Project description:When CDK19 was initially discovered, it was assumed that CDK19 played a redundant role to CDK8 because they share 84% amino acid sequence similarity. However, biological clues such as CDK19s different chromosomal location and its more limited tissue distribution suggested a role distinct from CDK8 To investigate whether CDK19 and CDK8 had distinct biological functions in Triple-Negative breast cancer, we knocked down CDK19 and CDK8 in a patient-derived xenograft (PDX-C69) and examined differences in the resulting gene expression.
Project description:The human Mediator complex regulates RNA Polymerase II transcription genomewide. A general factor that regulates Mediator function is the four-subunit Mediator kinase module, which contains either CDK8 or CDK19. Whereas CDK8 has been linked to specific signaling cascades and oncogenesis, the cellular roles of its paralog, CDK19, are poorly studied. To define cellular roles for CDK19, we used osteosarcoma cells (SJSA) that naturally lack endogenous CDK8 protein. Although stable CDK19 knockdown was tolerated in SJSA cells, it caused reduced proliferation vs. control shRNA cells. Global gene expression analyses (RNA-Seq) suggested that defects in cholesterol biosynthesis contributed to reduced proliferation in CDK19 knockdown cells (vs. shCTRL). Notably, proliferation defects were rescued with transient expression of wild-type or kinase-dead CDK19. Using RNA-Seq and other assays, we established a general role for CDK19 in the transcriptional response to 5-fluorouracil (5-FU), an inducer of genotoxic and metabolic stress. These experiments also implicated CDK19 in activation of p53 target genes during 5-FU treatment. To further probe a potential role for CDK19 in the p53 response, SJSA cells (shCDK19 vs. shCTRL) were treated with the p53 activator Nutlin-3. Remarkably, CDK19 was required for SJSA cells to return to a proliferative state following Nutlin-3 treatment, and this effect was kinase-independent. These results implicate CDK19 as a regulator of p53 stress responses and suggest a manifestation of CDK19 knockdown—potentially reduced levels of cholesterol metabolites—blocks cellular resistance to Nutlin-3.
Project description:To define the contribution of CDK8 versus CDK19 to gene expression control, we performed a series of microarray assays for cells where each kinase was stably knocked down. Toward this end, we subjected HCT116 cells to three different stress stimuli: 5-fluorouracil (5FU), glucose deprivation, and hypoxia. We found that CDK8, but not CDK19, functions as a widespread coactivator of HIF1A target genes in hypoxia. Total RNA from HCT116 cells harvested using an RNeasy kit (Qiagen) was used for gene expression analysis on Affymetrix HuGene 1.0 ST arrays following the manufacturer’s instructions. Differential gene expression was determined with Partek software using one-way ANOVA.
Project description:RNA-Seq analysis was carried out to investigate the effects of expression of wild-type CDK8 (CDK8) or CDK19 (CDK19) or their kinase-inactive D173A mutants (CDK8M and CDK19M) in HEK293 cells (WT) and their CDK8/19 double-knockout (dKO) derivatives
Project description:When CDK19 was initially discovered, it was assumed that CDK19 played a redundant role to CDK8 because they share 84% amino acid sequence similarity. However, biological clues such as CDK19s different chromosomal location and its more limited tissue distribution suggested a role distinct from CDK8 To investigate whether CDK19 and CDK8 had distinct biological functions in Triple-Negative breast cancer, we knocked down CDK19 and CDK8 in MDA-MB231 and examined differences in the resulting gene expression.
Project description:To identify novel functions of Mediator kinases CDK8 and CDK19 in the intestinal epithelium, we generated novel genetic mouse model enabling the individual and compound deletion of CDK8 and CDK19. RNA-sequencing was performed on primary intestinal epithelial cells and murine small intestinal organoids at different time points after CDK8/19 deletion.
Project description:RNA-Seq analysis was carried out to investigate the effects of selective CDK8/19 inhibitor SNX631 on gene expression in different 22RV1 derivatives grown in cell culture, under androgen-supplemented and androgen-deprived conditions. The 22Rv1 derivatives were generated as following: Parental 22Rv1 (Rv1-WT) were transduced with a lentivirus expressing luciferase, yielding the derivative Rv1-Luc. 22Rv1 cells with a double knockout of CDK8 and CDK19 (Rv1-dKO) were made via CRISPR/Cas9. Rv1-dKO cells were further transduced with lentiviruses to generate Rv1-dKO re-expression derivatives that express wild-type CDK8 or CDK19 (Rv1-dKO-CDK8 or Rv1-dKO-CDK19) and kinase-inactive D173A mutants (Rv1-dKO-CDK8M or Rv1-dKO-CDK19M).
Project description:To define the contribution of CDK8 versus CDK19 to gene expression control, we performed a series of microarray assays for cells where each kinase was stably knocked down. Toward this end, we subjected HCT116 cells to three different stress stimuli: 5-fluorouracil (5FU), glucose deprivation, and hypoxia. We found that CDK8, but not CDK19, functions as a widespread coactivator of HIF1A target genes in hypoxia.
Project description:RNA-Seq analysis was carried out to investigate the effects of CDK8/19 inactivation in the tumors formed in intact and castrated NSG mice by different 22Rv1 derivatives, with or without SNX631 treatment. The 22Rv1 derivatives were generated as following: Parental 22Rv1 (Rv1-WT) were transduced with a lentivirus expressing luciferase, yielding the derivative Rv1-Luc. 22Rv1 cells with a double knockout of CDK8 and CDK19 (Rv1-dKO) were made via CRISPR/Cas9. Rv1-dKO cells were further transduced with lentiviruses to generate Rv1-dKO re-expression derivatives that express wild-type CDK19 (Rv1-dKO-CDK19) and the kinase-inactive D173A mutant (Rv1-dKO-CDK19M). SNX631 is a selective and orally bioavalable CDK8/19 inhibtor.
