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In order to discover novel Hsp90 inhibitors targeting the C-terminal ATP binding pocket, a novobiocin derivative based ROCS model was constructed for virtual screening. Compound 13 was identified as the lead compound and then systematical structure activity relationship (SAR) study was conducted. These efforts led to compound 69, which exhibited potent anti-proliferative activities against MCF7 and SKBr3 breast cancer cell lines. In 4T1 mice breast cancer models, 69 exhibited potent tumor growth inhibition and anti-metastasis effect. Compound 69 as a potent antitumor agent targeting the Hsp90 C-terminal is worthy of further pre-clinical study.

Multidrug resistance is considered as a major obstacle for effective tumour chemotherapy. With the ability to deliver drugs into tumour cells, microparticles may act as a drug delivery vehicle to overcome drug resistance. In the present study, we developed an approach employing daunorubicin-loaded microparticles to surmount the drug resistance in leukaemia. The microparticles, derived from the drug-sensitive cells K562 and the drug-resistant cells K562/ADR, composed of cellular material, can effectively package drugs using intracellular and extracellular drug-loading method, respectively. The results demonstrated that the microparticles significantly improved the drug anti-tumour effect, which was influenced by the preparation methods and the source of donor cells. We further confirmed that the uptake of microparticles is mediated by an energy-driven endocytic process and mainly associated with clathrin-independent endocytosis and macropinocytosis. These results indicated that the microparticle could serve as a promising drug vehicle for the treatment of drug-resistant leukaemia.

Heat shock protein 90 (Hsp90) as a molecular target for oncology therapeutics has attracted much attention in the last decade. The Hsp90 multichaperone complex has important roles in the growth and/or survival of cancer cells. Cdc37, as a cochaperone, associates kinase clients to Hsp90 and promotes the development of malignant tumors. Disrupting the Hsp90-Cdc37 interaction provides an alternative strategy to inhibit the function of Hsp90 for cancer therapy. Celastrol, as a natural product, can disrupt the Hsp90-Cdc37 interaction and induce degradation of kinase clients. The study conducted here attempted to elucidate the structure-activity relationship of celastrol derivatives as Hsp90-Cdc37 disruptors and to improve the druglike properties. 23 celastrol derivatives were designed, synthesized, and the biological activities and physicochemical properties were determined. The derivative CEL20 showed improved Hsp90-Cdc37 disruption activity, anti-proliferative activities as well as druglike properties. Additionally, CEL20 induced clients degradation, cell cycle arrest and apoptosis in Panc-1 cells. This study can provide reference for the discovery of novel Hsp90-Cdc37 disruptors.

RhoA has been implicated in diverse cellular functions and is a potential cancer therapeutic target. Through virtual screening, we have identified a RhoA inhibitor, DDO-5701. DDO-5701 has an affinity to RhoA at the micromolar level in vitro. By structural modifications, considering the binding activity and synthesis ease of DDO-5701, 17 compounds were designed and synthesized accordingly. Among these compounds, 4 compounds (DDO-5713, DDO-5714, DDO-5715, DDO-5716) exhibited higher RhoA inhibition activities than DDO-5701, while DDO-5716 can effectively reverse the functions of breast cancer cells regulated by RhoA. Thus, the rationally designed small molecule inhibitor of RhoA (DDO-5716) is useful for studying the physiological and pathological roles of Rho GTPase. However, DDO-5701 is an approved drug – proglumide, which makes it and its derived compound DDO-5716 more likely to be well tolerated in humans and could quickly lead to further clinical development.

The formation of brain vasculature is an essential step during central nervous system development. The molecular mechanism underlying brain angiogenesis remains incompletely understood. The role of Atg7, an autophagy-related protein, in brain angiogenesis was investigated in this study. We found that the microvessel density in mice brains with endothelial-specific knockout of Atg7 (Atg7 EKO) was significantly decreased compared to wild-type control. Consistently, in vitro angiogenesis assays showed that Atg7 knockdown impaired angiogenesis in brain microvascular endothelial cells. Further results indicated that knockdown of Atg7 reduced interleukin-6 (IL-6) expression in brain microvascular endothelial cells, which is mediated by NF-κB-dependent transcriptional control. Interestingly, exogenous IL-6 restored the impaired angiogenesis and reduced cell motility caused by Atg7 knockdown. These results demonstrated that Atg7 has proangiogenic activity in brain angiogenesis which is mediated by IL-6 production in a NF-κB-dependent manner.

Heat shock protein 90 (Hsp90) is a potential target for oncology therapeutics. Some inhibitors have shown antitumor effects in clinical trials, spurring the discovery of small molecule Hsp90 inhibitors. Here, we describe the structural optimization studies of a hit compound, tetrahydropyrido[4,3-d]pyrimidine-based Hsp90 inhibitor 15, which exhibits inhibitory activity against Hsp90. A series of analogues were synthesized, and their structure–activity and structure–property relationships were analyzed. These explorations led to the discovery of compound 73, which exhibited potent in vitro activities, good physicochemical properties, favorable ADME properties, and a potent antitumor effect in an HCT116 xenograft model. Furthermore, 73 exhibited no ocular toxicity in a rat retinal damage model, suggesting it is a relatively safe Hsp90 inhibitor. As a promising antitumor agent, 73 was progressed for further preclinical evaluation.

Hydrophobins fulfill various physiological functions in fungal development and growth, based on their mechanism of self-assembly at hydrophilic–hydrophobic interfaces into nano-scale, amphipathic membranes. One hydrophobin with an approximate molecular weight of 15 kDa, designated Po.HYD1, was purified from aerial hyphae of Pleurotus ostreatus strain Pm039. Ultrastructures of self-assembled films formed by Po.HYD1 on hydrophobic and hydrophilic substrates were revealed by atomic force microscopy (AFM). A monomolecular adsorption layer, thickness ranging from 3.2 to 3.8 nm, was observed on the surface of highly oriented pyrolytic graphite (HOPG), while a typical rodlet layer with uniform thickness of 4.2 ± 0.1 nm formed on the mica surface. Comparison of CD spectra showed significant secondary structural changes between monomeric and self-assembled states. The spectrum of monomeric Po.HYD1 had a maximum ellipticity at 190 nm and a minimum at 209 nm, and that of assemblage showed the maximum at 195 nm and the minimum shifted to 215–218 nm. Po.HYD1 showed high surface activity, based on the dramatic drop of surface tension through self-assembly at the water–air interface. Moreover, Po.HYD1 is capable of stabilizing the emulsion consisting of water and hexane.

Promoters of the genesG3P, ICL1, POT1, POX1, POX2 andPOX5 of the yeastY. lipolytica were studied in respect to their regulations and activities during growth on different carbon sources. The aim of this study was to select suitable promoters for high expression of heterologous genes in this yeast. For this purpose the promoters were fused with the reporter genelacZ ofE. coli and integrated as single copies into the genome ofY. lipolytica strain PO1d. The measurement of expressed activities of β-galactosidase revealed thatpICL1, pPOX2 andpPOT1 are the strongest regulable promoters available forY. lipolytica, at present.pPOX2 andpPOT4 were highly induced during growth on oleic acid and were completely repressed by glucose and glycerol.pICL1 was strongly inducible by ethanol besides alkanes and fatty acids, however, not completely repressible by glucose or glycerol. Ricinoleic acid methyl ester appeared as a very strong inducer forpPOT1 andpPOX2, in spite of that it inhibited growth ofY. lipolytica transformants.

In the title coordination polymer, [Fe(C(8)H(6)N(5)O(4))(2)](n) {or [FeL(2)](n),where HL = 2-[(1H-1,2,4-triazol-1-yl) meth-yl]-1H-imidazole-4,5-dicarb-oxy-lic acid)}, the Fe(II) ion, located on an inversion centre, is six-coordinated by two O atoms and four N atoms from two L(-) ligands in a distorted octa-hedral geometry [Fe-O = 2.1452 (13), Fe-N = 2.1316 (14) and 2.2484 (15) Å]. There is an intra-molecular O-H⋯O hydrogen bond in each L(-) ligand. Being an effective tridentate bridging ligand, the deprotonated L(-) anions link two Fe(II) atoms, yielding a chain-like polymer propagating along [100]. In the crystal, these polymer chains are linked via N-H⋯N hydrogen bonds, forming a two-dimensional network.

Tagged mutants affected in the degradation of hydrophobic compounds (HC) were generated by insertion of a zeta-URA3 mutagenesis cassette (MTC) into the genome of a zeta -free and ura3 deletion-containing strain of Yarrowia lipolytica . MTC integration occurred predominantly at random by nonhomologous recombination. A total of 8,600 Ura + transformants were tested by replica plating for (i) growth on minimal media with alkanes of different chain lengths (decane, dodecane, and hexadecane), oleic acid, tributyrin, or ethanol as the C source and (ii) colonial defects on different glucose-containing media (YPD, YNBD, and YNBcas). A total of 257 mutants were obtained, of which about 70 were affected in HC degradation, representing different types of non-alkane-utilizing (Alk − ) mutants (phenotypic classes alkA to alkE) and tributyrin degradation mutants. Among Alk − mutants, growth defects depending on the alkane chain length were observed (alkAa to alkAc). Furthermore, mutants defective in yeast-hypha transition and ethanol utilization and selected auxotrophic mutants were isolated. Flanking borders of the integrated MTC were sequenced to identify the disrupted genes. Sequence analysis indicated that the MTC was integrated in the LEU1 locus in N083, a leucine-auxotrophic mutant, in the isocitrate dehydrogenase gene of N156 (alkE leaky), in the thioredoxin reductase gene in N040 (alkAc), and in a peroxine gene ( PEX14 ) in N078 (alkD). This indicates that MTC integration is a powerful tool for generating and analyzing tagged mutants in Y. lipolytica .