, it aims primarily at understanding. Both Peirce and Royce are animated by a commitment to the intelligibility of the cosmos in its full sweep and smallest detail. Peirce’s account of inquiry and Royce’s conception of interpretation are endeavors to detail how human actors render ever more deeply and widely intelligible the world of their experience. Much can be learned comparing them in this respect.No âmago deste artigo há uma comparação entre a investigação sobre o entendimento de Peirce o relato de interpretação de Royce. Estrutura-se por uma consideração do desentendimento de si (uma consideração desenvolvida em referência a Peirce) e, ligada a esta discussão do desentendimento de si, uma consideração sobre o próprio entendimento. Para Peirce, em razão de sua abordagem da investigação e Royce em sua meta-interpretação (i.e., sua interpretação do significado e da função da própria interpretação) alguma forma de entendimento está em jogo. Por exemplo, a tarefa do investigador científico é inacabada se ela para na descoberta de fatos nus (simplesmente que algo é verdadeiramente o caso – um corpo tal como uma pedra pequena sustentada no alto por uma pessoa cairá no solo se a pessoa soltá-la). Enquanto para ambos os pensadores, as ciências não um corpo de conhecimento seguro, mas uma forma de investigação contínua, ela visa principalmente o entendimento. Tanto Peirce quanto Royce estão animados por um compromisso com a inteligibilidade do cosmos em sua varredura plena e nos mínimos detalhes. A abordagem de Peirce sobre a investigação e a concepção de interpretação de Royce são esforços para detalhar como os atores humanos tornam cada vez mais profunda e amplamente inteligível o mundo de sua experiência. Muito pode ser aprendido comparando-os a este respeito