Biology subjects

Kovalova, M.

Publications and source records attributed to Kovalova, M..

3 recordsLinked to original sources

bioRxiv2023

Characterization of new highly selective pyrazolopyrimidine inhibitor of CDK7

Targeting cyclin-dependent kinase 7 (CDK7) provides an interesting therapeutic option in cancer therapy because this kinase participates in regulating the cell cycle and transcription. Here, we describe a new trisubstituted pyrazolo[4,3-d]pyrimidine derivative, LGR6768, that inhibits CDK7 in the nanomolar range and displays favourable selectivity across the CDK family. We determined the structure of fully active CDK2/cyclin A2 in complex with LGR6768 at 2.6 [A] resolution using X-ray crystallography, revealing conserved interactions within the active site. Structural analysis and comparison with LGR6768 docked to CDK7 provides an explanation of the observed biochemical selectivity, which is linked to a conformational difference in the biphenyl moiety. In cellular experiments, LGR6768 affected regulation of the cell cycle and transcription by inhibiting the phosphorylation of cell cycle CDKs and the carboxy-terminal domain of RNA polymerase II, respectively. LGR6768 limited the proliferation of several leukaemia cell lines, triggered significant changes in protein and mRNA levels related to CDK7 inhibition and induced apoptosis in dose- and time-dependent experiments. Our work supports previous findings and provides further information for the development of selective CDK7 inhibitors. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=58 SRC="FIGDIR/small/529844v1_ufig1.gif" ALT="Figure 1"> View larger version (25K): org.highwire.dtl.DTLVardef@1d13e99org.highwire.dtl.DTLVardef@64ea36org.highwire.dtl.DTLVardef@14c9705org.highwire.dtl.DTLVardef@14efc31_HPS_FORMAT_FIGEXP M_FIG C_FIG

cancer biology↗

bioRxiv2022

A-ring-fused pyrazoles of dihydrotestosterone targeting prostate cancer cells via the downregulation of the androgen receptor

High expression of the androgen receptor (AR) and the disruption of its regulation are strongly responsible for the development of prostate cancer (PCa). Therapeutically relevant non-steroidal or steroidal antiandrogens are able to block the AR effect by eliminating AR-mediated signalling. Herein we report the synthesis of novel steroidal pyrazoles derived from the natural sex hormone 5-dihydrotestosterone (DHT). 2-Ethylidene or 2-(hetero)arylidene derivatives of DHT obtained by regioselective Claisen-Schmidt condensation with acetaldehyde or (hetero)aromatic aldehydes in alkaline ethanol were reacted with monosubstituted hydrazines to give A-ring-fused 1,5-disubstituted pyrazoles as main or exclusive products, depending on the reaction conditions applied. Spontaneous or 2,3-dichloro-5,6-dicyanobenzoquinone (DDQ)-induced oxidation of the primarily formed pyrazolines resulted in the desired products in moderate to good yields, while 17-oxidation also occurred by using the Jones reagent as a strong oxidant. Transcriptional activity of the AR in a reporter cell line was examined for all novel compounds, and several previously synthesized similar DHT-based pyrazoles with differently substituted heteroring were also included to obtain information about the structure-activity relationship. Two specific regioisomeric groups of derivatives significantly diminished the transcriptional activity of AR in reporter cell line in 10 M concentration, and displayed reasonable antiproliferative activity in AR-positive PCa cell lines. Lead compound (3d) was found to be a potent AR antagonist (IC50 = 1.18 M), generally suppressed AR signalling in time and dose dependent manner, moreover, it also led to a sharp decrease in wt-AR protein level probably caused by proteasomal degradation. We confirmed the antiproliferative activity selective for AR-positive PCa cell lines (with GI50 in low micromolar ranges), cellular, biochemical and in silico binding of 3d in AR ligand-binding domain. Moreover, compound 3d was shown to be potent even ex vivo in patient-derived tissues, which highlights the therapeutic potential of A-ring-fused pyrazoles. Table of content graphic O_FIG_DISPLAY_L [Figure 1] M_FIG_DISPLAY C_FIG_DISPLAY HighlightsO_LIA-ring-fused pyrazoles of 5-dihydrotestosterone were introduced as AR modulators C_LIO_LISAR study of 55 differently substituted derivatives was discussed C_LIO_LICompound 3d suppressed the expression of AR targets in prostate cell lines C_LIO_LICompound 3d caused AR degradation in time-dependent manner C_LIO_LIEx vivo activity of 3d was demonstrated in patient-derived explants C_LI

pharmacology and toxicology↗

bioRxiv2018

Effect of simulated microgravity on gene expression during embryogenesis of Arabidopsis thaliana

Gravitational force is one of environmental factors that influence growth and development of plants. Changes in this force, including microgravity, can be one of the stress factor which plants have to adapt to cope with. That kind of stress can lead to several abnormalities such as chromosomal breakage, morphological abnormalities or changes in gene expression. The aim of this study was to examine the influence of simulated microgravity on gene expression of Arabidopsis thaliana embryos by use Random Positioning Machine (RPM). RPM is laboratory facility that can generate conditions comparable to the true microgravity. This paper studies effect of simulated microgravity on expression of genes which are involved in plant embryogenesis (LEAFY COTYLEDON, LATE EMBRYOGENESIS ABUNDANT), antioxidative system (CATALASE), mechanical stimuli (TOUCH) and gravitropism (SCARECROW, SHOOT GRAVITROPISM2). Changes in gene expression were detected using quantitative real-time PCR (qRT-PCR). Several of tested genes had increased transcript levels after the influence of simulated microgravity. Specifically, catalase (CAT3), LECs (LEC1), touch (TCH2/CML24), and gravitropism (SGR2) genes achieved significantly increased relative expression (level [≥] 2). The changes in the levels of expression on embryos of Arabidopsis depend on the type of genes and principally on the timing of the influence of the simulated microgravity.

plant biology↗