PIP degron proteins, substrates of CRL4Cdt2, and not PIP boxes, interfere with DNA polymerase η and κ focus formation on UV damage

International audienceProliferating cell nuclear antigen (PCNA) is a well-known scaffold for many DNA replication and repair proteins, but how the switch between partners is regulated is currently unclear. Interaction with PCNA occurs via a domain known as a PCNA-Interacting Protein motif (PIP box). More recently, an additional specialized PIP box has been described, the « PIP degron », that targets PCNA-interacting proteins for proteasomal degradation via the E3 ubiquitin ligase CRL4(Cdt2). Here we provide evidence that CRL4(Cdt2)-dependent degradation of PIP degron proteins plays a role in the switch of PCNA partners during the DNA damage response by facilitating accumulation of translesion synthesis DNA polymerases into nuclear foci. We show that expression of a nondegradable PIP degron (Cdt1) impairs both Pol η and Pol κ focus formation on ultraviolet irradiation and reduces cell viability, while canonical PIP box-containing proteins have no effect. Furthermore, we identify PIP degron-containing peptides from several substrates of CRL4(Cdt2) as efficient inhibitors of Pol η foci formation. By site-directed mutagenesis we show that inhibition depends on a conserved threonine residue that confers high affinity for PCNA-binding. Altogether these findings reveal an important regulative role for the CRL4(Cdt2) pathway in the switch of PCNA partners on DNA damage

Islet Endothelial Activation and Oxidative Stress Gene Expression Is Reduced by IL-1Ra Treatment in the Type 2 Diabetic GK Rat

Inflammation followed by fibrosis is a component of islet dysfunction in both rodent and human type 2 diabetes. Because islet inflammation may originate from endothelial cells, we assessed the expression of selected genes involved in endothelial cell activation in islets from a spontaneous model of type 2 diabetes, the Goto-Kakizaki (GK) rat. We also examined islet endotheliuml/oxidative stress (OS)/inflammation-related gene expression, islet vascularization and fibrosis after treatment with the interleukin-1 (IL-1) receptor antagonist (IL-1Ra)

Therapeutic Potential of HDL in Cardioprotection and Tissue Repair

Epidemiological studies support a strong association between high-density lipoprotein (HDL) cholesterol levels and heart failure incidence. Experimental evidence from different angles supports the view that low HDL is unlikely an innocent bystander in the development of heart failure. HDL exerts direct cardioprotective effects, which are mediated via its interactions with the myocardium and more specifically with cardiomyocytes. HDL may improve cardiac function in several ways. Firstly, HDL may protect the heart against ischaemia/reperfusion injury resulting in a reduction of infarct size and thus in myocardial salvage. Secondly, HDL can improve cardiac function in the absence of ischaemic heart disease as illustrated by beneficial effects conferred by these lipoproteins in diabetic cardiomyopathy. Thirdly, HDL may improve cardiac function by reducing infarct expansion and by attenuating ventricular remodelling post-myocardial infarction. These different mechanisms are substantiated by in vitro, ex vivo, and in vivo intervention studies that applied treatment with native HDL, treatment with reconstituted HDL, or human apo A-I gene transfer. The effect of human apo A-I gene transfer on infarct expansion and ventricular remodelling post-myocardial infarction illustrates the beneficial effects of HDL on tissue repair. The role of HDL in tissue repair is further underpinned by the potent effects of these lipoproteins on endothelial progenitor cell number, function, and incorporation, which may in particular be relevant under conditions of high endothelial cell turnover. Furthermore, topical HDL therapy enhances cutaneous wound healing in different models. In conclusion, the development of HDL-targeted interventions in these strategically chosen therapeutic areas is supported by a strong clinical rationale and significant preclinical data.status: publishe

An ATR-dependent function for the Ddx19 RNA helicase in nuclear R-loop metabolism

International audienc

Issues and limitations of available biomarkers for fluoropyrimidine-based chemotherapy toxicity, a narrative review of the literature

International audienc

OS5.4 Characteristics of adult diffuse H3K27M-mutant gliomas at recurrence

Abstract BACKGROUND Adult diffuse H3K27M-mutant gliomas are rare and associated with a poor prognosis but could benefit in the next future from specific therapeutic strategies. In this context, the aim of the present study was to describe the characteristics of these tumors at recurrence. MATERIAL AND METHODS We retrospectively analyzed the characteristics of a series of 27 adult diffuse H3K27M-mutant gliomas at recurrence RESULTS Median age at diagnosis was 37 years. Initial treatment consisted of temozolomide radiochemotherapy (n=17, 62%), radiotherapy alone (n=1, 4%), chemotherapy alone (n=4, 15%), wait and see (n=1, 4%) and palliative care (n=4, 15%). Median PFS and median OS were 11 and 22 months in the whole series and 15 and 29 months in the patients who were treated with temozolomide radiochemotherapy. The pattern of recurrence could be analyzed in 19 patients. Ten patients (50%) demonstrated a local recurrence, five patients a local and distant recurrence (25%), two patients only a distant recurrence (10%) and two patients a leptomeningeal progression (10%). At recurrence, 15 patients received an oncological treatment that consisted of an alkylating chemotherapy (n=5), a bevacizumab based chemotherapy regimen (n=9) and of radiotherapy (n=1). Median PFS and OS after first recurrence in these patients were 6 and 14 months, respectively. An activating FGFR1 mutation was identified in 4 out of the 9 patients in whom it was assessed. CONCLUSION At recurrence, adult diffuse H3K27M-mutant gliomas are associated with a high rate of distant locations. A subset of patients harbor targetable FGFR1 activating mutations. </jats:sec

Cellular and Molecular Effect of MEHP Involving LXRa in Human Fetal Testis and Ovary

International audienceBackground: Phthalates have been shown to have reprotoxic effects in rodents and human during fetal life. Previous studies indicate that some members of the nuclear receptor (NR) superfamilly potentially mediate phthalate effects. This study aimed to assess if expression of these nuclear receptors are modulated in the response to MEHP exposure on the human fetal gonads in vitro. Methodology/Principal Findings: Testes and ovaries from 7 to 12 gestational weeks human fetuses were exposed to 1024M MEHP for 72 h in vitro. Transcriptional level of NRs and of downstream genes was then investigated using TLDA (TaqMan Low Density Array) and qPCR approaches. To determine whether somatic or germ cells of the testis are involved in the response to MEHP exposure, we developed a highly efficient cytometric germ cell sorting approach. In vitro exposure of fetal testes and ovaries to MEHP up-regulated the expression of LXRa, SREBP members and of downstream genes involved in the lipid and cholesterol synthesis in the whole gonad. In sorted testicular cells, this effect is only observable in somatic cells but not in the gonocytes. Moreover, the germ cell loss induced by MEHP exposure, that we previously described, is restricted to the male gonad as oogonia density is not affected in vitro. Conclusions/Significance: We evidenced for the first time that phthalate increases the levels of mRNA for LXRa, and SREBP members potentially deregulating lipids/cholesterol synthesis in human fetal gonads. Interestingly, this novel effect is observable in both male and female whereas the germ cell apoptosis is restricted to the male gonad. Furthermore, we presented here a novel and potentially very useful flow cytometric cell sorting method to analyse molecular changes in germ cells versus somatic cells

Combination of arsenic and interferon-α inhibits expression of KSHV latent transcripts and synergistically improves survival of mice with primary effusion lymphomas

Background: Kaposi sarcoma-associated herpesvirus (KSHV) is the etiologic agent of primary effusion lymphomas (PEL). PEL cell lines infected with KSHV, but negative for Epstein-Barr virus have a tumorigenic potential in nonobese diabetic-severe combined immunodeficient mice and result in efficient engraftment and formation of malignant ascites with notable abdominal distension, consistent with the clinical manifestations of PEL in humans. Methodology-Principal Findings: Using this preclinical mouse model, we demonstrate that the combination of arsenic trioxide and interferon-alpha (IFN) inhibits proliferation, induces apoptosis and downregulates the latent viral transcripts LANA-1, v-FLIP and v-Cyc in PEL cells derived from malignant ascites. Furthermore, this combination decreases the peritoneal volume and synergistically increases survival of PEL mice. Conclusion-Significance: These results provide a promising rationale for the therapeutic use of arsenic-IFN in PEL patients. © 2013 El Hajj et al.Abou-Merhi R, 2007, LEUKEMIA, V21, P1792, DOI 10.1038-sj.leu.2404797; An J, 2004, LEUKEMIA, V18, P1699, DOI 10.1038-sj.leu.2403460; Sarosiek KA, 2010, P NATL ACAD SCI USA, V107, P13069, DOI 10.1073-pnas.1002985107; Ansari MQ, 1996, AM J CLIN PATHOL, V105, P221; Aoki Y, 2003, BLOOD, V101, P1535, DOI 10.1182-blood-2002-07-2130; Arvanitakis L, 1996, BLOOD, V88, P2648; Bazarbachi A, 1999, BLOOD, V93, P278; Bazarbachi A, 2004, LANCET ONCOL, V5, P664, DOI 10.1016-S1470-2045(04)01608-0; Boulanger E, 2003, AM J HEMATOL, V73, P143, DOI 10.1002-ajh.10341; Boulanger E, 2005, INT J CANCER, V115, P511, DOI 10.1002-ijc.20926; Cai QL, 2006, PLOS PATHOG, V2, P1002, DOI 10.1371-journal.ppat.0020116; Carbone A, 2005, J MOL DIAGN, V7, P17, DOI 10.1016-S1525-1578(10)60004-9; Carbone A, 2008, CANCER CYTOPATHOL, V114, P225, DOI 10.1002-cncr.23597; Carbone A, 1997, BRIT J HAEMATOL, V97, P515, DOI 10.1046-j.1365-2141.1997.00064.x; CESARMAN E, 1995, NEW ENGL J MED, V332, P1186, DOI 10.1056-NEJM199505043321802; Cesarman E, 1996, AM J PATHOL, V149, P53; CHANG Y, 1994, SCIENCE, V266, P1865, DOI 10.1126-science.7997879; Chen HS, 2012, J VIROL, V86, P9454, DOI 10.1128-JVI.00787-12; Chugh P, 2005, P NATL ACAD SCI USA, V102, P12885, DOI 10.1073-pnas.0408577102; DePond W, 1997, AM J SURG PATHOL, V21, P719, DOI 10.1097-00000478-199706000-00013; El Hajj H, 2010, J EXP MED, V207, P2785, DOI 10.1084-jem.20101095; El-Sabban ME, 2000, BLOOD, V96, P2849; Fakhari FD, 2006, J CLIN INVEST, V116, P735, DOI 10.1172-JCI26190; FOLKMAN J, 1989, NATURE, V339, P58, DOI 10.1038-339058a0; Gessain A, 1996, BLOOD, V87, P414; Ghavamzadeh A, 2011, J CLIN ONCOL, V29, P2753, DOI 10.1200-JCO.2010.32.2107; Ghosh SK, 2003, BLOOD, V101, P2321, DOI 10.1182-blood-2002-08-2525; GIMBRONE MA, 1972, J EXP MED, V136, P261, DOI 10.1084-jem.136.2.261; GoddenKent D, 1997, J VIROL, V71, P4193; Golks A, 2006, J EXP MED, V203, P1295, DOI 10.1084-jem.20051556; Goto H, 2012, CANCER SCI, V103, P775, DOI 10.1111-j.1349-7006.2012.02212.x; Halfdanarson TR, 2006, ANN ONCOL, V17, P1849, DOI 10.1093-annonc-mdl139; Hermine O, 2004, HEMATOL J, V5, P130, DOI 10.1038-sj.thj.6200374; Hu J, 2009, P NATL ACAD SCI USA, V106, P3342, DOI 10.1073-pnas.0813280106; Huang Q, 2002, AM J SURG PATHOL, V26, P1363, DOI 10.1097-01.PAS.0000027302.89469.AB; Hussain AR, 2011, FREE RADICAL BIO MED, V50, P978, DOI 10.1016-j.freeradbiomed.2010.12.034; Ito K, 2008, NATURE, V453, P1072, DOI 10.1038-nature07016; Kchour G, 2009, BLOOD, V113, P6528, DOI 10.1182-blood-2009-03-211821; Kogan SC, 2009, CANCER CELL, V15, P7, DOI 10.1016-j.ccr.2008.12.012; Komatsu T, 2002, FRONT BIOSCI, V7, pD726, DOI 10.2741-komatsu; Koopal S, 2007, PLOS PATHOG, V3, P1348, DOI 10.1371-journal.ppat.0030140; Lacoste V, 2007, BRIT J HAEMATOL, V138, P487, DOI 10.1111-j.1365-2141.2007.06697.x; Lallemand-Breitenbach V, 2008, NAT CELL BIOL, V10, P547, DOI 10.1038-ncb1717; Lee RK, 1999, CANCER RES, V59, P5514; Lo-Coco F, 2013, NEW ENGL J MED, V369, P111, DOI 10.1056-NEJMoa1300874; Low W, 2001, J VIROL, V75, P2938, DOI 10.1128-JVI.75.6.2938-2945.2001; Lubyova B, 2007, J BIOL CHEM, V282, P31944, DOI 10.1074-jbc.M706430200; Mahieux Renaud, 2005, Leuk Lymphoma, V46, P347, DOI 10.1080-10428190400019966; Mahieux R, 2001, BLOOD, V98, P3762, DOI 10.1182-blood.V98.13.3762; Moore PS, 1996, J VIROL, V70, P549; Nador RG, 1996, BLOOD, V88, P645; Nasr R, 2003, BLOOD, V101, P4576, DOI 10.1182-blood-2002-09-2986; Nasr R, 2009, CLIN CANCER RES, V15, P6321, DOI 10.1158-1078-0432.CCR-09-0209; Nasr R, 2008, NAT MED, V14, P1333, DOI 10.1038-nm.1891; Otsuki T, 1996, LEUKEMIA, V10, P1358; Petre CE, 2007, J VIROL, V81, P1912, DOI 10.1128-JVI.01757-06; Powell BL, 2010, BLOOD, V116, P3751, DOI 10.1182-blood-2010-02-269621; Renne R, 1996, NAT MED, V2, P342, DOI 10.1038-nm0396-342; Renne R, 2001, J VIROL, V75, P458, DOI 10.1128-JVI.75.1.458-468.2001; Riva G, 2012, BLOOD, V120, P4150, DOI 10.1182-blood-2012-04-421412; Shen ZX, 2004, P NATL ACAD SCI USA, V101, P5328, DOI 10.1073-pnas.0400053101; Simonelli C, 2003, J CLIN ONCOL, V21, P3948, DOI 10.1200-JCO.2003.06.013; Sin SH, 2007, BLOOD, V109, P2165, DOI 10.1182-blood-2006-06-028092; Song MJ, 2003, J VIROL, V77, P9451, DOI 10.1128-JVI.77.17.9451-9462.2003; SOULIER J, 1995, BLOOD, V86, P1276; Sunil Meena, 2010, Curr Infect Dis Rep, V12, P147, DOI 10.1007-s11908-010-0092-5; TOMAYKO MM, 1989, CANCER CHEMOTH PHARM, V24, P148, DOI 10.1007-BF00300234; Toomey NL, 2001, ONCOGENE, V20, P7029, DOI 10.1038-sj.onc.1204895; Uddin S, 2005, CLIN CANCER RES, V11, P3102, DOI 10.1158-1078-0432.CCR-04-1857; Verma SC, 2007, CURR TOP MICROBIOL, V312, P101; Verschuren EW, 2004, CANCER RES, V64, P581, DOI 10.1158-0008-5472.CAN-03-1863; Waddington TW, 2004, AIDS PATIENT CARE ST, V18, P67, DOI 10.1089-108729104322802498; Wang YF, 2004, ANN HEMATOL, V83, P739, DOI 10.1007-s00277-004-0949-5; Wies E, 2008, BLOOD, V111, P320, DOI 10.1182-blood-2007-05-092288; Wu W, 2005, LEUKEMIA RES, V29, P545, DOI 10.1016-j.leukres.2004.11.010; Zhu J, 1997, P NATL ACAD SCI USA, V94, P3978, DOI 10.1073-pnas.94.8.397811