Control of nutrient stress-induced metabolic reprogramming by PKCζ in tumorigenesis.

Tumor cells have high-energetic and anabolic needs and are known to adapt their metabolism to be able to survive and keep proliferating under conditions of nutrient stress. We show that PKCζ deficiency promotes the plasticity necessary for cancer cells to reprogram their metabolism to utilize glutamine through the serine biosynthetic pathway in the absence of glucose. PKCζ represses the expression of two key enzymes of the pathway, PHGDH and PSAT1, and phosphorylates PHGDH at key residues to inhibit its enzymatic activity. Interestingly, the loss of PKCζ in mice results in enhanced intestinal tumorigenesis and increased levels of these two metabolic enzymes, whereas patients with low levels of PKCζ have a poor prognosis. Furthermore, PKCζ and caspase-3 activities are correlated with PHGDH levels in human intestinal tumors. Taken together, this demonstrates that PKCζ is a critical metabolic tumor suppressor in mouse and human cancer.

10-Phenylphenothiazine-Organophotocatalyzed Bromo-Perfluoroalkylation of Unactivated Olefins.

In this study, we have developed a smooth metal-free visible-light-induced bromo-perfluoroalkylation of unactivated olefins with the aid of 10-phenylphenothiazine (PTH) as an organic photoredox catalyst. The reaction is 100% atom-economic redox-neutral and proceeds with stoichiometric amounts of olefin and perfluoroalkyl bromide. To show the potential of these unexplored motifs, we carried out various postfunctionalizations taking advantage of the bromine atom, including gram-scale experiments.

Nitroxide-Mediated Controlled Radical Copolymerization of α-Trifluoromethylstyrenes with Styrenes.

Fluorinated polymers are important materials in everyday life; however, most monomers of widely used fluoropolymers are gaseous, and their polymerization is difficult in an ordinary laboratory. Therefore, partially fluorinated polymers have recently been reported. As an easy-to-handle fluorine-containing monomer, α-trifluoromethylstyrene (TFMST) can be used to produce partially fluorinated polymers with trifluoromethyl groups in the main chain; however, TFMST does not homopolymerize, and there are limited reports on its copolymerization with styrene (ST). In this study, we applied the controlled radical polymerization method, which is effective for the polymerization of ST, to the copolymerization of TFMST and ST. We also showed that nitroxide-mediated polymerization is effective. The content ratio of TFMST in the TFMST-ST copolymer can be controlled between 10% and 40% by changing its monomer ratio. Additionally, the polymerization of TFMST and ST with substituents was performed to increase structural variations. The thermal stability as well as water and oil repellency of the synthesized polymers with different composition ratios and substituents were also evaluated.

Development of Electrophilic Radical Perfluoroalkylation of Electron-Deficient Olefins.

Fluorinated organic compounds have attracted significant attention over the past few decades owing to their unique properties and versatility. An established method for the synthesis of fluorinated organic compounds involves radical perfluoroalkylation reactions towards double bonds. In this radical pathway, electrophilic perfluoroalkyl radicals exhibit excellent reactivity towards electron-rich olefins. Therefore, several splendid perfluoroalkylation reactions of electron-rich olefins have been reported. However, there are only a few examples of reaction involving electron-deficient olefins because of their poor electronic compatibility with perfluoroalkyl radicals. This review focuses on the reports that challenge this long-standing issue. Radical perfluoroalkylation/bifunctionalization reactions of electron-deficient olefins are described according to the radical generation methods.

Fine-tuning of nitrogen-containing bisphosphonate esters that potently induce degradation of HMG-CoA reductase.

3-Hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase is the rate-limiting enzyme in the cholesterol biosynthetic pathway, and competitive inhibitors targeting the catalytic domain of this enzyme, so-called statins, are widely used for the treatment of hyperlipidemia. The membrane domain mediates the sterol-accelerated degradation, a post-translational negative feedback mechanism, and small molecules triggering such degradation have been studied as an alternative therapeutic option. Such strategies are expected to provide benefits over catalytic site inhibitors, as the inhibition leads to transcriptional and post-translational upregulation of the enzyme, necessitating a higher dose of the inhibitors and concomitantly increasing the risk of serious adverse effects, including myopathies. Through our previous study on SR12813, a synthetic small molecule that induces degradation of HMG-CoA reductase, we identified a nitrogen-containing bisphosphonate ester SRP3042 as a highly potent HMG-CoA reductase degrader. Here, we performed a systematic structure-activity relationship study to optimize its activity and physicochemical properties, specifically focusing on the reduction of lipophilicity. Mono-fluorination of tert-butyl groups on the molecules was found to increase the HMG-CoA reductase degradation activity while reducing lipophilicity, suggesting the mono-fluorination of saturated alkyl groups as a useful strategy to balance potency and lipophilicity of the lead compounds.

Hydroxy- and Hydro-Perfluoroalkylation of Styrenes by Controlling the Quenching Cycle of Eosin Y.

Fluoroalkyl compounds are widely used, underscoring a pressing need for the development of methods for their synthesis. However, reports on perfluoroalkylation to styrenes have been sparse. In this study, both hydroxy- and hydro-perfluoroalkylation of styrene were achieved using visible light reactions, catalyzed by eosin Y, by selecting appropriate additives and controlling the eosin Y quenching cycle. These reactions are heavy-metal free, use water as the hydroxyl or hydrogen source, and employ inexpensive and readily available reagents.

Eosin Y-Catalyzed Visible-Light-Induced Hydroperfluoroalkylation of Electron-Deficient Alkenes.

The eosin Y-catalyzed hydroperfluoroalkylation of electron-deficient alkenes is described herein. The reaction proceeded smoothly under visible light irradiation and selectively afforded a hydroperfluoroalkylated product. Various perfluoroalkyl bromides and electron-deficient olefins can be used in this reaction, and all chemicals required for this reaction are safe and readily available.

K63 polyubiquitination and activation of mTOR by the p62-TRAF6 complex in nutrient-activated cells.

The ability of cells to respond to changes in nutrient availability is critical for an adequate control of metabolic homeostasis. Mammalian target of rapamycin complex 1 (mTORC1) is a central complex kinase in these processes. The signaling adaptor p62 binds raptor, and integral component of the mTORC1 pathway. p62 interacts with TNF receptor associated factor 6 (TRAF6) and is required for mTORC1 translocation to the lysosome and its subsequent activation. Here we show that TRAF6 is recruited to and activates mTORC1 through p62 in amino acid-stimulated cells. We also show that TRAF6 is necessary for the translocation of mTORC1 to the lysosomes and that the TRAF6-catalyzed K63 ubiquitination of mTOR regulates mTORC1 activation by amino acids. TRAF6, through its interaction with p62 and activation of mTORC1, modulates autophagy and is an important mediator in cancer cell proliferation. Interfering with the p62-TRAF6 interaction serves to modulate autophagy and nutrient sensing.

Metal-free visible-light synthesis of quaternary α-perfluoroalkyl aldehydes via an enamine intermediate.

Visible-light induced perfluoroalkylation of the α-position of aldehydes via enamines was developed. The reaction proceeds by electron donor-acceptor complexation of the enamine and perfluoroalkyl iodide without any additional redox catalyst. A variety of perfluoroalkyl groups are tolerated to give various quaternary α-perfluoroalkyl aldehydes. An example using proline-derived chiral amine gives high enantioselectivity.

Stereochemical effects on dynamics in two-component systems of gelators with perfluoroalkyl and alkyl chains as revealed by vibrational circular dichroism.

A mixture of chiral low-molecular weight gelators, (1R,2R)- or (1S,2S)-N,N'-diperfluoroheptanoyl-1,2-diaminocyclohexane (denoted as RR- or SS-CF7, respectively) and (1R,2R)- or (1S,2S)-N,N'-diheptanoyl-1,2-diaminocyclohexane (denoted as RR- or SS-CH7, respectively), was used as a two-component gelator in acetonitrile solvent. The process of gelation was investigated by time-step vibrational circular dichroism (VCD) spectroscopy. The method enabled us to study the dynamical behavior of CF7 and CH7 molecules independent of their characteristic vibrational bands. We focused on the effects of the chirality relation between the two gelators. In the case of the enantiomeric mixtures (RR-CF7/RR-CH7 or SS-CF7/SS-CH7), the two components exhibited different time-courses in their VCD spectra. As for CF7, the couplet peak intensities assigned to C[double bond, length as m-dash]O stretching increased with time, while those for CH7 remained low. In the case of the racemic mixture (RR-CF7/SS-CH7 or SS-CF7/RR-CH7), the intensities of the peaks assigned to the C[double bond, length as m-dash]O stretching vibration for both CF7 and CH7 molecules maintained a constant level with time. The VCD results were compared with the SEM images of the freeze-dried gel samples taken at various time intervals. Furthermore, the mechanisms for the gelation of two-component systems are discussed.

Fluorine-Containing Dibenzoanthracene and Benzoperylene-Type Polycyclic Aromatic Hydrocarbons: Synthesis, Structure, and Basic Chemical Properties.

Intramolecular photocyclization of stilbene derivatives (Mallory reaction) is one of the efficient methods for building polycyclic aromatic hydrocarbon (PAH) frameworks, and is also expected to be applicable to synthesis of fluorine-containing PAHs (F-PAHs). In this study, dibenzoanthracene-type (4a) and benzoperylene-type (4b) F-PAHs were synthesized using the Mallory reaction of the 1,4-distyrylbenzene-type π-conjugated molecule (3a), which was prepared by addition-defluorination of available octafluorocyclopentene (OFCP) and aryllithium in three steps. The structure of 4a originating from π⁻π interaction was characterized by X-ray crystallographic analysis. The absorption maxima of UV-Vis spectra and emission maxima of photoluminescence spectra of the PAHs were positioned at a longer wavelength compared to those of the corresponding unsubstituted PAHs, presumably due to the electron-withdrawing nature of perfluorocyclopentene (PFCP) units. The effect of PFCP units in F-PAHs was also studied by time-dependent density functional theory (TD-DFT) calculation.

Synthesis of perfluoroalkylated pentacenes and evaluation of their fundamental physical properties.

Symmetrical and unsymmetrical pentacenes carrying two perfluoroalkyl (Rf) chains, at the 6 and 13 positions, were synthesized from easily available pentacene-6,13-quinone via facile three or four step reactions. After extensive evaluation, it was clearly found that the control of both the electron density of the aromatic rings on the pentacene core and molecular alignment in the crystalline state nicely affected their physical properties. Thus, we successfully prove in this article that (1) their anti-oxidation ability was significantly enhanced due to a decrease in the HOMO and LUMO energy and (2) a distinct difference in charge-transporting properties was observed between the symmetrical and unsymmetrical pentacenes.

Helical Inversion of Gel Fibrils by Elongation of Perfluoroalkyl Chains as Studied by Vibrational Circular Dichroism.

Vibrational circular dichroism (VCD) spectroscopy was applied to gelation by a chiral low-molecular mass weight gelator, N,N'-diperfluoroalkanoyl-1,2-trans-diaminocyclohexane. Attention was focused on the winding effects of (-CF2 )n chains on the gelating ability. For this purpose, a series of gelators were synthesized with perfluoroalkyl chains of different length (n = 6-8). When gelation was studied using acetonitrile as a solvent, the fibrils took different morphologies, depending on the chain length: twisted saddle-like ribbon or helical ribbon from fibril (n = 6) and a helical ribbon from platelet (n = 8). The signs of VCD peaks assigned to the couplet of C=O stretching and to the C-F stretching were also dependent on n, indicating that a gelator molecule changed conformation on elongating perfluoroalkyl chains. A model is proposed for the aggregation modes in fibrils. Chirality 28:361-364, 2016. © 2016 Wiley Periodicals, Inc.

c-Myc phosphorylation by PKCζ represses prostate tumorigenesis.

Studies showing reduced PKCζ expression or enzymatic activity in different types of human cancers support the clinical relevance of PKCζ as a tumor suppressor. However, the in vivo role of PKCζ and its mechanisms of action in prostate cancer remain unclear. Here we demonstrate that the genetic inactivation of PKCζ in mice results in invasive prostate carcinoma in vivo in the context of phosphatase and tensin homolog deficiency. Bioinformatic analysis of human prostate cancer gene-expression sets revealed increased c-Myc transcriptional activity in PKCζ-inactive cells, which correlated with increased cell growth, invasion, and metastasis. Interestingly, PKCζ knockdown or the overexpression of a kinase-inactive mutant resulted in enhanced cell proliferation and invasion in vitro through increased c-Myc mRNA and protein levels and decreased Ser-373 phosphorylation of c-Myc. Analysis of prostate cancer samples demonstrated increased expression and decreased phosphorylation of c-Myc at Ser-373 in PKCζ knockout tumors. In vivo xenograft studies revealed that c-Myc phosphorylation by PKCζ is a critical event in the control of metastasis. Collectively, these results establish PKCζ as an important tumor suppressor and regulator of c-Myc function in prostate cancer.

Stereochemical Investigation of the Products of the Photoinduced Perfluoroalkylation-Dimerization of Anthracene.

The photoinduced perfluoroalkylation of anthracene has been shown to provide 9,9',10,10'-tetrahydro-10,10'-diperfluoroalkyl-9,9'-bianthracenes in over 70% yields, each perfluoroalkyl iodide producing three diastereomers. The structures of all three diastereomers (cis,cis, cis,trans, and trans,trans isomers) have been elucidated by both NMR and X-ray crystallographic analyses. Most notably, an X-ray crystallographic analysis has revealed that the trans,trans diastereomer having the two trifluoromethyl groups in 10,10'-positions adopts a 74° twisted relationship of the two dihydroanthracene rings. Furthermore, each of the two trans,trans isomers 2a,b has been shown to exist as a mixture of new types of atropisomers and the energy barrier for the interconversion of the two atropisomers has been estimated to be 12 kcal/mol by variable-temperature NMR analysis.

Chiroptical studies on supramolecular chirality of molecular aggregates.

The attempts of applying chiroptical spectroscopy to supramolecular chirality are reviewed with a focus on vibrational circular dichroism (VCD). Examples were taken from gels, solids, and monolayers formed by low-molecular mass weight chiral gelators. Particular attention was paid to a group of gelators with perfluoroalkyl chains. The effects of the helical conformation of the perfluoroalkyl chains on the formation of chiral architectures are reported. It is described how the conformation of a chiral gelator was determined by comparing the experimental and theoretical VCD spectra together with a model proposed for the molecular aggregation in fibrils. The results demonstrate the potential utility of the chiroptical method in analyzing organized chiral aggregates.

Diastereoselective radical addition to γ-alkyl-α-methylene-γ-butyrolactams and the synthesis of a chiral pyroglutamic acid derivative.

The cis- and trans-stereoselective radical additions to α-methylene-γ-alkyl- γ-lactams were investigated and the scope and limitation of the reaction were also revealed. This stereoselective radical reaction was used for synthesis of chiral pyroglutamic acid derivatives starting from a commercially available chiral amino acid.

Amine-catalyzed Synthesis of Fluorine-containing Polymers through Halogen Bonding.

Fluorine-containing polymers are one of the most useful materials among various polymers. In this study, we have developed synthesis methods for fluorine-containing polymers through sequential and chain polymerization based on the generation of perfluoroalkyl radicals by photoirradiation halogen bonding of perfluoroalkyl iodide and amines. In sequential polymerization, fluoroalkyl-alkyl-alternating polymers were synthesized by the polyaddition of diene and diiodoperfluoroalkane. In chain polymerization, polymers with perfluoroalkyl terminals were synthesized by polymerization of general-purpose monomers, with perfluoroalkyl iodide as the initiating species. Block polymers were also synthesized by successive chain polymerization to the polyaddition product.

Absence of SOCS3 in the cardiomyocyte increases mortality in a gp130-dependent manner accompanied by contractile dysfunction and ventricular arrhythmias.

BACKGROUND: Suppressor of cytokine signaling-3 (SOCS3) is a key negative-feedback regulator of the gp130 receptor that provides crucial signaling for cardiac hypertrophy and survival; however, an in vivo role of SOCS3 regulation on cardiac gp130 signaling remains obscure. METHODS AND RESULTS: We generated cardiac-specific SOCS3 knockout (SOCS3 cKO) mice. These mice showed increased activation of gp130 downstream signaling targets (STAT3, ERK1/2, AKT, and p38) from 15 weeks of age and developed cardiac dysfunction from approximately 25 weeks of age with signs of heart failure. Surprisingly, SOCS3 cKO failing hearts had minimal histological abnormalities with intact myofibril ultrastructure. In addition, Ca(2+) transients were significantly increased in SOCS3 cKO failing hearts compared with wild-type hearts. We also found that Ser23/24 residues of troponin I were hypophosphorylated in SOCS3 cKO hearts before the manifestation of cardiac dysfunction. These data suggested the presence of abnormalities in myofilament Ca(2+) sensitivity in SOCS3 cKO mice. In addition to the contractile dysfunction, we found various ventricular arrhythmias in SOCS3 cKO nonfailing hearts accompanied by a sarcoplasmic reticulum Ca(2+) overload. To determine the contribution of gp130 signaling to the cardiac phenotype that occurs with SOCS3 deficiency, we generated cardiac-specific gp130 and SOCS3 double KO mice. Double KO mice lived significantly longer and had different histological abnormalities when compared with SOCS3 cKO mice, thus demonstrating the importance of gp130 signaling in the SOCS3 cKO cardiac phenotype. CONCLUSIONS: Our results demonstrate an important role of SOCS3 regulation on cardiac gp130 signaling in the pathogenesis of contractile dysfunction and ventricular arrhythmias.

Metal-free visible-light-induced hydroxy-perfluoroalkylation of conjugated olefins using enamine catalyst.

We developed a simple and sustainable method for the hydroxy-perfluoroalkylation of electron-deficient conjugated olefins and styrenes. In this protcol, in situ generated enamine forms electron-donor-accepter (EDA) complexes with perfluoroalkyl iodide, and reaction proceed with visible-light irradiation. Tertiary amine also interacts with perfluoroalkyl iodide via halogen-bonding, promoting the perfluoroalkyl radical generation. This reaction does not require any transition-metal or photoredox catalyst, and gaseous oxygen is used as the green hydroxy source. Moreover, various commercially available substrates and perfluoroalkyl iodides were tolerated, affording the desired hydroxy-perfluoroalkylated products in good to moderate yields (>50 examples, up to 90%).