3,5,7-Trisubstituted pyrazolo[4,3-d]pyrimidines have been identified as potent inhibitors of cyclin-dependent kinases (CDKs), which are established drug targets. Herein, we describe their further structural modifications leading to novel nanomolar inhibitors with strong antiproliferative activity. We determined the crystal structure of fully active CDK2/A2 with 5-(2-amino-1-ethyl)thio-3-cyclobutyl-7-[4-(pyrazol-1-yl)benzyl]amino-1(2)H-pyrazolo[4,3-d]pyrimidine (24) at 1.7 Å resolution, confirming the competitive mode of inhibition. Biochemical and cellular assays in lymphoma cell lines confirmed the expected mechanism of action through dephosphorylation of retinoblastoma protein and RNA polymerase II, leading to induction of apoptosis. Importantly, we also revealed an interesting ability of compound 24 to induce proteasome-dependent degradation of cyclin K both in vitro and in a patient-derived xenograft in vivo. We propose that 24 has a dual mechanism of action, acting as a kinase inhibitor and as a molecular glue inducing an interaction between CDK12 and DDB1 that leads to polyubiquitination of cyclin K and its subsequent degradation.
- MeSH
- antitumorózní látky * chemie farmakologie MeSH
- cyklin-dependentní kinasa 2 MeSH
- cyklin-dependentní kinasy * MeSH
- cykliny metabolismus MeSH
- inhibitory proteinkinas chemie MeSH
- lidé MeSH
- nádorové buněčné linie MeSH
- pyrimidiny chemie MeSH
- vztahy mezi strukturou a aktivitou MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Targeted cancer immunotherapy is a promising tool for restoring immune surveillance and eradicating cancer cells. Hydrophilic polymers modified with coiled coil peptide tags can be used as universal carriers designed for cell-specific delivery of such biologically active proteins. Here, we describe the preparation of pHPMA-based copolymer conjugated with immunologically active protein B7-H6 via complementary coiled coil VAALEKE (peptide E) and VAALKEK (peptide K) sequences. Receptor B7-H6 was described as a binding partner of NKp30, and its expression has been proven for various tumor cell lines. The binding of B7-H6 to NKp30 activates NK cells and results in Fas ligand or granzyme-mediated apoptosis of target tumor cells. In this work, we optimized the expression of coiled coil tagged B7-H6, its ability to bind activating receptor NKp30 has been confirmed by isothermal titration calorimetry, and the binding stoichiometry of prepared chimeric biopolymer has been characterized by analytical ultracentrifugation. Furthermore, this coiled coil B7-H6-loaded polymer conjugate activates NK cells in vitro and, in combination with coiled coil scFv, enables their targeting towards a model tumor cell line. Prepared chimeric biopolymer represents a promising precursor for targeted cancer immunotherapy by activating the cytotoxic activity of natural killer cells.
- Publikační typ
- časopisecké články MeSH
RNA silencing is a common term for homology-dependent silencing phenomena found in the majority of eukaryotic species. RNA silencing pathways share several conserved components. The common denominator of these pathways is the presence of specific, short (21-25 nt) RNA molecules generated from different double-stranded RNA substrates by a specific RNase III activity. Short RNA molecules serve as a template for sequence-specific effects including transcriptional silencing, mRNA degradation, and inhibition of translation. This review will discuss possible roles of RNA silencing pathways in mouse oocytes and early embryos as well as the use of RNA silencing for experimental inhibition of gene expression in this model system.
- MeSH
- embryo savčí metabolismus MeSH
- financování organizované MeSH
- myši MeSH
- oocyty metabolismus MeSH
- RNA interference MeSH
- signální transdukce MeSH
- zvířata MeSH
- Check Tag
- myši MeSH
- zvířata MeSH
- Publikační typ
- přehledy MeSH
Neural progenitors of the mouse forebrain can be propagated in vitro as neurospheres in the presence of bFGF and EGF. However, less is understood whether regional characteristics or developmental stage properties of these cells are maintained in neurosphere cultures. Here we show that the original cell fate is lost in neurosphere cultures. We isolated neural progenitors from the dorsal telencephalon of D6-GFP mice and cultured them in vitro. The expression profile was specifically changed in cultured cells in just three passages. Markers of the dorsal forebrain were downregulated and several ventrally-expressed genes were induced. The altered gene expression led to a profound phenotypic change of cultured cells. D6-GFP positive cortical progenitors produce excitatory neurons in the cortex and few astrocytes in vivo but after culture in vitro, these cells differentiate into many astrocytes and also oligodendrocytes and inhibitory neurons. Wnt signaling in cultured neurospheres was downregulated in the same manner as other dorsal markers but dominant active Wnt signaling slowed down the loss of the dorsal identity in neurospheres.
- MeSH
- astrocyty cytologie metabolismus MeSH
- buněčná diferenciace fyziologie MeSH
- buněčné sféroidy cytologie MeSH
- buněčný rodokmen fyziologie MeSH
- financování organizované MeSH
- genetické markery MeSH
- interneurony cytologie metabolismus MeSH
- kmenové buňky cytologie metabolismus MeSH
- mozková kůra cytologie embryologie metabolismus MeSH
- myši transgenní MeSH
- myši MeSH
- neuroglie cytologie metabolismus MeSH
- neurony cytologie metabolismus MeSH
- oligodendroglie cytologie metabolismus MeSH
- promotorové oblasti (genetika) imunologie MeSH
- rekombinantní fúzní proteiny genetika MeSH
- telencefalon cytologie embryologie metabolismus MeSH
- vývojová regulace genové exprese genetika MeSH
- zelené fluorescenční proteiny genetika MeSH
- zvířata MeSH
- Check Tag
- myši MeSH
- zvířata MeSH
