Bioquímica de la germinación de semillas

Las semillas de las angiospermas contienen al eje embrionario y a las reservas que lo abastecen de materia y energía hasta la emergencia de la plántula.La germinación es el proceso fisiológico que se inicia con la absorción de agua de las semillas (imbibición) y finaliza con la elongación del eje embrionario, lo que se visualiza cuando la radícula atraviesa la cubierta seminal. Las semillas almacenan compuestos de reserva tales como lípidos, carbohidratos y proteínas, que serán utilizados para solventar el crecimiento y el desarrollo de la plántula hasta que sea capaz de fotosintetizar y absorber nutrientes del suelo. Las reservas pueden ser almacenadas en el embrión (específicamente en los cotiledones) o en tejidos extraembrionarios, principalmente en el endosperma. Si bien los tres tipos de compuestos mencionados se encuentran en todas las semillas, las especies pueden agruparse según cuál de ellos represente la mayor proporción. Es así como las semillas pertenecientes al grupo de los cereales almacenan principalmente almidón, mientras que las que almacenan lípidos integran el grupo de las oleaginosas y aquellas que contienen principalmente proteínas son las legumbres. En este capítulo se analizarán los principales procesos bioquímicos que ocurren durante la acumulación de las reservas y la posterior germinación y movilización de dichas reservas en cada una de ellas.Fil: Caputo Suarez, Carla Paula. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones en Biociencias Agrícolas y Ambientales. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones en Biociencias Agrícolas y Ambientales; ArgentinaFil: Codó, Patricia Carolina. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Biología Aplicada y Alimentos. Cátedra de Bioquímica; ArgentinaFil: Peton, Andrés. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Biología Aplicada y Alimentos. Cátedra de Bioquímica; Argentin

Control of glioma cell migration and invasiveness by GDF-15

Growth and differentiation factor (GDF)-15 is a member of the transforming growth factor (TGF)-beta family of proteins. GDF-15 levels are increased in the blood and cerebrospinal fluid of glioblastoma patients. Using a TCGA database interrogation, we demonstrate that high GDF-15 expression levels are associated with poor survival of glioblastoma patients. To elucidate the role of GDF-15 in glioblastoma in detail, we confirmed that glioma cells express GDF-15 mRNA and protein in vitro. To allow for a detailed functional characterization, GDF-15 expression was silenced using RNA interference in LNT-229 and LN-308 glioma cells. Depletion of GDF-15 had no effect on cell viability. In contrast, GDF-15-deficient cells displayed reduced migration and invasion, in the absence of changes in Smad2 or Smad1/5/8 phosphorylation. Conversely, exogenous GDF-15 stimulated migration and invasiveness. Large-scale expression profiling revealed that GDF-15 gene silencing resulted in minor changes in the miRNA profile whereas several genes, including members of the plasminogen activator/inhibitor complex, were deregulated at the mRNA level. One of the newly identified genes induced by GDF-15 gene silencing was the serpin peptidase inhibitor, clade E nexin group 1 (serpine1) which is induced by TGF-beta and known to inhibit migration and invasiveness. However, serpine1 down-regulation alone did not mediate GDF-15-induced promotion of migration and invasiveness. Our findings highlight the complex contributions of GDF-15 to the invasive phenotype of glioma cells and suggest anti-GDF-15 approaches as a promising therapeutic strategy

Selenite and methylseleninic acid epigenetically affects distinct gene sets in myeloid leukemia : A genome wide epigenetic analysis

Selenium compounds have emerged as promising chemotherapeutic agents with proposed epigenetic effects, however the mechanisms and downstream effects are yet to be studied. Here we assessed the effects of the inorganic selenium compound selenite and the organic form methylseleninic acid (MSA) in a leukemic cell line K562, on active (histone H3 lysine 9 acetylation, H3K9ac and histone H3 lysine 4 tri-methylation, H3K4me3) and repressive (histone H3 lysine 9 tri-methylation, H3K9me3) histone marks by Chromatin immunoprecipitation followed by DNA sequencing (ChIP-Seq). Both selenite and MSA had major effects on histone marks but the effects of MSA were more pronounced. Gene ontology analysis revealed that selenite affected genes involved in response to oxygen and hypoxia, whereas MSA affected distinct gene sets associated with cell adhesion and glucocorticoid receptors, also apparent by global gene expression analysis using RNA sequencing. The correlation to adhesion was functionally confirmed by a significantly weakened ability of MSA treated cells to attach to fibronectin and linked to decreased expression of integrin beta 1. A striking loss of cellular adhesion was also confirmed in primary patient AML cells. Recent strategies to enhance the cytotoxicity of chemotherapeutic drugs by disrupting the interaction between leukemic and stromal cells in the bone marrow are of increasing interest; and organic selenium compounds like MSA might be promising candidates. In conclusion, these results provide new insight on the mechanism of action of selenium compounds, and will be of value for the understanding, usage, and development of new selenium compounds as anticancer agents

A phase 3, randomised, observer-blinded, placebo controlled-trial evaluating the safety and immunogenicity of investigational SARS-CoV-2 mRNA vaccine CVnCoV in adult healthcare workers in Mainz (Germany)

Background: CV-NCOV-005 was conducted to generate additional safety and immunogenicity data for the former CVnCoV SARS-CoV-2 mRNA vaccine candidate in healthcare workers (HCW). Methods: Randomised, observer blinded, placebo-controlled, phase 3 trial performed at the University Medical Center Mainz, Germany. HCWs aged ≥18 years with no history of SARS-CoV-2 infection/positive serology were randomly assigned to receive two doses of CVnCoV, or two doses of placebo (0.9% NaCl). The primary objectives were to expand the safety database of CVnCoV and assess antibody responses against SARS-CoV-2. Primary safety and reactogenicity outcomes included solicited adverse events (AEs) within 7 days after each dose and unsolicited AEs within 28 days after each dose, with safety follow-up for 13 months after first vaccination. Since HCWs became eligible to receive an authorised vaccine during enrolment and efficacy results from HERALD CVnCoV trial were made available on 30th of June 2021, this study was unblinded and converted to an open label design. Results: Most participants in the CVnCoV group reported at least one solicited AE, a relatively high number being Grade 3 (43.3% in CVnCoV group and 6.4% in placebo group). Most AEs were short in duration and did not affect vaccine compliance. The percentage of participants with unsolicited AEs up to 28 days after any dose was slightly higher in CVnCoV group (37.0%) compared with placebo group (31.2%). IgG binding antibodies against the receptor binding domain of the SARS-CoV-2 spike protein were observed after vaccination, with higher seroconversion rates and antibody levels after the second dose. Conclusion: No safety concerns for CVnCoV were identified up to 1 year post second dose. IgG responses against SARS-CoV-2 were observed after two doses, with a higher seroconversion rate and antibody levels observed after second vaccination.Study registration: ClinicalTrials.gov NCT04674189, study period: 23rd of December 2020 to 8th of June 2022

473 Immune profiling of patients with advanced solid tumors treated with intratumorally administered CV8102 as a single-agent or in combination with anti-PD-1 antibodies in phase I clinical trial

BackgroundCV8102 is a non-coding, non-capped RNA complexed with a carrier peptide activating the innate (via TLR7/8, RIG-I) and adaptive immune system.1 2 An ongoing phase I trial is investigating the intratumoral (i.t.) administration of CV8102 in patients with advanced cutaneous melanoma (cMEL), squamous cell carcinoma of the skin (cSCC) or head and neck (hnSCC) and adenoid cystic carcinoma (ACC), either as a single agent or in combination with systemic anti-PD-1 antibodies. Preliminary immune profiling results will be reported.MethodsAn open-label, cohort-based, dose escalation and expansion study in patients with advanced cMEL, cSCC, hnSCC or ACC is ongoing investigating CV8102 i.t. as single agent and in combination with anti-PD-1 antibodies. Eight i.t. injections of CV8102 were administered over a 12 week period with optional continuing treatment in case of clinical benefit. In the initial dose escalation part, the recommended phase II dose for subsequent cohort expansion was defined. Blood samples for immune cell phenotyping, RNA sequencing (RNAseq) and serum cytokine/chemokine analysis were collected at baseline and multiple time points during the treatment period. For characterization of the tumor microenvironment (TME), optional core needle biopsies of injected and/or non-injected lesions were taken before, during and after treatment. Changes on various tumor-infiltrating immune cells were assessed by multiplex immunofluorescence (MultiOmyx &lt; sup &gt;TM&lt;/sup &gt; ) and immune-related gene expression profiling using nCounter® Pan Cancer IO360 &lt; sup &gt;TM&lt;/sup &gt; panel (NanoString).ResultsDuring the dose escalation part, 33 patients received CV8102 (dose range of 25–900 µg) as single agent and 25 patients received CV8102 in combination with an anti-PD-1 antibody. A dose of 600 µg was selected as recommended phase II dose. Serum cytokine/chemokine and blood RNAseq analysis showed transient increases in several markers like interferons alpha and gamma after the first dose. First analyses of paired biopsies showed changes in the TME of injected and non-injected lesions. Complete results of cytokine and chemokine analysis in serum and blood RNAseq for the dose escalation cohorts will be presented. Multiplex immunofluorescence and gene expression profiling from paired biopsies from individual patients will be also included.ConclusionsIntratumoral injection of CV8102 activated several cytokine/chemokine pathways in the peripheral blood and showed immunological changes in the tumor microenvironment of injected and non-injected lesions.Trial RegistrationNCT03291002ReferencesZiegler A, Soldner C, Lienenklaus S, Spanier J, Trittel S, Riese P, Kramps T, Weiss S, Heidenreich R, Jasny E, Guzmán CA, Kallen KJ, Fotin-Mleczek M, Kalinke U. A New RNA-Based Adjuvant Enhances Virus-Specific Vaccine Responses by Locally Triggering TLR- and RLH-Dependent Effects. J Immunol 2017;198(4):1595–1605. doi: 10.4049/jimmunol.1601129.Heidenreich R, Jasny E, Kowalczyk A, Lutz J, Probst J, Baumhof P, Scheel B, Voss S, Kallen KJ, Fotin-Mleczek M. A novel RNA-based adjuvant combines strong immunostimulatory capacities with a favorable safety profile. Int J Cancer 2015 Jul 15;137(2):372–84. doi: 10.1002/ijc.29402.Ethics ApprovalThe study was approved by the Central Ethics Committees in Tuebingen, Germany under 785/2016AMG1, in France by the COMITE DE PROTECTION DES PERSONNES SUD-EST I under 2019–49, approval dated 17-May-2019, in Barcelona, Spain by the CEC COMITÉ DE ÉTICA DE INVESTIGACIÓN CLÍNICA CON MEDICAMENTOS del Hospital Universitari Vall d’Hebron, approval date 28-Nov-2019 under the EUdraCT number, in Austria by the Central Ethics Committee in Graz under 31–426 ex 18/19 approved on 19-Sep-2019.ConsentWritten informed consent from the patient was obtained for publication of this abstract and any accompanying images. A copy of the written consent is available for review by the Editor of this journal.</jats:sec

Phase I study of intratumoral administration of CV8102 in patients with advanced melanoma, squamous cell carcinoma of the skin, squamous cell carcinoma of the head and neck, or adenoid cystic carcinoma

Background CV8102, a toll-like receptor 7/8 and RIG I agonist, has demonstrated antitumor immune responses in preclinical studies. We investigated intratumoral (IT) administration of CV8102 in patients with anti-programmed cell death protein-1 (PD-1) therapy-naïve or anti-PD-1 therapy-refractory cutaneous melanoma (cMEL) and in patients with advanced cutaneous squamous cell carcinoma, head and neck squamous cell carcinoma and adenoid cystic carcinoma.Methods This open-label, cohort-based, phase I dose escalation study aimed to establish the maximum tolerated dose (MTD), recommended dose (RD), safety and preliminary efficacy of CV8102 as monotherapy or in combination with a PD-1 inhibitor. The preliminary efficacy of the RD was assessed in patients with cMEL in the expansion cohorts.Results Between September 2017 and October 2022, 98 patients were enrolled in monotherapy and combination therapy dose escalation and dose expansion cohorts. Two patients in the CV8102 monotherapy dose escalation cohort experienced relevant toxicities at the 900 µg dose level. One patient had Grade 3 aspartate transaminase/alanine aminotransferase elevation which met dose-limiting toxicity (DLT) criteria. Another patient experienced Grade 3 immune-mediated pneumonitis. No DLTs occurred in the combination therapy dose escalation cohort. The MTD was not formally reached and the RD for expansion was 600 µg. Common treatment-emergent adverse events were fever (57%), chills (37%) and fatigue (25%). In the dose escalation part, objective responses occurred in 3/33 patients treated with CV8102 as monotherapy and in 2/25 patients treated with CV8102 plus a PD-1 inhibitor. In the expansion cohorts in patients with anti-PD-1 therapy-refractory melanoma, 0/10 patients treated with CV8102 as monotherapy and 5/30 patients (17%) treated in combination with a PD-1 inhibitor experienced objective responses.Conclusions IT CV8102 was generally well tolerated with preliminary signs of efficacy as monotherapy and in combination with a PD-1 inhibitor.Trial registration number NCT03291002