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:Adenocarcinoma of the ovary is the fifth leading cause of cancer death among American women. Most mortality results from high-grade serous ovarian carcinoma (HGS-OvCa)—a disease type resistant to conventional chemotherapy, and therein requiring urgent preclinical modeling for pharmaceutical testing. We generated a novel serous ovarian carcinoma model by employing Ovgp1-driven Cre recombinase to catalyze CRISPR-Cas9-medicated ablation of the Trp53, Rb1 and Nf1 tumor suppressor genes in the mouse ovary (m-sgPRN mice). The gene encoding cyclin dependent kinase 12 (CDK12) is among the most frequently inactivated in HGS-OvCa. Its loss corresponds with increased mortality, DNA damage (including tandem duplications) and tumor immunogenicity. Co-ablation of Cdk12 in the m-sgPRN model (m-sgPRN; Cdk12KO mice) accelerated tumor progression leading to bona fide HGS-OvCa, and early mortality. In a conventional (Cre-lox-medicated) Trp53/ Nf1/ Rb1 triple knockout model, Cdk12 ablation (PRN; Cdk12KO mice) effected immune infiltration characterized by CD3, CD8, CD4, and Granzyme B positivity like that seen in clinical HGS-OvCa. We observed recapitulation of this immunogenic phenotype—with corresponding sensitivity to immune checkpoint blockade—in a novel syngeneic allograft model derived from these animals. To screen for synthetic lethal interactions with Cdk12 loss, we conducted a CRISPR-Cas9 screen in PRN; Cdk12KO cell lines. The gene encoding CDK12 paralog CDK13 emerged as the most depleted, suggesting CDK13 could be targeted to promote paralog-induced synthetic lethality as previously demonstrated in CDK12-mutant prostate cancer. Indeed, m-sgPRN; Cdk12KO and PRN; Cdk12KO -derived cell lines exhibited enhanced sensitivity to the CDK13/12 degrader YJ1206. Our work defines CDK13-targeting as a novel treatment modality for CDK12-inactive HGS-OvCa while establishing biological resources for the in vivo modeling of this disease.
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.