Downregulation of c-Myc expression confers sensitivity to CHK1 inhibitors in hematologic malignancies.

Checkpoint kinase 1 inhibitors (CHK1i) have shown impressive single-agent efficacy in treatment of certain tumors, as monotherapy or potentiators of chemotherapy in clinical trials, but the sensitive tumor types and downstream effectors to dictate the therapeutic responses to CHK1i remains unclear. In this study we first analyzed GDSC (Genomics of Drug Sensitivity in Cancer) and DepMap database and disclosed that hematologic malignancies (HMs) were relatively sensitive to CHK1i or CHK1 knockdown. This notion was confirmed by examining PY34, a new and potent in-house selective CHK1i, which exhibited potent anti-HM effect in vitro and in vivo, as single agent. We demonstrated that the downregulation of c-Myc and its signaling pathway was the common transcriptomic profiling response of sensitive HM cell lines to PY34, whereas overexpressing c-Myc could partially rescue the anticancer effect of PY34. Strikingly, we revealed the significant correlations between downregulation of c-Myc and cell sensitivity to PY34 in 17 HM cell lines and 39 patient-derived cell (PDC) samples. Thus, our results demonstrate that HMs are more sensitive to CHK1i than solid tumors, and c-Myc downregulation could represent the CHK1i efficacy in HMs.

Microenvironment-Responsive Small-Molecule Probe for Pulmonary Fibrosis Detection.

Pulmonary fibrosis (PF) is a fatal disease with increasing prevalence. Nonradioactive and noninvasive diagnosis of PF at an early stage can improve the prognosis but represents a daunting challenge. Up-regulation of nitric oxide (NO) is a typical microenvironmental feature of PF. Here, we report a small-molecule probe, PNO1, that can fluorogenically sense this microenvironmental feature for PF diagnosis. We demonstrate that PNO1 fluorescence is 6-fold higher in PF-diseased mice lungs than in normal-control groups. In addition to this in vivo result, PNO1 can also be applied in vitro to detect PF-diseased cells and ex vivo to detect PF-diseased tissues from clinical patients. These results highlight PNO1 as a complement to the traditional immunostaining-based methods for PF detection to facilitate quick screening for anti-PF drug candidates.

Compartmentalization of Incompatible Polymers within Metal-Organic Frameworks towards Homogenization of Heterogeneous Hybrid Catalysts for Tandem Reactions.

New catalytic systems that contain incompatible catalytic sites were constructed by the in situ polymerization of acidic and basic polymers into metal-organic frameworks, which resulted in highly porous, recyclable, and durable catalytic composites with excellent compartmentalization, so that opposing agents were spatially isolated. These synthesized hybrid catalysts exhibited excellent catalytic activity for one-pot "wolf and lamb" reactions (deacetalization/Knoevenagel or Henry), which was attributed to their unique characteristic of having a locally homogeneous, but globally heterogeneous, structure.

Design, synthesis, and molecular docking study of 3H-imidazole[4,5-c]pyridine derivatives as CDK2 inhibitors.

A novel series of imidazo[4,5-c]pyridine-based CDK2 inhibitors were designed from the structure of CYC202 via scaffold hopping strategy. These compounds were synthesized and biologically evaluated for their CDK2 inhibitory and in vitro anti-proliferation potential against cancer cell lines. Several compounds exhibited potent CDK2 inhibition with IC50 values of less than 1 µM. The most potent compound 5b showed excellent CDK2 inhibitory (IC50 = 21 nM) and in vitro anti-proliferation activity against three different cell lines (HL60, A549, and HCT116). The molecular docking and dynamic studies portrayed the potential binding mechanism between 5b and CDK2, and several key interactions between them were observed, which would be the reason for its potent CDK2 inhibitory and anti-proliferation activities. Therefore, the pyridin-3-ylmethyl moiety would serve as an excellent pharmacophore for the development of novel CDK2 inhibitors for targeted anti-cancer therapy.

Discovery of 4-chloro-3-(5-(pyridin-3-yl)-1,2,4-oxadiazole-3-yl)benzamides as novel RET kinase inhibitors.

A series of novel 4-chloro-benzamides derivatives containing substituted five-membered heteroaryl ring were designed, synthesized and evaluated as RET kinase inhibitors for cancer therapy. Most of compounds exhibited moderate to high potency in ELISA-based kinase assay. In particular, compound I-8 containing 1,2,4-oxadiazole strongly inhibited RET kinase activity both in molecular and cellular level. In turn, I-8 inhibited cell proliferation driven by RET wildtype and gatekeeper mutation. The results implied that 4-chloro-3-(5-(pyridin-3-yl)-1,2,4-oxadiazole-3-yl)benzamides are promising lead compounds as novel RET kinase inhibitor for further investigation.

Design and synthesis of novel hydroxypyridinone derivatives as potential tyrosinase inhibitors.

Two groups of novel hydroxypyridinone derivatives 6(a-e) and 12(a-c), were designed as potential tyrosinase inhibitors, and synthesized using kojic acid as a starting material. The tyrosinase inhibitory activity of these two groups was demonstrated to be potent, especially compounds 6e and 12a, whose IC50 values for monophenolase activity were 1.95µM and 2.79µM, respectively. Both of these values are lower than that of kojic acid (IC50=12.50µM). Compounds 6e and 12a were investigated for the inhibitory effect on diphenolase activity. The results showed that the inhibitory mechanism of these two compounds was reversible and that the inhibitory type was a competitive-uncompetitive mixed-type. The values of IC50 of 6e and 12a on the diphenolase activity of tyrosinase were determined to be 8.97µM and 26.20µM, respectively. The inhibitory constants (KI and KIS) of 6e were determined as 17.17µM and 22.09µM, respectively; and the KI and KIS values of 12a were 34.41µM and 79.02µM, respectively. Compound 6e showed a greater ability to reduce copper and a stronger copper chelating ability than kojic acid.

Design, Synthesis and Evaluation of Indene Derivatives as Retinoic Acid Receptor α Agonists.

A series of novel indene-derived retinoic acid receptor α (RARα) agonists have been designed and synthesized. The use of receptor binding, cell proliferation and cell differentiation assays demonstrated that most of these compounds exhibited moderate RARα binding activity and potent antiproliferative activity. In particular, 4-((3-isopropoxy-2,3-dihydro-1H-inden-5-yl)-carbamoyl)benzoic acid (36d), which showed a moderate binding affinity, exhibited a great potential to induce the differentiation of NB4 cells (68.88% at 5 µM). Importantly, our work established indene as a promising skeleton for the development of novel RARα agonists.

Visualizing peroxynitrite fluxes in endothelial cells reveals the dynamic progression of brain vascular injury.

Accumulating evidence suggests that formation of peroxynitrite (ONOO(-)) in the cerebral vasculature contributes to the progression of ischemic damage, while the underlying molecular mechanisms remain elusive. To fully understand ONOO(-) biology, efficient tools that can realize the real-time tracing of endogenous ONOO(-) fluxes are indispensable. While a few ONOO(-) fluorescent probes have been reported, direct visualization of ONOO(-) fluxes in the cerebral vasculature of live mice remains a challenge. Herein, we present a fluorescent switch-on probe (NP3) for ONOO(-) imaging. NP3 exhibits good specificity, fast response, and high sensitivity toward ONOO(-) both in vitro and in vivo. Moreover, NP3 is two-photon excitable and readily blood-brain barrier penetrable. These desired photophysical and pharmacokinetic properties endow NP3 with the capability to monitor brain vascular ONOO(-) generation after injury with excellent temporal and spatial resolution. As a proof of concept, NP3 has enabled the direct visualization of neurovascular ONOO(-) formation in ischemia progression in live mouse brain by use of two-photon laser scanning microscopy. Due to these favorable properties, NP3 holds great promise for visualizing endogenous peroxynitrite fluxes in a variety of pathophysiological progressions in vitro and in vivo.

Discovery of novel quinoline-based mTOR inhibitors via introducing intra-molecular hydrogen bonding scaffold (iMHBS): The design, synthesis and biological evaluation.

A series of quinoline derivatives featuring the novelty of introducing intra-molecular hydrogen bonding scaffold (iMHBS) were designed, synthesized and biologically evaluated for their mTOR inhibitory activity, as well as anti-proliferative efficacies against HCT-116, PC-3 and MCF-7 cell lines. As a result, six compounds exhibited significant inhibition against mTOR with IC50 values below 35nM. Compound 15a, the most potent mTOR inhibitor reported herein (IC50=14nM), also displayed the most favorable cellular activities, with the IC50 values of 0.46, 0.61 and 0.24µM against HCT-116, PC-3 and MCF-7, respectively. Besides, several compounds in this series were identified to be selective over class I PI3Ks. Further western blot analysis of 16b, a representative compound in this series, highlighted their advantage in surmounting the S6K/IRS1/PI3K negative feedback loop upon dual inhibition of mTORC1 and mTORC2. In addition to the remarkable activity, 15a demonstrated acceptable stability in simulated gastric fluid (SGF), simulated intestinal fluid (SIF) and liver microsome, thereby being valuable for extensive in vivo investigation.

Design, synthesis, and biological evaluation of novel 2-methylpiperazine derivatives as potent CCR5 antagonists.

Three series of novel 2-methylpiperazine derivatives were designed and synthesized using a fragment-assembly strategy. Among them, six compounds (13, 16, 18, 22, 33, and 36) showed potent activity against CCR5 comparable to that of the positive control, maraviroc, in calcium mobilization assay. Moreover, some compounds were selected and further tested for their antiviral activity in HIV-1 single cycle assay. As a result, four compounds (13, 16, 33, and 36) showed antiviral activity at the nanomolar level. Additionally, the potent four compounds showed no cytotoxicity at a concentration of 10µM.

Identification of novel inhibitors of Aurora A with a 3-(pyrrolopyridin-2-yl)indazole scaffold.

A novel series of 3-(pyrrolopyridin-2-yl)indazole derivatives were synthesized and biologically evaluated for their anti-proliferative effects on five human cancer cell lines. As a result, all of them exhibited vigorous potency against HL60 cell line with IC50 values ranging from singe digital nanomolar to micromolar level. Besides, a majority of them displayed modest to good antiproliferative activities against the other four cell lines, including KB, SMMC-7721, HCT116, and A549. Particularly, compound 2y, as the most distinguished one in this series, demonstrated IC50 values of 8.3nM and 1.3nM against HL60 and HCT116 cell lines, respectively. Afterwards, for exploring the molecular target, compounds2d, 2g and 2y were further selected to evaluate the inhibitory activities against a panel of kinases. Finally, they were identified to be targeting Aurora A kinase with significant selectivity over other kinases, such as CHK1, CDK2, MEK1, GSK3ß, BRAF, IKKß and PKC.

Alkenyl/thiol-derived metal-organic frameworks (MOFs) by means of postsynthetic modification for effective mercury adsorption.

The synthesis of new functionally diverse alkenyl-derived Cr-MIL-101s (MIL=material of Institute Lavoisier) was realized by a novel and convenient postsynthetic modification (PSM) protocol by means of the carbon-carbon bond-forming Mizoroki-Heck reaction. The new PSM protocol demonstrates a broad scope of substrates with excellent tolerance of functionality under mild reaction conditions. Moreover, a new metal-organic framework (MOF) that bears both alkenyl and thiol side chains prepared by means of the tandem PSM method has shown excellent adsorbent ability in removing mercury ions from water.

Identification of novel 4-anilinoquinazoline derivatives as potent EGFR inhibitors both under normoxia and hypoxia.

A novel series of 4-anilinoquinazoline derivatives (19a-19t) were designed and synthesized through incorporation of the 2-nitroimidazole moiety into the 4-anilinoquinazoline scaffold of EGFR inhibitors. The most promising compound 19h displayed potent EGFR inhibitory activity with the IC50 value of 0.47 nM. It also strongly suppressed the proliferation of A549 and HT-29 cells with sub-micromolar IC50 values both under normoxia and hypoxia, which were several folds more potent than gefitinib and erlotinib. Further reductive mimic investigation revealed that 19h could be reductive activated under hypoxia and was fully consistent with the results of cell apoptotic assay and in vitro metabolism evaluation. Our results suggest that the incorporation of hypoxia-activated moiety into EGFR inhibitor scaffold might be a tractable strategy to overcome the tumor hypoxia.

Design, synthesis and evaluation of rivastigmine and curcumin hybrids as site-activated multitarget-directed ligands for Alzheimer's disease therapy.

A series of novel 2-methoxy-phenyl dimethyl-carbamate derivatives were designed, synthesized and evaluated as site-activated MTDLs based on rivastigmine and curcumin. Most of them exhibited good to excellent AChE and BuChE inhibitory activities with sub-micromolar IC50 values. Among all the compounds, 6a demonstrated the most potent AChE inhibition with IC50 value of 0.097µM, which is about 20-fold than that of rivastigmine. In addition, the three selected compounds 5a, 6a and 6e demonstrated inhibitory activity against Aß self-aggregation similar to cucurmin in TEM assay, which is obviously different from the weak activity of rivastigmine. Moreover, the hydrolysate of 6a (compound 7) also showed potent ABTS(+) scavenging and moderate copper ion chelating activity in vitro.

Design, synthesis and biological evaluation of novel tripeptidyl epoxyketone derivatives constructed from ß-amino acid as proteasome inhibitors.

A series of novel tripeptidyl epoxyketone derivatives constructed from ß-amino acid were designed, synthesized and evaluated as proteasome inhibitors. All target compounds were tested for their proteasome inhibitory activities and selected compounds were tested for their anti-proliferation activities against two multiple myeloma (MM) cell lines RPMI 8226 and NCI-H929. Among them, eleven compounds exhibited proteasome inhibitory rates of more than 50% at the concentration of 1 µg/mL and nine compounds showed anti-proliferation activities with IC50 values at low micromolar level. Compound 20h displayed the most potent proteasome inhibitory activities (IC50: 0.11 ± 0.01 µM) and anti-proliferation activities with IC50 values at 0.23 ± 0.01 and 0.17 ± 0.02 µM against two tested cell lines. Additionally, the poly-ubiquitin accumulation in the western blot analysis supported that proteasome inhibition in a cellular system was induced by compound 20h. All these experimental results confirmed that ß-amino acid can be introduced as a building block for the development of proteasome inhibitors.

Design, synthesis and biological evaluation of thienopyridinones as Chk1 inhibitors.

A series of thienopyridinone derivatives was designed and synthesized as inhibitors of checkpoint kinase 1 (Chk1). Most of them exhibited moderate to good Chk1 inhibitory activities. Among them, compounds 8q, 8t, and 8w with excellent Chk1 inhibitory activities (IC50 values of 4.05, 6.23, and 2.33nM, respectively) displayed strong synergistic effects with melphalan, a DNA-damaging agent in the cell-based assay. Further kinase profiling indicated that compound 8t was highly selective against CDK2/cyclinA, Aurora A, and PKC.

Design, synthesis and biological evaluation of novel 3,4,5-trisubstituted aminothiophenes as inhibitors of p53-MDM2 interaction. Part 2.

Five series of novel 3,4,5-trisubstituted aminothiophene derivatives and analogs were designed and synthesized based on our previous studies. All target compounds were evaluated for their p53-MDM2 binding inhibitory activities and anti-proliferation activities against A549 and PC3 tumor cell lines. Twelve compounds displayed comparable p53-MDM2 binding inhibitory activities to that of Nutlin-3. Among them, compound 7a exhibited marked binding affinity (IC50=0.086 µM). In addition, most target compounds showed potent anti-proliferation activities with IC50 values at low micromolar level. A good selective profile for wild-type p53 expression cell line was also observed. Molecular docking analysis was performed as well to predict possible binding modes of target compounds with MDM2.

Design, synthesis and biological evaluation of novel 3,4,5-trisubstituted aminothiophenes as inhibitors of p53-MDM2 interaction. Part 1.

A series of 3,4,5-trisubstituted aminothiophenes were designed, synthesized, and evaluated for their p53-MDM2 binding inhibitory potency and anti-proliferation activities against A549 and PC3 tumor cell lines. Fourteen compounds had appreciably improved MDM2 binding affinities than lead compound MCL0527 (3) and a few compounds showed comparable activities to that of Nutlin-3. Meanwhile, most of the 3,4,5-trisubstituted aminothiophenes displayed better or equivalent anti-proliferation activities against wild-type p53 cell line A549 compared to that of Nutlin-3. Over ten compounds exhibited desirable selective profiles of p53 status. Particularly, compounds 9, 16 and 18 displayed 22-, 6- and 22-fold selectivity of p53 status, respectively, much better than that of Nutlin-3 (fourfold).

Design and synthesis of novel 3-substituted-indole derivatives as selective H3 receptor antagonists and potent free radical scavengers.

A series of novel 3-substituted-indole derivatives with a benzyl tertiary amino moiety were designed, synthesized and evaluated as H3 receptor antagonists and free radical scavengers for Alzheimer's disease therapy. Most of these synthesized compounds exhibited moderate to potent antagonistic activities in CREs driven luciferase assay. In particular, compound 2d demonstrated the most favorable H3 receptor antagonistic activity with the IC50 value of 0.049µM. Besides, it also displayed high binding affinity to H3 receptor (Ki=4.26±2.55nM) and high selectivity over other three histamine receptors. Moreover, 2d and other two 3-substituted indole derivatives 1d and 3d exerted potent ABTS radical cation scavenging capacities similar to melatonin. Above results illustrate that 2d is an interesting lead for extensive optimization to explore new drug candidate for AD therapy.

Synthesis and biological evaluation of novel benzyl-substituted (S)-phenylalanine derivatives as potent dipeptidyl peptidase 4 inhibitors.

A series of novel benzyl-substituted (S)-phenylalanine derivatives were synthesized and evaluated for their dipeptidyl peptidase 4 (DPP-4) inhibitory activity and selectivity. It was found that most synthesized target compounds were potent DPP-4 inhibitors with IC50 values in 3.79-25.52 nM, which were significantly superior to that of the marketed drug sitagliptin. Furthermore, the 4-fluorobenzyl substituted phenylalanine derivative 6g not only displayed the potent DPP-4 inhibition with an IC50 value of 3.79 nM, but also showed better selectivity against DPP-4 over other related enzymes including DPP-7, DPP-8, and DPP-9. In an oral glucose tolerance test (OGTT) in normal Sprague Dawley rats, compound 6g reduced blood glucose excursion in a dose-dependent manner.