ERK5 signalling pathway is a novel target of sorafenib: Implication in EGF biology

© 2021 The Authors.Sorafenib is a multikinase inhibitor widely used in cancer therapy with an antitumour effect related to biological processes as proliferation, migration or invasion, among others. Initially designed as a Raf inhibitor, Sorafenib was later shown to also block key molecules in tumour progression such as VEGFR and PDGFR. In addition, sorafenib has been connected with key signalling pathways in cancer such as EGFR/EGF. However, no definitive clue about the molecular mechanism linking sorafenib and EGF signalling pathway has been established so far. Our data in HeLa, U2OS, A549 and HEK293T cells, based on in silico, chemical and genetic approaches demonstrate that the MEK5/ERK5 signalling pathway is a novel target of sorafenib. In addition, our data show how sorafenib is able to block MEK5-dependent phosphorylation of ERK5 in the Ser218/Tyr220, affecting the transcriptional activation associated with ERK5. Moreover, we demonstrate that some of the effects of this kinase inhibitor onto EGF biological responses, such as progression through cell cycle or migration, are mediated through the effect exerted onto ERK5 signalling pathway. Therefore, our observations describe a novel target of sorafenib, the ERK5 signalling pathway, and establish new mechanistic insights for the antitumour effect of this multikinase inhibitor.This work was supported by grants from Fundación Leticia Castillejo Castillo, Ministerio de Ciencia, Innovación y Universidades (MCIU), Agencia Estatal de Investigación (AEI) and Fondo Europeo de Desarrollo Regional (FEDER) (RTI2018-094093-B-I00) to RSP and MJRH. OR holds a contract for accessing the Spanish System of Science, Technology, and Innovation (SECTI) funded by the University of Castilla-La Mancha (UCLM) and received partial support from the European Social Fund (FSE) through its Operative Program for Castilla-La Mancha (2007–2013). RSP and MJRH's Research Institute, and the work carried out in their laboratory, received partial support from the European Community through the FEDER. RPS and EAL hold a research predoctoral contract cofounded by the European Social Fund and UCLM. The Spanish Ministry of Economy and Competitiveness (MINECO, Project RTI2018-096724-B-C21) and the Generalitat Valenciana (PROMETEO/2016/006) support work in the Encinar´s laboratory. Authors are grateful to Dr.G- Ferrer Mayorga for her assistance in the transwell assays, and to the ‘Centro de Computación Científica’ (CCC-UAM) for letting us to take advantage of the computer cluster Cibeles (https://www.ccc.uam.es/) and for providing computing facilities

Blockage of autophagic ux is associated with lymphocytosis and higher percentage of tumoral cells in chronic lymphocytic leukemia of B-cells

Póster presentado al 42nd Congress of the Spanish Society of Biochemistry and Molecular Biology (SEBBM), celebrado en Madrid del 16 al 19 de julio de 2019.[Objective] Autophagy has lately emerged as an important biological process with implications in several hematological pathologies. Recently, a growing body of evidence supports a putative role of autophagy in chronic lymphocytic leukemia, however no definitive clue has been established so far. To elucidate this issue, we have developed a pilot study to measure autophagic flux in peripheral blood mononuclear cells from chronic lymphocytic leukemia patients, and explored its correlation with classical clinical/analytical parameters. [Methods/Patients] Thirty-three chronic lymphocytic leukemia patients participated in the study. Autophagic flux in peripheral blood mononuclear cells was determined by western blot measuring the levels of the proteins p62 and lipidated LC3. Moreover, p62 mRNA levels were studied by RT-qPCR. [Results] Lymphocytosis and the percentage of tumoral lymphocytes in chronic lymphocityc leukemia patients statistically correlates with a blocked autophagic flux. [Conclusion] Alterations in autophagic flux could play an important role in the physiopathology of chronic lymphocytic leukemia.Fundación Leticia Castillejo Castillo, Ministerio de Economía y Competitividad. Sociedad Castellano Manchega de Hematología y Hemoterapia. RSP and MJRH Research Institutes, and the work carried out in their laboratories received support from the European Community through the Regional Development Funding Program (FEDER).Peer reviewe

ERK5 Is a major determinant of chemical sarcomagenesis: implications in human pathology

Sarcomas are a heterogeneous group of tumors in which the role of ERK5 is poorly studied. To clarify the role of this MAPK in sarcomatous pathology, we used a murine 3-methyl-cholanthrene (3MC)-induced sarcoma model. Our data show that 3MC induces pleomorphic sarcomas with muscle differentiation, showing an increased expression of ERK5. Indeed, this upregulation was also observed in human sarcomas of muscular origin, such as leiomyosarcoma or rhabdomyosarcoma. Moreover, in cell lines derived from these 3MC-induced tumors, abrogation of Mapk7 expression by using specific shRNAs decreased in vitro growth and colony-forming capacity and led to a marked loss of tumor growth in vivo. In fact, transcriptomic profiling in ERK5 abrogated cell lines by RNAseq showed a deregulated gene expression pattern for key biological processes such as angiogenesis, migration, motility, etc., correlating with a better prognostic in human pathology. Finally, among the various differentially expressed genes, Klf2 is a key mediator of the biological effects of ERK5 as indicated by its specific interference, demonstrating that the ERK5–KLF2 axis is an important determinant of sarcoma biology that should be further studied in human pathology.This work has been supported with Grant RTI2018-094093-B-I00 funded by MCIN/AEI/10.13039/501100011033, “ERDF A way of making Europe” to RSP. Also supported with funds from Fundación Leticia Castillejo Castillo, Roche España and ACEPAIN to RSP and MJRH. RSP and MJRH’s Research Institute and the work carried out in their laboratory, received partial support from the European Community through the FEDER. JJ and EAL hold a predoctoral research contract cofounded by the European Social Fund and UCLM. OR holds a contract for accessing the Spanish System of Science, Technology, and Innovation (SECTI) funded by the University of Castilla-La Mancha (UCLM) and received partial support from the European Social Fund (FSE) through its Operative Program for Castilla-La Mancha (2007–2013)

ERK5 Is a Major Determinant of Chemical Sarcomagenesis : Implications in Human Pathology

Sarcoma is a heterogeneous group of tumors poorly studied with few therapeutic opportunities. Interestingly, the role of MAPKs still remains unclear in sarcomatous pathology. Here, we describe for the first time the critical role of ERK5 in the biology of soft tissue sarcoma by using in vitro and in vivo approaches in a murine experimental model of chemical sarcomagenesis. Indeed, our observations were extrapolated to a short series of human leiomyosarcoma and rhabdomyosarcomas. Furthermore, transcriptome analysis allows us to demonstrate the critical role of KLF2 in the biological effects of ERK5. Therefore, the data presented here open new windows in the diagnosis and therapy of soft tissue sarcomas. Sarcomas are a heterogeneous group of tumors in which the role of ERK5 is poorly studied. To clarify the role of this MAPK in sarcomatous pathology, we used a murine 3-methyl-cholanthrene (3MC)-induced sarcoma model. Our data show that 3MC induces pleomorphic sarcomas with muscle differentiation, showing an increased expression of ERK5. Indeed, this upregulation was also observed in human sarcomas of muscular origin, such as leiomyosarcoma or rhabdomyosarcoma. Moreover, in cell lines derived from these 3MC-induced tumors, abrogation of Mapk7 expression by using specific shRNAs decreased in vitro growth and colony-forming capacity and led to a marked loss of tumor growth in vivo. In fact, transcriptomic profiling in ERK5 abrogated cell lines by RNAseq showed a deregulated gene expression pattern for key biological processes such as angiogenesis, migration, motility, etc., correlating with a better prognostic in human pathology. Finally, among the various differentially expressed genes, Klf2 is a key mediator of the biological effects of ERK5 as indicated by its specific interference, demonstrating that the ERK5-KLF2 axis is an important determinant of sarcoma biology that should be further studied in human pathology

Nuclear receptors: A rendezvous for chromatin remodeling factors

El pdf del artículo es la versión de autor.Nuclear receptors (NRs) are a large family of ligand-induced transcription factors that include the vitamin D receptor. The recent discovery of WINAC, a novel ATP-dependent chromatin remodeling complex, has shed new light on the molecular mechanisms by which the vitamin D receptor controls gene expression with unexpected clinical implications.Peer Reviewe

Nuclear receptor regulation gears up another Notch

4 pages, 2 figure.In this perspective we describe examples of crosstalk between nuclear receptors (NRs) and Notch signaling by means of direct functional interactions between components of both pathways. This crosstalk may provide eukaryotic organisms with molecular mechanisms for the coordination of llong-distance endocrine signals with cell-to-cell juxtacrine communication.Our work was funded by the Wellcome Trust (grant 061930), the Association for International Cancer Research (03-098) and Ministerio de Educación y Ciencia (SAF2004-02549).Peer reviewe

Mechanisms of androgen receptor repression in prostate cancer

4 pages, 2 figures, 1 table.-- El pdf del artículo es la versión de autor.-- et al.Anti-androgens used in prostate cancer therapy inhibit AR (androgen receptor) activity via largely unknown mechanisms. Although initially successful in most cases, they eventually fail and the disease progresses. We need to elucidate how anti-androgens work to understand why they fail, and prolong their effects or design further therapies. Using a cellular model, we found different anti-androgens have diverse effects on subcellular localization of AR, revealing that they work via different mechanisms and suggesting that an informed sequential treatment regime may benefit patients. In the presence of the anti-androgens bicalutamide and hydroxyflutamide, a significant proportion of the AR is translocated to the nucleus but remains inactive. Receptor inhibition under these conditions is likely to involve recruitment of co-repressor proteins, which interact with antagonist-occupied receptor but inhibit receptor-dependent transcription. Which co-repressors are required in vivo for AR repression by anti-androgens is not clear, but one candidate is the Notch effector Hey1. This inhibits ligand-dependent activity of the AR but not other steroid receptors. Further, it is excluded from the nucleus in most human prostate cancers, suggesting that abnormal subcellular distribution of co-repressors may contribute to the aberrant hormonal responses observed in prostate cancer. A decrease in co-repressor function is one possible explanation for the development of anti-androgen-resistant prostate cancer, and this suggests that it may not occur at the gross level of protein expression.Studies described here were supported by grants from The Prostate Cancer Charity and the Association for International Cancer Research.Peer reviewe

Thyroid hormones regulate β-amyloid gene splicing and protein secretion in neuroblastoma cells

7 pages, 6 figures.The β-amyloid protein (Aβ), the major component of the senile plaques found in Alzheimer brains, derives from a larger β-amyloid precursor protein (APP). Alternative splicing of the APP gene yields three major APP messenger RNAs (mRNAs), which, in turn, give rise to the APP770, APP751, and APP695 protein isoforms. In this study we examined the effects of thyroid hormone on APP expression in N2a-β neuroblastoma cells. T3 caused a significant increase in the APP770 mRNA band, in detriment of the APP695 mRNA, which was proportionately reduced. In agreement with these results, T3 markedly altered the relative ratio of intracellular APP isoforms, increasing the amount of APP770 and causing an equivalent reduction of the immature APP695 isoform. In accordance with these results, the soluble APP695-derived form was specifically reduced in the culture medium obtained from T3-treated cells. In contrast, the increase in intracellular APP770 was not followed by an enhanced release of soluble derivatives of this isoform. These results suggest that T3 regulates not only APP gene splicing, but also the processing and secretion of the APP peptides. According to our results, thyroid hormone might play a role in the development of Alzheimer’s disease by modulating the intracellular and extracellular contents of APP isoforms.This work was supported by grants from the Dirección General de Investigación Científica y Técnica (PB93–0135), Comisión Interministerial de Ciencia y Tecnología (SAF 97–0183), and Fondo de Investigación Sanitaria (94/0272). Recipient of a fellowship from the Departamento de Educación y Cultura del Gobierno de Navarra.Peer reviewe

Attenuation of ribosomal protein S6 phosphatase activity in chicken embryo fibroblasts transformed by Rous sarcoma virus

In chicken embryo fibroblasts, phosphorylation of the 40S ribosomal protein S6 increases during G1 but returns to basal level by mitosis. In contrast, in Rous sarcoma virus (RSV)-transformed fibroblasts, S6 remains highly phosphorylated throughout mitosis. This study investigated the mechanism by which RSV alters the pattern of S6 phosphorylation. Pulse-chase experiments demonstrate that phosphate turnover in S6 is rapid in normal cells and in cells infected with an RSV transformation-defective virus. In contrast, phosphate turnover in S6 is severely reduced in cells infected with temperature-sensitive RSV at a temperature permissive for transformation, indicating a diminished S6 phosphatase activity. Fractionation of cell lysates by DEAE chromatography showed an almost threefold lower S6 phosphatase activity in RSV-transformed versus normal cells. The S6 phosphatase was sensitive to inhibitor 2 and specifically recognized by an antibody to type 1 phosphatase (PP1). The S6 phosphatase activity recovered by immunoprecipitation of PP1 was threefold lower in transformed cells, but the steady-state level of expression and the rate of synthesis of PP1 were not altered by oncogenic transformation. Together, the results show that transformation by RSV reduced the S6-PP1 activity.This research was supported by grants from DGICYT (PM89-0017 and PB92-0116), CAM (C263/91), and NATO (0010/89) to J.M.-P. and PHS grant DK-31374 to D.L.B. B.B. was supported by a fellowship from the Gobierno Vasco.Peer Reviewe

Atenuacion de la actividad proteina fosfatasa 1 en celulas transformadas por el oncogen v-src

Centro de Informacion y Documentacion Cientifica (CINDOC). C/Joaquin Costa, 22. 28002 Madrid. SPAIN / CINDOC - Centro de Informaciòn y Documentaciòn CientìficaSIGLEESSpai