Project description:Recent studies reveal that a subset of cancers in various indications are dependent on high and constant expression of certain transcription factors for growth and survival, a phenomenon termed as transcriptional addiction. Therefore, targeting transcriptional machinery can potentially lead to potent and selective anticancer effects. CDK7 is the catalytic subunit of the CDK-activating kinase (CAK) complex. Its function is required for both cell cycle regulation and transcriptional control of gene expression. CDK7 has recently emerged as an attractive target in cancer since its inhibition leads to decrease of the transcript levels of oncogenic transcription factors, especially those associated with super-enhancers (SEs). Here we describe a first-in-class CDK7 inhibitor SY-1365, which covalently targets a cysteine outside the kinase domain, resulting in sustained, highly selective inhibition of CDK7. In vitro studies reveal that SY-1365 has potency in a wide range of cancer models with low micromolar IC50 values. Cancer cells with low BCL-XL expression are found to be more dependent on MCL1 for survival and therefore particularly sensitive towards SY-1365 treatment since SY-1365 downregulates MCL1 protein level. SY-1365 treatment induces distinct transcriptional changes in acute myeloid leukemia (AML) cell lines. SY-1365 also demonstrates substantial anti-tumor effects in multiple AML xenograft models. Additionally, combination treatment with venetoclax shows synergistic effects in AML models both in vitro and in vivo. Our findings support targeting CDK7 as a new approach for treating transcriptionally addicted cancers. SY-1365 is currently being assessed in a Phase I trial in adult patients (NCT03134638) We performed microarray based expression profiling to quantify transcriptional changes upon treatment with the CDK7 inhibitor, SY-1365 and to compare it to transcriptional changes induced by treatment with other transcriptional drugs JQ1 (BRD4 inhibitor), NVP2 (CDK9 inhibitor) and flavopiridol (pan-CDK inhibitor). We profiled a human acute myeloid leukemia (AML) cell line THP-1. Cells were treated with either DMSO, 100nm SY-1365, 25nM NVP2 , 250nM JQ1 or 200nM flavopiridol for two and six hours. All samples were prepared in biological triplicate.
Project description:Gene expression profiling of immortalized human mesenchymal stem cells with hTERT/E6/E7 transfected MSCs. hTERT may change gene expression in MSCs. Goal was to determine the gene expressions of immortalized MSCs.
Project description:Recent studies reveal that a subset of cancers in various indications are dependent on high and constant expression of certain transcription factors for growth and survival, a phenomenon termed as transcriptional addiction. Therefore, targeting transcriptional machinery can potentially lead to potent and selective anticancer effects. CDK7 is the catalytic subunit of the CDK-activating kinase (CAK) complex. Its function is required for both cell cycle regulation and transcriptional control of gene expression. CDK7 has recently emerged as an attractive target in cancer since its inhibition leads to decrease of the transcript levels of oncogenic transcription factors, especially those associated with super-enhancers (SEs). Here we describe a first-in-class CDK7 inhibitor SY-1365, which covalently targets a cysteine outside the kinase domain, resulting in sustained, highly selective inhibition of CDK7. In vitro studies reveal that SY-1365 has potency in a wide range of cancer models with low micromolar IC50 values. Cancer cells with low BCL-XL expression are found to be more dependent on MCL1 for survival and therefore particularly sensitive towards SY-1365 treatment since SY-1365 downregulates MCL1 protein level. SY-1365 treatment induces distinct transcriptional changes in acute myeloid leukemia (AML) cell lines. SY-1365 also demonstrates substantial anti-tumor effects in multiple AML xenograft models. Additionally, combination treatment with venetoclax shows synergistic effects in AML models both in vitro and in vivo. Our findings support targeting CDK7 as a new approach for treating transcriptionally addicted cancers. SY-1365 is currently being assessed in a Phase I trial in adult patients (NCT03134638)
Project description:Kynureninase is a member of a large family of catalytically diverse but structurally homologous pyridoxal 5'-phosphate (PLP) dependent enzymes known as the aspartate aminotransferase superfamily or alpha-family. The Homo sapiens and other eukaryotic constitutive kynureninases preferentially catalyze the hydrolytic cleavage of 3-hydroxy-l-kynurenine to produce 3-hydroxyanthranilate and l-alanine, while l-kynurenine is the substrate of many prokaryotic inducible kynureninases. The human enzyme was cloned with an N-terminal hexahistidine tag, expressed, and purified from a bacterial expression system using Ni metal ion affinity chromatography. Kinetic characterization of the recombinant enzyme reveals classic Michaelis-Menten behavior, with a Km of 28.3 +/- 1.9 microM and a specific activity of 1.75 micromol min-1 mg-1 for 3-hydroxy-dl-kynurenine. Crystals of recombinant kynureninase that diffracted to 2.0 A were obtained, and the atomic structure of the PLP-bound holoenzyme was determined by molecular replacement using the Pseudomonas fluorescens kynureninase structure (PDB entry 1qz9) as the phasing model. A structural superposition with the P. fluorescens kynureninase revealed that these two structures resemble the "open" and "closed" conformations of aspartate aminotransferase. The comparison illustrates the dynamic nature of these proteins' small domains and reveals a role for Arg-434 similar to its role in other AAT alpha-family members. Docking of 3-hydroxy-l-kynurenine into the human kynureninase active site suggests that Asn-333 and His-102 are involved in substrate binding and molecular discrimination between inducible and constitutive kynureninase substrates.
Project description:We have sequenced miRNA libraries from human embryonic, neural and foetal mesenchymal stem cells. We report that the majority of miRNA genes encode mature isomers that vary in size by one or more bases at the 3’ and/or 5’ end of the miRNA. Northern blotting for individual miRNAs showed that the proportions of isomiRs expressed by a single miRNA gene often differ between cell and tissue types. IsomiRs were readily co-immunoprecipitated with Argonaute proteins in vivo and were active in luciferase assays, indicating that they are functional. Bioinformatics analysis predicts substantial differences in targeting between miRNAs with minor 5’ differences and in support of this we report that a 5’ isomiR-9-1 gained the ability to inhibit the expression of DNMT3B and NCAM2 but lost the ability to inhibit CDH1 in vitro. This result was confirmed by the use of isomiR-specific sponges. Our analysis of the miRGator database indicates that a small percentage of human miRNA genes express isomiRs as the dominant transcript in certain cell types and analysis of miRBase shows that 5’ isomiRs have replaced canonical miRNAs many times during evolution. This strongly indicates that isomiRs are of functional importance and have contributed to the evolution of miRNA genes
Project description:AML cell lines were treated with either vehicle or SY-1425 (tamibarotene), a potent and selective agonist of retinoic acid receptor alpha (RARa), and assayed by microarray expression analysis.
Project description:As the evolution of miRNA genes has been found to be one of the important factors in formation of the modern type of man, we performed a comparative analysis of the evolution of miRNA genes in two archaic hominines, Homo sapiens neanderthalensis and Homo sapiens denisova, and elucidated the expression of their target mRNAs in bain.A comparative analysis of the genomes of primates, including species in the genus Homo, identified a group of miRNA genes having fixed substitutions with important implications for the evolution of Homo sapiens neanderthalensis and Homo sapiens denisova. The mRNAs targeted by miRNAs with mutations specific for Homo sapiens denisova exhibited enhanced expression during postnatal brain development in modern humans. By contrast, the expression of mRNAs targeted by miRNAs bearing variations specific for Homo sapiens neanderthalensis was shown to be enhanced in prenatal brain development.Our results highlight the importance of changes in miRNA gene sequences in the course of Homo sapiens denisova and Homo sapiens neanderthalensis evolution. The genetic alterations of miRNAs regulating the spatiotemporal expression of multiple genes in the prenatal and postnatal brain may contribute to the progressive evolution of brain function, which is consistent with the observations of fine technical and typological properties of tools and decorative items reported from archaeological Denisovan sites. The data also suggest that differential spatial-temporal regulation of gene products promoted by the subspecies-specific mutations in the miRNA genes might have occurred in the brains of Homo sapiens denisova and Homo sapiens neanderthalensis, potentially contributing to the cultural differences between these two archaic hominines.
Project description:PurposeWe investigated the evidence of recent positive selection in the human phototransduction system at single nucleotide polymorphism (SNP) and gene level.MethodsSNP genotyping data from the International HapMap Project for European, Eastern Asian, and African populations was used to discover differences in haplotype length and allele frequency between these populations. Numeric selection metrics were computed for each SNP and aggregated into gene-level metrics to measure evidence of recent positive selection. The level of recent positive selection in phototransduction genes was evaluated and compared to a set of genes shown previously to be under recent selection, and a set of highly conserved genes as positive and negative controls, respectively.ResultsSix of 20 phototransduction genes evaluated had gene-level selection metrics above the 90th percentile: RGS9, GNB1, RHO, PDE6G, GNAT1, and SLC24A1. The selection signal across these genes was found to be of similar magnitude to the positive control genes and much greater than the negative control genes.ConclusionsThere is evidence for selective pressure in the genes involved in retinal phototransduction, and traces of this selective pressure can be demonstrated using SNP-level and gene-level metrics of allelic variation. We hypothesize that the selective pressure on these genes was related to their role in low light vision and retinal adaptation to ambient light changes. Uncovering the underlying genetics of evolutionary adaptations in phototransduction not only allows greater understanding of vision and visual diseases, but also the development of patient-specific diagnostic and intervention strategies.