Jie Zang

JAK/STAT Signal Transduction: Promising Attractive Targets for Immune, Inflammatory and Hematopoietic Diseases

BACKGROUND JAK/STAT signal pathway, a requisite part in the signaling process of growth factors and cytokines, has become attractive targets for numerous immune, inflammatory and hematopoietic diseases. OBJECTIVE Herein, we present a review of the JAK/STAT signal pathway, the structure, biological function, mechanism of the JAKs and STATs along with a summary of the up-to-date clinical or approved JAK inhibitors which are involved in the treatment of various kinds of tumors and other immunity indications. Moreover, kinds of recently discovered JAKs inhibitors with potent activity or promising selectivity are also briefly discussed. CONCLUSION Research and development of isoform selective JAK inhibitors has become a hot topic in this field. With the assistance of high throughput screening and rational drug design, more and more JAK inhibitors with improved selective profiles will be discovered as biological probes and even therapeutic agents.

Design, synthesis and anti-tumor activity study of novel histone deacetylase inhibitors containing isatin-based caps and o-phenylenediamine-based zinc binding groups

As a hot topic of epigenetic studies, histone deacetylases (HDACs) are related to lots of diseases, especially cancer. Further researches indicated that different HDAC isoforms played various roles in a wide range of tumor types. Herein a novel series of HDAC inhibitors with isatin-based caps and o-phenylenediamine-based zinc binding groups have been designed and synthesized through scaffold hopping strategy. Among these compounds, the most potent compound 9n exhibited similar if not better HDAC inhibition and antiproliferative activities against multiple tumor cell lines compared with the positive control entinostat (MS-275). Additionally, compared with MS-275 (IC50 values for HDAC1, 2 and 3 were 0.163, 0.396 and 0.605µM, respectively), compound 9n with IC50 values of 0.032, 0.256 and 0.311µM for HDAC1, 2 and 3 respectively, showed a moderate HDAC1 selectivity.

Preclinical and Clinical Studies of Chidamide (CS055/HBI-8000), An Orally Available Subtype-selective HDAC Inhibitor for Cancer Therapy

Epigenetic modifications play central roles in cellular differentiation and their deregulations really contribute to tumor development. Histone deacetylase (HDAC) enzymes can exert their functions in the epigenetic regulation of gene expression related to oncogenesis via deacetylating the lysine residues of histones in the chromatin and various non-histone proteins. A majority of HDAC inhibitors (HDACIs) have been in different stages of preclinical and clinical trials with potent anticancer activity recently. Among these agents, chidamide tested as either monotherapeutic agent or in combination regimens for numerous hematological and solid malignancies has shown promising potential as an orally active subtype-selective HDACI. Herein we will highlight the progress of clinical trials of chidamide and rationally analyze those results from both preclinical and clinical studies about chidamide as an epigenetic modulator in cancer therapy.

PXD101 analogs with L-phenylglycine-containing branched cap as histone deacetylase inhibitors.

Histone deacetylases (HDACs) allow histones to wrap DNA more tightly and finally lead to the repression of some tumor suppressor genes. Histone deacetylase inhibitors (HDACIs) have been proved to have effects on tumorigenesis and tumor progression. In this study, we reported the design, synthesis, and in vitro activity evaluation of novel PXD101 analogs with L‐phenylglycine‐containing cap as HDACIs. Our results showed that HDACs inhibitory activities of compounds 10k, 10r, and 10s were not only superior to the first approved HDACI SAHA, but also comparable to their parent compound PXD101, a recently approved HDACI in 2014. However, all 6 selected PXD101 analogs exhibited moderate in vitro antiproliferative activities, less potent than PXD101 and SAHA. Representative compound 10s showed similar HDACs isoform selective profile to PXD101, which demonstrated that introduction of L‐phenylglycine‐containing branched cap group could not change the isoform selectivity of PXD101 dramatically.

Development of N-hydroxycinnamamide-based HDAC inhibitors with improved HDAC inhibitory activity and in vitro antitumor activity

Histone deacetylase inhibitors (HDACIs) are promising in the treatment of various diseases, among which cancer treatment has achieved the most success. We have previously developed series of HDACIs combining N-hydroxycinnamamide bioactive fragment and indole bioactive fragment, which showed moderate to potent antitumor activities. Herein, further structural derivatization based on our previous structure-activity relationship (SAR) got 25 novel compounds. Most compounds showed much more potent histone deacetylases (HDACs) inhibitory activity than their parent compound 1 and even the positive control SAHA. Whats more, compared with the approved HDACs inhibitor SAHA, compounds 6i, 6k, 6q and 6t displayed better in vitro antiproliferation against multiple tumor cell lines. It is worth noting that though the 4-hydroxycinnamic acid-based compound 2 showed HDAC1/3 dual selectivity, its 4-hydroxy-3-methoxycinnamic acid-based analog 6t turned out to be a pan-HDACs inhibitor as SAHA, indicating that the 3-methoxy group on the N-hydroxycinnamamide fragment could dramatically influence the HDACs isoform selectivity of this series of compounds.

Nitric oxide donor hybrid compounds as promising anticancer agents

Nitric oxide (NO) plays important roles in cardiovascular regulation, nerve transmission delivery and immune responses. In the last semicenturry, it has been proved that though low concentration of NO is tumor-promoting, high concentration of NO could exhibit multiple antitumor effects, which led to the research and development of kinds of NO donors and NO donor hybrid compounds as antitumor agents. Herein, the recent development of NO donor hybrid compounds is briefly reviewed.

Design, synthesis and preliminary biological evaluation of 4-aminopyrazole derivatives as novel and potent JAKs inhibitors.

JAKs inhibitors were widely applied in the treatment of immunodeficiency diseases, inflammation and cancers. We designed and synthesized a novel series of 4-aminopyrazole derivatives, which showed inhibitory potency against various JAKs. The in vitro protein kinase inhibition experiment indicated that compounds 17k, 17l, 17m and 17n could inhibit JAKs effectively. Among them, compound 17m possessed the highest protein kinase inhibitory rates (%) at 10μM, which were 97, 96 and 100 to JAK1, JAK2 and JAK3, respectively. Further evaluation revealed that the IC50 values of 17m against JAK1, JAK2 and JAK3 were 0.67μM, 0.098μM and 0.039μM, respectively. Moreover, western blotting results showed compound 17m could inhibit the phosphorylation of JAK2 in Hela cells effectively. The data supports the further investigation of these compounds as novel JAKs inhibitors.

Discovery of Novel Pazopanib-based HDAC and VEGFR Dual Inhibitors Targeting Cancer Epigenetics and Angiogenesis Simultaneously

Herein a novel series of pazopanib hybrids as polypharmacological antitumor agents were developed based on the crosstalk between histone deacetylases (HDACs) and vascular endothelial growth factor (VEGF) pathway. Among them, one ortho-aminoanilide 6d and one hydroxamic acid 13f exhibited considerable total HDACs and VEGFR-2 inhibitory activities. The HDAC inhibitory activities endowed 6d and 13f with potent antiproliferative activities, which was not observed in the approved VEGFR inhibitor pazopanib. Compounds 6d and 13f possessed comparable HDAC isoform selectivity profiles to the clinical class I HDAC inhibitor MS-275 and the approved pan-HDAC inhibitor SAHA, respectively. 6d and 13f also exhibited uncompromised multiple tyrosine kinases inhibitory activities relative to pazopanib. The intracellular dual inhibition to HDAC and VEGFR of 6d and 13f was validated by Western blot analysis. In both HUVECs tube formation assay and rat thoracic aorta rings assay, 6d and 13f showed comparable antiangiogenic potencies to pazopanib. Whats more, 6d possessed desirable pharmacokinetic profiles with the oral bioavailability of 72% in SD rats and considerable in vivo antitumor efficacy in a human colorectal adenocarcinoma (HT-29) xenograft model.

Discovery of meta-sulfamoyl N-hydroxybenzamides as HDAC8 selective inhibitors

In the past decade, although research and development of histone deacetylase (HDAC) inhibitors as therapeutic agents have achieved great accomplishments, especially in oncology field, there is still an urgent need for the discovery of isoform-selective HDAC inhibitors considering the side effects caused by nonselective HDAC inhibitors. HDAC8, a unique class I zinc-dependent HDAC, is becoming a potential target in cancer and other diseases. In the current study, a novel series of N-hydroxy-3-sulfamoylbenzamide-based HDAC8 selective inhibitors (12a-12p) were designed and synthesized, among which compounds 12a, 12b and 12c exhibited potent HDAC8 inhibition with two-digit nanomolar IC50 values, and considerable selectivity over HDAC2 (>180-fold) and HDAC6 (∼30-fold) which was confirmed by western blot analysis. It is worth noting that 12a, 12b and 12c displayed highly selective anti-proliferative activity to T-cell leukemia cell lines Jurkat, Molt-4 and neuroblastoma cell line SK-N-BE-(2). Such selective cytotoxicity was also observed in the well-known HDAC8 selective inhibitor PCI-34051 but not in the pan-HDAC inhibitors SAHA and PXD101, indicating that HDAC8 selective inhibitor should have preferable benefit-risk profile in comparison with pan-HDAC inhibitor. Finally, the HDAC8 selectivity of 12a, 12b and 12c was rationalized by molecular docking study.

Design, Synthesis, and Biological Evaluation of Pyrazoline-Based Hydroxamic Acid Derivatives as Aminopeptidase N (APN) Inhibitors

Aminopeptidase N (APN) has been recognized as a target for anticancer treatment due to its overexpression on diverse malignant tumor cells and association with cancer invasion, metastasis and angiogenesis. Herein we describe the synthesis, biological evaluation, and structure–activity relationship study of two new series of pyrazoline analogues as APN inhibitors. Among these compounds, 5‐(2‐(2‐(hydroxyamino)‐2‐oxoethoxy)phenyl)‐3‐phenyl‐4,5‐dihydro‐1H‐pyrazole‐1‐carboxamide (compound 13 e) showed the best APN inhibition with an IC50 value of 0.16±0.02 μm, which is more than one order of magnitude lower than that of bestatin (IC50=9.4±0.5 μm). Moreover, compound 13 e was found to inhibit the proliferation of diverse carcinoma cells and to show potent anti‐angiogenesis activity. At the same concentration, compound 13 e presents significantly higher anti‐angiogenesis activity than bestatin in human umbilical vein endothelial cells (HUVECs) capillary tube formation assays. The putative binding mode of 13 e in the active site of APN is also discussed.