Project description:Cyclin-dependent kinases 12 and 13 (CDK12 and CDK13) play critical roles in the regulation of gene transcription. However, the absence of CDK12 and CDK13 inhibitors has hindered the ability to investigate the consequences of their inhibition in healthy cells and cancer cells. Here we describe the rational design of a first-in-class CDK12 and CDK13 covalent inhibitor, THZ531. Co-crystallization of THZ531 with CDK12–cyclin K indicates that THZ531 irreversibly targets a cysteine located outside the kinase domain. THZ531 causes a loss of gene expression with concurrent loss of elongating and hyperphosphorylated RNA polymerase II. In particular, THZ531 substantially decreases the expression of DNA damage response genes and key super-enhancer-associated transcription factor genes. Coincident with transcriptional perturbation, THZ531 dramatically induced apoptotic cell death. Small molecules capable of specifically targeting CDK12 and CDK13 may thus help identify cancer subtypes that are particularly dependent on their kinase activities.
Project description:Cyclin-dependent kinases 12 and 13 (CDK12 and CDK13) play critical roles in the regulation of gene transcription. However, the absence of CDK12 and CDK13 inhibitors has hindered the ability to investigate the consequences of their inhibition in healthy cells and cancer cells. Here we describe the rational design of a first-in-class CDK12 and CDK13 covalent inhibitor, THZ531. Co-crystallization of THZ531 with CDK12–cyclin K indicates that THZ531 irreversibly targets a cysteine located outside the kinase domain. THZ531 causes a loss of gene expression with concurrent loss of elongating and hyperphosphorylated RNA polymerase II. In particular, THZ531 substantially decreases the expression of DNA damage response genes and key super-enhancer-associated transcription factor genes. Coincident with transcriptional perturbation, THZ531 dramatically induced apoptotic cell death. Small molecules capable of specifically targeting CDK12 and CDK13 may thus help identify cancer subtypes that are particularly dependent on their kinase activities.
Project description:CDK12 and CDK13 promote transcription elongation within the gene body and regulate the processivity of RNAPII. THZ531 inhibits the enzymatic activity of CDK12 and 13 through covalent binding. Gene expression profiling was performed to investigate the THZ531-induced transcription effect, and search the subset of sensitive genes in osteosarcoma cell lines, U2-OS and SJSA-1.
Project description:We report the total RNA-seq results after CDK9, CDK12 and CDK13 depletion in human HCT116 cells for three days. RNA-seq was performed in cells using two non-targeting replicates and two different shRNAs for each CDK knockdown. For each CDK knockdown, most of the differentially expressed genes were down-regulated with a very small subset of genes upregulated. Different CDK proteins control distinct subsets of genes in vivo, with CDK12 and CDK13 sharing more overlap in function compared to CDK9. Besides, CDK12 and CDK13 loss preferentially affects DNA damage response and snRNA gene expression, respectively.
Project description:We used 3' RNA-Seq to determine the effects of analog senstive CDK12, CDK13 and dual inhibition on gene expression and polyadenatltion site usages, and to test the redundancy between CDK12 and CDK13 in maintaining global transcrition on the tramcrotpomte level.
Project description:High-grade serous ovarian cancer is characterized by extensive copy number alterations, among which the amplification of MYC oncogene occurs in nearly half of tumors. We demonstrate that ovarian cancer cells highly depend on MYC for maintaining their oncogenic growth, indicating MYC as a therapeutic target for this difficult-to-treat malignancy. However, targeting MYC directly has proven difficult. We screen small molecules targeting transcriptional and epigenetic regulation, and find that THZ1 –a chemical inhibiting CDK7, CDK12, and CDK13–markedly downregulates MYC. Notably, abolishing MYC expression cannot be achieved by targeting CDK7 alone, but require the combined inhibition of CDK7, CDK12, and CDK13. In all 11 independent patient derived xenografts models derived from heavily pre-treated ovarian cancer patients, administration of THZ1 induces significant tumor growth inhibition with concurrent abrogation of MYC expression. Our study indicates that targeting these transcriptional CDKs with agents such as THZ1 may be an effective approach for MYC-dependent ovarian malignancies.
Project description:The RNA polymerase II (POLII) driven transcription cycle is tightly regulated at distinct checkpoints through cyclin dependent kinases (CDKs) and their cognate Cyclins. The molecular events underpinning transcriptional elongation and processivity and CDK-Cyclins involved remain poorly understood. Using CRISPR-CAS9 homology-directed-repair we generated analog-sensitive-kinase variants of CDK12 and CDK13 to probe their individual and shared biological and molecular roles. Single inhibition of CDK12 or CDK13 induced transcriptional responses associated with DNA-damage and cellular growth signaling pathways respectively, with minimal effects on cell viability. In contrast, dual-kinase inhibition potently induced cell death, which was associated with extensive genome-wide transcriptional changes including wide-spread use of alternative 3’ polyadenylation sites. At the molecular level dual-kinase inhibition resulted in the loss of POLII CTD phosphorylation and greatly reduced POLII elongation rates and processivity. These data define significant redundancy between CDK12 and CDK13, and identify both as fundamental regulators of global POLII processivity and transcription elongation.