Derivatives of aryl amines containing the cytotoxic 1,4-dioxo-2-butenyl pharmacophore

Development of applicable thiol-linked antibody-drug conjugates with improved stability and therapeutic index

Maleimides are typically applicable for coupling with reactive thiol moieties of antibodies in antibody–drug conjugates (ADCs) via the thiol-Michael click chemistry. Even so, the thiosuccinimide group produced in ADCs is unstable under physiological conditions, which is a unresolved issue in the ADC industry that can cause serious off-target toxicity. Committed to solving the stability defects of traditional thiosuccinimide-containing ADCs, we explored a series of linkers based on the ring-opening hydrolysates of thiosuccinimide. Meanwhile, a type of linkers based on maleamic methyl ester were used to conjugate the popular monomethyl auristatin E to an anti-HER2 antibody to generate the target ADCs, which enhances the stability and do not need to change the structure of the ideal stable metabolite of traditional ADCs. In vivo studies demonstrate that our preferred ADC mil40-12b not only has better efficacy than traditional ADCs but also exhibits better safety parameters in mice. For example, complete tumor regression can still be achieved even when the dose is halved (2.5 mg/kg), and the maximum tolerable dose is increased by 40 mg/kg. This strategy is expected to provide an applicable tool for the construction of thiol-linked ADCs with improved therapeutic index.

Novel Immune Modulators Enhance Caenorhabditis elegans Resistance to Multiple Pathogens

Trends moving in opposite directions (increasing antimicrobial resistance and declining novel antimicrobial development) have precipitated a looming crisis: a nearly complete inability to safely and effectively treat bacterial infections. To avert this, new approaches are needed.

Traditionally, treatments for bacterial infection have focused on killing the microbe or preventing its growth. As antimicrobial resistance becomes more ubiquitous, the feasibility of this approach is beginning to wane and attention has begun to shift toward disrupting the host-pathogen interaction by improving the host defense. Using a high-throughput, fragment-based screen to identify compounds that alleviate Pseudomonas aeruginosa-mediated killing of Caenorhabditis elegans, we identified over 20 compounds that stimulated host defense gene expression. Five of these molecules were selected for further characterization. Four of five compounds showed little toxicity against mammalian cells or worms, consistent with their identification in a phenotypic, high-content screen. Each of the compounds activated several host defense pathways, but the pathways were generally dispensable for compound-mediated rescue in liquid killing, suggesting redundancy or that the activation of unknown pathway(s) may be driving compound effects. A genetic mechanism was identified for LK56, which required the Mediator subunit MDT-15/MED15 and NHR-49/HNF4 for its function. Interestingly, LK32, LK34, LK38, and LK56 also rescued C. elegans from P. aeruginosa in an agar-based assay, which uses different virulence factors and defense mechanisms. Rescue in an agar-based assay for LK38 entirely depended upon the PMK-1/p38 MAPK pathway. Three compounds—LK32, LK34, and LK56—also conferred resistance to Enterococcus faecalis, and the two lattermost, LK34 and LK56, also reduced pathogenesis from Staphylococcus aureus. This study supports a growing role for MDT-15 and NHR-49 in immune response and identifies five molecules that have significant potential for use as tools in the investigation of innate immunity.

IMPORTANCE Trends moving in opposite directions (increasing antimicrobial resistance and declining novel antimicrobial development) have precipitated a looming crisis: the nearly complete inability to safely and effectively treat bacterial infections. To avert this, new approaches are needed. One idea is to stimulate host defense pathways to improve the clearance of bacterial infection. Here, we describe five small molecules that promote resistance to infectious bacteria by activating C. elegans’ innate immune pathways. Several are effective against both Gram-positive and Gram-negative pathogens. One of the compounds was mapped to the action of MDT-15/MED15 and NHR-49/HNF4, a pair of transcriptional regulators more generally associated with fatty acid metabolism, potentially highlighting a new link between these biological functions. These studies pave the way for future characterization of the anti-infective activity of the molecules in higher organisms and highlight the compounds’ potential utility for further investigation of immune modulation as a novel therapeutic approach.

Assessment of the toxicogenic effects and cell death potential of the ester (Z)-methyl 4-((1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazol-4-yl)amino)-4-oxobut-2-anoate in combination with cisplatin, cyclophosphamide and doxorubicin

Despite rapid advances in both the early detection and treatment of cancer, the mortality from this disease remains high, which justifies the development of new products that are more selective and effective and have fewer side effects. Accordingly, a novel ester was synthesized that contains two pharmacophores with important biological activities: (I) 4-aminoantipyrine, which has anti-inflammatory and antioxidant effects, and (II) the pharmacophore 1,4-dioxo-butenyl, which has cytotoxic activity. When administered alone, this compound is non-genotoxic, and it does not cause an increasing in splenic phagocytosis. Nevertheless, it can induce cell death. When administered in combination with commercial chemotherapeutic agents, such as doxorubicin, cisplatin, and cyclophosphamide, the ester shows antigenotoxic activity and decreases phagocytosis and reduces the potential to cause cell death. These results indicate that the compound should not be used in combination with chemotherapeutic agents that exert their effect through DNA damage, an important feature of antitumor drugs.

Synthesis of fluorescent drug molecules for competitive binding assay based on molecularly imprinted polymers

Fluorescent immunosorbent assay (FIA) is very promising for sensitive and selective analysis in bio-medical applications. Here, we proposed an assay, using fluorescent engineering of analytes and the corresponding molecularly imprinted polymers (MIPs) as a plastic antibody. Three drug molecules (metronidazole, zidovudine and lamivudine) were condensed with 9-aminoacridine, using succinic anhydride as a spacer. The target products were characterized with 1H-NMR, IR and mass spectrometry. UV-vis absorption and fluorescent properties of the fluorophore-labeled drug molecules were investigated. Feasibility of the fluorescent biomimetic immunosorbent assay based on MIPs was demonstrated in the solution. This work will provide sound foundation for the future application in real sample.

Assessment of genetic integrity, splenic phagocytosis and cell death potential of (Z)-4-((1,5-dimethyl-3-oxo-2-phenyl-2,3dihydro-1H-pyrazol-4-yl) amino)-4-oxobut-2-enoic acid and its effect when combined with commercial chemotherapeutics

The increased incidence of cancer and its high treatment costs have encouraged the search for new compounds to be used in adjuvant therapies for this disease. This study discloses the synthesis of (Z)-4-((1,5-dimethyl-3-oxo-2-phenyl-2,3dihydro-1H-pyrazol-4-yl) amino)-4-oxobut-2-enoic acid (IR-01) and evaluates not only the action of this compound on genetic integrity, increase in splenic phagocytosis and induction of cell death but also its effects in combination with the commercial chemotherapeutic agents doxorubicin, cisplatin and cyclophosphamide. IR-01 was designed and synthesized based on two multifunctionalyzed structural fragments: 4-aminoantipyrine, an active dipyrone metabolite, described as an antioxidant and anti-inflammatory agent; and the pharmacophore fragment 1,4-dioxo-2-butenyl, a cytotoxic agent. The results indicated that IR-01 is an effective chemoprotector because it can prevent clastogenic and/or aneugenic damage, has good potential to prevent genomic damage, can increase splenic phagocytosis and lymphocyte frequency and induces cell death. However, its use as an adjuvant in combination with chemotherapy is discouraged since IR-01 interferes in the effectiveness of the tested chemotherapeutic agents. This is a pioneer study as it demonstrates the chemopreventive effects of IR-01, which may be associated with the higher antioxidant activity of the precursor structure of 4-aminoantipyrine over the effects of the 1,4-dioxo-2-butenyl fragment.

Curcumin-inspired cytotoxic 3,5-bis(arylmethylene)-1-(N-(ortho-substituted aryl)maleamoyl)-4-piperidones: A novel group of topoisomerase II alpha inhibitors

Three series of novel 3,5-bis(arylmethylene)-1-(N-(ortho-substituted aryl)maleamoyl)-4-piperidones, designed as simplified analogs of curcumin with maleic diamide tether, were synthesized and bioevaluated. These compounds displayed potent cytotoxicity towards human Molt 4/C8 and CEM T-lymphocytes as well as murine L1210 leukemic cells. In contrast, the related N-arylmaleamic acids possessed little or no cytotoxicity in these three screens. Design of these compounds was based on molecular modeling studies performed on a related series of molecule in a previous study. Representative title compounds were found to be significantly potent in inhibiting the activity of topoisomerase II alpha indicating the possible mode of action of these compounds. These compounds were also potent antioxidants in vitro and attenuated the AAPH triggered peroxyl radical production in human fibroblasts. Various members of these series were also well tolerated in both in vitro and in vivo toxicity analysis.

Synthesis, anti-inflammatory activity and COX-1/COX-2 inhibition of novel substituted cyclic imides. Part 1: Molecular docking study

A group of cyclic imides (1-13) was designed for evaluation as selective COX-2 inhibitors and investigated in vivo for their anti-inflammatory activities using carrageenan-induced rat paw edema model. Compounds 5b, 6b, 11b, 11c, 12b and 12c were proved to be potent COX-2 inhibitors with IC50 range of 0.1-1.0 μM. In vitro COX-1/COX-2 inhibition structure-activity studies identified compound 5b as a highly potent (IC50=0.1 μM), and an extremely selective [COX-2 (SI)=400] comparable to celecoxib [COX-2 (SI)>333.3], COX-2 inhibitor that showed superior anti-inflammatory activity (ED50=104 mg/kg) relative to diclofenac (ED50=114 mg/kg). A Virtual screening was carried out through docking the designed compounds into the COX-2 binding site to predict if these compounds have analogous binding mode to the COX-2 inhibitors. Molecular modeling (docking) study showed that the CH3O substituents of 5b inserted deep inside the 2°-pocket of the COX-2 active site, where the O-atoms of such group underwent a H-bonding interaction with His90 (2.43, 2.83 Å), Arg513 (2.89 Å) and Tyr355 (3.34 Å). Docking study of the synthesized compound 5b into the active site of COX-2 revealed a similar binding mode to SC-558, a selective COX-2 inhibitor.