Subtle structural alteration in indisulam switches the molecular mechanisms for the inhibitory effect on the migration of gastric cancer cells.

Gastric cancer is a highly metastatic malignant tumor with high morbidity and mortality globally. Recent studies reported that sulfonamide derivatives such as indisulam exhibited inhibitory effects on the viability and migration of cancer cells. However, multiple clinical trials revealed that indisulam did not significantly prevent cancer progression due to metastasis and drug resistance. Therefore, it is necessary to discover new potent derivatives to explore alternative therapeutic strategies. Here, we synthesize multiple indisulam derivatives and examine their inhibitory effects on the viability and migration of gastric cancer cells. Among them, compounds SR-3-65 and WXM-1-170 exhibit better inhibitory effects on the migration of gastric cancer cells than indisulam. Mechanistically, we discover that they could attenuate the PI3K/AKT/GSK-3ß/ß-catenin signaling pathway and lead to the suppression of epithelial-to-mesenchymal transition (EMT)-related transcription factors. The influence of SR-3-65 on the migration of gastric cancer cells is blocked by the PI3K inhibitor LY294002 while SR-3-65 and WXM-1-170 reverse the effect of PI3K activator 740 Y-P on the migration of gastric cancer cells. Molecular docking and molecular dynamics simulation further confirm that PI3K is the target of SR-3-65. Our study unveils a novel mechanism by which SR-3-65 and WXM-1-170 inhibit the migration of gastric cancer cells. Together with the previous discovery, we reveal that subtle structural change in indisulam results in a striking switch on the molecular targets and their associated signaling pathways for the inhibition of the migration of gastric cancer cells. These findings might provide informative insights for the development of targeted therapy for gastric cancer.

Benzothiozinone derivatives with anti-tubercular Activity-Further side chain investigation.

A series of novel benzothiozinone (BTZ) derivatives were designed, prepared and evaluated for antituberculosis activity. Specifically, the BTZ pharmacophore is retained and the previous heterocyclic ring linker is replaced by alkynyl or vinyl linker, the resulting compounds displayed about 5-fold improved antimycobacterial activity. We further revealed that the linker attached tail group affects the compound metabolic stability, potency and other drug like properties. This work led to the discovery of two compounds (A1 and A11) with acceptable low MICs and improved metabolic stability. The representative compound A11 demonstrated bactericidal efficacy in an acute TB infection mouse model.

Side Chain-Modified Benzothiazinone Derivatives with Anti-Mycobacterial Activity.

Tuberculosis (TB) is a leading infectious disease with serious antibiotic resistance. The benzothiazinone (BTZ) scaffold PBTZ169 kills Mycobacterium tuberculosis (Mtb) through the inhibition of the essential cell wall enzyme decaprenylphosphoryl-ß-D-ribose 2'-oxidase (DprE1). PBTZ169 shows anti-TB potential in animal models and pilot clinical tests. Although highly potent, the BTZ type DprE1 inhibitors in general show extremely low aqueous solubility, which adversely affects the drug-like properties. To improve the compounds physicochemical properties, we generated a series of BTZ analogues. Several optimized compounds had MIC values against Mtb lower than 0.01 µM. The representative compound 37 displays improved solubility and bioavailability compared to the lead compound. Additionally, compound 37 shows Mtb-killing ability in an acute infection mouse model.

The aryl sulfonamide indisulam inhibits gastric cancer cell migration by promoting the ubiquitination and degradation of the transcription factor ZEB1.

Gastric cancer is one of the cancers with high morbidity and mortality worldwide. The aryl sulfonamide indisulam inhibits the proliferation of several types of cancer cells through its function as a molecular glue to promote the ubiquitination and degradation of RNA-binding motif protein 39 (RBM39). However, it is unknown whether and how indisulam regulates the migration of cancer cells. In this work, using label-free quantitative proteomics, we discover that indisulam significantly attenuates N-cadherin, a marker for epithelial to mesenchymal transition and migration of cancer cells. Our bioinformatics analysis and biochemical experiments reveal that indisulam promotes the interaction between the zinc finger E-box-binding homeobox 1 (ZEB1), a transcription factor of N-cadherin, and DCAF15, a substrate receptor of CRL4 E3 ubiquitin ligase, and enhances ZEB1 ubiquitination and proteasomal degradation. In addition, our cell line-based experiments demonstrate that indisulam inhibits the migration of gastric cancer cells in a ZEB1-dependent manner. Analyses of patient samples and datasets in public databases reveal that tumor tissues from patients with gastric cancer express high ZEB1 mRNA and this high expression reduces patient survival rate. Finally, we show that treatment of gastric tumor samples with indisulam significantly reduces ZEB1 protein levels. Therefore, this work discloses a new mechanism by which indisulam inhibits the migration of gastric cancer cells, indicating that indisulam exhibits different biological functions through distinct signaling molecules.

Development of 6-Methanesulfonyl-8-nitrobenzothiazinone Based Antitubercular Agents.

The 6-trifluoro substituted 8-nitrobenzothiazinones (BTZs) represent a novel type of antitubercular agents, and their high antimycobacterial activity is related to the inhibition of decaprenylphosphoryl-ß-d-ribose 2'-oxidase (DprE1), an enzyme essential for the biosynthesis of mycobacterial cell wall. While extraordinary whole-cell activity was reported for the clinically advanced compound PBTZ169, its poor aqueous solubility signals the potential low bioavailability. To ameliorate the BTZ physiochemical property, a series of 6-methanesulfonyl substituted compounds were designed and prepared, and their antitubercular activity and DprE1 inhibition ability were evaluated. Among these compounds, MsPBTZ169 and compounds 2 and 8 exhibited minimum inhibitory concentrations (MICs) of less than 40 nM; moreover, these compounds displayed increased aqueous solubility and acceptable metabolic stability. Taken together, this study suggested that the 6-methanesulfonyl substituted 8-nitrobenzothiazinone derivatives, in combination with side chain modification, might provide BTZ type antitubercular agents with improved drug-like properties.

Structural and Activity Relationships of 6-Sulfonyl-8-Nitrobenzothiazinones as Antitubercular Agents.

The benzothiazinone (BTZ) scaffold compound PBTZ169 kills Mycobacterium tuberculosis by inhibiting the essential flavoenzyme DprE1, consequently blocking the synthesis of the cell wall component arabinans. While extraordinarily potent against M. tuberculosis with a minimum inhibitory concentration (MIC) less than 0.2 ng/mL, its low aqueous solubility and bioavailability issues need to be addressed. Here, we designed and synthesized a series of 6-methanesulfonyl substituted BTZ analogues; further exploration introduced five-member aromatic heterocycles as linkers to attach an aryl group as the side chain. Our work led to the discovery of a number of BTZ derived compounds with potent antitubercular activity. The optimized compounds 6 and 38 exhibited MIC 47 and 30 nM, respectively. Compared to PBTZ169, both compounds displayed increased aqueous solubility and higher stability in human liver microsomes. This study suggested that an alternative side-chain modification strategy could be implemented to improve the druglike properties of the BTZ-based compounds.

Copper(II) and iron(III) complexes of chiral dehydroabietic acid derived from natural rosin: metal effect on structure and cytotoxicity.

A novel optically pure dinuclear copper(II) complex of a rosin derivative dehydroabietic acid (DHA, HL) was synthesized and fully characterized. The in vitro antitumor activities of the copper(II) complex Cu2(µ2-O)(L)4(DMF)2 (1) were explored and compared with those of a trinuclear iron(III) complex [Fe3(µ3-O)(L)6(CH3OH)2(CH3O)]·H2O (2). 1 was more cytotoxic than 2, and the in vitro cytotoxicity of 1 was comparable to that of cisplatin and oxaliplatin. The metal coordination improved the cytotoxicity of DHA. 1 could arrest cycle in G1 phase and induce apoptosis in MCF-7 cell. 1 increased reactive oxygen species level, GSSG/GSH ratio, and Ca2+ production, and caused the loss of mitochondrial membrane potential (Δψm) in MCF-7 cells. The up-regulated Bax and down-regulated Bcl-2 expression levels, caspase-9/caspase-3 activation, and the release of Cyt c demonstrate that 1 triggered mitochondria-mediated intrinsic apoptosis in MCF-7 cells. Caspase-8/caspase-4 activation and up-regulated Fas expression indicate that death receptor-mediated extrinsic apoptosis was included. Comet assay and up-regulated γ-H2AX and p53 expressions confirmed that 1 caused DNA damage in MCF-7 cells. Moreover, 1 led to enhancement of the biomarker of lipid peroxidation and the indicator of protein carbonylation in MCF-7 cells. All the results suggest that 1 could kill MCF-7 cells by generating oxidative stress, impairing DNA, promoting lipid peroxidation and protein carbonylation, and inducing apoptosis and autophagy. Furthermore, 1 also displayed antimetastatic activities with inhibition of cell invasion and migration, together with antiangiogenesis properties. On the whole, copper complex based on rosin derivatives is worth developing as metal-based antitumor drugs.

Design, synthesis and evaluation of covalent inhibitors of DprE1 as antitubercular agents.

Decaprenylphosphoryl-ß-d-ribose 2'-oxidoreductase (DprE1) is a promising drug target for the development of novel anti-tubercular agents, and inhibitors of DprE1 are being investigated extensively. Among them, the 1,3-benzothiazinone compounds such as BTZ043, and its closer congener, PBTZ169, are undergoing clinical studies. It has been shown that both BTZ compounds are prodrugs, the nitro group is reduced to nitroso first, to which an adjacent Cys387 in the DprE1 binding pocket is covalently bound and results in suicide enzyme inhibition. We figured that replacement of the nitro with an electrophilic warhead would still achieve covalent interaction with nucleophilic Cys387, while the required reductive activation could be circumvented. To test this hypothesis, a number of covalent inhibitors of DprE1 were designed and prepared. The compounds inhibitory potency against DprE1 and anti-tubercular activity were investigated, their chemical reactivity, formation of covalent adduct between the warhead and the enzyme was demonstrated by mass spectrometry.

Insights into the Mechanism of Thiol-Triggered COS/H2S Release from N-Dithiasuccinoyl Amines.

The hydrolysis of carbonyl sulfide (COS) to form H2S by carbonic anhydrase has been demonstrated to be a viable strategy to deliver H2S in a biological system. Herein, we describe N-dithiasuccinoyl amines as thiol-triggered COS/H2S donors. Notably, thiol species especially GSH and homocysteine can trigger the release of both COS and H2S directly from several specific analogues via an unexpected mechanism. Importantly, two representative analogues Dts-1 and Dts-5 show intracellular H2S release, and Dts-1 imparts potent anti-inflammatory effects in LPS-challenged microglia cells. In conclusion, N-dithiasuccinoyl amine could serve as promising COS/H2S donors for either H2S biological studies or H2S-based therapeutics development.

Novel conjugates of endoperoxide and 4-anilinoquinazoline induce myeloma cell apoptosis by inhibiting the IGF1-R/AKT/mTOR signaling pathway.

4-anilinoquinazoline-containing inhibitors of the epidermal growth factor receptor (EGFR) are widely used in non-small cell lung cancer patients with mutated EGFR, but they are less effective in multiple myeloma (MM), a fatal malignancy derived from plasma cells. The present study designed a series of novel compounds by conjugating a peroxide bridge to the 4-anilinoquinazoline pharmacophore. Further studies showed that these agents such as 4061 and 4065B displayed potent activity to induce MM cell apoptosis by upregulating pro-apoptotic p53 and Bax while downregulating pro-survival Bcl-2. The mechanistic analysis revealed that both 4061 and 4065B inhibited IGF1-R, AKT and mTOR activation in a concentration dependent manner but had no effects on the expression of their total proteins, suggesting the conjugates of endoperoxide and 4-anilinoquinazoline may exert its anti-myeloma activity by targeting the IGF1-R/AKT/mTOR pathway.

An atom-economical design of PET tracer for imaging αvß3 integrin via utilizing the three-in-one function of 64Copper.

In this study, αvß3 integrin in U87 tumor cells was imaged with a 64Cu-peptidic probe, in which the linear peptide GHRGDHG is used as a pre-ligand, while 64Cu bears three functional roles that include generation of the PET signal, coordination with two GH moieties of the pre-ligand, and cyclizing the linear pre-ligand into an active cyclic-RGD form (termed as 64Cu-Cyclo-RGD) for αvß3 integrin.

Correction: A novel PI3K inhibitor PIK-C98 displays potent preclinical activity against multiple myeloma.

[This corrects the article DOI: 10.18632/oncotarget.2688.].

Biological evaluation of optically pure chiral binuclear copper(ii) complexes based on a rosin derivative as highly potential anticancer agents.

Two optically pure chiral binuclear copper(ii) complexes [Cu2(µ-Cl)2L2]·CH2Cl2 (1) and Cu2L4 (2) based on the natural product rosin derivative N-(5-dehydroabietyl-1,3,4-thiadiazole)-2-substituted pyridinecarboxamide (HL) were prepared, fully characterized and their biological activities were evaluated. The circular dichroism (CD), fluorescence spectroscopy, and DNA melting studies indicate that 1 and 2 interact with calf thymus DNA (CT DNA) via intercalation. It can be concluded that 1 and 2 have a strong affinity to bovine serum albumin (BSA) based on the fluorescence and CD spectral evidence. The MTT assay illustrates that the selective cytotoxic activity of 1 is better than that of HL, 2, cisplatin and oxaliplatin. The exposure of 1 to MCF-7 cells resulted in cell cycle arrest in the G1 phase, apoptosis, mitochondrial dysfunction and an elevated ROS level. The western blot analysis results indicate that 1 might induce apoptosis through intrinsic and extrinsic pathways, autophagy and DNA damage in MCF-7 cells. Furthermore, the down-regulated VEGFR2, MMP-2 and MMP-9 expression levels indicate that 1 should have the ability to resist metastasis and angiogenesis. Thus, based on the above described results 1 has high potential value for anticancer applications.

Hybrid molecules of scutellarein and tertramethylpyrazine's active metabolites for ischemic stroke.

A series of hybrid molecules of scutellarein and tertramethylpyrazine's active metabolites have been synthesized. Compared to the original compound, these prepared compounds exhibited higher water solubility, more appropriate logP and better stability. Importantly, compounds 11b, 11d and 11e showed improved neuroprotective activity against the H2O2-induced cell death in PC12 cells, and better antithrombosis activity. The optimized compound 11b was further evaluated by cerebral ischemia/ reperfusion in the middle cerebral artery occlusion (MCAO) model, the results showed that the compound could significantly reduce the infarct area and decrease the neuronal cell damage in CA1 pyramidal neurons. Overall, we demonstrated that the twin drug strategy could be applied in the development of agents for the treatment of ischemic stroke.

Optically pure chiral copper(II) complexes of rosin derivative as attractive anticancer agents with potential anti-metastatic and anti-angiogenic activities.

The development of optically pure drugs is the trend of new drugs research. Searching for optically pure metallodrugs against cancer has not been taken seriously. [CuL4Cl]Cl·2CH2Cl2·H2O (1) and [CuL4Br]Br·2CH2Cl2 (2) (L = 2-amino-5-dehydroabietyl-1,3,4-thiadiazole), two rosin-derivative based optically pure chiral copper(II) complexes, are rationally synthesized as potential anticancer agents. 1 exhibits effective in vitro and in vivo anticancer activities and tolerable toxicities. 1 promotes MCF-7 cell death by combination of cell arrest at G1 phase, apoptosis (both extrinsic and intrinsic apoptotic pathways), anti-metastasis, anti-angiogenesis, damage of DNA, protein and lipid, and autophagy mediated by the oxidative stress which is confirmed by ROS generation and intracellular glutathione depletion assays. 1 can be identified as a lead anticancer molecule of therapeutic importance. This work may offer insights into the design and mechanism study of multifunctional optically pure metal-based anticancer candidates derived from natural products.

Design, synthesis and fungicidal evaluation of novel pyraclostrobin analogues.

A series of novel pyraclostrobin derivatives were designed and prepared as antifungal agents. Their antifungal activities were tested in vitro with five important phytopathogenic fungi, namely, Batrylis cinerea, Phytophthora capsici, Fusarium sulphureum, Gloeosporium pestis and Sclerotinia sclerotiorum using the mycelium growth inhibition method. Among these compounds, 5s displayed IC50 value of 0.57 µg/mL against Batrylis cinerea and 5k-II displayed IC50 value of 0.43 µg/mL against Sclerotinia sclerotiorum, which were close to that of the positive control pyraclostrobin (0.18 µg/mL and 0.15 µg/mL). Other compounds 5f, 5k-II, 5j, 5m and 5s also exhibited strong antifungal activity. Further enzymatic assay demonstrated compound 5s inhibited porcine bc1 complex with IC50 value of 0.95 µM. The statistical results from an integrated computational pipeline demonstrated the predicted total binding free energy for compound 5s is the highest. Consequently, compound 5s with the biphenyl-4-methoxyl side chain could serve as a new motif as inhibitors of bc1 complex and deserve to be further investigated.

N-Arylsulfonylsubstituted-1H indole derivatives as small molecule dual inhibitors of signal transducer and activator of transcription 3 (STAT3) and tubulin.

Signal transducer and activator of transcription (STAT3) is a proposed therapeutic target for the development of anti-cancer agents. In this report, a series of N-arylsulfonylsubstituted-1H indole derivatives were designed and synthesized as STAT3 inhibitors, their anti-proliferative activities were evaluated against a number of tumor cells, some potent compounds exhibited IC50 values less than 10 µM. The most potent compound 4a was further confirmed to inhibit STAT3 phosphorylation at Tyr705. It was further revealed that 4a arrested the cell cycle at the G2/M phase and inhibited tubulin polymerization. This study describes a series of N-arylsulfonylsubstituted-1H indole derivatives as potent anti-cancer agents targeting both STAT3 and tubulin.

Organo-Catalyzed Asymmetric Michael-Hemiketalization-Oxa-Pictet-Spengler Cyclization for Bridged and Spiro Heterocyclic Skeletons: Oxocarbenium Ion as a Key Intermediate.

A Michael-hemiketalization-oxa-Pictet-Spengler cyclization has been developed for the construction of chiral bridged and spiro heterocyclic skeletons with one spiro stereogenic carbon center and two bridgehead carbon centers, utilizing cooperative catalysts of a Takemoto thiourea catalyst and a triflimide. In particular, an oxocarbenium ion acts as a key intermediate for this cyclization reaction. Additionally, biological evaluation of this type of novel structure has revealed obvious antiproliferative activity against some cancer cell lines.

The double-edged role of copper in the fate of amyloid beta in the presence of anti-oxidants.

The biological fate of amyloid beta (Aß) species is a fundamental question in Alzheimer's disease (AD) pathogenesis. The competition between clearance and aggregation of Aßs is critical for the onset of AD. Copper has been widely considered to be an inducer of harmful crosslinking of Aßs, and an important triggering factor for the onset of AD. In this report, however, we present data to show that copper can also be an inducer of Aß degradation in the presence of a large excess of well-known intrinsic (such as dopamine) or extrinsic (such as vitamin C) anti-oxidants. The degraded fragments were identified using SDS-Page gels, and validated via nanoLC-MS/MS. A tentative mechanism for the degradation was proposed and validated with model peptides. In addition, we performed electrophysiological analysis to investigate the synaptic functions in brain slices, and found that in the presence of a significant excess of vitamin C, Cu(ii) could prevent an Aß-induced deficit in synaptic transmission in the hippocampus. Collectively, our evidence strongly indicated that a proper combination of copper and anti-oxidants might have a positive effect on the prevention of AD. This double-edged function of copper in AD has been largely overlooked in the past. We believe that our report is very important for fully understanding the function of copper in AD pathology.

Novel conjugates of endoperoxide and 4-anilinoquinazoline as potential anticancer agents.

In the present study, endoperoxide and 4-anilinoqnazoline were conjugated to obtain a series of compounds. These conjugates exhibited high antiproliferative potency against a number of cancer cell lines, including the epidermal growth factor receptor (EGFR) L858R/T790M mutant cell. Compound 5 was selected as a representative for mechanistic study. Further experiments revealed the conjugate's reactive oxygen species (ROS) generating ability, apoptosis inducing activity and involvement in EGFR downstream signaling pathways.