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Experimental Hematology & Oncology Mar 2024Acute myeloid leukemia (AML) is a highly aggressive hematologic cancer with poor survival across a broad range of molecular subtypes. Development of efficacious and...
The multi-CDK inhibitor dinaciclib reverses bromo- and extra-terminal domain (BET) inhibitor resistance in acute myeloid leukemia via inhibition of Wnt/β-catenin signaling.
Acute myeloid leukemia (AML) is a highly aggressive hematologic cancer with poor survival across a broad range of molecular subtypes. Development of efficacious and well-tolerable therapies encompassing the range of mutations that can arise in AML remains an unmet need. The bromo- and extra-terminal domain (BET) family of proteins represents an attractive therapeutic target in AML due to their crucial roles in many cellular functions, regardless of any specific mutation. Many BET inhibitors (BETi) are currently in pre-clinical and early clinical development, but acquisition of resistance continues to remain an obstacle for the drug class. Novel methods to circumvent this development of resistance could be instrumental for the future use of BET inhibitors in AML, both as monotherapy and in combination. To date, many investigations into possible drug combinations of BETi with CDK inhibitors have focused on CDK9, which has a known physical and functional interaction with the BET protein BRD4. Therefore, we wished to investigate possible synergy and additive effects between inhibitors of these targets in AML. Here, we describe combination therapy with the multi-CDK inhibitor dinaciclib and the BETi PLX51107 in pre-clinical models of AML. Dinaciclib and PLX51107 demonstrate additive effects in AML cell lines, primary AML samples, and in vivo. Further, we demonstrate novel activity of dinaciclib through inhibition of the canonical/β-catenin dependent Wnt signaling pathway, a known resistance mechanism to BETi in AML. We show dinaciclib inhibits Wnt signaling at multiple levels, including downregulation of β-catenin, the Wnt co-receptor LRP6, as well as many Wnt pathway components and targets. Moreover, dinaciclib sensitivity remains unaffected in a setting of BET resistance, demonstrating similar inhibitory effects on Wnt signaling when compared to BET-sensitive cells. Ultimately, our results demonstrate rationale for combination CDKi and BETi in AML. In addition, our novel finding of Wnt signaling inhibition could have potential implications in other cancers where Wnt signaling is dysregulated and demonstrates one possible approach to circumvent development of BET resistance in AML.
PubMed: 38438856
DOI: 10.1186/s40164-024-00483-w -
Cancers Mar 2021Endometrial cancer (EC) is the sixth most prevalent female cancer globally and although high rates of success are achieved when diagnosed at an early stage, the 5-year...
Endometrial cancer (EC) is the sixth most prevalent female cancer globally and although high rates of success are achieved when diagnosed at an early stage, the 5-year survival rate for cancers diagnosed at Stages II-IV is below 50%. Improving patient outcomes will necessitate the introduction of novel therapies to the clinic. Pan-cyclin-dependent kinase inhibitors (CDKis) have been explored as therapies for a range of cancers due to their ability to simultaneously target multiple key cellular processes, such as cell cycle progression, transcription, and DNA repair. Few studies, however, have reported on their potential for the treatment of EC. Herein, we examined the effects of the pan-CDKi dinaciclib in primary cells isolated directly from tumors and EC cell lines. Dinaciclib was shown to elicit a bimodal action in EC cell lines, disrupting both cell cycle progression and phosphorylation of the RNA polymerase carboxy terminal domain, with a concomitant reduction in Bcl-2 expression. Furthermore, the therapeutic potential of combining dinaciclib and cisplatin was explored, with the drugs demonstrating synergy at specific doses in Type I and Type II EC cell lines. Together, these results highlight the potential of dinaciclib for use as an effective EC therapy.
PubMed: 33800911
DOI: 10.3390/cancers13051135 -
The Journal of Clinical Investigation Feb 2018Blockade of the checkpoint inhibitor programmed death 1 (PD1) has demonstrated remarkable success in the clinic for the treatment of cancer; however, a majority of...
Blockade of the checkpoint inhibitor programmed death 1 (PD1) has demonstrated remarkable success in the clinic for the treatment of cancer; however, a majority of tumors are resistant to anti-PD1 monotherapy. Numerous ongoing clinical combination therapy studies will likely reveal additional therapeutics that complement anti-PD1 blockade. Recent studies found that immunogenic cell death (ICD) improves T cell responses against different tumors, thus indicating that ICD may further augment antitumor immunity elicited by anti-PD1. Here, we observed antitumor activity following combinatorial therapy with anti-PD1 Ab and the cyclin-dependent kinase inhibitor dinaciclib in immunocompetent mouse tumor models. Dinaciclib induced a type I IFN gene signature within the tumor, leading us to hypothesize that dinaciclib potentiates the effects of anti-PD1 by eliciting ICD. Indeed, tumor cells treated with dinaciclib showed the hallmarks of ICD including surface calreticulin expression and release of high mobility group box 1 (HMGB1) and ATP. Mice treated with both anti-PD1 and dinaciclib showed increased T cell infiltration and DC activation within the tumor, indicating that this combination improves the overall quality of the immune response generated. These findings identify a potential mechanism for the observed benefit of combining dinaciclib and anti-PD1, in which dinaciclib induces ICD, thereby converting the tumor cell into an endogenous vaccine and boosting the effects of anti-PD1.
Topics: Adenocarcinoma; Adenosine Triphosphate; Animals; Antibodies, Monoclonal; Apoptosis; Bridged Bicyclo Compounds, Heterocyclic; CD8-Positive T-Lymphocytes; Cell Death; Cell Line, Tumor; Cyclic N-Oxides; Cytokines; Dendritic Cells; Drug Synergism; Female; HMGB1 Protein; Immune System; Immunotherapy; Indolizines; Mice; Mice, Inbred BALB C; Mice, Inbred C57BL; Mice, Knockout; Neoplasm Transplantation; Phagocytosis; Programmed Cell Death 1 Receptor; Protein Kinase Inhibitors; Pyridinium Compounds
PubMed: 29337311
DOI: 10.1172/JCI94586 -
Molecular Carcinogenesis Apr 2018In the present study, we investigated the effect of CDK inhibitors (ribociclib, palbociclib, seliciclib, AZD5438, and dinaciclib) on malignant human glioma cells for...
In the present study, we investigated the effect of CDK inhibitors (ribociclib, palbociclib, seliciclib, AZD5438, and dinaciclib) on malignant human glioma cells for cell viability, apoptosis, oxidative stress, and mitochondrial function using various assays. None of the CDK inhibitors induced cell death at a clinically relevant concentration. However, low nanomolar concentrations of dinaciclib showed higher cytotoxic activity against Bcl-xL silenced cells in a time- and concentration-dependent manner. This effect was not seen with other CDK inhibitors. The apoptosis-inducing capability of dinaciclib in Bcl-xL silenced cells was evidenced by cell shrinkage, mitochondrial dysfunction, DNA damage, and increased phosphatidylserine externalization. Dinaciclib was found to disrupt mitochondrial membrane potential, resulting in the release of cytochrome c, AIF, and smac/DIABLO into the cytoplasm. This was accompanied by the downregulation of cyclin-D1, D3, and total Rb. Dinaciclib caused cell cycle arrest in a time- and concentration-dependent manner and with accumulation of cells in the sub-G1 phase. Our results also revealed that dinaciclib, but not ribociclib or palbociclib or seliciclib or AZD5438 induced intrinsic apoptosis via upregulation of the levels of pro-apoptotic proteins (Bax and Bak), resulting in the activation of caspases and cleavage of PARP. We also found an additional mechanism for the dinaciclib-induced augmentation of apoptosis due to abrogation RAD51-cyclin D1 interaction, specifically proteolysis of the DNA repair proteins RAD51 and Ku80. Our results suggest that successfully interfering with Bcl-xL function may restore sensitivity to dinaciclib and could hold the promise for an effective combination therapeutic strategy.
Topics: Apoptosis; Apoptosis Regulatory Proteins; Bridged Bicyclo Compounds, Heterocyclic; Cell Line, Tumor; Cyclic N-Oxides; Cyclin-Dependent Kinases; Glioma; Humans; Indolizines; Ku Autoantigen; Membrane Potential, Mitochondrial; Mitochondria; Protein Kinase Inhibitors; Proteolysis; Pyridinium Compounds; RNA Interference; Rad51 Recombinase; Up-Regulation; bcl-X Protein
PubMed: 29240261
DOI: 10.1002/mc.22771 -
Cells Jan 2022Pregnane X receptor (PXR) is a member of the nuclear receptor superfamily that is activated by a variety of endogenous metabolites or xenobiotics. Its downstream target...
Pregnane X receptor (PXR) is a member of the nuclear receptor superfamily that is activated by a variety of endogenous metabolites or xenobiotics. Its downstream target genes are involved in metabolism, inflammation and processes closely related to cancer. However, the stability regulation of PXR protein resulting from post-translational modification is still largely undefined. In the present study, primary mouse hepatocytes, hepatoma HepG2 cells and HEK 293T cells were used to investigate gene expression and protein interactions. The role of kinases was evaluated by RNA interference and overexpression constructs with or without PXR phosphorylation site mutations. The activity of CYP3A4 and P-gp was determined by enzymatic and substrate accumulation assays. It was found that E3 ubiquitin ligase TRIM21 mediates the ubiquitination and degradation of PXR and plays an important role in regulating the activity of PXR. On this basis, PXR phosphorylation-associated kinases were evaluated regarding regulation of the stability of PXR. We found cyclin dependent kinase 2 (CDK2) exclusively phosphorylates PXR at Ser350, promotes its disassociation with Hsp90/DNAJC7, and leads to subsequent TRIM21-mediated PXR ubiquitination and degradation. As well-known CDK inhibitors, dinaciclib and kenpaullone stabilize PXR and result in elevated expression and activity of PXR-targeted DMETs, including carboxylesterases, CYP3A4 and P-gp. The suppressed degradation of PXR by CDK2 inhibitors denotes dinaciclib-induced promotion of PXR-targeted genes. The findings of CDK2-mediated PXR degradation indicate a wide range of potential drug-drug interactions during clinical cancer therapy using CDK inhibitors and imply an alternative direction for the development of novel PXR antagonists.
Topics: Cyclic N-Oxides; Cyclin-Dependent Kinase 2; Gene Expression Regulation; HEK293 Cells; HSP90 Heat-Shock Proteins; Heat-Shock Proteins; Hep G2 Cells; Hepatocytes; Humans; Indolizines; Molecular Chaperones; Phosphorylation; Phosphoserine; Pregnane X Receptor; Proteasome Endopeptidase Complex; Protein Binding; Protein Kinase Inhibitors; Protein Stability; Proteolysis; Pyridinium Compounds; Ribonucleoproteins; Signal Transduction; Ubiquitin; Ubiquitination
PubMed: 35053380
DOI: 10.3390/cells11020264 -
Cell Cycle (Georgetown, Tex.) 2016CDK9 is a protein in constant development in cancer therapy. Herein we present an overview of the enzyme as a target for cancer therapy. We provide data on its... (Review)
Review
CDK9 is a protein in constant development in cancer therapy. Herein we present an overview of the enzyme as a target for cancer therapy. We provide data on its characteristics and mechanism of action. In recent years, CDK9 inhibitors that have been designed with molecular modeling have demonstrated good antitumoral activity in vitro. Clinical studies of the drugs flavopiridol, dinaciclib, seliciclib, SNS-032 and RGB-286638 used as CDK9 inhibitors are also reviewed, with their additional targets and their relative IC50 values. Unfortunately, treatment with these drugs remains unsuccessful and involves many adverse effects. We could conclude that there are many small molecules that bind to CDK9, but their lack of selectivity against other CDKs do not allow them to get to the clinical use. However, drug designers currently have the tools needed to improve the selectivity of CDK9 inhibitors and to make successful treatment available to patients.
Topics: Bridged Bicyclo Compounds, Heterocyclic; Cell Cycle; Cyclic N-Oxides; Cyclin-Dependent Kinase 9; Flavonoids; Humans; Indolizines; Molecular Targeted Therapy; Neoplasms; Oxazoles; Piperidines; Protein Kinase Inhibitors; Purines; Pyrazoles; Pyridinium Compounds; Roscovitine; Thiazoles; Urea
PubMed: 26766294
DOI: 10.1080/15384101.2016.1138186 -
Scientific Reports Oct 2020Cholangiocarcinoma (CCA) is a highly invasive cancer, diagnosed at an advanced stage, and refractory to surgical intervention and chemotherapy. Cyclin-dependent kinases...
Cholangiocarcinoma (CCA) is a highly invasive cancer, diagnosed at an advanced stage, and refractory to surgical intervention and chemotherapy. Cyclin-dependent kinases (CDKs) regulate cell cycle progression and transcriptional processes, and are considered potential therapeutic targets for cancer. Dinaciclib is a small molecule multi-CDK inhibitor targeting CDK 2/5/9. In this study, the therapeutic efficacy of dinaciclib was assessed using patient-derived xenograft cells (PDXC) and CCA cell lines. Treatment with dinaciclib significantly suppressed cell proliferation, induced caspase 3/7 levels and apoptotic activity in PDXC and CCA cell lines. Dinaciclib suppressed expression of its molecular targets CDK2/5/9, and anti-apoptotic BCL-XL and BCL2 proteins. Despite the presence of cyclin D1 amplification in the PDXC line, palbociclib treatment had no effect on cell proliferation, cell cycle or apoptosis in the PDXC as well as other CCA cell lines. Importantly, dinaciclib, in combination with gemcitabine, produced a robust and sustained inhibition of tumor progression in vivo in a PDX mouse model, greater than either of the treatments alone. Expression levels of two proliferative markers, phospho-histone H3 and Ki-67, were substantially suppressed in samples treated with the combination regimen. Our results identify dinaciclib as a novel and potent therapeutic agent alone or in combination with gemcitabine for the treatment of CCA.
Topics: Animals; Apoptosis; Bile Duct Neoplasms; Cell Line, Tumor; Cell Proliferation; Cell Survival; Cholangiocarcinoma; Cyclic N-Oxides; Cyclin-Dependent Kinase 2; Cyclin-Dependent Kinase 5; Cyclin-Dependent Kinase 9; Deoxycytidine; Gastrointestinal Neoplasms; Histones; Humans; Indolizines; Inhibitory Concentration 50; Ki-67 Antigen; Male; Mice; Mice, Inbred NOD; Proto-Oncogene Proteins c-bcl-2; Pyridinium Compounds; Xenograft Model Antitumor Assays; bcl-X Protein; Gemcitabine
PubMed: 33116269
DOI: 10.1038/s41598-020-75578-5 -
International Journal of Molecular... Apr 2022Casein kinase II (CK2) and cyclin-dependent kinases (CDKs) frequently interact within multiple pathways in pancreatic ductal adenocarcinoma (PDAC). Application of CK2-...
Casein kinase II (CK2) and cyclin-dependent kinases (CDKs) frequently interact within multiple pathways in pancreatic ductal adenocarcinoma (PDAC). Application of CK2- and CDK-inhibitors have been considered as a therapeutic option, but are currently not part of routine chemotherapy regimens. We investigated ten PDAC cell lines exposed to increasing concentrations of silmitasertib and dinaciclib. Cell proliferation, metabolic activity, biomass, and apoptosis/necrosis were evaluated, and bioinformatic clustering was used to classify cell lines into sensitive groups based on their response to inhibitors. Furthermore, whole exome sequencing (WES) and RNA sequencing (RNA-Seq) was conducted to assess recurrent mutations and the expression profile of inhibitor targets and genes frequently mutated in PDAC, respectively. Dinaciclib and silmitasertib demonstrated pronounced and limited cell line specific effects in cell death induction, respectively. WES revealed no genomic variants causing changes in the primary structure of the corresponding inhibitor target proteins. RNA-Seq demonstrated that the expression of all inhibitor target genes was higher in the PDAC cell lines compared to non-neoplastic pancreatic tissue. The observed differences in PDAC cell line sensitivity to silmitasertib or dinaciclib did not depend on target gene expression or the identified gene variants. For the PDAC hotspot genes kirsten rat sarcoma virus () and tumor protein p53 (), three and eight variants were identified, respectively. In conclusion, both inhibitors demonstrated in vitro efficacy on the PDAC cell lines. However, aberrations and expression of inhibitor target genes did not appear to affect the efficacy of the corresponding inhibitors. In addition, specific aberrations in and affected the efficacy of both inhibitors.
Topics: Carcinoma, Pancreatic Ductal; Casein Kinase II; Cell Line; Cell Line, Tumor; Cell Proliferation; Cyclic N-Oxides; Humans; Indolizines; Naphthyridines; Pancreatic Neoplasms; Phenazines; Protein Kinase Inhibitors; Proto-Oncogene Proteins p21(ras); Pyridinium Compounds
PubMed: 35457227
DOI: 10.3390/ijms23084409 -
Expert Opinion on Investigational Drugs Jun 2013Cyclin-dependent kinases (CDKs) regulate cell cycle progression. Certain CDKs (e.g., CDK7, CDK9) also control cellular transcription. Consequently, CDKs represent... (Review)
Review
INTRODUCTION
Cyclin-dependent kinases (CDKs) regulate cell cycle progression. Certain CDKs (e.g., CDK7, CDK9) also control cellular transcription. Consequently, CDKs represent attractive targets for anticancer drug development, as their aberrant expression is common in diverse malignancies, and CDK inhibition can trigger apoptosis. CDK inhibition may be particularly successful in hematologic malignancies, which are more sensitive to inhibition of cell cycling and apoptosis induction.
AREAS COVERED
A number of CDK inhibitors, ranging from pan-CDK inhibitors such as flavopiridol (alvocidib) to highly selective inhibitors of specific CDKs (e.g., CDK4/6), such as PD0332991, that are currently in various phases of development, are profiled in this review. Flavopiridol induces cell cycle arrest, and globally represses transcription via CDK9 inhibition. The latter may represent its major mechanism of action via down-regulation of multiple short-lived proteins. In early phase trials, flavopiridol has shown encouraging efficacy across a wide spectrum of hematologic malignancies. Early results with dinaciclib and PD0332991 also appear promising.
EXPERT OPINION
In general, the antitumor efficacy of CDK inhibitor monotherapy is modest, and rational combinations are being explored, including those involving other targeted agents. While selective CDK4/6 inhibition might be effective against certain malignancies, broad-spectrum CDK inhibition will likely be required for most cancers.
Topics: Animals; Antineoplastic Agents; Apoptosis; Cell Cycle; Cyclin-Dependent Kinases; Drug Design; Hematologic Neoplasms; Humans; Molecular Targeted Therapy; Protein Kinase Inhibitors
PubMed: 23647051
DOI: 10.1517/13543784.2013.789859 -
Clinical and Translational Science Nov 2020The combination of drugs targeting Ral and PI3K/AKT signaling has antitumor efficacy in preclinical models of pancreatic cancer. We combined dinaciclib (small molecule... (Randomized Controlled Trial)
Randomized Controlled Trial
The combination of drugs targeting Ral and PI3K/AKT signaling has antitumor efficacy in preclinical models of pancreatic cancer. We combined dinaciclib (small molecule cyclin dependent kinase inhibitor with MK-2206 (Akt inhibitor) in patients with previously treated/metastatic pancreatic cancer. Patients were treated with dinaciclib (6-12 mg/m i.v.) and MK-2206 (60-135 mg p.o.) weekly. Tumor biopsies were performed to measure pAKT, pERK, and Ki67 at baseline and after one completed cycle (dose level 2 and beyond). Thirty-nine patients participated in the study. The maximum tolerated doses were dinaciclib 9 mg/m and MK-2206 135 mg. Treatment-related grade 3 and 4 toxicities included neutropenia, lymphopenia, anemia, hyperglycemia, hyponatremia, and leukopenia. No objectives responses were observed. Four patients (10%) had stable disease as their best response. At the recommended dose, median survival was 2.2 months. Survival rates at 6 and 12 months were 11% and 5%, respectively. There was a nonsignificant reduction in pAKT composite scores between pretreatment and post-treatment biopsies (mean 0.76 vs. 0.63; P = 0.635). The combination of dinaciclib and MK-2206 was a safe regimen in patients with metastatic pancreatic cancer, although without clinical benefit, possibly due to not attaining biologically effective doses. Given the strong preclinical evidence of Ral and AKT inhibition, further studies with better tolerated agents should be considered.
Topics: Administration, Oral; Adult; Aged; Antineoplastic Combined Chemotherapy Protocols; Biopsy; Carcinoma, Pancreatic Ductal; Cyclic N-Oxides; Female; Heterocyclic Compounds, 3-Ring; Humans; Indolizines; Male; Maximum Tolerated Dose; Middle Aged; Neoplasm Staging; Pancreas; Pancreatic Neoplasms; Protein Kinase Inhibitors; Pyridinium Compounds; Survival Rate; Treatment Outcome
PubMed: 32738099
DOI: 10.1111/cts.12802