Identification and characterization of two Bacillus anthracis bacteriophages.

Anthrax is an acute infectious zoonotic disease caused by Bacillus anthracis, a bacterium that is considered a potential biological warfare agent. Bacillus bacteriophages shape the composition and evolution of bacterial communities in nature and therefore have important roles in the ecosystem community. B. anthracis phages are not only used in etiological diagnostics but also have promising prospects in clinical therapeutics or for disinfection in anthrax outbreaks. In this study, two temperate B. anthracis phages, vB_BanS_A16R1 (A16R1) and vB_BanS_A16R4 (A16R4), were isolated and showed siphovirus-like morphological characteristics. Genome sequencing showed that the genomes of phages A16R1 and A16R4 are 36,569 bp and 40,059 bp in length, respectively. A16R1 belongs to the genus Wbetavirus, while A16R4 belongs to the genus Hubeivirus and is the first phage of that genus found to lyse B. anthracis. Because these two phages can comparatively specifically lyse B. anthracis, they could be used as alternative diagnostic tools for identification of B. anthracis infections.

Phylogenetic Relationships and Evolution of the Genus Eganvirus (186-Type) Yersinia pestis Bacteriophages.

Plague is an endemic infectious disease caused by Yersinia pestis. In this study, we isolated fourteen phages with similar sequence arrangements to phage 186; these phages exhibited different lytic abilities in Enterobacteriaceae strains. To illustrate the phylogenetic relationships and evolutionary relationships between previously designated 186-type phages, we analysed the complete sequences and important genes of the phages, including whole-genome average nucleotide identity (ANI) and collinearity comparison, evolutionary analysis of four conserved structural genes (V, T, R, and Q genes), and analysis of the regulatory genes (cI, apl, and cII) and integrase gene (int). Phylogenetic analysis revealed that thirteen of the newly isolated phages belong to the genus Eganvirus and one belongs to the genus Felsduovirus in the family Peduoviridae, and these Eganvirus phages can be roughly clustered into three subgroups. The topological relationships exhibited by the whole-genome and structural genes seemed similar and stable, while the regulatory genes presented different topological relationships with the structural genes, and these results indicated that there was some homologous recombination in the regulatory genes. These newly isolated 186-type phages were mostly isolated from dogs, suggesting that the resistance of Canidae to Y. pestis infection may be related to the wide distribution of phages with lytic capability.

Discovery of novel polysubstituted N-alkyl acridone analogues as histone deacetylase isoform-selective inhibitors for cancer therapy.

Pan-histone deacetylase (HDAC) inhibitors often have some toxic side effects. In this study, three series of novel polysubstituted N-alkyl acridone analogous were designed and synthesised as HDAC isoform-selective inhibitors. Among them, 11b and 11c exhibited selective inhibition of HDAC1, HDAC3, and HDAC10, with IC50 values ranging from 87 nM to 418 nM. However, these compounds showed no inhibitory effect against HDAC6 and HDAC8. Moreover, 11b and 11c displayed potent antiproliferative activity against leukaemia HL-60 cells and colon cancer HCT-116 cells, with IC50 values ranging from 0.56 µM to 4.21 µM. Molecular docking and energy scoring functions further analysed the differences in the binding modes of 11c with HDAC1/6. In vitro anticancer studies revealed that the hit compounds 11b and 11c effectively induced histone H3 acetylation, S-phase cell cycle arrest, and apoptosis in HL-60 cells in a concentration-dependent manner.

Two Novel Yersinia pestis Bacteriophages with a Broad Host Range: Potential as Biocontrol Agents in Plague Natural Foci.

Bacteriophages (phages) have been successfully used as disinfectors to kill bacteria in food and the environment and have been used medically for curing human diseases. The objective of this research was to elucidate the morphological and genomic characteristics of two novel Yersinia pestis phages, vB_YpeM_ MHS112 (MHS112) and vB_YpeM_GMS130 (GMS130), belonging to the genus Gaprivervirus, subfamily Tevenvirinae, family Myoviridae. Genome sequencing showed that the sizes of MHS112 and GMS130 were 170507 and 168552 bp, respectively. A total of 303 and 292 open reading frames with 2 tRNA and 3 tRNA were predicted in MHS112 and GMS130, respectively. The phylogenetic relationships were analysed among the two novel Y. pestis phages, phages in the genus Gaprivervirus, and several T4-like phages infecting the Yersinia genus. The bacteriophage MHS112 and GMS130 exhibited a wider lytic host spectrum and exhibited comparative temperature and pH stability. Such features signify that these phages do not need to rely on Y. pestis as their host bacteria in the ecological environment, while they could be based on more massive Enterobacteriales species to propagate and form ecological barriers against Y. pestis pathogens colonised in plague foci. Such characteristics indicated that the two phages have potential as biocontrol agents for eliminating the endemics of animal plague in natural plague foci.

In silico, synthesis and anticancer evaluation of benzamide tryptamine derivatives as novel eEF2K inhibitors.

Eukaryotic elongation factor 2 kinase (eEF2K), a member of the atypical α-kinase family, is highly expressed in a variety of tumor tissues. Inhibition of eEF2K function can effectively kill cancer cells without affecting the function of normal cells. Therefore, eEF2K is a promising new target for cancer therapy. In this study, a series of benzamide tryptamine derivatives were designed and synthesized as novel eEF2K inhibitors. The druggability properties of the synthesized compounds were predicted in silico and performed well. The MTT assay indicated that most of these compounds displayed good antiproliferative activity against human leukemia CCRF-CEM and K562 cell lines. The structure-activity relationship (SAR) revealed that substituents with different electronic effects on the C5 position of indole ring or C2', C4' positions of benzene ring have a great influence on the anti-proliferative activity. Among them, 5j demonstrated the highest anti-proliferative activity with IC50 value of 1.63-3.54 µM. this compound displayed an effective eEF2K inhibition by down-regulated the level of phosphorylated eEF2 in CCRF-CEM cells. Additionally, the western blot analysis further revealed that 5j also significantly affected eEF2K-related signaling pathways. Anticancer mechanism studies have shown that 5j arrested the cell cycle in G0/G1 and induced CCRF-CEM cells apoptosis. Furthermore, 5j activated cleaved caspase-9, 8, 3 and cleaved PARP in a time-dependent manner, which suggesting that 5j induced cancer cells apoptosis through both intrinsic and extrinsic pathways. In summary, benzamide tryptamine derivative 5j represents a novel and promising lead structure for the development of eEF2K inhibitors in cancer therapy.

Design and synthesis of novel tacrine-dipicolylamine dimers that are multiple-target-directed ligands with potential to treat Alzheimer's disease.

Alzheimer's disease (AD) is a prevalent neurodegenerative disorder that has multiple causes. Therefore, multiple-target-directed ligands (MTDLs), which act on multiple targets, have been developed as a novel strategy for AD therapy. In this study, novel drug candidates were designed and synthesized by the covalent linkings of tacrine, a previously used anti-AD acetylcholinesterase (AChE) inhibitor, and dipicolylamine, an ß-amyloid (Aß) aggregation inhibitor. Most tacrine-dipicolylamine dimers potently inhibited AChE and Aß1-42 aggregation in vitro, and 13a exhibited nanomolar level inhibition. Molecular docking analysis suggested that 13a could interact with the catalytic active sites and the peripheral anion site of AChE, and bind to Aß1-42 pentamers. Moreover, 13a effectively attenuated Aß1-42 oligomers-induced cognitive dysfunction in mice by activating the cAMP-response element binding protein/brain-derived neurotrophic factor signaling pathway, decreasing tau phosphorylation, preventing synaptic toxicity, and inhibiting neuroinflammation. The safety profile of 13a in mice was demonstrated by acute toxicity experiments. All these results suggested that novel tacrine-dipicolylamine dimers, especially 13a, have multi-target neuroprotective and cognitive-enhancing potentials, and therefore might be developed as MTDLs to combat AD.

Antiviral potential of natural products from marine microbes.

Humans have been suffered from viral infections over the centuries, such as influenza, HSV, and HIV, which have killed millions of people worldwide. However, the availability of effective treatments for infectious diseases remains limited until now, as most of the viral pathogens resisted to many medical treatments. Marine microbes are currently one of the most copious sources of pharmacologically active natural products, which have constantly provided promising antivirus agents. To date, a large number of marine microbial secondary metabolites with antiviral activities have been widely reported. In this review, we have summarized the potential antivirus compounds from marine microorganisms over the last decade. In addition, the structures, bioactivities, and origins of these compounds were discussed as well.

A Novel Methoxybenzyl 5-Nitroacridone Derivative Effectively Triggers G1 Cell Cycle Arrest in Chronic Myelogenous Leukemia K562 Cells by Inhibiting CDK4/6-Mediated Phosphorylation of Rb.

Chronic myeloid leukemia (CML) is a malignant tumor caused by the abnormal proliferation of hematopoietic stem cells. Among a new series of acridone derivatives previously synthesized, it was found that the methoxybenzyl 5-nitroacridone derivative 8q has nanomolar cytotoxicity in vitro against human chronic myelogenous leukemia K562 cells. In order to further explore the possible anti-leukemia mechanism of action of 8q on K562 cells, a metabolomics and molecular biology study was introduced. It was thus found that most of the metabolic pathways of the G1 phase of K562 cells were affected after 8q treatment. In addition, a concentration-dependent accumulation of cells in the G1 phase was observed by cell cycle analysis. Western blot analysis showed that 8q significantly down-regulated the phosphorylation level of retinoblastoma-associated protein (Rb) in a concentration-dependent manner, upon 48 h treatment. In addition, 8q induced K562 cells apoptosis, through both mitochondria-mediated and exogenous apoptotic pathways. Taken together, these results indicate that 8q effectively triggers G1 cell cycle arrest and induces cell apoptosis in K562 cells, by inhibiting the CDK4/6-mediated phosphorylation of Rb. Furthermore, the possible binding interactions between 8q and CDK4/6 protein were clarified by homology modeling and molecular docking. In order to verify the inhibitory activity of 8q against other chronic myeloid leukemia cells, KCL-22 cells and K562 adriamycin-resistant cells (K562/ADR) were selected for the MTT assay. It is worth noting that 8q showed significant anti-proliferative activity against these cell lines after 48 h/72 h treatment. Therefore, this study provides new mechanistic information and guidance for the development of new acridones for application in the treatment of CML.

Structural and functional investigation of AerF, a NADPH-dependent alkenal double bond reductase participating in the biosynthesis of Choi moiety of aeruginosin.

The 2-carboxy-6-hydroxyoctahydroindole (Choi) moiety is an essential residue for the antithrombotic activities of aeruginosins, which are a class of cyanobacterial derived bioactive linear tetrapeptides. Biosynthetic pathway of Choi is still elusive. AerF was suggested to be involved in the biosynthesis of Choi, and can be assigned to the short-chain dehydrogenase/reductase (SDR) superfamily. However, both the exact role and the catalytic mechanism of AerF have not been elucidated. In this study, functional and mechanistic analyses of AerF from Microcystis aeruginosa were performed. Observation of enzymatic assay demonstrates that AerF is a NADPH-dependent alkenal double bond reductase that catalyzes the reduction of dihydro-4-hydroxyphenylpyruvate (H2HPP) to generate tetrahydro-4-hydroxyphenylpyruvate (H4HPP), which is the third step of the biosynthetic pathway from prephenate to Choi. Comparative structural analysis indicates that ligand binding-induced conformational change of AerF is different from that of the other SDR superfamily reductase using H2HPP as a substrate. Analyses of NADPH and substrate analogue binding sites combined with the results of mutagenesis analyses suggest that a particular serine residue mainly involves in the initiation of the proton transfer between the substrate and the residues of AerF, which is an uncommon feature in SDR superfamily reductase. Furthermore, based on the observations of structural and mutagenesis analyses, the catalytic mechanism of AerF is proposed and a proton transfer pathway in AerF is deduced.

Design, synthesis and biological research of novel N-phenylbenzamide-4-methylamine acridine derivatives as potential topoisomerase I/II and apoptosis-inducing agents.

A series of novel N-phenylbenzamide-4-methylamine acridine derivatives were designed and synthesized based initially on the structure of amsacrine (m-AMSA). Molecular docking suggested that the representative compound 9a had affinity for binding DNA topoisomerase (Topo) II, which was comparable with that of m-AMSA, and furthermore that 9a could have preferential interactions with Topo I. After synthesis of 9a and analogues 9b-9f, these were all tested in vitro and the synthesized compounds displayed potent antiproliferative activity against three different cancer cell lines (K562, CCRF-CEM and U937). Among them, compounds 9b, 9c and 9d exhibiting the highest activity with IC50 value ranging from 0.82 to 0.91 µM against CCRF-CEM cells. In addition, 9b and 9d also showed high antiproliferative activity against U937 cells, with IC50 values of 0.33 and 0.23 µM, respectively. The pharmacological mechanistic studies of these compounds were evaluated by Topo I/II inhibition, western blot assay and cell apoptosis detection. In summary, 9b effectively inhibited the activity of Topo I/II and induced DNA damage in CCRF-CEM cells and, moreover, significantly induced cell apoptosis in a concentration-dependent manner. These observations provide new information and guidance for the structural optimization of more novel acridine derivatives.

Fascaplysin Derivatives Are Potent Multitarget Agents against Alzheimer's Disease: in Vitro and in Vivo Evidence.

Alzheimer's disease (AD) is characterized by progressive neurodegeneration and impaired cognitive functions. Fascaplysin is a ß-carboline alkaloid isolated from marine sponge Fascaplysinopsis bergquist in 1988. Previous studies have shown that fascaplysin might act on acetylcholinesterase and ß-amyloid (Aß) to produce anti-AD properties. In this study, a series of fascaplysin derivatives were synthesized. The cholinesterase inhibition activities, the neuronal protective effects, and the toxicities of these compounds were evaluated in vitro. Compounds 2a and 2b, the two most powerful compounds in vitro, were further selected to evaluate their cognitive-enhancing effects in animals. Both 2a and 2b could ameliorate cognitive dysfunction induced by scopolamine or Aß oligomers without affecting locomotor functions in mice. We also found that 2a and 2b could prevent cholinergic dysfunctions, decrease pro-inflammatory cytokine expression, and inhibit Aß-induced tau hyperphosphorylation in vivo. Most importantly, pharmacodynamics studies suggested that 2b could penetrate the blood-brain barrier and be retained in the central nervous system. All these results suggested that fascaplysin derivatives are potent multitarget agents against AD and might be clinical useful for AD treatment.

Phthalideisoquinoline Hemiacetal Alkaloids from Corydalis decumbens That Inhibit Spontaneous Calcium Oscillations, Including Alkyl Derivatives of (+)-Egenine That Are Strikingly Levorotatory.

The new phthalideisoquinoline hemiacetal alkaloids (2-7) and the known analogues (1 and 8) were isolated from the bulbs of Corydalis decumbens. The new compounds were characterized by analysis of their NMR spectroscopic data, chemical degradation syntheses, X-ray crystallography, and comparison of experimental and calculated ECD data. All the isolates were screened in vitro for inhibitory activity of spontaneous calcium oscillations in primary cultured neocortical neurons. Compounds 1-3 and 5-7 were found to be active in the suppression of spontaneous calcium oscillations with IC50 values of 6.8, 5.6, 11.6, 10.2, 8.3, and 3.1 µM, respectively. It was also observed that the presence of hydroxy, methoxy, and ethoxy groups at the remote stereogenic center C-7' of some isolated phthalideisoquinoline hemiacetal alkaloids could alter the preferred conformation and invert the sign of optical rotation, rather than this resulting from configurational isomerism at C-1 or C-9, and that the 3J1,9 coupling constants of these analogues varied accordingly. For example, compounds 1 and 6 are levorotatory, despite these molecules having the same carbon skeleton and absolute configuration as (+)-egenine. This emphasizes the potential risk of incorrectly assigning absolute configuration based only on observed coupling constants or optical rotation when comparing the data of new compounds with literature values for known analogues, especially within this class of molecules.

A new lateral root growth inhibitor from the sponge-derived fungus Aspergillus sp. LS45.

Two new γ-lactones, aspergilactones A (1) and B (2), were discovered along with two known compounds, annularin A (3) and pericoterpenoid A (4), from a culture of the sponge-associated fungus Aspergillus sp. LS45. The planar structures of 1-4 were characterized using comprehensive spectroscopic methods and comparison with literature data. The absolute configurations of 1 and 2 were determined by comparison of electronic circular dichroism (ECD) spectroscopic and optical rotation data with those of known analogues as well as calculated ECD analysis. Compounds 1-4 were tested in a variety of bioassays, and both 1 and 4 exhibited significant inhibition against the lateral root growth of Arabidopsis thaliana Columbia-0 at a concentration of 100 µM. In addition, the in vitro cytotoxic activities of 1-4 against six human cancer cell lines CCRF-CEM, K562, BGC823, AGS, HCT-116 and MDA-MB-231 were evaluated. Compound 4 showed moderate inhibitory effects on CCRF-CEM and K562 cancer cell lines with IC50 values of 13.8 ±â€¯1.6 and 12.9 ±â€¯2.5 µM, respectively. However, compounds 1-4 did not show any notable AChE inhibitory activity in vitro.

Isolation and Characterization of Two New Metabolites from the Sponge-Derived Fungus Aspergillus sp. LS34 by OSMAC Approach.

The application of an OSMAC (One Strain-Many Compounds) approach on the sponge-derived fungus Aspergillus sp. LS34, using two different media including solid rice medium and potato dextrose broth (PDB) resulted in the isolation and identification of two new compounds, named asperspin A (1) and asperther A (2) along with seven known compounds 3-9. Compounds 1-5 were detected in fungal extracts from rice medium, while compounds 6-9 were isolated from PDB medium. Their structures were unambiguously characterized by HRESIMS and NMR spectroscopic data. The growth inhibitory activity of these compounds against four pathogenic bacteria (Vibrio parahaemolyticus, Vibrio harveyi, Escherichia coli, and Staphylococcus aureus) were evaluated. All the compounds were also tested for their cytotoxicity against seven cancer cell lines, including CCRF-CEM, K562, BGC823, AGS, HCT-116, MDA-MB-453, and COR-L23. Among them, compound 9 showed strong activity against CCRF-CEM and K562 cells with IC50 values of 1.22 ± 0.05 µM and 10.58 ± 0.19 µM, respectively. Notably, compound 7 also showed pronounced activity against S. aureus with an MIC value of 3.54 µM.

Structural and functional insights into the role of a cupin superfamily isomerase in the biosynthesis of Choi moiety of aeruginosin.

The 2-carboxy-6-hydroxyoctahydroindole (Choi) moiety is a hallmark of aeruginosins, a class of cyanobacterial derived bioactive linear tetrapeptides that possess antithrombotic activity. The biosynthetic pathway of Choi has yet to be resolved. AerE is a cupin superfamily enzyme that was shown to be involved in the biosynthesis of Choi, but its exact role remains unclear. This study reports the functional characterization and structural analyses of AerE. Enzymatic observation reveals that AerE can dramatically accelerate 1,3-allylic isomerization of the non-aromatic decarboxylation product of prephenate, dihydro-4-hydroxyphenylpyruvate (H2HPP). This olefin isomerization reaction can occur non-enzymatically and is the second step of the biosynthetic pathway from prephenate to Choi. The results of comparative structural analysis and substrate analogue binding geometry analysis combined with the results of mutational studies suggest that AerE employs an induced fit strategy to bind and stabilize the substrate in a particular conformation that is possibly favorable for 1,3-allylic isomerization of H2HPP through coordinate bonds, hydrogen bonds, π-π conjugation interaction and hydrophobic interactions. All of these interactions are critical for the catalytic efficiency.

Discovery and Structure-Based Optimization of 6-Bromotryptamine Derivatives as Potential 5-HT2A Receptor Antagonists.

5-Hydroxytryptamine type 2A (5-HT2A) receptor is an important target for developing innovative antipsychotic agents in neuropsychiatric disorder therapies. To search for 5-HT2A receptor antagonists, a new indole alkaloid termed 6-bromo-N-propionyltryptamine (1), together with one known homologue 6-bromo-N-acetyltryptamine (2) were isolated and identified from a marine bacterium Pseudoalteromonas rubra QD1-2. Compound 1 with an N-propionyl side chain exhibited stronger 5-HT2A receptor antagonist activity than that of N-acetyl derivative (2), indicating that 6-bromotryptamine analogues with a longer chain acyl group perhaps displayed a more potent capacity to the target. Therefore, a series of new 6-bromotryptamine analogues (3-7) with different chain length of the acyl group (C4-C8) were prepared and evaluated activity against 5-HT2A receptor. Remarkably, 6-bromo-N-hexanoyltryptamine (5) displayed the most effective inhibitory activity, which was 5-fold stronger than that of the parent compound 1 and showed 70% efficacy of the positive control (ketanserin tartrate).

Preparative isolation and purification of lignans from Justicia procumbens using high-speed counter-current chromatography in stepwise elution mode.

Lignans, which are recognized as main constituents in Justicia procumbens, have attracted considerable attention due to their pharmacological activities, including antitumor, anti-hepatitic, cytotoxic, anti-microbial, and anti-virus properties. Preparative high-speed counter-current chromatography (HSCCC) was successfully applied to the isolation and purification of four lignans (justicidin B (1), justicidin A (2), 6'-hydroxyjusticidin C (3) and lignan J1 (4)) from J. procumbens using stepwise elution with a pair of two-phase solvent systems composed of n-hexane-ethyl acetate-methanol-water at (1.3:1:1.3:1, v/v) and (2.5:1:2.5:1, v/v). The preparative HSCCC separation was performed on 300 mg of crude sample yielding compounds 1 (19.7 mg), 2 (9.86 mg), 3 (11.26 mg), and 4 (2.54 mg) in a one-step separation, with purities over 95% as determined by HPLC. The structures of these compounds were identified by MS, 1H-NMR and 13C-NMR. This is the first report on the application of HSCCC to the efficient separation of lignans from J. procumbens.

Determining the Functions of HIV-1 Tat and a Second Magnesium Ion in the CDK9/Cyclin T1 Complex: A Molecular Dynamics Simulation Study.

The current paradigm of cyclin-dependent kinase (CDK) regulation based on the well-established CDK2 has been recently expanded. The determination of CDK9 crystal structures suggests the requirement of an additional regulatory protein, such as human immunodeficiency virus type 1 (HIV-1) Tat, to exert its physiological functions. In most kinases, the exact number and roles of the cofactor metal ions remain unappreciated, and the repertoire has thus gained increasing attention recently. Here, molecular dynamics (MD) simulations were implemented on CDK9 to explore the functional roles of HIV-1 Tat and the second Mg2+ ion at site 1 (Mg12+). The simulations unveiled that binding of HIV-1 Tat to CDK9 not only stabilized hydrogen bonds (H-bonds) between ATP and hinge residues Asp104 and Cys106, as well as between ATP and invariant Lys48, but also facilitated the salt bridge network pertaining to the phosphorylated Thr186 at the activation loop. By contrast, these H-bonds cannot be formed in CDK9 owing to the absence of HIV-1 Tat. MD simulations further revealed that the Mg12+ ion, coupled with the Mg22+ ion, anchored to the triphosphate moiety of ATP in its catalytic competent conformation. This observation indicates the requirement of the Mg12+ ion for CDK9 to realize its function. Overall, the introduction of HIV-1 Tat and Mg12+ ion resulted in the active site architectural characteristics of phosphorylated CDK9. These data highlighted the functional roles of HIV-1 Tat and Mg12+ ion in the regulation of CDK9 activity, which contributes an important complementary understanding of CDK molecular underpinnings.

Functionalized tetrahydro-1H-pyrido[4,3-b]indoles: a novel chemotype with Sirtuin 2 inhibitory activity.

Sirtuins are protein deacylases with regulatory roles in metabolism and stress response. Functionalized tetrahydro-1H-pyrido[4,3-b]indoles were identified as preferential sirtuin 2 inhibitors, with in vitro inhibitory potencies in the low micromolar concentrations (IC50 3-4 µM) for the more promising candidates. The functional relevance of sirtuin inhibition was corroborated in western blots that showed hyperacetylation of p53 and α-tubulin in treated HepG2 and MDA-MB-231 cells. Molecular docking showed that the tetrahydropyridoindole scaffold was positioned in the NAD + pocket and the acetylated substrate channel of the sirtuin 2 protein by van der Waals/hydrophobic, H bonding and stacking interactions. Functionalized tetrahydropyridoindoles represent a novel class of sirtuin 2 inhibitors that could be further explored for its therapeutic potential.

Synthesis and evaluation of bisbenzylidenedioxotetrahydrothiopranones as activators of endoplasmic reticulum (ER) stress signaling pathways and apoptotic cell death in acute promyelocytic leukemic cells.

Curcumin is known to trigger ER-stress induced cell death of acute promyelocytic leukemic (APL) cells by intercepting the degradation of nuclear co-repressor (N-CoR) protein which has a key role in the pathogenesis of APL. Replacing the heptadienedione moiety of curcumin with a monocarbonyl cross-conjugated dienone embedded in a tetrahydrothiopyranone dioxide ring resulted in thiopyranone dioxides that were more resilient to hydrolysis and had greater growth inhibitory activities than curcumin on APL cells. Several members intercepted the degradation of misfolded N-CoR and triggered the signaling cascade in the unfolded protein response (UPR) which led to apoptotic cell death. Microarray analysis showed that genes involved in protein processing pathways that were germane to the activation of the UPR were preferentially up-regulated in treated APL cells, supporting the notion that the UPR was a consequential mechanistic pathway affected by thiopyranone dioxides. The Michael acceptor reactivity of the scaffold may have a role in exacerbating ER stress in APL cells.