Novel 2-Amino-1,4-Naphthoquinone Derivatives Induce A549 Cell Death through Autophagy.

A series of 1,4-naphthoquinone derivatives containing were synthesized as anti-cancer agents and the crystal structure of compound 5a was confirmed by X-ray diffraction. In addition, the inhibitory activities against four cancer cell lines (HepG2, A549, K562, and PC-3) were tested, respectively, and compound 5i showed significant cytotoxicity on the A549 cell line with the IC50 of 6.15 µM. Surprisingly, in the following preliminary biological experiments, we found that compound 5i induced autophagy by promoting the recycling of EGFR and signal transduction in the A549 cell, resulting in the activation of the EGFR signal pathway. The potential binding pattern between compound 5i and EGFR tyrosine kinase (PDB ID: 1M17) was also identified by molecular docking. Our research paves the way for further studies and the development of novel and powerful anti-cancer drugs.

Heat Shock Cognate Protein 70 Enhanced Integrin ß1 Mediated Invasion in Cancer Cells.

PURPOSE: Glioblastoma is one of the most common malignant cancers worldwide. In our previous work, we have shown that heat shock cognate protein 70 (Hsc70) functions as a positive growth regulator in glioma. We investigated the role of Hsc70 in integrin ß1 mediated invasion of glioma cells. METHODS: In order to investigate whether the down-regulation of Hsc70 would affect the expression of integrin ß1 subunit, HeLa cells were transiently transfected with Hsc70-AS or pcDNA3.0 vectors and the down-regulation of Hsc70 was confirmed by Western blotting. Human brain glioma U87 cells were stably transfected with Hsc70-AS or pcDNA3.0 vectors to further elucidate the relationship between Hsc70 and integrin ß1 in human glioma cells. Cellular localization of integrin ß1 was detected using immunofluorescence confocal microscopy analysis. RESULTS: Here we reported that down-regulation of the expression of Hsc70 in U87 cells by transfection with antisense cDNA specifically increased the expression of cell surface integrin ß1 without changing its mRNA. Meanwhile, the integrin ß1 125-kD mature form increased while 105-kD precursor form decreased when Hsc70 was down-regulated. Mechanically, the U87 cells transfected with antisense cDNA of Hsc70 decreased the Golgi localization of integrin ß1, strengthened its interaction with integrin α5 subunit, and enhanced the adhesion ability to fibronectin (FN) and the phosphorylation level of focal adhesion kinase (FAK). CONCLUSION: Overall, these results suggested that the down-regulation of Hsc70 expression could promote the expression of cell surface integrin ß1 and subsequently inhibit glioma invasion phenotype.

Complementary Oxidative Generation of Iminyl Radicals from α-Imino-oxy Acids: Silver-Catalyzed C-H Cyanoalkylation of Heterocycles and Quinones.

A complementary and general strategy for the oxidative generation of iminyl radicals from the readily available α-imino-oxy acids has been established through silver-catalyzed decarboxylation. To demonstrate its synthesis utility, the direct C-H cyanoalkylation of heterocycles and quinones with cyclic α-imino-oxy acids via the iminyl radical-mediated C-C bond cleavage is developed. This cost-effective method takes place under mild reaction conditions and exhibits a broad substrate scope.

Correction: Multi-color electrochromism from coordination nanosheets based on a terpyridine-Fe(ii) complex.

Correction for 'Multi-color electrochromism from coordination nanosheets based on a terpyridine-Fe(ii) complex' by Yu Kuai et al., Dalton Trans., 2019, DOI: 10.1039/c9dt02980j.

Multi-color electrochromism from coordination nanosheets based on a terpyridine-Fe(ii) complex.

A metal complex nanosheet was synthesized by the liquid-liquid interface self-assembly method from a star-shaped ligand of tris[4-(4'-2,2':6',2''-terpyridyl)-phenyl]amine in organic solvents and metal ion Fe(ii) in water solution. The as-prepared nanosheet possessed excessively smooth morphology with a thickness of hundreds of nanometers. Adhering to an ITO glass, the nanosheet showed noticeable electrochromism from purplish red at 0 V to orange-yellow at 1.4 V and green at 1.6 V. Besides, the nanosheet exhibited outstanding stability with the optical contrast maintained at almost 100% of its original electrochemical activity over 500 cycles. The liquid-liquid interface self-assembly method was proven to be promising to prepare a polymeric metal complex for potential electrochromic applications.

Overexpression of Hsc70 promotes proliferation, migration, and invasion of human glioma cells.

Migration and invasion are often recognized as the main reasons for the high recurrence and death rates of glioma and limit the efficacy of surgery and other antitumor therapies. In this study, we found over activation of heat shock cognate protein 70 (Hsc70) in human glioma specimens, which was closely related to glioma grade. We investigated whether Hsc70 induced the migration and invasion of glioma cells. Wound healing and transwell migration assay were used to determine the migration and invasion ability of human glioma U251 and U87 cells, in which the expression of Hsc70 was knocked down by small interfering RNA. Western blot analysis was performed to determine the expression of FAK-Src signaling in malignant glioma cells. The results showed that Hsc70 deficiency significantly retarded migration and invasion and reduced the phosphorylation of FAK, Src, and Pyk2 in U251 and U87 cells. Overall, our results indicate that the migration and invasion capacity of human brain glioma cells is at least partly induced by Hsc70-dependent activation of FAK-Src signaling.

Photo-irradiated E/Z isomerization reaction of star-shaped isomers containing two cyanostilbene arms with charge transfer excited states.

The E/Z isomerization reaction of the multi-cyanostilbene molecule is still not clear. Herein, we have designed and synthesized three star-shaped molecular isomers with a triphenylamine core linked to two cyanostilbene groups with E/Z isomerization, Z,Z-TPDCF, Z,E-TPDCF and E,E-TPDCF, possessing three different isomeric molecular configurations, to investigate the specific E/Z isomerization reaction of the cyanostilbene groups in the two molecular arms. The in situ UV, 1H NMR and HPLC spectra under UV-irradiation clearly showed that the E/Z isomerization reactions of both E,E-TPDCF and Z,Z-TPDCF firstly turned them into Z,E-TPDCF, and the Z,E-TPDCF was almost simultaneously turned into more E,E-TPDCF and less Z,Z-TPDCF due to the calculated lowest unoccupied molecular orbitals of Z,E-TPDCF on the cyanostilbene arm with the Z-configuration. In general, Z,E-TPDCF exhibited a relatively better configurational stability than Z,Z-TPDCF or E,E-TPDCF under the photo-irradiation conditions. Further research demonstrated that all three isomers exhibited excellent aggregation-induced emission (AIE) properties.

Multi-color electrochromism containing green color based on electrochemically polymerized star-shaped phenyl bithiophene.

A star-shaped thiophene derivative, namely PHBT, consisting of one central core of phenyl and three arms of bithiophene, was newly synthesized and characterized, in order to further investigate the relationship between the star-shaped monomer structure (central core and peripheral arm) and the polymeric electrochromic properties. Then it was further successfully prepared into the corresponding cross-linked polymer pPHBT via electrochemical polymerization. After applying positive voltage, pPHBT exhibited excellent electrochromic properties with surprising multi-color changes between three colors, orange-yellow, green and blue, and a fast color switching speed. Furthermore, electronic structure, cyclic voltammetry and electrochromic results of pPHBT can contribute much to explain the electrochromic behavior of pTPABT with the triphenylamine core and the quadruple thiophene arm. The electrochromism of pTPABT might consist of two parts derived from the oxidative states of triphenylamine and quadruple thiophene groups, respectively. This offers a new insight into the electrochromism mechanics of conjugated polymers.

A fast electrochromic polymer based on TEMPO substituted polytriphenylamine.

A novel strategy to obtain rapid electrochromic switching response by introducing 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO) moiety into polytriphenylamine backbone has been developed. The electrochromic properties of the integrated polymer film are investigated and a possible mechanism is proposed with TEMPO as a counterion-reservoir group to rapidly balance the charges during electrochromic switching, which leads to significantly improved electrochromism performance.