SY-1365, a covalent, first in-class CDK7 inhibitor for cancer treatment (ChIP-Seq)
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ABSTRACT: 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: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:Rising blast-percentage or secondary (s) AML transformation (sAML) in MPNs leads to JAK inhibitor (JAKi) therapy-resistance and poor survival. Here, we demonstrate that the CDK7 inhibitor (CDK7i) SY-5609 treatment depletes phenotypically-characterized post-MPN-sAML stem/progenitor cells. In the cultured post-MPN sAML SET2 and HEL as well as patient-derived (PD) post-MPN-sAML cells, SY-5609 treatment inhibited growth and induced lethality, while sparing normal cells. RNA-Seq analysis following SY-5609 treatment demonstrated reduced mRNA expressions of MYC, MYB, CDK4/6, PIM1, and CCND1, but increased mRNA levels of CDKN1A and BCL2L1. Mass spectrometry of SY-5609-treated MPN-sAML cells also demonstrated reduced c-Myc, c-Myb, PIM1, and CDK4/6 but increased p21, caspase 9 and BAD protein levels. CRISPR-mediated CDK7 depletion also reduced viability of HEL cells. CyTOF analysis of SY-5609-treated PD, post-MPN-sAML stem/progenitor cells showed reduced c-Myc, CDK6 and PU.1, but increased protein levels of CD11b, p21 and cleaved Caspase 3. Co-treatment with SY-5609 and ruxolitinib was synergistically lethal in HEL, SET2 and PD post-MPN-sAML cells. A CRISPR screen in SET2 and HEL cells revealed BRD4, CBP and p300 as co-dependencies with SY-5609 treatment. Accordingly, co-treatment with SY-5609 and the BETi OTX015 or pelabresib or with the CBP/p300 inhibitor GNE-049 was synergistically lethal in MPN-sAML cells (including those exhibiting TP53 loss). Finally, in the HEL-Luc/GFP xenograft model, compared to each agent alone, co-treatment with SY-5609 and OTX015 reduced post-MPN-sAML burden and improved survival without inducing host toxicity. These findings demonstrate promising preclinical activity of the CDK7i-based combinations with BETi or HATi against advanced-MPNs, including post-MPN-sAML.
Project description:Type II testicular germ cell tumors (TGCT) are the most frequently diagnosed solid malignancy in young men. Up to 15 % of patients with metastatic non-seminomas show cisplatin resistance having a very poor survival rate due to lacking treatment options. Transcriptional cyclin-dependent kinases (CDK) have been shown to be effective targets in treatment of different types of cancer. Here, we investigated the effects of the CDK inhibitors dinaciclib, flavopiridol, YKL-5-124, THZ1, NVP2, SY0351 and THZ531. XTT viability assay revealed strong cytotoxic impact of CDK7/ 12/ 13 inhibitor SY0351 and CDK9 inhibitor NVP2 on the TGCT wild type cell lines (2102EP, NCCIT, TCam2) and the cisplatin resistant cell lines (2102EP-R, NCCIT-R). The CDK7 inhibitor YKL-5-124 showed strong impact on 2102EP, 2102EP-R, NCCIT and NCCIT-R cell lines leaving the MPAF control cell line mostly unaffected. FACS based analysis revealed mild effects on the cell cycle of 2102EP and TCam2 cells after SY0351, YKL-5-124 or NVP2 treatment. Molecular analysis showed a cell line specific response for SY0351 and NVP2 inhibition while YKL-5-124 induced similar molecular changes in 2102EP, TCam2 and MPAF cells. Thus, after TGCT subtype determination CDK inhibitors might be a potential alternative for optimized and individualized therapy independent of chemotherapy sensitivity.
Project description:Here we evaluate the effect of CDK7 inhibition in the context of heat shock across three distinct inhibitors. Two inhibitors are Syros compounds SY-5609 and SY-5102. The final inhibitor is 3MBPP1 in a CDK7 analog sensitive cell line. We find that overall the same gene programs are impacted.
Project description:Triple-negative breast cancer (TNBC) is a highly aggressive form of breast cancer that exhibits extremely high levels of genetic complexity and yet a relatively uniform transcriptional program. We postulate that TNBC might be highly dependent on uninterrupted transcription of a key set of genes within this gene expression program and might therefore be exceptionally sensitive to inhibitors of transcription. Utilizing a novel kinase inhibitor and CRISPR/Cas9-mediated gene editing, we show here that triple-negative but not ER/PR+ breast cancer cells are exceptionally dependent on CDK7, a transcriptional cyclin-dependent kinase. TNBC cells are unique in their dependence on this transcriptional CDK and suffer apoptotic cell death upon CDK7 inhibition. An “Achilles cluster” of TNBC-specific genes are extremely sensitive to CDK7 inhibition and frequently associated with super-enhancers. We conclude that CDK7 mediates transcriptional addiction to a vital cluster of genes in TNBC and CDK7 inhibition may be useful therapy for this challenging cancer. Expression microarrays in H3K27ac in triple-negative breast cancer +/- treatment with covalent CDK7 inhibitor THZ1 treatment
Project description:The effects of the CDK inhibitor Flavopiridol on the A2780 human adenocarcinoma ovary cell line were analysed by gene expression profiling. A2780 cells were treated with Flavopiridol for 6 hours at a dose equal to 5 times the IC50. Untreated A2780 cells were used as a control. Two replicates per treatment.
Project description:Cyclin-dependent kinase 7 (CDK7) plays a critical role in the general regulation of RNA polymerase II-mediated transcription. However, the absence of selective CDK7 inhibitors has hindered the ability to investigate the consequences of acute and prolonged inhibition of CDK7 under normal and pathological conditions. Here we present the discovery and characterization of the first covalent CDK7 inhibitor, CDK7-IN-1, that has the unprecedented ability to target a unique cysteine residue located outside of the canonical kinase domain, providing an unanticipated means of achieving selectivity for CDK7 amongst the 20 known CDKs. Cancer cell line profiling indicates that a subset of cancer cell lines, including T-cell acute lymphoblastic leukemia (T-ALL), exhibit 100-fold greater sensitivity to CDK7-IN-1 over other tumor and normal cell lines. Genome-wide expression analysis in Jurkat T-ALL indicates that CDK7-IN-1 disproportionally affects RUNX1 as well as other components of the TAL1 transcriptional network and its targets, downregulating key regulators of transcription and apoptosis critical for the T-ALL state. These oncogenes are encoded by short-lived mRNA transcripts, are associated with super-enhancers, and exhibit a strong dependency on continuous transcription for sustained expression. Therefore, pharmacological modulation of CDK7 kinase activity may define a method for the identification and treatment of tumor types exhibiting extreme dependencies on transcription for maintenance of the oncogenic state. Jurkat cells were treated with various drugs including a covalent inhibitor of CDK7 (CDK7-IN-1), a reversible inhibitor of CDK7 (CDK7-IN-1), Flavopiridol, Actinomycin D, and DMSO controls. Replicates are annotated.