Identification and characterization of isocitrate dehydrogenase 1 (IDH1) as a functional target of marine natural product grincamycin B.

Grincamycins (GCNs) are a class of angucycline glycosides isolated from actinomycete Streptomyces strains that have potent antitumor activities, but their antitumor mechanisms remain unknown. In this study, we tried to identify the cellular target of grincamycin B (GCN B), one of most dominant and active secondary metabolites, using a combined strategy. We showed that GCN B-selective-induced apoptosis of human acute promyelocytic leukemia (APL) cell line NB4 through increase of ER stress and intracellular reactive oxygen species (ROS) accumulation. Using a strategy of combining phenotype, transcriptomics and protein microarray approaches, we identified that isocitrate dehydrogenase 1(IDH1) was the putative target of GCN B, and confirmed that GCNs were a subset of selective inhibitors targeting both wild-type and mutant IDH1 in vitro. It is well-known that IDH1 converts isocitrate to 2-oxoglutarate (2-OG), maintaining intracellular 2-OG homeostasis. IDH1 and its mutant as the target of GCN B were validated in NB4 cells and zebrafish model. Knockdown of IDH1 in NB4 cells caused the similar phenotype as GCN B treatment, and supplementation of N-acetylcysteine partially rescued the apoptosis caused by IDH1 interference in NB4 cells. In zebrafish model, GCN B effectively restored myeloid abnormality caused by overexpression of mutant IDH1(R132C). Taken together, we demonstrate that IDH1 is one of the antitumor targets of GCNs, suggesting wild-type IDH1 may be a potential target for hematological malignancies intervention in the future.

Effects of electroacupuncture at different acupoints on the histomorphology of neurogenic bladder and the expression of hyperpolarization-activated cyclic nucleotide-gated channels in interstitial cells of Cajal in a rat model of suprasacral spinal cord injury.

BACKGROUND: To investigate the effects of electroacupuncture at different acupoints on the histomorphology of neurogenic bladder and the expression of hyperpolarization-activated cyclic nucleotide-gated (HCN) channels in interstitial cells of Cajal (ICC) in a rat model of suprasacral spinal cord injury (SCI). METHODS: A incomplete suprasacral SCI rat model was induced using a MASCIS impactor. Rats were randomly divided into a sham operation group, SCI model group, Ciliao treatment group or Guanyuan treatment group. The histomorphology of bladder cells was observed after hematoxylin and eosin (H&E) staining of bladder tissue sections. The expression of HCN channel proteins in ICC cells was detected by western blot and immunofluorescence, and HCN channel mRNA expression was measured using real-time PCR. RESULTS: In terms of histomorphology, the level of bladder cells after SCI increased significantly, and marked inflammation and edema were observed. Electroacupuncture treatment at the Ciliao acupoint significantly reduced inflammation and edema, whilst electroacupuncture treatment at the Guanyuan point partially reduced inflammation and edema. In terms of HCN channel protein and mRNA expression, western blotting, immunofluorescence and real-time PCR all confirmed that HCN channel expression after SCI was significantly upregulated, while electroacupuncture treatment at the Ciliao and Guanyuan acupoints inhibited HCN channel expression. CONCLUSIONS: Electroacupuncture treatment at the Ciliao acupoint significantly reduced histomorphological abnormalities in ICCs, and inhibited the expression of HCN channel proteins after SCI.

Survey of ex vivo drug combination effects in chronic lymphocytic leukemia reveals synergistic drug effects and genetic dependencies.

Drug combinations that target critical pathways are a mainstay of cancer care. To improve current approaches to combination treatment of chronic lymphocytic leukemia (CLL) and gain insights into the underlying biology, we studied the effect of 352 drug combination pairs in multiple concentrations by analysing ex vivo drug response of 52 primary CLL samples, which were characterized by "omics" profiling. Known synergistic interactions were confirmed for B-cell receptor (BCR) inhibitors with Bcl-2 inhibitors and with chemotherapeutic drugs, suggesting that this approach can identify clinically useful combinations. Moreover, we uncovered synergistic interactions between BCR inhibitors and afatinib, which we attribute to BCR activation by afatinib through BLK upstream of BTK and PI3K. Combinations of multiple inhibitors of BCR components (e.g., BTK, PI3K, SYK) had effects similar to the single agents. While PI3K and BTK inhibitors produced overall similar effects in combinations with other drugs, we uncovered a larger response heterogeneity of combinations including PI3K inhibitors, predominantly in CLL with mutated IGHV, which we attribute to the target's position within the BCR-signaling pathway. Taken together, our study shows that drug combination effects can be effectively queried in primary cancer cells, which could aid discovery, triage and clinical development of drug combinations.

A Sphingosine-1-Phosphate Modulator Ameliorates Polycystic Kidney Disease in Han:SPRD Rats.

BACKGROUND: Inflammation plays an important role in polycystic kidney disease (PKD). Cordyceps sinensis, a prized -Chinese medicinal herb, exerts anti-tumor, anti-inflammatory and anti-metastatic effects and benefits patients with kidney diseases. The aim of this study was to test the efficacy of FTY720, an immunosuppressant derived from C. sinensis, in a rat cystic kidney disease model, and explore its underlining mechanism. METHODS: Male wild type and Cy/+ Han:SPRD rats were treated with FTY720 at 3 and 10 mg/kg/day for 5 weeks and 12 weeks by gavage. Blood and kidney were collected for functional, morphological, RNA, and protein analysis. RESULTS: Inflammation is activated in Cy/+ Han:SPRD rats. Inflammatory cytokines including interleukin 6 and tumor necrosis factor alpha were upregulated and inflammation-related pathways were activated, such as nuclear factor κB and signal transducer and activator of transcription 3 (STAT3) pathways. Furthermore, the bioactive sphingolipid mediator sphingosine-1-phosphate (S1P), a regulator of inflammation, was accumulated in the Cy/+ Han:SPRD rats. FTY720 significantly reduced cyst growth and delayed disease progression by reducing the accumulation of S1P, thereby inhibiting inflammatory responses. CONCLUSION: FTY720 treatment reduced the expression of inflammatory cytokines and attenuated the activation of NK-κB and STAT3 pathways in Cy/+ Han:SPRD rats. It suggests that FTY720 may serve as a therapeutic agent for clinical autosomal dominant PKD treatment.

Identification of novel EZH2 inhibitors through pharmacophore-based virtual screening and biological assays.

Polycomb repressive complex 2 (PRC2) acts as a primary writer for di- and tri-methylation of histone H3 at lysine 27. This protein plays an essential role in silencing gene expression. Enhancer of zeste 2 (EZH2), the catalytic subunit of PRC2, is considered as a promising therapeutic target for cancer. GSK126, a specific inhibitor of EZH2, is undergoing phase I trials for hypermethylation-related cancers. In addition, many derivatives of GSK126 are also commonly used in laboratory investigations. However, studies on the mechanism and drug development of EZH2 are limited by the absence of structural diversity of these inhibitors because they share similar SAM-like scaffolds. In this study, we generated a pharmacophore model based on reported EZH2 inhibitors and performed in silico screenings. Experimental validations led to the identification of two novel EZH2 inhibitors, DCE_42 and DCE_254, with IC50 values of 23 and 11µM, respectively. They also displayed significant anti-proliferation activity against lymphoma cell lines. Thus, we discovered potent EZH2 inhibitors with novel scaffold using combined in silico screening and experimental study. Results from this study can also guide further development of novel specific EZH2 inhibitors.

Application of epigenome-modifying small molecules in induced pluripotent stem cells.

Recent breakthroughs in generating induced pluripotent stem cells (iPSCs) using four defined factors have revealed the potential utility of stem cells in biological research and clinical applications. However, the low efficiency and slow kinetics of reprogramming related to producing these cells and underlying safety issues, such as viral integration and genetic and epigenetic abnormalities of iPSCs, hamper the further application of iPSCs in laboratory and clinical settings. Previous studies have suggested that reprogramming efficiency can be enhanced and that reprogramming kinetics can be accelerated by manipulating epigenetic status. Herein, we review recent studies on the application of epigenome-modifying small molecules in enhancing reprogramming and functionally replacing some reprogramming factors. We mainly focus on studies that have used small molecules to interfere with epigenome-modifying enzymes, such as DNA methyltransferase, histone acetyltransferase, and histone methyltransferase. The potential use of these small molecules in inducing iPSCs and new ways to identify small molecules of higher potency and fewer side effects are also discussed.

Development of a novel class of B-Raf(V600E)-selective inhibitors through virtual screening and hierarchical hit optimization.

Oncogenic mutations in critical nodes of cellular signaling pathways have been associated with tumorigenesis and progression. The B-Raf protein kinase, a key hub in the canonical MAPK signaling cascade, is mutated in a broad range of human cancers and especially in malignant melanoma. The most prevalent B-Raf(V600E) mutant exhibits elevated kinase activity and results in constitutive activation of the MAPK pathway, thus making it a promising drug target for cancer therapy. Herein, we describe the development of novel B-Raf(V600E) selective inhibitors via multi-step virtual screening and hierarchical hit optimization. Nine hit compounds with low micromolar IC(50) values were identified as B-Raf(V600E) inhibitors through virtual screening. Subsequent scaffold-based analogue searching and medicinal chemistry efforts significantly improved both the inhibitor potency and oncogene selectivity. In particular, compounds 22f and 22q possess nanomolar IC(50) values with selectivity for B-Raf(V600E)in vitro and exclusive cytotoxicity against B-Raf(V600E) harboring cancer cells.

[Effects of acupuncture on different acupoints in combination with rehabilitation on hemiplegic muscle spasticity in hemiplegia patients].

OBJECTIVE: To observe the clinical effect of hemiplegic muscle spasticity treated with acupuncture on different acupoints in combination with rehabilitation. METHODS: Ninety cases of post-stroke muscle spasticity were randomized into a corresponding and central axis acupuncture group (group A), a conventional acupuncture group (group B) and a rehabilitation group (group C), 30 cases in each one. In group A, the acupoints on the Governor Vessel were mainly selected, as well as those on Hand-Shaoyang meridian and Foot-Taiyang meridian. In group B, the conventional needling and rehabilitation training were applied in combination, of which, the acupoints were mainly from Hand and Foot-Yangming meridians, associated with the acupoints of Shaoyang meridian. In group C, only rehabilitation training was applied. The assessments according to modified Ashworth scale and CSS score were performed before treatment, after 2 weeks and 4 weeks treatment respectively. RESULTS: The level of modified Ashworth scale of the flexor of elbow and wrist was reduced apparently after treatment in group A as compared with that before treatment (P < 0.01). The level of modified Ashworth scale of the flexor of elbow was reduced apparently after treatment in group C as compared with that before treatment (P < 0.05). There was significant difference on the level change in modified Ashworth scale for the flexor of elbow between group A and group C after 4 weeks treatment (P < 0.05). CSS score decreased significantly in group A as compared with that before treatment (P < 0.01), the improvement after treatment in group A was apparent as compared with the other two groups (P < 0.01). CONCLUSION: The corresponding and central axis acupuncture can improve muscle tone of hemiplegic limb, which is superior to the effect achieved by the conventional acupuncture in combination with rehabilitation training and the simple rehabilitation training.