Selective inhibition of CDK7 ameliorates experimental arthritis in mice

Targeting cyclin-dependent kinases in rheumatoid arthritis and psoriasis - a review of current evidence

INTRODUCTION

Rheumatoid arthritis (RA) is a chronic inflammatory disease associated with synovial proliferation and bone erosion, which leads to the structural and functional impairment of the joints. Immune cells, together with synoviocytes, induce a pro-inflammatory environment and novel treatment agents target inflammatory cytokines. Psoriasis is a chronic immune-mediated skin disease, and several cytokines are considered as typical mediators in the progression of the disease, including IL-23, IL-22, and IL-17, among others.

AREA COVERED

In this review, we try to evaluate whether cyclin-dependent kinases (CDK), enzymes that regulate cell cycle and transcription of various genes, could become novel therapeutic targets in RA and psoriasis. We present the main results of in vitro and in vivo studies, as well as scarce clinical reports.

EXPERT OPINION

CDK inhibitors seem promising for treating RA and psoriasis because of their multidirectional effects. CDK inhibitors may affect not only the process of osteoclastogenesis, thereby reducing joint destruction in RA, but also the process of apoptosis of neutrophils and macrophages responsible for the development of inflammation in both RA and psoriasis. However, assessing the efficacy of these drugs in clinical practice requires multi-center, long-term clinical trials evaluating the effectiveness and safety of CDK-blocking therapy in RA and psoriasis.

Carbon dots conjugated to SN38 for improved colorectal anticancer therapy

Irinotecan (CTP-11) is one of the standard therapies for colorectal cancer (CRC). CTP-11 is enzymatically converted to the hydrophobic 7-ethyl-10-hydroxycamptothecin (SN38), a one hundred-fold more active metabolite. Conjugation of hydrophobic anticancer drugs to nanomaterials is a strategy to improve their solubility, efficacy, and selectivity. Carbon dots (CDs) have garnered interest for their small sizes (<10 ​nm), low toxicity, high water solubility, and bright fluorescence. This paper describes the use of CDs to improve drug vehiculation, stability, and chemotherapeutic efficiency of SN38 through a direct intracellular uptake in CRC. The covalent conjugation of SN38 to CDs via a carbamate bond provides a CD-SN38 hybrid material for slow, sustained, and pH-responsive drug release. CD-SN38 successfully penetrates the CRC cells with a release in the nucleus affecting first the cell cycle and then the cytoskeleton. Moreover, CD-SN38 leads to a deregulation of the extracellular matrix (ECM), one of the major components of the cancer niche considered a possible target therapy for reducing the cancer progression. This work shows the combined therapeutic and imaging potential of CD-based hybrid materials for the treatment of CRC. Future efforts for targeted therapy of chronic diseases characterized by altered ECM deposition, such as chronic kidney disease and chronic allograft nephropathy in kidney transplant patients are envisaged.

Cyclin-Dependent Kinase 7 Promotes Th17/Th1 Cell Differentiation in Psoriasis by Modulating Glycolytic Metabolism

Excessive activation of CD4⁺ T cells and T helper type (Th) 17/Th1 cell differentiation are critical events in psoriasis pathogenesis, but the associated molecular mechanism is still unclear. Here, using quantitative proteomics analysis, we found that cyclin-dependent kinase 7 (CDK7) expression was markedly increased in CD4⁺ T cells from patients with psoriasis compared with healthy controls and was positively correlated with psoriasis severity. Meanwhile, genetic or pharmacological inhibition of CDK7 ameliorated the severity of psoriasis in the imiquimod-induced psoriasis-like mouse model and suppressed CD4⁺ T-cell activation as well as Th17/Th1 cell differentiation in vivo and in vitro. Furthermore, the CDK7 inhibitor also reduced the enhanced glycolysis of CD4⁺ T cells from patients with psoriasis. Proinflammatory cytokine IL-23 induced increased CDK7 expression in CD4⁺ T cells and activated the protein kinase B/mTOR/HIF-1α signaling pathway, enhancing glycolytic metabolism. Correspondingly, CDK7 inhibition significantly impaired IL-23-induced glycolysis via the protein kinase B/mTOR/HIF-1α pathway. In summary, this study shows that CDK7 promotes CD4⁺ T-cell activation and Th17/Th1 cell differentiation by regulating glycolysis, thus contributing to the pathogenesis of psoriasis. Targeting CDK7 might be a promising immunosuppressive strategy to control skin inflammation mediated by IL-23.

Super-enhancers: A new frontier for glioma treatment

Glioma is the most common primary malignant tumor in the human brain. Although there are a variety of treatments, such as surgery, radiation and chemotherapy, glioma is still an incurable disease. Super-enhancers (SEs) are implicated in the control of tumor cell identity, and they promote oncogenic transcription, which supports tumor cells. Inhibition of the SE complex, which is required for the assembly and maintenance of SEs, may repress oncogenic transcription and impede tumor growth. In this review, we discuss the unique characteristics of SEs compared to typical enhancers, and we summarize the recent advances in the understanding of their properties and biological role in gene regulation. Additionally, we highlight that SE-driven lncRNAs, miRNAs and genes are involved in the malignant phenotype of glioma. Most importantly, the application of SE inhibitors in different cancer subtypes has introduced new directions in glioma treatment.

Cdk7: a kinase at the core of transcription and in the crosshairs of cancer drug discovery

The transcription cycle of RNA polymerase II (Pol II) is regulated by a set of cyclin-dependent kinases (CDKs). Cdk7, associated with the transcription initiation factor TFIIH, is both an effector CDK that phosphorylates Pol II and other targets within the transcriptional machinery, and a CDK-activating kinase (CAK) for at least one other essential CDK involved in transcription. Recent studies have illuminated Cdk7 functions that are executed throughout the Pol II transcription cycle, from promoter clearance and promoter-proximal pausing, to co-transcriptional chromatin modification in gene bodies, to mRNA 3´-end formation and termination. Cdk7 has also emerged as a target of small-molecule inhibitors that show promise in the treatment of cancer and inflammation. The challenges now are to identify the relevant targets of Cdk7 at each step of the transcription cycle, and to understand how heightened dependence on an essential CDK emerges in cancer, and might be exploited therapeutically.

CDK7 inhibition suppresses rheumatoid arthritis inflammation via blockage of NF-κB activation and IL-1β/IL-6 secretion

Rheumatoid arthritis (RA) is a chronic inflammatory disease characterized by joint swelling, joint tenderness and destruction of synovial joints, leading to severe disability. Anti‐inflammatory drugs and disease‐modifying anti‐rheumatic drugs (DMARDs) may improve RA process. However, in most patients the treatment effect is still not satisfactory. Cyclin‐dependent kinase 7 (CDK7) plays a well‐established role in the regulation of the eukaryotic cell division cycle, and recent studies indicated that it exerted anti‐inflammatory effect. In our previous research, we found that inhibition of CDK7 by highly selective inhibitor BS‐181 significantly impeded the development of collagen‐induced arthritis (CIA) mice. However, the underlying mechanism of CDK7 in RA remains to be explored. We elucidated the molecular mechanism of CDK7 inhibition in RA inflammation by administration of CDK7 highly selective inhibitor BS‐181 and siRNA‐CDK7. We found that both IL‐1β, IL‐6, IL‐8 and RANKL transcript levels and IL‐1β/IL‐6 secretion were effectively suppressed by BS‐181 treatment as well as CDK7 knockdown. Furthermore, CDK7 inhibition prevented NF‐κB signalling pathway activation and restrained p65 nuclear translocation. Moreover, CDK7 selective inhibitor BS‐181 also blocked phosphorylation of p65 in MH7A cells. These results strongly indicate that CDK7 inhibition by BS‐181 and siRNA‐CDK7 significantly suppresses rheumatoid arthritis inflammation, which may be via blockage of NF‐κB signalling pathway and IL‐1β/IL‐6 secretion.

Support for phosphoinositol 3 kinase and mTOR inhibitors as treatment for lupus using in-silico drug-repurposing analysis

Background

Systemic lupus erythematosus (SLE) is an autoimmune disease with few treatment options. Current therapies are not fully effective and show highly variable responses. In this regard, large efforts have focused on developing more effective therapeutic strategies. Drug repurposing based on the comparison of gene expression signatures is an effective technique for the identification of new therapeutic approaches. Here we present a drug-repurposing exploratory analysis using gene expression signatures from SLE patients to discover potential new drug candidates and target genes.

Methods

We collected a compendium of gene expression signatures comprising peripheral blood cells and different separate blood cell types from SLE patients. The Lincscloud database was mined to link SLE signatures with drugs, gene knock-down, and knock-in expression signatures. The derived dataset was analyzed in order to identify compounds, genes, and pathways that were significantly correlated with SLE gene expression signatures.

Results

We obtained a list of drugs that showed an inverse correlation with SLE gene expression signatures as well as a set of potential target genes and their associated biological pathways. The list includes drugs never or little studied in the context of SLE treatment, as well as recently studied compounds.

Conclusion

Our exploratory analysis provides evidence that phosphoinositol 3 kinase and mammalian target of rapamycin (mTOR) inhibitors could be potential therapeutic options in SLE worth further future testing.

Electronic supplementary material

The online version of this article (doi:10.1186/s13075-017-1263-7) contains supplementary material, which is available to authorized users.