In silico and in vitro analyses of a novel FoxO1 agonist reducing Aß levels via downregulation of BACE1.

AIMS: FoxO1 is an important target in the treatment of Alzheimer's disease (AD). However, FoxO1-specific agonists and their effects on AD have not yet been reported. This study aimed to identify small molecules that upregulate the activity of FoxO1 to attenuate the symptoms of AD. METHODS: FoxO1 agonists were identified by in silico screening and molecular dynamics simulation. Western blotting and reverse transcription-quantitative polymerase chain reaction assays were used to assess protein and gene expression levels of P21, BIM, and PPARγ downstream of FoxO1 in SH-SY5Y cells, respectively. Western blotting and enzyme-linked immunoassays were performed to explore the effect of FoxO1 agonists on APP metabolism. RESULTS: N-(3-methylisothiazol-5-yl)-2-(2-oxobenzo[d]oxazol-3(2H)-yl) acetamide (compound D) had the highest affinity for FoxO1. Compound D activated FoxO1 and regulated the expression of its downstream target genes, P21, BIM, and PPARγ. In SH-SY5Y cells treated with compound D, BACE1 expression levels were downregulated, and the levels of Aß1-40 and Aß1-42 were also reduced. CONCLUSIONS: We present a novel small-molecule FoxO1 agonist with good anti-AD effects. This study highlights a promising strategy for new drug discovery for AD.

A comprehensive review of BET-targeting PROTACs for cancer therapy.

Targeted protein degradation using proteolysis-targeting chimeras (PROTACs) has emerged as an effective strategy for drug discovery, given their unique advantages over target protein inhibition. The bromodomain and extra-terminal (BET) family proteins play a key role in regulating oncogene expression and are considered attractive therapeutic targets for cancer therapy. Considering the therapeutic potential of BET proteins in cancer and the marked attractiveness of PROTACs, BET-targeting PROTACs have been extensively pursued. Recently, BET-targeting PROTACs based on new E3 ligases and novel strategies, such as light-activated, macrocyclic, folate-caged, aptamer-PROTAC conjugation, antibody-coupling, and autophagy-targeting strategies, have emerged. In the present review, we provide a comprehensive summary of advances in BET-targeting PROTACs.

Recent strategies targeting Embryonic Ectoderm Development (EED) for cancer therapy: Allosteric inhibitors, PPI inhibitors, and PROTACs.

The polycomb repressive complex 2 (PRC2), which comprised of the core subunits: Enhancer of Zeste Homolog 2 (EZH2), Suppressor of Zeste 12 (SUZ12), and Embryonic Ectoderm Development (EED), is an essential epigenetic gene silencer responsible for depositing repressive histone H3 lysine 27 trimethylation (H3K27me3) marks on chromatin. The aberrant activity of PRC2 is closely involved in tumorigenesis and progression, making its inhibition a viable strategy for epigenetic cancer therapy. Although the clinical development of small PRC2 inhibitors has made impressive progress, with one EZH2 inhibitor approved for cancer therapy and several other candidates in clinical trials, current EZH2 inhibitors are limited to treating certain hematological malignancies and have acquired drug resistance. EED is essential for PRC2 stabilization and allosterically stimulating PRC2 activity because it functions as a scaffold protein and an H3K27me3-recognizing protein. Thus, due to its novel mechanism of action, targeting EED provides a promising new strategy for inhibiting PRC2 function and exhibits the potential to overcome the issues encountered by EZH2 inhibitors. This review provides a comprehensive overview of available cancer therapy strategies that target EED, including allosteric inhibitors, protein-protein interaction (PPI) inhibitors, and proteolysis-targeting chimeras (PROTACs).

Research progress of dual inhibitors targeting crosstalk between histone epigenetic modulators for cancer therapy.

Abnormal epigenetics is a critical hallmark of human cancers. Anticancer drug discovery directed at histone epigenetic modulators has gained impressive advances with six drugs available for cancer therapy and numerous other candidates undergoing clinical trials. However, limited therapeutic profile, drug resistance, narrow safety margin, and dose-limiting toxicities pose intractable challenges for their clinical utility. Because histone epigenetic modulators undergo intricate crosstalk and act cooperatively to shape an aberrant epigenetic profile, co-targeting histone epigenetic modulators with a different mechanism of action has rapidly emerged as an attractive strategy to overcome the limitations faced by the single-target epigenetic inhibitors. In this review, we summarize in detail the crosstalk of histone epigenetic modulators in regulating gene transcription and the progress of dual epigenetic inhibitors targeting this crosstalk.

Design, synthesis, and biological evaluation of novel dual inhibitors targeting lysine specific demethylase 1 (LSD1) and histone deacetylases (HDAC) for treatment of gastric cancer.

LSD1 and HDAC are physical and functional related to each other in various human cancers and simultaneous pharmacological inhibition of LSD1 and HDAC exerts synergistic anti-cancer effects. In this work, a series of novel LSD1/HDAC bifunctional inhibitors with a styrylpyridine skeleton were designed and synthesized based on our previously reported LSD1 inhibitors. The representative compounds 5d and 5m showed potent activity against LSD1 and HDAC at both molecular and cellular level and displayed high selectivity against MAO-A/B. Moreover, compounds 5d and 5m demonstrated potent antiproliferative activities against MGC-803 and HCT-116 cancer cell lines. Notably, compound 5m showed superior in vitro anticancer potency against a panel of gastric cancer cell lines than ORY-1001 and SP-2509 with IC50 values ranging from 0.23 to 1.56 µM. Compounds 5d and 5m significantly modulated the expression of Bcl-2, Bax, Vimentin, ZO-1 and E-cadherin, induced apoptosis, reduced colony formation and suppressed migration in MGC-803 cancer cells. In addition, preliminary absorption, distribution, metabolism, excretion (ADME) studies revealed that compounds 5d and 5m showed acceptable metabolic stability in human liver microsomes with minimal inhibition of cytochrome P450s (CYPs). Those results indicated that compound 5m could be a promising lead compound for further development as a therapeutic agent in gastric cancers via LSD1 and HDAC dual inhibition.

Design and synthesis of tranylcypromine derivatives as novel LSD1/HDACs dual inhibitors for cancer treatment.

Lysine specific demethylase 1 (LSD1) and Histone deacetylases (HDACs) are promising drug targets for cancers. Recent studies reveal an important functional interplay between LSD1 and HDACs, and there is evidence for the synergistic effect of combined LSD1 and HDAC inhibitors on cancers. Therefore, development of inhibitors targeting both LSD1 and HDACs might be a promising strategy for epigenetic therapy of cancers. We report herein the synthesis of a series of tranylcypromine derivatives as LSD1/HDACs dual inhibitors. Most compounds showed potent LSD1 and HDACs inhibitory activity, especially compound 7 displayed the most potent inhibitory activity against HDAC1 and HDAC2 with IC50 of 15 nM and 23 nM, as well as potent inhibition against LSD1 with IC50 of 1.20 µM. Compound 7 demonstrated stronger anti-proliferative activities than SAHA with IC50 values ranging from 0.81 to 4.28 µM against MGC-803, MCF-7, SW-620 and A-549 human cancer cell lines. Further mechanistic studies showed that compound 7 treatment in MGC-803 cells dose-dependently increased cellular H3K4 and H3K9 methylation, as well as H3 acetylation, decreased the mitochondrial membrane potential and induced remarkable apoptosis. Docking studies showed that compound 7 can be well docked into the active binding sites of LSD1 and HDAC2. This finding highlights the potential for the development of LSD1/HDACs dual inhibitors as novel anticancer drugs.

Discovery of resveratrol derivatives as novel LSD1 inhibitors: Design, synthesis and their biological evaluation.

Inhibition of lysine-specific demethylase 1 (LSD1) has recently emerged as an attractive therapeutic target for treating cancer and other diseases. As a continuity of our ongoing effort to identify novel small-molecule LSD1-inhibitors, we designed and synthesized a series of resveratrol derivatives, which were shown to be potent inhibitors of LSD1. Among them, compounds 4e and 4m displayed the most potent LSD1-inhibitory activities in enzyme assays, with IC50 values of 121 nM and 123 nM, respectively. Biochemistry study and docking analysis indicated that compounds 4e and 4m were reversible LSD1 inhibitors. High content analysis showed that 4e and 4m induced a dose-dependent increase of dimethylated Lys4 of histone H3 and had no impact on the expression of LSD1 in MGC-803 cells. Furthermore, 4e or 4m could remarkably increase the mRNA level of CD86, a surrogate cellular biomarker for LSD1 activity, in MGC-803 cells, suggesting that they are likely to exhibit LSD1-inhibitory activities intracellularly. These findings should encourage further modification of these compounds to produce more potent LSD1 inhibitors with potential anticancer activity.

1,2,3-Triazole-Dithiocarbamate Hybrids, a Group of Novel Cell Active SIRT1 Inhibitors.

BACKGROUND/AIMS: Human SIRT1 is reported to be involved in tumorgenesis, mainly due to its modulating effect on p53 by deacetylation on lysine382. A large quantity of SIRT1 inhibitors was applied in chemotherapeutic study, but few of them were applied into clinical trials. METHODS AND RESULTS: In the current study, a novel series of compounds with 1,4-bispiperazinecarbodithioic acid methyl esters scaffold were characterized to have inhibitory potency to SIRT1 by molecular docking and biochemical evaluation. Further cell level study revealed that one of the most potent SIRT1 inhibitors, compound 3a, is cell active. It can upregulate the amount of p53 by accumulating the K382 acetylation of p53, which lead to the stabilization of p53 in human gastric cancer cell line MGC-803 cells. Meanwhile, we also found compound 3a can inactivate SIRT2 in cells, which suggests the compound as a non-selective SIRT inhibitor. CONCLUSION: All these findings indicate that compound 3a is a potent, reversible and cell active SIRT1 inhibitor and deserves further investigation as an anticancer agent or a biological tool.

Triazole-dithiocarbamate based selective lysine specific demethylase 1 (LSD1) inactivators inhibit gastric cancer cell growth, invasion, and migration.

Lysine specific demethylase 1 (LSD1), the first identified histone demethylase, plays an important role in epigenetic regulation of gene activation and repression. The up-regulated LSD1's expression has been reported in several malignant tumors. In the current study, we designed and synthesized five series of 1,2,3-triazole-dithiocarbamate hybrids and screened their inhibitory activity toward LSD1. We found that some of these compounds, especially compound 26, exhibited the most specific and robust inhibition of LSD1. Interestingly, compound 26 also showed potent and selective cytotoxicity against LSD1 overexpressing gastric cancer cell lines MGC-803 and HGC-27, as well as marked inhibition of cell migration and invasion, compared to 2-PCPA. Furthermore, compound 26 effectively reduced the tumor growth bared by human gastric cancer cells in vivo with no signs of adverse side effects. These findings suggested that compound 26 deserves further investigation as a lead compound in the treatment of LSD1 overexpressing gastric cancer.

Stereoselective synthesis and anti-proliferative effects on prostate cancer evaluation of 5-substituted-3,4-diphenylfuran-2-ones.

Series of 5-substituted-3,4-diphenylfuran-2-ones were stereoselectively prepared. Their potential anti-proliferative effects on prostate cancer and some of their cyclooxygenases (COXs) inhibitory activities were evaluated. Structure-activity relationship (SAR) data, acquired by substituent modification at the para-position and ortho-position of the C-3 phenyl ring and 5-substituted modification of the central furanone, showed that 3-(2-chloro-phenyl)-4-(4-methanesulfonyl-phenyl)-5-(1-methoxy-ethyl)-5H-furan-2-one (13p) was the most potent compound and could effectively reduce the proliferation of prostate cancer cells (PC3 cell IC50 = 20 µM; PC3 PCDNA cell IC50 = 5 µM; PC3 SKP2 cell IC50 = 5 µM; DU145 cell IC50 = 25 µM). The cell cycle analysis for 13p in DU145 indicated that 13p may induce G1 phase arrest.

Design, synthesis and antiproliferative activity studies of novel 1,2,3-triazole-dithiocarbamate-urea hybrids.

A series of novel 1,2,3-triazole-dithiocarbamate-urea hybrids were designed, synthesized and their antiproliferative activities against four selected human cancer cell lines were evaluated. The results showed that a number of the hybrids exhibited potent activity in selected human cancer cell lines. Among them, compounds 27 and 34 showed broad spectrum anticancer activity with IC50 values ranging from 1.62 to 20.84 µM and 0.76 to 13.55 µM, respectively. Interestingly, compounds 27 and 34, being very potent against MGC-803 cells, exhibited no significant cytotoxicity against normal human embryonic kidney cells at up to 55 µM and 70 µM, respectively. Evidences of cell cycle arrest and apoptosis induction were obtained for the most effective compounds 27 and 34 by means of flow cytometry and microscopic techniques.

Design and synthesis of novel 1,2,3-triazole-dithiocarbamate hybrids as potential anticancer agents.

A series of novel 1,2,3-triazole-dithiocarbamate hybrids were designed, synthesized and evaluated for anticancer activity against four selected human tumor cell lines (MGC-803, MCF-7, PC-3, EC-109). Majority of the synthesized compounds exhibited moderate to potent activity against MGC-803 and MCF-7. Among them, compounds 3a and 3c showed excellent broad spectrum anticancer activity with IC50 values ranging from 0.73 to 11.61 µM and 0.49-12.45 µM, respectively. Particularly, compound 3a was more potent than 5-fluorouracil against all tested human cancer cell lines. Flow cytometry analysis demonstrated that treatment of MGC-803 with 3c led to cell cycle arrest at G2/M phase accompanied by an increase in apoptotic cell death after 12 h.