Krzysztof Reiss

Publications of Krzysztof Reiss

• Inhibition of ERβ Induces Resistance to Cisplatin by Enhancing Rad51-Mediated DNA Repair in Human Medulloblastoma Cell Lines.

  Authors: Anna Wilk, Agnieszka Waligorska, Piotr Waligorski, Augusto Ochoa, Krzysztof Reiss

  PloS one. 01/2012; 7(3):e33867.

  Cisplatin is one of the most widely used and effective anticancer drugs against solid tumors including cerebellar tumor of the childhood, Medulloblastoma. However, cancer cells often developCisplatin is one of the most widely used and effective anticancer drugs against solid tumors including cerebellar tumor of the childhood, Medulloblastoma. However, cancer cells often develop resistance to cisplatin, which limits therapeutic effectiveness of this otherwise effective genotoxic drug. In this study, we demonstrate that human medulloblastoma cell lines develop acute resistance to cisplatin in the presence of estrogen receptor (ER) antagonist, ICI182,780. This unexpected finding involves a switch from the G2/M to G1 checkpoint accompanied by decrease in ATM/Chk2 and increase in ATR/Chk1 phosphorylation. We have previously reported that ERβ, which is highly expressed in medulloblastomas, translocates insulin receptor substrate 1 (IRS-1) to the nucleus, and that nuclear IRS-1 binds to Rad51 and attenuates homologous recombination directed DNA repair (HRR). Here, we demonstrate that in the presence of ICI182,780, cisplatin-treated medulloblastoma cells show recruitment of Rad51 to the sites of damaged DNA and increase in HRR activity. This enhanced DNA repair during the S phase preserved also clonogenic potential of medulloblastoma cells treated with cisplatin. In conclusion, inhibition of ERβ considered as a supplemental anticancer therapy, has been found to interfere with cisplatin-induced cytotoxicity in human medulloblastoma cell lines.

• Nuclear IRS-1 and cancer.

  Authors: Krzysztof Reiss, Luis Del Valle, Adam Lassak, Joanna Trojanek

  Journal of cellular physiology. 12/2011;

  The family of insulin receptor substrates (IRS) consists of four proteins (IRS-1 - IRS-4), which were initially characterized as typical cytosolic adaptor proteins involved in insulin receptor (IR)The family of insulin receptor substrates (IRS) consists of four proteins (IRS-1 - IRS-4), which were initially characterized as typical cytosolic adaptor proteins involved in insulin receptor (IR) and insulin-like growth factor I receptor (IGF-IR) signaling. The first cloned and characterized member of the IRS family, IRS-1, has predicted molecular weight of 132 kDa, however, as a result of its extensive serine phosphorylation it separates on a SDS gel as a band of approximately 160-185 kDa. In addition to its metabolic and growth-promoting functions, IRS-1 is also suspected to play a role in malignant transformation. The mechanism by which IRS-1 supports tumor growth is not fully understood, and the argument that IRS-1 merely amplifies the signal from the IGF-1R and/or IR requires further investigation. Almost a decade ago, we reported the presence of nuclear IRS-1 in medulloblastoma clinical samples, which express viral oncoprotein, large T-antigen of human polyomavirus JC (JCV T-antigen). This first demonstration of nuclear IRS-1 was confirmed in several other laboratories. The nuclear IRS-1 was also detected by cells expressing the SV40 T-antigen, v-Src, in immortalized fibroblasts stimulated with IGF-I, in hepatocytes, 32D cells, and in an osteosarcoma cell line. More recently, nuclear IRS-1 was detected in breast cancer cells in association with estrogen receptor alpha (ERα), and in JC virus negative medulloblastoma cells expressing ERb, further implicating nuclear IRS-1 in cellular transformation. Here, we discuss how nuclear IRS-1 acting on DNA repair fidelity, transcriptional activity, and cell growth can support tumor development and progression. J. Cell. Physiol. © 2011 Wiley Periodicals, Inc.

• Fenofibrate attenuates contact-stimulated cell motility and gap junctional coupling in DU-145 human prostate cancer cell populations.

  Authors: Ewa Wybieralska, Katarzyna Szpak, Andrzej Górecki, Piotr Bonarek, Katarzyna Miękus, Justyna Drukała, Marcin Majka, Krzysztof Reiss, Zbigniew Madeja, Jarosław Czyż

  Oncology reports. 08/2011; 26(2):447-53.

  In the present study, we investigated the effects of fenofibrate on the invasive potential of DU-145 human prostate cancer cells in the context of gap junctional intercellular coupling and theIn the present study, we investigated the effects of fenofibrate on the invasive potential of DU-145 human prostate cancer cells in the context of gap junctional intercellular coupling and the formation of reactive oxygen species. Time-lapse analyses of cell motility, accompanied by tests of cell viability, membrane microviscosity, reactive oxygen species accumulation and the function of gap junctional protein connexin 43 were performed in monolayer cultures of DU-145 cells following fenofibrate administration. Fenofibrate inhibited the motility of DU-145 cells and attenuated gap junctional intercellular coupling in a manner independent of its effects on cell viability, PPARα activation and cell membrane micro-viscosity. Instead, N-acetyl-L-cysteine, a scavenger of reactive oxygen species, restored cell motility and gap junctional coupling in fenofibrate-treated DU-145 cell populations. These data indicate that two parameters crucial for cancer cell metastatic potential, i.e. cell motility and gap junctional coupling, are inhibited by fenofibrate. Thus, fenofibrate affects prostate cancer cell invasion via an orchestrated action on versatile cancer cell properties determining this process. A novel mechanism of anti-invasive activity of fenofibrate, which depends on its interference with cell motility and the function of gap junctions regulated by reactive oxygen species, is suggested.

• Insulin-like growth factor-I-forkhead box O transcription factor 3a counteracts high glucose/tumor necrosis factor-α-mediated neuronal damage: implications for human immunodeficiency virus encephalitis.

  Authors: Anna Wilk, Katarzyna Urbanska, Shuo Yang, Jin Ying Wang, Shohreh Amini, Luis Del Valle, Francesca Peruzzi, Leonard Meggs, Krzysztof Reiss

  Journal of neuroscience research. 02/2011; 89(2):183-98.

  In HIV patients, antiretroviral medications trigger metabolic abnormalities, including insulin resistance. In addition, the inflammatory cytokine tumor necrosis factor-α (TNFα), which is elevated inIn HIV patients, antiretroviral medications trigger metabolic abnormalities, including insulin resistance. In addition, the inflammatory cytokine tumor necrosis factor-α (TNFα), which is elevated in human immunodeficiency virus encephalitis (HIVE), also induces insulin resistance and inflicts neuronal damage in vitro. In differentiated PC12 cells and rat cortical neurons, high glucose (HG; 25 mM) triggers reactive oxygen species (ROS) accumulation, contributing to the retraction of neuronal processes, with only a minimal involvement of neuronal apoptosis. In the presence of TNFα, HG-treated neurons undergo massive apoptosis. Because mammalian homolog of the Forkhead family of transcription factors, Forkhead box O transcription factor 3a (FOXO3a), controls ROS metabolism, we asked whether FOXO3a could affect the fate of differentiated neurons in the paradigm of HIVE. We observed FOXO3a nuclear translocation in HG-treated neuronal cultures, accompanied by partial loss of mitochondrial potential and gradual retraction of neuronal processes. Addition of TNFα to HG-treated neurons increased expression of the FOXO-dependent proapoptotic gene Bim, which resulted in extensive apoptotic death. Insulin-like growth factor-I (IGF-I) significantly lowered intracellular ROS, which was accompanied by IGF-I-mediated FOXO3a nuclear export and decrease in its transcriptional activity. The clinical relevance of these findings is supported by detection of nuclear FOXO3a in TUNEL-positive cortical neurons from HIVE, especially in brain areas characterized by elevated TNFα.

• Peroxisome Proliferator Activated Receptor α Ligands As Anti-Cancer Drugs Targeting Mitochondrial Metabolism.

  Authors: Maja Grabacka, Malgorzata Pierzchalska, Krzysztof Reiss

  Current pharmaceutical biotechnology. 12/2010;

  Tumor cells show metabolic features distinctive from normal tissues, with characteristic enhanced aerobic glycolysis, glutaminolysis and lipid synthesis. Peroxisome proliferator activated receptor αTumor cells show metabolic features distinctive from normal tissues, with characteristic enhanced aerobic glycolysis, glutaminolysis and lipid synthesis. Peroxisome proliferator activated receptor α (PPAR α) is activated by nutrients (fatty acids and their derivatives) and influences these metabolic pathways acting antagonistically to oncogenic Akt and c-Myc activities. Therefore PPAR α can be regarded as a candidate target molecule in supplementary anti-cancer pharmacotherapy as well as dietary therapeutic approach. This idea is based on hitting the cancer cell metabolic weak points through PPAR α mediated stimulation of mitochondrial fatty acid oxidation and ketogenesis with simultaneous reduction of glucose and glutamine consumption. PPAR α activity is induced by fasting and its molecular consequences overlap with the effects of calorie restriction and ketogenic diet (CRKD). CRKD induces increase of NAD(+)/NADH ratio and drop in ATP/AMP ratio. The former is the main stimulus for enhanced sirtuin - protein deacetylase SIRT1 activity; the latter activates AMP-dependent protein kinase (AMPK). Both SIRT1 and AMPK exert their major metabolic activities such as fatty acid oxidation and block of glycolysis and protein, nucleotide and fatty acid synthesis through the effector protein peroxisome proliferator activated receptor gamma 1 α coactivator (PGC-1α). PGC-1α cooperates with PPAR α and their activities might contribute to potential anti-cancer effects of CRKD, which were reported for various brain tumors. Interplay between SIRT1, AMPK, PGC-1α and PPAR α seems to be the basis of anti-tumor dietary approach which may effectively supplement chemotherapy, especially that it is cheap and safe.

• Erratum: Caracciolo V, Reiss K, Crozier-Fitzgerald C, De Pascali F, Macaluso M, Khalili K, Giordano A. 2007. Interplay between the retinoblastoma related pRb2/p130 and E2F-4 and -5 in relation to JCV-TAg. J Cell Physiol 212: 96-104.

  Authors: Valentina Caracciolo, Krzysztof Reiss, Catena Crozier-Fitzgerald, Francesco De Pascali, Marcella Macaluso, Kamel Khalili, Antonio Giordano

  Journal of cellular physiology. 03/2010; 223(3):827.

• Cross-talk between T-Ag presence and pRb family and p53/p73 signaling in mouse and human medulloblastoma.

  Authors: Valentina Caracciolo, Marcella Macaluso, Luca D'Agostino, Micaela Montanari, Jonathan Scheff, Krzysztof Reiss, Kamel Khalili, Antonio Giordano

  Journal of cellular biochemistry. 03/2010; 110(1):182-90.

  The formation and progression of mudulloblastoma (MB) is poorly understood. However, somatic inactivation of pRb/p105, in combination with a somatic or a germ-line TP53 inactivation, leads to MB in aThe formation and progression of mudulloblastoma (MB) is poorly understood. However, somatic inactivation of pRb/p105, in combination with a somatic or a germ-line TP53 inactivation, leads to MB in a mouse model. Presently, there is no specific evidence of pathway/s alterations for the other two members of the retinoblastoma family, pRb2/p130 and/or p107 in MB. JC virus (JCV) is a human polyomavirus. Although there is no firm evidence that this virus plays a causal role in human neoplasia, it has been clearly proven that JCV is highly oncogenic when injected into the brain of experimental animals. The mechanism of JCV-induced tumorigenesis is not entirely clear. However, several studies relate the oncogenic properties of JCV mainly to its early protein large T-antigen (T-Ag), which is able to bind and inactivate both TP53 and Rb family proteins. Here, we compared the protein expression profiles of p53, p73, pRb family proteins, and PCNA, as main regulators of cell proliferation and death, in different cell lines of mouse primitive neuroectodermal tumors (PNET), either T-Ag-positive or -negative, and in human MB cell lines. Our goal was to determine if changes in the relative expression of these regulators could trigger molecular perturbations underlying MB pathogenesis in mouse and human cells. Our results support that the presence of JCV T-Ag may interfere with the expression of pRb family proteins, specific p73 isoforms, and p53. In turn, this "perturbation" may trigger a network of signals strictly connected with survival and apoptosis.

• ROS accumulation and IGF-IR inhibition contribute to fenofibrate/PPARalpha -mediated inhibition of glioma cell motility in vitro.

  Authors: Justyna Drukala, Katarzyna Urbanska, Anna Wilk, Maja Grabacka, Ewa Wybieralska, Luis Del Valle, Zbigniew Madeja, Krzysztof Reiss

  Molecular cancer. 01/2010; 9:159.

  Glioblastomas are characterized by rapid cell growth, aggressive CNS infiltration, and are resistant to all known anticancer regimens. Recent studies indicate that fibrates and statins possessGlioblastomas are characterized by rapid cell growth, aggressive CNS infiltration, and are resistant to all known anticancer regimens. Recent studies indicate that fibrates and statins possess anticancer potential. Fenofibrate is a potent agonist of peroxisome proliferator activated receptor alpha (PPARalpha) that can switch energy metabolism from glycolysis to fatty acid beta-oxidation, and has low systemic toxicity. Fenofibrate also attenuates IGF-I-mediated cellular responses, which could be relevant in the process of glioblastoma cell dispersal. The effects of fenofibrate on Glioma cell motility, IGF-I receptor (IGF-IR) signaling, PPARalpha activity, reactive oxygen species (ROS) metabolism, mitochondrial potential, and ATP production were analyzed in human glioma cell lines. Fenofibrate treatment attenuated IGF-I signaling responses and repressed cell motility of LN-229 and T98G Glioma cell lines. In the absence of fenofibrate, specific inhibition of the IGF-IR had only modest effects on Glioma cell motility. Further experiments revealed that PPARalpha-dependent accumulation of ROS is a strong contributing factor in Glioma cell lines responses to fenofibrate. The ROS scavenger, N-acetyl-cysteine (NAC), restored cell motility, improved mitochondrial potential, and increased ATP levels in fenofibrate treated Glioma cell lines. Our results indicate that although fenofibrate-mediated inhibition of the IGF-IR may not be sufficient in counteracting Glioma cell dispersal, PPARalpha-dependent metabolic switch and the resulting ROS accumulation strongly contribute to the inhibition of these devastating brain tumor cells.

• Inhibtion of P66SHCA longevity gene rescues podocytes from HIV-1-induced oxidative stress and apoptosis.

  Authors: Mohammad Husain, Leonard G Meggs, Himanshu Vashishtha, Sonia Simoes, Kevin O. Griffiths, Dileep Kumar, Joanna Mikulak, Peter W Mathieson, Moin A Saleem, Louis Del Valle, Sergio Pina-Oviedo, Jin Ying Wang, Surya V. Seshan, Ashwani Malhotra, Krzysztof Reiss, Pravin C Singhal

  The Journal of biological chemistry. 05/2009;

  Glomerular visceral epithelial cells (podocytes) play a critical role in the pathogenesis of HIV associated nephropathy (HIVAN). A key question concerns the mechanism(s) by which the HIV-1 genomeGlomerular visceral epithelial cells (podocytes) play a critical role in the pathogenesis of HIV associated nephropathy (HIVAN). A key question concerns the mechanism(s) by which the HIV-1 genome alters the phenotype of the highly specialized, terminally differentiated podocytes. Here, using an in vitro system of conditionally immortalized differentiated human podocytes (CIDHP), we document a pivotal role for the p66ShcA protein in HIV-1-induced reactive oxygen species (ROS) generation and CIDHP apoptosis. CIDHP transfected with truncated HIV-1 construct (NL4-3) exhibit increased ROS metabolism, DNA strand breaks and 5-fold increase in apoptosis, whereas the opposite was true for NL4-3/CIDHP, co-transfected with mu-36p66ShcA (mu-36) dominant negative expression vector or isoform specific p66-siRNA. Phosphorylation at Ser-36 of the wild type p66ShcA protein, required for p66ShcA redox function and inhibition of the potent stress response regulator Foxo3a, was unchanged in mu-36/NL4-3/CIDHP, but increased in NL4-3/CIDHP. Acute knockdown of Foxo3a by siRNA induced 50% increase in mu-36/NL4-3/CIDHP apoptosis, indicating that Foxo3a dependent responses promote the survival phenotype in mu-36 cells. We conclude that inhibition of p66ShcA redox activity prevents generation of HIV-1 stress signals and activation of the CIDHP apoptosis program.

• IGF-IR in neuroprotection and brain tumors.

  Authors: Elisa Gualco, Jin Ying Wang, Luis Del Valle, Katarzyna Urbanska, Francesca Peruzzi, Kamel Khalili, Shohreh Amini, Krzysztof Reiss

  Frontiers in bioscience : a journal and virtual library. 02/2009; 14:352-75.

  The IGF-IR is a multifunctional tyrosine kinase receptor involved in several biological processes including cell proliferation, differentiation, DNA repair, and cell survival. In the brain IGF-IThe IGF-IR is a multifunctional tyrosine kinase receptor involved in several biological processes including cell proliferation, differentiation, DNA repair, and cell survival. In the brain IGF-I plays a critical role during embryonic and early postnatal development. In the mature brain, IGF-I binding sites have been found in different regions of the brain, and multiple reports confirmed a strong neuroprotective action of the IGF-IR against different pro-apoptotic insults. When the IGF-IR signaling system is insufficiently deployed, either by low level of expression in elderly individuals, or by the inhibition associated with inflammatory cytokines, neuronal function and survival could be compromised. The examples of such CNS pathologies include HIV associated dementia, diabetic neuropathies, and Alzheimer's disease. On the other hand, elevated expression activity of the IGF-IR may support uncontrolled cell proliferation and protection from apoptosis. Probably the best example of the IGF-IR involvement in brain tumors is medulloblastomas in which functional cooperation between viral oncoprotein, JC virus large T-antigen, and IGF-IR has been recently established. Therefore, better understanding of the beneficial and potentially harmful aspects of the IGF-IR can be critical for the development of new clinical regimens against neurodegenerative disorders and brain tumors.

• Estrogen receptor beta-mediated nuclear interaction between IRS-1 and Rad51 inhibits homologous recombination directed DNA repair in medulloblastoma.

  Authors: Katarzyna Urbanska, Paola Pannizzo, Adam Lassak, Elisa Gualco, Eva Surmacz, Sidney Croul, Luis Del Valle, Kamel Khalili, Krzysztof Reiss

  Journal of cellular physiology. 01/2009;

  In medulloblastomas, which are highly malignant cerebellar tumors of the childhood genotoxic treatments such as cisplatin or gamma-irradiation are frequently associated with DNA damage, which oftenIn medulloblastomas, which are highly malignant cerebellar tumors of the childhood genotoxic treatments such as cisplatin or gamma-irradiation are frequently associated with DNA damage, which often associates with unfaithful DNA repair, selection of new adaptations and possibly tumor recurrences. Therefore, better understanding of molecular mechanisms which control DNA repair fidelity upon DNA damage is a critical task. Here we demonstrate for the first time that estrogen receptor beta (ERbeta) can contribute to the development of genomic instability in medulloblastomas. Specifically, ERbeta was found highly expressed and active in mouse and human medulloblastoma cell lines. Nuclear ERbeta was also present in human medulloblastoma clinical samples. Expression of ERbeta coincided with nuclear translocation of insulin receptor substrate 1 (IRS-1), which was previously reported to interfere with the faithful component of DNA repair when translocated to the nucleus. We demonstrated that ERbeta and IRS-1 bind each other, and the interaction involves C-terminal domain of IRS-1 (aa 931-1233). Following cisplatin-induced DNA damage, nuclear IRS-1 localized at the sites of damaged DNA, and interacted with Rad51-an enzymatic component of homologous recombination directed DNA repair (HRR). In medulloblastoma cells, engineered to express HRR-DNA reporter plasmid, ER antagonist, ICI 182,780, or IRS mutant (931-1233) significantly increased DNA repair fidelity. These data strongly suggest that both molecular and pharmacological interventions are capable of preventing ERbeta-mediated IRS-1 nuclear translocation, which in turn improves DNA repair fidelity and possibly counteracts accumulation of malignant mutations in actively growing medulloblastomas. J. Cell. Physiol. (c) 2008 Wiley-Liss, Inc.

• Activation of PPARalpha inhibits IGF-I-mediated growth and survival responses in medulloblastoma cell lines.

  Authors: Katarzyna Urbanska, Paola Pannizzo, Maja Grabacka, Sidney Croul, Luis Del Valle, Kamel Khalili, Krzysztof Reiss

  International journal of cancer. Journal international du cancer. 10/2008; 123(5):1015-24.

  Recent studies suggest a potential role of lipid lowering drugs, fibrates and statins, in anticancer treatment. One candidate for tumor chemoprevention is fenofibrate, which is a potent agonist ofRecent studies suggest a potential role of lipid lowering drugs, fibrates and statins, in anticancer treatment. One candidate for tumor chemoprevention is fenofibrate, which is a potent agonist of peroxisome proliferator activated receptor alpha (PPARalpha). Our results demonstrate elevated expression of PPARalpha in the nuclei of neoplatic cells in 12 out of 13 cases of medulloblastoma, and of PPARgamma in six out of 13 cases. Further analysis demonstrated that aggressive mouse medulloblastoma cells, BsB8, express PPARalpha in the absence PPARgamma, and human medulloblastoma cells, D384 and Daoy, express both PPARalpha and PPARgamma. Mouse and human cells responded to fenofibrate by a significant increase of PPAR-mediated transcriptional activity, and by a gradual accumulation of cells in G1 and G2/M phase of the cell cycle, leading to the inhibition of cell proliferation and elevated apoptosis. Preincubation of BsB8 cells with fenofibrate attenuated IGF-I-induced IRS-1, Akt, ERKs and GSK3beta phosphorylation, and inhibited clonogenic growth. In Daoy and D384 cells, fenofibrate also inhibited IGF-I-mediated growth responses, and simultaneous delivery of fenofibrate with low dose of the IGF-IR inhibitor, NVP-AEW541, completely abolished their clonogenic growth and survival. These results indicate a strong supportive role of fenofibrate in chemoprevention against IGF-I-induced growth responses in medulloblastoma.

• Integrins mediate adhesion of medulloblastoma cells to tenascin and activate pathways associated with survival and proliferation.

  Authors: Paul Fiorilli, Darren Partridge, Izabela Staniszewska, Jin Y Wang, Maja Grabacka, Kelvin So, Cezary Marcinkiewicz, Krzysztof Reiss, Kamel Khalili, Sidney E Croul

  Laboratory investigation; a journal of technical methods and pathology. 10/2008;

  Medulloblastoma spreads by leptomeningeal dissemination rather than by infiltration that characterizes other CNS tumors, eg, gliomas. This study represents an initial attempt to identify both theMedulloblastoma spreads by leptomeningeal dissemination rather than by infiltration that characterizes other CNS tumors, eg, gliomas. This study represents an initial attempt to identify both the molecules that mediate medulloblastoma adhesion to leptomeninges and the pathways that are key to survival and proliferation of tumor following adhesion. As a first step in molecule identification, we produced adhesion of D283 medulloblastoma cells to the extracellular matrix (ECM) of H4 glioma cells in vitro. Within this context, D283 cells preferentially expressed the alpha9 and beta1 integrin subunits; antibody and disintegrin blockade of alpha9 and beta1 binding eliminated the adhesion. The H4 ECM was enriched in tenascin, a binding partner for the alpha9beta1 integrin heterodimer. Purified tenascin-C supported D283 cell adhesion. The adhesion was blocked by antibodies to alpha9 and beta1 integrin. In vivo data were similar; immunohistochemistry of primary human medulloblastomas with leptomeningeal extension demonstrated increased expression of alpha9 and beta1 integrins as well as tenascin at the interface of brain and leptomeningeal tumor. These data suggest that tumor-cell expressions of alpha9 and beta1 integrins in combination with extracellular tenascin are necessary for medulloblastoma adhesion to the leptomeninges. As a first step in the identification of pathways that mediate survival and proliferation of tumor following adhesion, we demonstrated that adhesion to H4 ECM was associated with survival and proliferation of D283 cells as well as activation of the MAPK pathway in a growth factor deficient environment. Antibody blockade of alpha9 and beta1 integrin binding that eliminated adhesion also eliminated the in vitro survival benefit. These data suggest that adhesion of medulloblastoma to the meninges is necessary for the survival and proliferation of these tumor cells at the secondary site.Laboratory Investigation advance online publication, 15 September 2008; doi:10.1038/labinvest.2008.89.

• HIV-1 Tat inhibits NGF-induced Egr-1 transcriptional activity and consequent p35 expression in neural cells.

  Authors: Nune Darbinian, Armine Darbinyan, Marta Czernik, Francesca Peruzzi, Kamel Khalili, Krzysztof Reiss, Jennifer Gordon, Shohreh Amini

  Journal of cellular physiology. 08/2008; 216(1):128-34.

  Infection with HIV-1 causes degeneration of neurons leading to motor and cognitive dysfunction in AIDS patients. One of the key viral regulatory proteins, Tat, which is released by infected cells,Infection with HIV-1 causes degeneration of neurons leading to motor and cognitive dysfunction in AIDS patients. One of the key viral regulatory proteins, Tat, which is released by infected cells, can be taken up by various uninfected cells including neurons and by dysregulating several biological events induces cell injury and death. In earlier studies, we demonstrated that treatment of neuronal cells with Tat affects the nerve growth factor (NGF) signaling pathway involving MAPK/ERK. Here we demonstrate that a decrease in the level of Egr-1, one of the targets for MAPK, by Tat has a negative impact on the level of p35 expression in NGF-treated neural cells. Further, we demonstrate a reduced level of Egr-1 association with the p35 promoter sequence in NGF-treated cells expressing Tat. As p35, by associating with Cdk5, phosphorylates several neuronal proteins including neurofilaments and plays a role in neuronal differentiation and survival, we examined kinase activity of p35 complexes obtained from cells expressing Tat. Results from H1 kinase assays showed reduced activity of the p35 complex from Tat-expressing cells in comparison to that from control cells. Accordingly, the level of phosphorylated neurofilaments was diminished in Tat-expressing cells. Similarly, treatment of PC12 cells with Tat protein or supernatant from HIV-1 infected cells decreased kinase activity of p35 in these cells. These observations ascribe a role for Tat in altering p35 expression and its activity that affects phosphorylation of proteins involved in neuronal cell survival.

• PPAR gamma regulates MITF and beta-catenin expression and promotes a differentiated phenotype in mouse melanoma S91.

  Authors: Maja Grabacka, Wojciech Placha, Krystyna Urbanska, Piotr Laidler, Przemysław M Płonka, Krzysztof Reiss

  Pigment cell & melanoma research. 07/2008; 21(3):388-96.

  Melanoma represents one of the most rapidly metastasizing, hence deadly tumors due to its high proliferation rate and invasiveness, characteristics of undifferentiated embryonic tissues. Given theMelanoma represents one of the most rapidly metastasizing, hence deadly tumors due to its high proliferation rate and invasiveness, characteristics of undifferentiated embryonic tissues. Given the absence of effective therapy for metastatic melanoma, understanding more fully the molecular mechanisms underlying melanocyte differentiation may provide opportunities for novel therapeutic intervention. Here we show that in mouse melanoma S91 cells activation of the peroxisome proliferator activated receptor (PPAR) gamma induces events resembling differentiation, such as growth arrest accompanied by apoptosis, spindle morphology and enhanced tyrosinase expression. These events are preceded by an initial transient increase in expression from the Microphthalmia-associated transcription factor gene, (MITF) promoter, whereas exposure to a PPAR gamma ligand- ciglitazone that exceeds 8 h, causes a gradual decrease of MITF, until by 48 h MITF expression is substantially reduced. Beta-catenin, an MITF transcriptional activator, shows a similar pattern of decline during ciglitazone treatment, consistent with previous reports that activated PPAR gamma inhibits the Wnt/beta-catenin pathway through induction of beta-catenin proteasomal degradation. We suggest that the PPAR gamma-mediated beta-catenin down-regulation is likely to be responsible for changes in MITF levels. The data suggest that PPAR gamma, besides its well-established role in mesenchymal cell differentiation towards adipocytes, might regulate differentiation in the melanocytic lineage.

• Medulloblastoma: from molecular pathology to therapy.

  Authors: Alessandra Rossi, Valentina Caracciolo, Giuseppe Russo, Krzysztof Reiss, Antonio Giordano

  Clinical cancer research : an official journal of the American Association for Cancer Research. 03/2008; 14(4):971-6.

  Medulloblastoma is the most common malignant tumor of central nervous system in children. Patients affected by medulloblastoma may be categorized as high-risk and standard-risk patients, based on theMedulloblastoma is the most common malignant tumor of central nervous system in children. Patients affected by medulloblastoma may be categorized as high-risk and standard-risk patients, based on the clinical criteria and histologic features of the disease. Currently, multimodality treatment, including surgery, radiotherapy, and chemotherapy is considered as the most effective strategy against these malignant cerebellar tumors of the childhood. Despite the potential poor outcomes of these lesions, the 5-year survival stands, at present, at 70% to 80% for standard-risk patients, whereas high-risk patients have a 5-year survival of 55% to 76%. Attempts to further reduce the morbidity and mortality associated with medulloblastoma have been restricted by the toxicity of conventional treatments and the infiltrative nature of the disease. Over the past decade, new discoveries in molecular biology have revealed new insights in signaling pathways regulating medulloblastoma tumor formation. Recent advances in the molecular biology of medulloblastoma indicate that the classification of these embryonal tumors, solely based on histology and clinical criteria, may not be adequate enough. Better understanding of the growth control mechanisms involved in the development and progression of medulloblastoma will allow a better classification, leading to the improvement of the existing therapies, as well as to the development of new therapeutic approaches.

• Anticancer Properties of PPARalpha-Effects on Cellular Metabolism and Inflammation.

  Authors: Maja Grabacka, Krzysztof Reiss

  PPAR research. 02/2008; 2008:930705.

  Peroxisome proliferator-activated receptors (PPARs) have lately attracted much attention as therapeutic targets. Previously, PPAR ligands were associated with the treatment of diabetes,Peroxisome proliferator-activated receptors (PPARs) have lately attracted much attention as therapeutic targets. Previously, PPAR ligands were associated with the treatment of diabetes, hyperlipidemia and cardiovascular diseases, as they modulate the expression of genes regulating glucose and lipid metabolism. Recently, PPAR ligands have been also considered as potential anticancer agents, with relatively low systemic toxicity. The emerging evidence for antiproliferative, proapoptotic, antiinflammatory and potential antimetastatic properties of PPARalpha ligands prompted us to discuss possible roles of PPARalpha in tumor suppression. PPARalpha activation can target cancer cells energy balance by blocking fatty acid synthesis and by promoting fatty acid beta-oxidation. In the state of limited nutrient availability, frequently presents in the tumor microenvironment, PPARalpha cooperates with AMP-dependent protein kinase in: (i) repressing oncogenic Akt activity, (ii) inhibiting cell proliferation, and (iii) forcing glycolysis-dependent cancer cells into "metabolic catastrophe." Other potential anticancer effects of PPARalpha include suppression of inflammation, and upregulation of uncoupling proteins (UCPs), which attenuates mitochondrial reactive oxygen species production and cell proliferation. In conclusion, there are strong premises that the low-toxic and well-tolerated PPAR ligands should be considered as new therapeutic agents to fight disseminating cancer, which represents the major challenge for modern medicine and basic research.

• Interaction between serine phosphorylated IRS-1 and beta1-integrin affects the stability of neuronal processes.

  Authors: Jin Ying Wang, Elisa Gualco, Francesca Peruzzi, Bassel E Sawaya, Giovanni Passiatore, Cezary Marcinkiewicz, Izabella Staniszewska, Pasquale Ferrante, Shohreh Amini, Kamel Khalili, Krzysztof Reiss

  Journal of neuroscience research. 09/2007; 85(11):2360-73.

  Tumor necrosis factor-alpha (TNFalpha) released in the brain by HIV-activated macrophages/microglia is suspected to compromise neuronal survival. Previously, we have demonstrated that activatedTumor necrosis factor-alpha (TNFalpha) released in the brain by HIV-activated macrophages/microglia is suspected to compromise neuronal survival. Previously, we have demonstrated that activated receptor for insulin-like growth factor I (IGF-IR) protects neurons from TNFalpha-induced neuronal damage (Wang et al. [ 2006] J. Neurosci. Res. 83:7-18). Because TNFalpha triggers phosphorylation of insulin receptor substrate 1 (IRS-1) on serine residues (pS-IRS-1; Rui et al. [ 2001] J. Clin. Invest. 107:181-189), and pS-IRS-1 binds integrins (Reiss et al. [ 2001] Oncogene 20:490-500), we asked how these events affect neuronal processes. We show that beta1-integrin and pS-IRS-1 colocalize in PC12 cells and in primary cortical neurons. TNFalpha treatment elevated membrane-associated pS-IRS-1, enhanced pS-IRS-1 interaction with beta1-integrin, and attenuated cell attachment to collagen IV. In contrast, IGF-I inhibited pS-IRS-1-beta1-integrin complexes and improved cell attachment. The domain of IRS-1 involved in beta1-integrin binding mapped between amino acids 426 and 740, and the expression of 426-740/IRS-1 mutant attenuated neuronal outgrowth. Our results indicate that TNFalpha facilitates the interaction of pS-IRS-1 and beta1-integrin and destabilizes neuronal processes. IGF-I counteracts TNFalpha-mediated accumulation of pS-IRS-1-beta1-integrin complexes supporting the stability of neuronal processes.

• Interplay between the retinoblastoma related pRb2/p130 and E2F-4 and -5 in relation to JCV-TAg.

  Authors: Valentina Caracciolo, Krzysztof Reiss, Catena Crozier-Fitzgerald, Francesco De Pascali, Marcella Macaluso, Kamel Khalili, Antonio Giordano

  Journal of cellular physiology. 08/2007; 212(1):96-104.

  Human polyomaviruses, which include JC virus (JCV) and BK virus (BKV), as well as the simian virus 40 (SV40), have been associated with human tumors and have been shown to be highly tumorigenic inHuman polyomaviruses, which include JC virus (JCV) and BK virus (BKV), as well as the simian virus 40 (SV40), have been associated with human tumors and have been shown to be highly tumorigenic in experimental animal models. Although the mechanism by which JCV induces tumorigenesis is not entirely clear, earlier studies point to the involvement of the viral early protein T-antigen which has the ability to bind and inactivate tumor suppressors and cell cycle regulatory proteins, such as the retinoblastoma family proteins and p53. We investigated if the distribution between nucleus and cytoplasm of the transcription factors E2F4 and E2F5 is mediated by pRb2/p130 and if the presence of JCV T-antigen may impair this shuttling by sequestering pRb2/p130. The results showed that E2F4 was prevalently localized in the nucleus of both T-antigen positive and -negative R503 cells independently of the cell cycle phase. E2F5 instead was prevalently localized in the cytoplasmic fraction in G(0)/G(1), S-phase synchronized, and asynchronous R503 and R503 T-Ag positive cells. The presence of T-antigen did not influence the subcellular localization of these transcription factors E2F4 and E2F5, at least in this murine cellular model. Moreover, Small interference RNA experiments directed toward silencing the Rb2/p130 gene demonstrated that pRb2/p130 does not play a predominant role in the nuclear transportation of E2F4 and E2F5.

• Enhanced phosphorylation of Nbs1, a member of DNA repair/checkpoint complex Mre11-RAD50-Nbs1, can be targeted to increase the efficacy of imatinib mesylate against BCR/ABL-positive leukemia cells.

  Authors: Lori Rink, Artur Slupianek, Tomasz Stoklosa, Margaret Nieborowska-Skorska, Katarzyna Urbanska, Ilona Seferynska, Krzysztof Reiss, Tomasz Skorski

  Blood. 08/2007; 110(2):651-60.

  Nbs1, a member of the Mre11-RAD50-Nbs1 complex, is phosphorylated by ATM, the product of the ataxia-telangiectasia mutated gene and a member of the phosphatidylinositol 3-kinase-related family ofNbs1, a member of the Mre11-RAD50-Nbs1 complex, is phosphorylated by ATM, the product of the ataxia-telangiectasia mutated gene and a member of the phosphatidylinositol 3-kinase-related family of serine-threonine kinases, in response to DNA double-strand breaks (DSBs) to regulate DNA damage checkpoints. Here we show that BCR/ABL stimulated Nbs1 expression by induction of c-Myc-dependent transactivation and protection from caspase-dependent degradation. BCR/ABL-related fusion tyrosine kinases (FTKs) such as TEL/JAK2, TEL/PDGFbetaR, TEL/ABL, TEL/TRKC, BCR/FGFR1, and NPM/ALK as well as interleukin 3 (IL-3), granulocyte-macrophage colony-stimulating factor (GM-CSF), and stem cell factor (SCF) also stimulated Nbs1 expression. Enhanced ATM kinase-dependent phosphorylation of Nbs1 on serine 343 (S343) in response to genotoxic treatment was detected in leukemia cells expressing BCR/ABL and other FTKs in comparison to normal counterparts stimulated with IL-3, GM-CSF, and SCF. Expression of Nbs1-S343A mutant disrupted the intra-S-phase checkpoint, decreased homologous recombinational repair (HRR) activity, down-regulated XIAP expression, and sensitized BCR/ABL-positive cells to cytotoxic drugs. Interestingly, inhibition of Nbs1 phosphorylation by S343A mutant enhanced the antileukemia effect of the combination of imatinib and genotoxic agent.