RESUMEN
Hippuristanol (Hipp) is a natural product that selectively inhibits protein synthesis by targeting eukaryotic initiation factor (eIF) 4A, a DEAD-box RNA helicase required for ribosome recruitment to mRNA templates. Hipp binds to the carboxyl-terminal domain of eIF4A, locks it in a closed conformation, and inhibits its RNA binding. The dependencies of mRNAs for eIF4A during initiation is contingent on the degree of secondary structure within their 5' leader region. Interest in targeting eIF4A therapeutically in cancer and viral-infected settings stems from the dependencies that certain cellular (e.g. pro-oncogenic, pro-survival) and viral mRNAs show towards eIF4A. Using a CRISPR/Cas9-based variomics screen, we identify functional EIF4A1 Hipp-resistant alleles, which in turn allowed us to link the translation-inhibitory and cytotoxic properties of Hipp to eIF4A1 target engagement. Genome-wide translational profiling in the absence or presence of Hipp were undertaken and our validation studies provided insight into the structure-activity relationships of eIF4A-dependent mRNAs. We find that mRNA 5' leader length, overall secondary structure and cytosine content are defining features of Hipp-dependent mRNAs.
Asunto(s)
Regiones no Traducidas 5' , Resistencia a Antineoplásicos/genética , Factor 4A Eucariótico de Iniciación/genética , Esteroles/farmacología , Sistemas CRISPR-Cas , Línea Celular Tumoral , Resistencia a Antineoplásicos/efectos de los fármacos , Factor 4A Eucariótico de Iniciación/antagonistas & inhibidores , Factor 4A Eucariótico de Iniciación/metabolismo , Humanos , Leucemia Mielógena Crónica BCR-ABL Positiva/tratamiento farmacológico , Leucemia Mielógena Crónica BCR-ABL Positiva/genética , Leucemia Mielógena Crónica BCR-ABL Positiva/patología , Mutación , Ribosomas/genética , Ribosomas/metabolismoRESUMEN
Biotherapeutics have revolutionized modern medicine by providing medicines that would not have been possible with small molecules. With respect to cancer therapies, this represents the current sector of the pharmaceutical industry having the largest therapeutic impact, as exemplified by the development of recombinant antibodies and cell-based therapies. In cancer, one of the most common regulatory alterations is the perturbation of translational control. Among these, changes in eukaryotic initiation factor 4F (eIF4F) are associated with tumor initiation, progression, and drug resistance in a number of settings. This, coupled with the fact that systemic suppression of eIF4F appears well tolerated, indicates that therapeutic agents targeting eIF4F hold much therapeutic potential. Here, we discuss opportunities offered by biologicals for this purpose.
Asunto(s)
Antineoplásicos/farmacología , Descubrimiento de Drogas , Factor 4F Eucariótico de Iniciación/antagonistas & inhibidores , Animales , Transformación Celular Neoplásica/metabolismo , Transformación Celular Neoplásica/patología , Factor 4F Eucariótico de Iniciación/metabolismo , Humanos , Virus Oncolíticos/efectos de los fármacos , Virus Oncolíticos/metabolismo , Biosíntesis de Proteínas/efectos de los fármacosRESUMEN
B lymphocyte differentiation into long-lived plasma cells is the keystone event for the production of long-term protective antibodies. CD40-CD154 and CD27-CD70 interactions are involved in human B lymphocyte differentiation into CD38(hi)CD138(+) cells in vivo as well as in vitro. In this study, we have compared these interactions in their capacity to drive switched-memory B lymphocytes differentiation into CD38(hi)CD138(+) plasma cells. The targeted B lymphocytes were isolated from human peripheral blood, expanded for 19 days, and then submitted to CD70 or CD154 interactions for 14 days. The expanded B lymphocytes were constitutively expressing CD39, whereas CD31's expression was noticed only following the in vitro differentiation step (day 5) and was exclusively present on the CD38(hi) cell population. Furthermore, the generated CD38(hi)CD138(+) cells showed a higher proportion of CD31(+) cells than the CD38(hi)CD138(-) cells. Besides, analyses done with human blood and bone marrow plasma cells showed that in vivo and de novo generated CD38(hi)CD138(+) cells have a similar CD31 expression profile but are distinct according to their reduced CD39 expression level. Overall, we have evidences that in vitro generated plasma cells are heterogeneous and appear as CD39(+) precursors to the ones present in bone marrow niches.
Asunto(s)
Linfocitos B/fisiología , Células de la Médula Ósea/fisiología , Células Plasmáticas/fisiología , ADP-Ribosil Ciclasa 1/metabolismo , Ligando CD27/metabolismo , Antígenos CD40/metabolismo , Ligando de CD40/metabolismo , Técnicas de Cultivo de Célula , Diferenciación Celular , Proliferación Celular , Células Cultivadas , Humanos , Cambio de Clase de Inmunoglobulina , Memoria Inmunológica , Inmunofenotipificación/métodos , Activación de Linfocitos , Sindecano-1/metabolismoRESUMEN
The use of CRISPR/Cas9 (clustered regularly interspaced short palindromic repeats/CRISPR-associated protein) for targeted genome editing has been widely adopted and is considered a "game changing" technology. The ease and rapidity by which this approach can be used to modify endogenous loci in a wide spectrum of cell types and organisms makes it a powerful tool for customizable genetic modifications as well as for large-scale functional genomics. The development of retrovirus-based expression platforms to simultaneously deliver the Cas9 nuclease and single guide (sg) RNAs provides unique opportunities by which to ensure stable and reproducible expression of the editing tools and a broad cell targeting spectrum, while remaining compatible with in vivo genetic screens. Here, we describe methods and highlight considerations for designing and generating sgRNA libraries in all-in-one retroviral vectors for such applications.