Identification of potential edible mushroom as SARS-CoV-2 main protease inhibitor using rational drug designing approach.

Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) is highly pathogenic to humans and has created health care threats worldwide. This urgent situation has focused the researchers worldwide towards the development of novel vaccine or small molecule therapeutics for SARS-CoV-2. Although several vaccines have already been discovered and are in use for the masses, no therapeutic medication has yet been approved by FDA for the treatment of COVID-19. Keeping this in view, in the present study, we have identified promising hits against the main protease (Mpro) of SARS-CoV-2 from edible mushrooms. Structure-based virtual screening (VS) of 2433 compounds derived from mushrooms was performed with Mpro protein (6LU7). Four promising hits, namely, Kynapcin-12 (M_78), Kynapcin-28 (M_82), Kynapcin-24 (M_83), and Neonambiterphenyls-A (M_366) were identified based on the result of docking, Lipinski's rule, 100 ns molecular dynamics (MD) simulation and MM/PBSA binding free energy calculations. Finally, the inhibitory properties of these hits were compared with three known inhibitors, baicalein (1), baicalin (2), and biflavonoid (3). Data indicated that M_78, M_82 and M_83 compounds present in edible mushroom Polyozellus multiplex were potent inhibitors of Mproprotein (6LU7). It could be concluded that edible mushroom Polyozellus multiplex has potential activity against SARS-CoV-2 infection and identified molecules could be further explored as therapeutic inhibitors against SARS-CoV-2.

HDAC6 inhibitor WT161 performs anti-tumor effect on osteosarcoma and synergistically interacts with 5-FU.

BACKGROUND: WT161, as a selective HDAC6 inhibitor, has been shown to play anti-tumor effects on several kinds of cancers. The aim of the present study is to explore the roles of WT161 in osteosarcoma and its underlying mechanisms. METHODS: The anti-proliferative effect of WT161 on osteosarcoma cells was examined using MTT assay and colony formation assay. Cell apoptosis was analyzed using flow cytometer. The synergistic effect was evaluated by isobologram analysis using CompuSyn software. The osteosarcoma xenograft models were established to evaluate the anti-proliferative effect of WT161 in vivo. RESULTS: WT161 suppressed the cell growth and induced apoptosis of osteosarcoma cells in a dose- and time-dependent manner. Mechanistically, we found that WT161 treatment obviously increased the protein level of PTEN and decreased the phosphorylation level of protein kinase-B (AKT). More importantly, WT161 showed synergistic inhibition with 5-FU on osteosarcoma cells in vitro and in vivo. CONCLUSIONS: These results indicate that WT161 inhibits the growth of osteosarcoma through PTEN and has a synergistic efficiency with 5-FU.

Highly Stable Organic Small Molecular Nanoparticles as an Advanced and Biocompatible Phototheranostic Agent of Tumor in Living Mice.

Near-infrared (NIR)-absorbing organic small molecules hold great promise as the phototheranostic agents for clinical translation by virtue of their intrinsic advantages such as well-defined chemical structure, high purity, and good reproducibility. However, most of the currently available ones face the challenges in varying degrees in terms of photothermal instability, and photobleaching/reactive oxygen nitrogen species (RONS) inresistance, which indeed impair their practical applications in precise diagnosis and treatment of diseases. Herein, we developed highly stable and biocompatible organic nanoparticles (ONPs) for effective phototheranostic application by design and synthesis of an organic small molecule (namely TPA-T-TQ) with intensive absorption in the NIR window. The TPA-T-TQ ONPs with no noticeable in vivo toxicity possess better capacities in photothermal conversion and photoacoustic imaging (PAI), as well as show far higher stabilities including thermal/photothermal stabilities, and photobleaching/RONS resistances, when compared with the clinically popularly used indocyanine green. Thanks to the combined merits, the ONPs can serve as an efficient probe for in vivo PAI in a high-contrast manner, which also significantly causes the stoppage of tumor growth in living mice through PAI-guided photothermal therapy. This study thus provides an insight into the development of advanced NIR-absorbing small molecules for practical phototheranostic applications.

3-Hydroxyterphenyllin, a natural fungal metabolite, induces apoptosis and S phase arrest in human ovarian carcinoma cells.

In the present study, we evaluated 3-Hydroxyter-phenyllin (3-HT) as a potential anticancer agent using the human ovarian cancer cells A2780/CP70 and OVCAR-3, and normal human epithelial ovarian cells IOSE-364 as an in vitro model. 3-HT suppressed proliferation and caused cytotoxicity against A2780/CP70 and OVCAR-3 cells, while it exhibited lower cytotoxicity in IOSE-364 cells. Subsequently, we found that 3-HT induced S phase arrest and apoptosis in a dose-independent manner. Further investigation revealed that S phase arrest was related with DNA damage which mediated the ATM/p53/Chk2 pathway. Downregulation of cyclin D1, cyclin A2, cyclin E1, CDK2, CDK4 and Cdc25C, and the upregulation of Cdc25A and cyclin B1 led to the accumulation of cells in S phase. The apoptotic effect was confirmed by Hoechst 33342 staining, depolarization of mitochondrial membrane potential and activation of cleaved caspase-3 and PARP1. Additional results revealed both intrinsic and extrinsic apoptotic pathways were involved. The intrinsic apoptotic pathway was activated through decreasing the protein levels of Bcl2, Bcl-xL and procaspase-9 and increasing the protein level of Puma. The induction of DR5 and DR4 indicated that the extrinsic apoptotic pathway was also activated. Induction of ROS and activation of ERK were observed in ovarian cancer cells. We therefore concluded that 3-HT possessed anti-proliferative effect on A2780/CP70 and OVCAR-3 cells, induced S phase arrest and caused apoptosis. Taken together, we propose that 3-HT shows promise as a therapeutic candidate for treating ovarian cancer.

Discovery of selective small-molecule HDAC6 inhibitor for overcoming proteasome inhibitor resistance in multiple myeloma.

Multiple myeloma (MM) has proven clinically susceptible to modulation of pathways of protein homeostasis. Blockade of proteasomal degradation of polyubiquitinated misfolded proteins by the proteasome inhibitor bortezomib (BTZ) achieves responses and prolongs survival in MM, but long-term treatment with BTZ leads to drug-resistant relapse in most patients. In a proof-of-concept study, we previously demonstrated that blocking aggresomal breakdown of polyubiquitinated misfolded proteins with the histone deacetylase 6 (HDAC6) inhibitor tubacin enhances BTZ-induced cytotoxicity in MM cells in vitro. However, these foundational studies were limited by the pharmacologic liabilities of tubacin as a chemical probe with only in vitro utility. Emerging from a focused library synthesis, a potent, selective, and bioavailable HDAC6 inhibitor, WT161, was created to study the mechanism of action of HDAC6 inhibition in MM alone and in combination with BTZ. WT161 in combination with BTZ triggers significant accumulation of polyubiquitinated proteins and cell stress, followed by caspase activation and apoptosis. More importantly, this combination treatment was effective in BTZ-resistant cells and in the presence of bone marrow stromal cells, which have been shown to mediate MM cell drug resistance. The activity of WT161 was confirmed in our human MM cell xenograft mouse model and established the framework for clinical trials of the combination treatment to improve patient outcomes in MM.

Novel diamidines with activity against Babesia divergens in vitro and Babesia microti in vivo.

Dicationic diamidines, such as diminazene and pentamidine, are well-studied chemotherapeutic agents with significant activity against parasitic diseases. The in vitro activities of novel diamidine compounds against the Babesia divergens strains 1903B and 4201 were investigated. The most potent compound, a diphenyl furan, had a 50% inhibitory concentration (IC(50)) of 1.5 ng/ml. In a murine model, several test compounds were effective enough to cure mice infected with Babesia microti at a dose of 12.5 and/or 25 mg/kg of body weight given by the subcutaneous route for 4 days. The best antibabesial properties were exhibited by terphenyls, benzimidazoles, diphenyl furans, pentamidine, and pentamidine analogues.

In vitro chemopreventive potential of fucophlorethols from the brown alga Fucus vesiculosus L. by anti-oxidant activity and inhibition of selected cytochrome P450 enzymes.

Within a project focusing on the chemopreventive potential of algal phenols, two phloroglucinol derivatives, belonging to the class of fucophlorethols, and the known fucotriphlorethol A were obtained from the ethanolic extract of the brown alga Fucus vesiculosus L. The compounds trifucodiphlorethol A and trifucotriphlorethol A are composed of six and seven units of phloroglucinol, respectively. The compounds were examined for their cancer chemopreventive potential, in comparison with the monomer phloroglucinol. Trifucodiphlorethol A, trifucotriphlorethol A as well as fucotriphlorethol A were identified as strong radical scavengers, with IC(50) values for scavenging of 1,1-diphenyl-2 picrylhydrazyl radicals (DPPH) in the range of 10.0-14.4 microg/ml. All three compounds potently scavenged peroxyl radicals in the oxygen radical absorbance capacity (ORAC) assay. In addition, the compounds were shown to inhibit cytochrome P450 1A activity with IC(50) values in the range of 17.9-33 microg/ml, and aromatase (Cyp19) activity with IC(50) values in the range of 1.2-5.6 microg/ml.

Antithrombotic effects of 3-([1:1',2':1"]-3'-terphenyl)propanol in animals.

3-([1:1',2':1"]-3'-Terphenyl)propanol (CAS 186835-06-3, F050) and acetylsalicylic acid (ASA) inhibited platelet aggregation induced by CaCl2, arachidonic acid, collagen, adenosine diphosphate (ADP) and thrombin in guinea pigs, rabbits and rats in vitro. However, F050 had a wider spectrum of actions than ASA. Orally administered F050 inhibited platelet aggregation ex vivo. F050 significantly reduced the thrombus formation in the extracorporeal circulation thrombosis model in guinea pigs. It inhibited erythrocyte hemolysis induced by hypotonic NaCl, while ASA did not. F050, but not ASA, inhibited increases in platelet [CA2+]i caused by thrombin in guinea pigs. F050 is a parent compound that will facilitate the development of an orally active drug for the treatment of thrombotic diseases.

Antithrombotic effects of the novel inhibitor of thrombin-induced offtelet aggregation and thrombus formation, 3-[2-[1,1':2',1"]-terphenyl-4'-yl)ethyl]phenoxyacetic acid.

The new compound 3-[2-([1,1':2,1"]-terphenyl-4'yl)ethyl]phenoxyacetic acid (F1070) was synthesized and its effects on platelet aggregation induced by thrombin, thrombin receptor agonist peptide (TRAP), ADP and collagen were evaluated in humans, guinea pigs and rats, and were compared with the effects of he thrombin antagonists argipidine and (D)Phe-Pro-Arg-CH2Cl (FPR). F1070 inhibited the platelet aggregation induced by these agonists and was highly selective in its inhibition of thrombin. F1070 inhibited fibrin formation induced by thrombin, but far less effectively than argipidine. In a guinea pig model of extracorporeal circulation thrombosis, F1070 (10 mg/kg p.o.) significantly inhibited the development of a thrombus. F1070 is thus a key compound that should facilitate the development of new orally active antithrombotic drugs that are specific for thrombin.

Novel terphenyls as selective cyclooxygenase-2 inhibitors and orally active anti-inflammatory agents.

A novel series of terphenyl methyl sulfones and sulfonamides have been shown to be highly potent and selective cyclooxygenase-2 (COX-2) inhibitors. The sulfonamide analogs 17 and 21 were found to be much more potent COX-2 inhibitors and orally active anti-inflammatory agents than the corresponding methyl sulfone analogs 16 and 20, respectively, albeit with some decrease in COX-2 selectivity. Structure-activity relationship studies have determined that incorporation of two fluorine atoms in the central phenyl group, as in 20 and 21, is extremely advantageous for both in vitro COX-2 potency and selectivity as well as in vivo activity. Several noticeable examples in the 1,2-diaryl-4,5-difluorobenzenesulfonamide series are 21a-c,k,l,n (COX-2, IC50 = 0.002-0.004 microM), in which all have in vitro COX-1/COX-2 selectivity > 1000. In addition, sulfonamides 21a,b,d,g,j,m,n,q were shown to have greatly enhanced oral activity with more than 90% inhibition of prostaglandin E2 production in the air pouch model of inflammation. Furthermore, sulfonamide 21b was found to be very active in the rat adjuvant-induced arthritis model (ED50 = 0.05 mg/kg) and carrageenan-induced hyperalgesia assay (ED50 = 38.7 mg/kg) with no indication of gastrointestinal toxicity in rats at doses as high as 200 mg/kg.

Acetoxy-substituted 1,1,2-triphenylbut-1-enes with antiestrogenic and mammary tumor inhibiting properties.

1,1,2-Triphenylbut-1-enes (E- and Z-10-12), which are substituted with one p- and one m-acetoxy group in two different aromatic rings, were synthesized. The E and Z isomers were isolated, and their identity was established by 1H NMR spectroscopy. A study of the structure-activity relationship was carried out with regard to estradiol receptor affinity in vitro, estrogenic and antiestrogenic properties (mouse), inhibition of the hormone-dependent human MCF7 breast cancer cell line in vitro, and the hormone-dependent MXT mammary tumor of the mouse in vivo. Among the tested compounds, (E)- and (Z)-1-(3-acetoxyphenyl)-1-(4-acetoxyphenyl)-2-phenylbut-1-enes+ ++ (E-10 and Z-10) and (Z)-1-(3-acetoxyphenyl)-1-phenyl-2-(4-acetoxyphenyl)-but-1-ene (Z-12) proved to be partial antiestrogens, which lead to an inhibition of the MCF7 cell line. They exert a growth-inhibiting activity on the hormone-dependent MXT mammary carcinoma of the mouse. In the case of E-10 and Z-10, this effect is only slightly weaker than that of 1,1-bis(4-acetoxyphenyl)-2-phenylbut-1-ene (13) and tamoxifen. Under the applied experimental conditions, there were no significant changes of uterine weight as an indicator of estrogenic side effects.

A new chemical series active against African trypanosomes: benzyltriphenylphosphonium salts.

Antitrypanosomal activity for benzyltriphenylphosphonium salts is reported for the first time. Testing was conducted using Trypanosoma rhodesiense infected mice. Of 70 phosphorus-containing compounds tested, 21 were active. Sixteen of these active chemical species were benzyltriphenylphosphonium salts. Four were nonbenzyl triphenyl compounds. The remaining active drug was a benzyldiphenylphosphonium salt.

Synthesis and antitumor properties of some isoindolylalkylphosphonium salts.

Antitumor evaluation of 2-(1,3-dihydro-1,3-dioxo-2H-isoindol-2-yl)ethyltriphenylphosphonium bromide (1) revealed significant activity in P-388 lymphocytic leukemia (T/C = 160%). As a follow-up to this chemical lead, a series of closely related phosphonium salts was prepared in which the 1,3-dihydro-1,3-dioxo-2H-isoindole ring system was maintained or in which it was replaced by other moieties such as maleimido, bromo, methoxy, and isoindoline. Syntheses generally involved treatment of the appropriate N-(bromoalkyl)phthalimide with the required phosphine or condensation of the K salt of the substituted imide with beta-(bromoethyl)triphenylphosphonium bromide (12). From the biological data obtained for these compounds, several requirements can be defined for substantial antileukemic activity. Of utmost importance is the presence of a triarylphosphonium halide moiety, coupled to an alkyl chain of two or three carbon atoms. The preferred terminus of the alkyl chain is the 1,3-dihydro-1,3-dioxo-2H-isoindole ring system, although the observed activity of beta-(bromoethyl)-triphenylphosphonium bromide (12) (T/C = 127%) would suggest that a superior carrier molecule could be developed.