Construction and performance evaluation of a sustained release implant material polyetheretherketone with antibacterial properties

OBJECTIVE

This study aimed to construct a tightly binding antibiotic sustained release system on the polyetheretherketone (PEEK) surface and investigate the cellular activity and antibacterial properties of the new oral implant materials.

METHODS

Low-temperature argon plasma under certain parameters was used to prepare P-PEEK with nano-topology, and chemical deposition technology was adopted to form a polydopamine (PDA) coating on the PEEK surface to build a biological binding platform, PDA/P-PEEK. Subsequently, vancomycin gelatin nanoparticles (Van-GNPs) were prepared by two-step desolvation method. Finally, Van-GNPs were combined with PEEK implant material surface to form a new composite material, Van-GNPs/PEEK. scanning electron microscope (SEM), atomic force microscope (AFM), energy dispersive spectrometer (EDS), and contact angle tester were used to comprehensively characterize the materials. The in vitro release test of Van was performed by dynamic dialysis with ultraviolet spectrophotometer. The cell cytotoxicity and adhesion tests were studied by mouse embryonic osteoblasts. The antibacterial properties were evaluated by bacterial adhesion test, plate colony counting, and antimicrobial ring test with Staphylococcus aureus and Streptococcus mutans.

RESULTS

PEEK was treated with low-temperature argon plasma and attached to PDA to form a biological binding platform. The synthesized Van-GNPs were smooth, round, with uniform particle size distribution, and bound to PEEK to form a new composite material, which can release Van constantly. Cell experiments showed that Van-GNPs/PEEK had no cytotoxicity and had good interaction with osteoblasts. Bacterial experiments showed that surface conjugation with Van-GNPs could significantly improve the antibacterial performance of PEEK against S. aureus and S. mutans.

SIGNIFICANCE

This study demonstrated that Van-GNPs/PEEK have good cellular compatibility and autonomous antibacterial properties, which provide a theoretical basis for the wide application of PEEK in the field of stomatology.

Eribulin Inhibits Osteosarcoma in a Clinically-accurate Bone-tumor-insertion PDOX Mouse Model

BACKGROUND/AIM

Osteosarcoma is a rare type of bone cancer that affects mostly children and adolescents. First-line chemotherapy for osteosarcoma has not been improved for many decades. Eribulin has been used to treat breast cancer and liposarcoma in the clinic.

MATERIALS AND METHODS

A patient-derived orthotopic xenograft (PDOX) mouse model of osteosarcoma was established by tumor insertion within the tibia. This model more closely mimics osteosarcoma in clinical settings and was used to test the efficacy of eribulin. Tibia-insertion osteosarcoma PDOX mouse models were randomized into two groups: a control group (n=4) and an eribulin-treatment group (n=5). Mice were treated for fourteen days, four weeks after initial implantation. Tumor size and body weight were measured, and tumor histology was examined.

RESULTS

Significant tumor growth inhibition (p=0.044) was observed in mice treated with eribulin compared to the control group. Histology demonstrated necrosis in the eribulin-treated tumors. There was no body-weight loss in the treated mice.

CONCLUSION

Eribulin may be a clinically-effective, off-label chemotherapy for recalcitrant osteosarcoma that has failed first- and second-line therapy.

PI3K activation promotes resistance to eribulin in HER2-negative breast cancer

BACKGROUND

Eribulin is a microtubule-targeting agent approved for the treatment of advanced or metastatic breast cancer (BC) previously treated with anthracycline- and taxane-based regimens. PIK3CA mutation is associated with worse response to chemotherapy in oestrogen receptor-positive (ER+)/human epidermal growth factor receptor 2-negative (HER2-) metastatic BC. We aimed to evaluate the role of phosphoinositide 3-kinase (PI3K)/AKT pathway mutations in eribulin resistance.

METHODS

Resistance to eribulin was evaluated in HER2- BC cell lines and patient-derived tumour xenografts, and correlated with a mutation in the PI3K/AKT pathway.

RESULTS

Eleven out of 23 HER2- BC xenografts treated with eribulin exhibited disease progression. No correlation with ER status was detected. Among the resistant models, 64% carried mutations in PIK3CA, PIK3R1 or AKT1, but only 17% among the sensitive xenografts (P = 0.036). We observed that eribulin treatment induced AKT phosphorylation in vitro and in patient tumours. In agreement, the addition of PI3K inhibitors reversed primary and acquired resistance to eribulin in xenograft models, regardless of the genetic alterations in PI3K/AKT pathway or ER status. Mechanistically, PI3K blockade reduced p21 levels likely enabling apoptosis, thus sensitising to eribulin treatment.

CONCLUSIONS

PI3K pathway activation induces primary resistance or early adaptation to eribulin, supporting the combination of PI3K inhibitors and eribulin for the treatment of HER2- BC patients.

A new class of α-ketoamide derivatives with potent anticancer and anti-SARS-CoV-2 activities

Inhibitors of the proteasome have been extensively studied for their applications in the treatment of human diseases such as hematologic malignancies, autoimmune disorders, and viral infections. Many of the proteasome inhibitors reported in the literature target the non-primed site of proteasome’s substrate binding pocket. In this study, we designed, synthesized and characterized a series of novel α-keto phenylamide derivatives aimed at both the primed and non-primed sites of the proteasome. In these derivatives, different substituted phenyl groups at the head group targeting the primed site were incorporated in order to investigate their structure-activity relationship and optimize the potency of α-keto phenylamides. In addition, the biological effects of modifications at the cap moiety, P1, P2 and P3 side chain positions were explored. Many derivatives displayed highly potent biological activities in proteasome inhibition and anticancer activity against a panel of six cancer cell lines, which were further rationalized by molecular modeling analyses. Furthermore, a representative α-ketoamide derivative was tested and found to be active in inhibiting the cellular infection of SARS-CoV-2 which causes the COVID-19 pandemic. These results demonstrate that this new class of α-ketoamide derivatives are potent anticancer agents and provide experimental evidence of the anti-SARS-CoV-2 effect by one of them, thus suggesting a possible new lead to develop antiviral therapeutics for COVID-19.

Nanostructured Coating of Non-Crystalline Tantalum Pentoxide on Polyetheretherketone Enhances RBMS Cells/HGE Cells Adhesion

PURPOSE

As a dental material, polyetheretherketone (PEEK) is bioinert that does not induce cellular response and bone/gingival tissues regeneration. This study was to develop bioactive coating on PEEK and investigate the effects of coating on cellular response.

MATERIALS AND METHODS

Tantalum pentoxide (TP) coating was fabricated on PEEK surface by vacuum evaporation and responses of rat bone marrow mesenchymal stem (RBMS) cells/human gingival epithelial (HGE) were studied.

RESULTS

A dense coating (around 400 nm in thickness) of TP was closely combined with PEEK (PKTP). Moreover, the coating was non-crystalline TP, which contained many small humps (around 10 nm in size), exhibiting a nanostructured surface. In addition, the roughness, hydrophilicity, surface energy, and protein adsorption of PKTP were remarkably higher than that of PEEK. Furthermore, the responses (adhesion, proliferation, and osteogenic gene expression) of RBMS cells, and responses (adhesion and proliferation) of HGE cells to PKTP were remarkably improved in comparison with PEEK. It could be suggested that the nanostructured coating of TP on PEEK played crucial roles in inducing the responses of RBMS/HGE cells.

CONCLUSION

PKTP with elevated surface performances and outstanding cytocompatibility might have enormous potential for dental implant application.

Synthetic β-hydroxy ketone derivative inhibits cholinesterases, rescues oxidative stress and ameliorates cognitive deficits in 5XFAD mice model of AD

Alzheimer's disease (AD) is a progressive, chronic and age-related neurodegenerative disorder that affects millions of people across the world. In pursuit of new anti-AD remedies, 2-[Hydroxy-(4-nitrophenyl)methyl]-cyclopentanone (NMC), a β hydroxyl ketone derivative was studied to explore its neuroprotective potentials against AD. The in-vitro AChE and BuChE enzymes inhibition were evaluated by Ellman protocol and antioxidant potentials of NMC by DPPH free radical scavenging assay. In-vivo behavioral studies were performed in the transgenic 5xFAD mice model of AD using shallow water maze (SWM), Paddling Y-Maze (PYM), elevated plus maze (EPM) and balance beam (BB) tests. Also, the ex-vivo cholinesterase inhibitory effects of NMC and histopathological analysis of amyloid-β plaques were determined in the frontal cortex and hippocampal regions of the mice brain. NMC exhibited significant in vitro anti-cholinesterase enzyme potentials with an IC₅₀ value of 67 μg/ml against AChE and 96 μg/ml against BuChE respectively. Interestingly, the activities of AChE and BuChE enzymes were also significantly lower in the cortex and hippocampus of NMC-treated groups. Also, in the DPPH assessment, NMC displayed substantial antioxidant properties with an IC₅₀ value observed as 171 μg/ml. Moreover, histopathological analysis via thioflavin-s staining displayed significantly lower plaques depositions in the cortex and hippocampus region of NMC-treated mice groups. Furthermore, SWM, PYM, EPM, and BB behavioral analysis indicated that NMC enhanced spatial learning, memory consolidation and improved balance performance. Altogether, to the best of our knowledge, we believe that NMC may serve as a potential and promising anti-cholinesterase, antioxidant and neuroprotective agent against AD.

Fungal-bacterial interaction selects for quorum sensing mutants with increased production of natural antifungal compounds

Soil microorganisms coexist and interact showing antagonistic or mutualistic behaviors. Here, we show that an environmental strain of Bacillus subtilis undergoes heritable phenotypic variation upon interaction with the soil fungal pathogen Setophoma terrestris (ST). Metabolomics analysis revealed differential profiles in B. subtilis before (pre-ST) and after (post-ST) interacting with the fungus, which paradoxically involved the absence of lipopeptides surfactin and plipastatin and yet acquisition of antifungal activity in post-ST variants. The profile of volatile compounds showed that 2-heptanone and 2-octanone were the most discriminating metabolites present at higher concentrations in post-ST during the interaction process. Both ketones showed strong antifungal activity, which was lost with the addition of exogenous surfactin. Whole-genome analyses indicate that mutations in ComQPXA quorum-sensing system, constituted the genetic bases of post-ST conversion, which rewired B. subtilis metabolism towards the depletion of surfactins and the production of antifungal compounds during its antagonistic interaction with S. terrestris.

Discovery of Ketone-Based Covalent Inhibitors of Coronavirus 3CL Proteases for the Potential Therapeutic Treatment of COVID-19

The novel coronavirus disease COVID-19 that emerged in 2019 is caused by the virus SARS CoV-2 and named for its close genetic similarity to SARS CoV-1 that caused severe acute respiratory syndrome (SARS) in 2002. Both SARS coronavirus genomes encode two overlapping large polyproteins, which are cleaved at specific sites by a 3C-like cysteine protease (3CLpro) in a post-translational processing step that is critical for coronavirus replication. The 3CLpro sequences for CoV-1 and CoV-2 viruses are 100% identical in the catalytic domain that carries out protein cleavage. A research effort that focused on the discovery of reversible and irreversible ketone-based inhibitors of SARS CoV-1 3CLpro employing ligand-protease structures solved by X-ray crystallography led to the identification of 3 and 4. Preclinical experiments reveal 4 (PF-00835231) as a potent inhibitor of CoV-2 3CLpro with suitable pharmaceutical properties to warrant further development as an intravenous treatment for COVID-19.

Efficacy and safety evaluation of eribulin-trastuzumab combination therapy with heavily pretreated HER2-positive metastatic breast cancer

PURPOSE

Eribulin mesylate is a non-taxane microtubule inhibitor which is a synthetic holichondrin B analog that can be used after anthracycline and taxane treatment in patients with metastatic breast cancer. We aimed to analyze the results of eribulin-trastuzumab combination in aggressively pretreated metastatic HER2-positive breast cancer patients.

METHODS

In this single-center study, the records of 36 patients with HER-2-positive metastatic breast cancer who received at least one cycle of eribulin-trastuzumab in our clinic between 2015 and 2018 were analyzed retrospectively. Kaplan-Meier survival analysis was used for progression-free survival (PFS), and overall survival (OS) analyzes. Two-sided p values <0.05 were considered statistically significant.

RESULTS

A total of 36 patients with metastatic breast cancer were eligible and included in this study. The median age of the patients was 41 years (range 20-60). Most patients were heavily pretreated with a median of 5 (range 3-8) previous chemotherapy lines before eribulin. At the end of the follow up period (February 2018) all patients received a median of 5.5 cycles of eribulin-trastuzumab. Partial response (PR) was achieved in 9 patients (25%) and stable disease (SD) in 17 patients (47%). Median PFS was 4 months (95% CI: 3.8-6.1), and median OS was 10 months (95% CI: 7.5-12.4). The most common adverse events were grade 1-2 anemia (n=12, 33%), neutropenia (n=12, 33%) and grade 3-4 neuropathy (n=4, 11.1%).

CONCLUSION

Eribulin-trastuzumab combination is an effective and safe treatment option with a low toxicity profile for aggressively pre-treated patients with metastatic breast cancer.

MXene-Based Hydrogels Endow Polyetheretherketone with Effective Osteogenicity and Combined Treatment of Osteosarcoma and Bacterial Infection

After an osteosarcoma resection, the risks of cancer recurrence, postoperative infection, and large bone loss still threaten patients' health. Conventional treatment relies on implanting orthopedic materials to fill bone defects after surgery, but it has no ability of destroying residual tumor cells and preventing bacterial invasion. To tackle this challenge, here, we develop a novel multifunctional implant (SP@MX/GelMA) that mainly consists of MXene nanosheets, gelatin methacrylate (GelMA) hydrogels, and bioinert sulfonated polyetheretherketone (SP) with the purpose of facilitating tumor cell death, combating pathogenic bacteria, and promoting osteogenicity. Because of the synergistic photothermal effects of MXene and polydopamine (pDA), osteosarcoma cells are effectively killed on the multifunctional coatings under 808 nm near-infrared (NIR) irradiation through thermal ablation. After loading tobramycin (TOB), the SP@MX-TOB/GelMA implants display robust antibacterial properties against Gram-negative/Gram-positive bacteria. More importantly, the multifunctional implants are demonstrated to have superior cytocompatibility and osteogenesis-promoting capability in terms of cell replication, spreading, alkaline phosphatase activity, calcium matrix mineralization, and in vivo osseointegration. Accordingly, such photothermally controlled multifunctional implants not only defeat osteosarcoma cells and bacteria but also intensify osteogenicity, which hold a greatly promising countermeasure for curing postoperative tissue lesion from an osteosarcoma excision.

Safety and Tolerability of Stromal Vascular Fraction Combined with β-Tricalcium Phosphate in Posterior Lumbar Interbody Fusion: Phase I Clinical Trial

The rates of pseudarthrosis remain high despite recent advances in bone graft substitutes for spinal fusion surgery. The aim of this single center, non-randomized, open-label clinical trial was to determine the feasibility of combined use of stromal vascular fraction (SVF) and β-tricalcium phosphate (β-TCP) for patients who require posterior lumbar interbody fusion (PLIF) and pedicle screw fixation. Two polyetheretherketone (PEEK) cages were inserted into the intervertebral space following complete removal of the intervertebral disc. The PEEK cage (SVF group) on the right side of the patient was filled with β-TCP in combination with SVF, and the cage on the left side (control group) was filled with β-TCP alone. Fusion rate and cage subsidence were assessed by lumbar spine X-ray and CT at 6 and 12 months postoperatively. At the 6-month follow-up, 54.5% of the SVF group (right-sided cages) and 18.2% of the control group (left-sided cages) had radiologic evidence of bone fusion (p = 0.151). The 12-month fusion rate of the right-sided cages was 100%, while that of the left-sided cages was 91.6% (p = 0.755). Cage subsidence was not observed. Perioperative combined use of SVF with β-TCP is feasible and safe in patients who require spinal fusion surgery, and it has the potential to increase the early bone fusion rate following spinal fusion surgery.

β-Diketonate versus β-Ketoiminate: The Importance of a Ferrocenyl Moiety in Improving the Anticancer Potency

Herein we present a library of fully characterized β-diketonate and β-ketoiminate compounds that are functionalized with a ferrocenyl moiety. Their cytotoxic potential has been determined by screening against human breast adenocarcinomas (MCF-7 and MDA-MB-231), human colorectal carcinoma p53 wild type (HCT116 p53+/+ ) and normal human prostate (PNT2) cell lines. The ferrocenyl β-diketonate compounds are more than 18 times more cytotoxic than the ferrocenyl β-ketoiminate analogues. Against MCF-7, compounds functionalized at the meta position are up to nine times more cytotoxic than when functionalized at the para position. The ferrocenyl β-diketonate compounds have increased selectivity towards MCF-7 and MDA-MB-231, with several complexes having selectivity index (SI) values that are more than nine times (MCF-7) and more than six times (MDA-MB-231) that of carboplatin. The stability of these compounds in dimethyl sulfoxide (DMSO) and dimethylformamide (DMF) has been assessed by NMR spectroscopy and mass spectrometry studies, and the compounds show no oxidation of the iron center from FeII to FeIII . Cytotoxicity screening was performed in both DMSO and DMF, with no significant differences observedin their potency.

The Cocultured Nigrospora oryzae and Collectotrichum gloeosporioides, Irpex lacteus, and the Plant Host Dendrobium officinale Bidirectionally Regulate the Production of Phytotoxins by Anti-phytopathogenic Metabolites

The distinctive nature of the endophyte Irpex lacteus, host plant, and the phytopathogen Collectotrichum gloeosporioides resulted in both negative and positive regulation of the production of phytotoxins from Nigrospora oryzae. The coculture of nonhomologous I. lacteus and N. oryzae resulted in a greater number of anti-phytopathogenic metabolites from the dominant endophyte than the coculture of homologous I. lacteus and N. oryzae. The coculture of the phytopathogen N. oryzae and either the nonhomologous (isolation of I. lacteus and N. oryzae from the different plants) or homologous (isolation of I. lacteus and N. oryzae from the same plant) endophyte I. lacteus from different sources indicated that the nonhomologous I. lacteus grew faster than the homologous I. lacteus, and the production of phytotoxic azaphilone from the phytopathogenic N. oryzae decreased due to the inhibition resulting from being cocultured with nonhomologous I. lacteus. On the other hand, the production of phytotoxic azaphilone was promoted by the coculture of two phytopathogens, N. oryzae and C. gloeosporioides. The extract of the host plant, Dendrobium officinale, also increased anti-phytopathogenic metabolite production. Six new phytotoxic azaphilones from N. oryzae, four new tremulane sesquiterpenes from I. lacteus, and a new polyketone were isolated. The endophyte-phytopathogen, phytopathogen-phytopathogen, and endophyte-phytopathogen-host interactions can induce the chemical diversity of novel anti-phytopathogenic metabolites.

Enhanced bioactivity and osteogenic property of carbon fiber reinforced polyetheretherketone composites modified with amino groups

Polyetheretherketone (PEEK) is considered as a potential dental and orthopedic implant material owing to its favorable thermal and chemical stability, biocompatibility and mechanical properties. However, the inherent bio-inert and inferior osseointegration of PEEK have hampered its clinical application. In addition, carbon fiber is widely used as a filler to reinforce polymers for sturdy composites owing to its high strength, modulus, etc. In the study, carbon fiber reinforced PEEK (CPEEK) composites were fabricated and modified with amino groups by plasma-enhanced chemical vapor deposition surface modification technique. The surface characterization of composites was evaluated by FE-SEM, EDS, AFM, Water contact angle, XPS and FTIR, which revealed that amino groups were successfully incorporated on the modified CPEEK surface and significantly increased the hydrophilicity. In vitro study, cell adhesion, proliferation, ALP activity, ECM mineralization, real-time PCR analysis, and ELISA analysis showed the adhesion, proliferation and osteogenic differentiation of MG-63 cells on the amino group-modified CPEEK surface were higher than the CPEEK, equal to or better than pure titanium. Hence, the results indicated that the amino group-modified CPEEK possessed enhanced bioactivity and osteogenic property, which may be a potential candidate material for dental implants.

Is eribulin treatment prognostic factor in patients with metastatic breast cancer treated with this drug? Retrospective analysis of a multicentre study

PURPOSE

This study aimed to analyze prognostic factors for survival and the reliability and the effectiveness of eribulin therapy in metastatic breast cancer (MBC) patients.

METHODS

A total of 80 patients treated with eribulin in 12 medical oncology centers in Turkey between 2013-2017 were retrospectively evaluated. Sixteen potential prognostic variables were assessed for analysis.

RESULTS

The patients had received a median of 5 prior chemotherapy regimens and a median of 3 eribulin cycles for MBC. Median progression-free survival (PFS) was 5.5 months (95% Cl: 4.1-7.8) and median overall survival (OS) was 11 months (95 % Cl: 6-15). Multivariate analysis showed that eribulin treatment line was shown to have independent prognostic significance for PFS. PFS difference was demostrated in patients who received 3 chemotherapy lines for advanced disease compared to those who had more than 3 chemotherapy lines [median PFS; 3 lines: 8.6 months (6.2-11) and ˃3 lines: 4.6 months (3.7-4.6) p=0.00]. The clinical benefit rate (CBR) was 52.5 and 35% in patients treated with three lines and with ˃3 previous chemotherapeutic regimens. Most common toxicities were neutropenia (62.5%), fatigue (52.5%), alopecia (50%) and nausea (37.5%).

CONCLUSIONS

Eribulin treatment line was identified as indepedent prognostic factor for PFS in MBC patients.

Enhanced Osseointegration Capability of Poly(ether ether ketone) via Combined Phosphate and Calcium Surface-Functionalization

Biomedical applications of poly(ether ether ketone) (PEEK) are hindered by its inherent bioinertness and lack of osseointegration capability. In the present study, to enhance osteogenic activity and, hence, the osseointegration capability of PEEK, we proposed a strategy of combined phosphate and calcium surface-functionalization, in which ozone-gas treatment and wet chemistry were used for introduction of hydroxyl groups and modification of phosphate and/or calcium, respectively. Surface functionalization significantly elevated the surface hydrophilicity without changing the surface roughness or topography. The cell study demonstrated that immobilization of phosphate or calcium increased the osteogenesis of rat mesenchymal stem cells compared with bare PEEK, including cell proliferation, alkaline phosphatase activity, and bone-like nodule formation. Interestingly, further enhancement was observed for samples co-immobilized with phosphate and calcium. Furthermore, in the animal study, phosphate and calcium co-functionalized PEEK demonstrated significantly enhanced osseointegration, as revealed by a greater direct bone-to-implant contact ratio and bond strength between the bone and implant than unfunctionalized and phosphate-functionalized PEEK, which paves the way for the orthopedic and dental application of PEEK.

Surface sulfonation and nitrification enhance the biological activity and osteogenesis of polyetheretherketone by forming an irregular nano-porous monolayer

Polyether-ether-ketone (PEEK) is becoming a popular component of clinical spinal and orthopedic applications, but its practical use suffers from several limitations. In this study, irregular nano-porous monolayer with differently functional groups was formed on the surface of PEEK through sulfonation and nitrification. The surface characteristics were detected by field-emission scanning electron microscopy, atomic force microscopy, energy-dispersive X-ray spectrometry, water contact angle measurements and Fourier transform infrared spectroscopy. In vitro cellular behaviors were evaluated by cell adhesion, morphological changes, proliferation, alkalinity, phosphatase activity, real-time RT-PCR and western blot analyses. In vivo osseointegration was examined through micro-CT and histological assessments. Our results reveal that the irregular nano-porous of PEEK affect the biological properties. High-temperature hydrothermal NP treatment induced early osteogenic differentiation and early osteogenesis. Modification by sulfonation and nitrification can broaden the use of PEEK in orthopedic and dental applications. This study provides a theoretical basis for the wider clinical application of PEEK. a To obtain a uniform porous structure, PEEK samples were treated by concentrated sulfuric acid and fuming nitric acid (82-80%) with magnetic stirring sequentially. b Effects of nanopores on biological behavior of bMSCS.

Ketalization of 2-heptanone to prolong its activity as mite repellant for the protection of honey bees

BACKGROUND

2-Heptanone is a volatile liquid known to be effective in protecting honey bees from parasitic mite infestations in hives. The present study aimed to show that chemical derivatives of 2-heptanone would release the ketone for a significantly longer time than it takes for the pure ketone to evaporate and preferably for as long as two brood cycles of a honey bee (42 days).

RESULTS

A liquid ketal of 2-heptanone with glycerol (Glyc-Ket) and solid ketals of the ketone with polyvinyl alcohol (PVAl-Ket), containing different amounts of the ketone, were synthesized. The fully resolved ¹ H and ¹³ C nuclear magenetic resonance (NMR) spectra of the ketals are discussed. In the case of the polymer, differential scanning calorimetry (DSC) of a ketal was also compared with the unketalized polyvinyl alcohol. The length of time for which 2-heptanone was released by the ketals was determined by gas chromatography-mass spectrometry of the headspace. In the case of Glyc-Ket, the concentration of the 2-heptanone in the liquid phase was also monitored by ¹ H NMR spectroscopy. The deketalization was pH dependent, ranging between 2.0 and 2.5 for Glyc-Ket and between 2.0 and 3.5 for PVAl-Ket.

CONCLUSION

Under bee hive conditions, the release of 55 mmol 2-heptanone from Glyc-Ket lasted for 42 days, whereas the release of the ketone from the PVAl-Ket with a similar amount of the ketone lasted for 23 days, versus a maximum of 17 days for an equivalent amount of the pure ketone. These ketals therefore have the potential to be effective mite repellants for the protection of honey bees. © 2019 Society of Chemical Industry.

Discovery of N-Aroyl Diketone/Triketone Derivatives as Novel 4-Hydroxyphenylpyruvate Dioxygenase Inhibiting-Based Herbicides

4-Hydroxyphenylpyruvate dioxygenase (HPPD, EC 1.13.11.27) is an important target site for discovering new bleaching herbicides. To explore novel HPPD inhibitors with excellent herbicidal activity, a series of novel N-aroyl diketone/triketone derivatives were rationally designed by splicing active groups and bioisosterism. Bioassays revealed that most of these derivatives displayed preferable herbicidal activity against Echinochloa crus-galli (EC) at 0.045 mmol/m² and Abutilon juncea (AJ) at 0.090 mmol/m². In particular, compound I-f was more potent compared to the commercialized compound mesotrione. Molecular docking indicated that the corresponding active molecules of target compounds and mesotrione shared similar interplay with surrounding residues, which led to a perfect interaction with the active site of Arabidopsis thaliana HPPD.

A Nature-Inspired Design Yields a New Class of Steroids Against Trypanosomatids

Chagas disease and Leishmaniasis are neglected endemic protozoan diseases recognized as public health problems by the World Health Organization. These diseases affect millions of people around the world however, efficient and low-cost treatments are not available. Different steroid molecules with antimicrobial and antiparasitic activity were isolated from diverse organisms (ticks, plants, fungi). These molecules have complex structures that make de novo synthesis extremely difficult. In this work, we designed new and simpler compounds with antiparasitic potential inspired in natural steroids and synthesized a series of nineteen steroidal arylideneketones and thiazolidenehydrazines. We explored their biological activity against Leishmania infantum, Leishmania amazonensis, and Trypanosoma cruzi in vitro and in vivo. We also assayed their genotoxicity and acute toxicity in vitro and in mice. The best compound, a steroidal thiosemicarbazone compound 8 (ID_1260) was active in vitro (IC₅₀ 200 nM) and in vivo (60% infection reduction at 50 mg/kg) in Leishmania and T. cruzi. It also has low toxicity in vitro and in vivo (LD₅₀ >2000 mg/kg) and no genotoxic effects, being a promising compound for anti-trypanosomatid drug development.

Design, synthesis and biological evaluation of new steroidal β-triazoly enones as potent antiproliferative agents

β-Triazoly enones are biologically interesting scaffolds, incorporation of such scaffolds into the steroid nucleus may generate new bioactive steroids and further enrich structural types of steroids. In this work, a series of new steroidal β-triazoly enones were synthesized based on click chemistry and Claisen-Schmidt condensation reaction and further evaluated for their antiproliferative activity against a panel of cancer cells. Most of these compounds showed better potency against PC-3 and MGC-803 cells. Particularly, compound 5a inhibited PC-3 and MGC-803 cells potently with the IC₅₀ values of 1.61 and 1.16 μM, respectively, and was less toxic toward GES-1 with an IC₅₀ value of 20.72 μM. Further mechanistic studies showed that compound 5a inhibited migration and invasion of MGC-803 and PC-3 dose-dependently. Treatment with compound 5a varied mRNA levels and protein expression of EMT markers in both cells. Collectively, the steroidal β-triazoly enones could be potentially utilized to develop new anticancer agents with the ability of inhibiting cell migration and invasion.

Phenolic acid phenethylesters and their corresponding ketones: Inhibition of 5-lipoxygenase and stability in human blood and HepaRG cells

5-lipoxygenase (5-LO) catalyzes the biosynthesis of leukotrienes, potent lipid mediators involved in inflammatory diseases, and both 5-LO and the leukotrienes are validated therapeutic targets. Caffeic acid phenethyl ester (CAPE) is an effective inhibitor of 5-LO and leukotriene biosynthesis but is susceptible to hydrolysis by esterases. In this study a number of CAPE analogues were synthesized with modifications to the caffeoyl moiety and the replacement of the ester linkage with a ketone. Several new molecules showed better inhibition of leukotriene biosynthesis than CAPE in isolated human neutrophils and in whole blood with IC50 values in the nanomolar (290-520 nmol/L) and low micromolar (1.0-2.3 µmol/L) ranges, respectively. Sinapic acid and 2,5-dihydroxy derivatives were more stable than CAPE in whole blood, and ketone analogues were degraded more slowly in HepaRG hepatocyte cultures than esters. All compounds underwent modification consistent with glucuronidation in HepaRG cultures as determined using LC-MS/MS analysis, though the modified sinapoyl ketone (10) retained 50% of its inhibitory activity after up to one hour of incubation. This study has identified at least one CAPE analogue, compound 10, that shows favorable properties that warrant further in vivo investigation as an antiinflammatory compound.

Serum microRNA-based prediction of responsiveness to eribulin in metastatic breast cancer

The identification of biomarkers for predicting the responsiveness to eribulin in patients with metastatic breast cancer pretreated with an anthracycline and a taxane remains an unmet need. Here, we established a serum microRNA (miRNA)-based prediction model for the emergence of new distant metastases after eribulin treatment. Serum samples were collected from metastatic breast cancer patients prior to eribulin treatment and comprehensively evaluated by miRNA microarray. The prediction model for estimating eribulin efficacy was established using the logistic LASSO regression model. Serum samples were collected from 147 patients, of which 52 developed at least one new distant metastasis after eribulin monotherapy and 95 did not develop new distant metastases. A combination of eight serum miRNAs (miR-4483, miR-8089, miR-4755-3p, miR-296-3p, miR-575, miR-4710, miR-5698 and miR-3160-5p) predicted the appearance of new distant metastases with an area under the curve of 0.79, sensitivity of 0.69 and specificity of 0.82. The serum levels of miR-8089 and miR-5698 were significantly associated with overall survival after the initiation of eribulin treatment. The present study provides evidence that serum miRNA profiling may serve as a biomarker for the responsiveness to eribulin and for predicting the development of new distant metastases in metastatic breast cancer.

A novel fluorescent probe for the early detection of prostate cancer based on endogenous zinc sensing

BACKGROUND

The early detection of prostate cancer can significantly optimize the prognosis, prolong patient lifespan, and improve quality of life. It has been well documented that prostate cancer tissues have lower zinc content than normal prostate tissues due to an impairment of the zinc accumulation mechanism.

METHODS

A novel diketopyrrolopyrrole (DPP)-based fluorescent zinc ion probe named DPP-C2 was prepared. The fluorescent intensity of this novel molecule is in direct proportion to environmental zinc concentration. Malignant (DU145 and PC3 cells) and normal prostate epithelial RWPE-1 cells were tested. Prostate cancer tissues were also cultured and observed as tissue sections. The probe was also intravenously administered to tumor-bearing (DU145 and PC3 cells) nude mice and observed under a whole-body fluorescence live-imaging system.

RESULTS

The probe showed minimal cytotoxicity to malignant and normal prostate cells. The RWPE-1 cells showed not only stronger baseline fluorescence but also a significant increase in signal intensity after culturing in a zinc-supplemented medium. In human prostate sections, the pathologically confirmed cancer tissues exhibited weaker fluorescence signals than normal and benign hyperplastic tissues. With proper excitation, prostate tissues revealed more intense fluorescence signals than tumor tissues, whereas other surrounding tissues showed almost no fluorescence.

CONCLUSIONS

The novel zinc ion fluorescent probe DPP-C2 is low toxic and showed potential application for the early detection of prostate cancer based on endogenous zinc sensing.

Eribulin Synergistically Increases Anti-Tumor Activity of an mTOR Inhibitor by Inhibiting pAKT/pS6K/pS6 in Triple Negative Breast Cancer

Unlike other breast cancer subtypes, patients with triple negative breast cancer (TNBC) have poor outcomes and no effective targeted therapies, leaving an unmet need for therapeutic targets. Efforts to profile these tumors have revealed the PI3K/AKT/mTOR pathway as a potential target. Activation of this pathway also contributes to resistance to anti-cancer agents, including microtubule-targeting agents. Eribulin is one such microtubule-targeting agent that is beneficial in treating taxane and anthracycline refractory breast cancer. In this study, we compared the effect of eribulin on the PI3K/AKT/mTOR pathway with other microtubule-targeting agents in TNBC. We found that the phosphorylation of AKT was suppressed by eribulin, a microtubule depolymerizing agent, but activated by paclitaxel, a microtubule stabilizing agent. The combination of eribulin and everolimus, an mTOR inhibitor, resulted in an increased reduction of p-S6K1 and p-S6, a synergistic inhibition of cell survival in vitro, and an enhanced suppression of tumor growth in two orthotopic mouse models. These findings provide a preclinical foundation for targeting both the microtubule cytoskeleton and the PI3K/AKT/mTOR pathway in the treatment of refractory TNBC.