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The eukaryotic translation initiation factor 4E (eIF4E) is the master regulator of cap-dependent protein synthesis. Overexpression of eIF4E is implicated in diseases such as cancer, where dysregulation of oncogenic protein translation is frequently observed. eIF4E has been an attractive target for cancer treatment. Here we report a high-resolution X-ray crystal structure of eIF4E in complex with a novel inhibitor (i4EG-BiP) that targets an internal binding site, in contrast to the previously described inhibitor, 4EGI-1, which binds to the surface. We demonstrate that i4EG-BiP is able to displace the scaffold protein eIF4G and inhibit the proliferation of cancer cells. We provide insights into how i4EG-BiP is able to inhibit cap-dependent translation by increasing the eIF4E-4E-BP1 interaction while diminishing the interaction of eIF4E with eIF4G. Leveraging structural details, we designed proteolysis targeted chimeras (PROTACs) derived from 4EGI-1 and i4EG-BiP and characterized these on biochemical and cellular levels. We were able to design PROTACs capable of binding eIF4E and successfully engaging Cereblon, which targets proteins for proteolysis. However, these initial PROTACs did not successfully stimulate degradation of eIF4E, possibly due to competitive effects from 4E-BP1 binding. Our results highlight challenges of targeted proteasomal degradation of eIF4E that must be addressed by future efforts.

A simple analytical method is designed for the detection of micro-molar concentrations of an antibiotic with a β-lactam subunit. The sensor for ampicillin has a limit of detection, LOD, value of 0.165 × 10−4 M and exhibited linearity over a wide range of ampicillin concentrations (6.6–200 ppm). The detection of the antibiotic is based on the in situ generation of carbon nanodots (CNDs) via a hydrothermal reaction between glucose and the antibiotic moiety. The CNDs exhibited characteristic absorption at 340 nm whose intensity is a measure of the initial ampicillin concentration. The CNDs possess peculiar blue emission which is excitation independent. The particle size of CNDs is in the range of 8–40 nm and they are hydrophilic in nature. NMR spectral analysis revealed insights into the carbon nano-structure comprising of an aromatic core with carbonyl type functionalities on its surface. Synthesis of carbon dots from ampicillin in aqueous medium and utilizing the absorption properties as well as the emission properties of the carbon dots generated for the detection of ampicillin make the design and operation of the sensor environmentally friendly and simple.

Cancer death is a leading cause of global mortality. An estimated 14.1 million new cancer cases and 8.2 million cancer deaths occurred worldwide in 2012 alone. Cancer stem cells (CSCs) within tumors are essential for tumor metastasis and reoccurrence, the key factors of cancer lethality. Here we report that 4EGI-1, an inhibitor of the interaction between translation initiation factors eIF4E1 and eIF4G1 effectively inhibits breast CSCs through selectively reducing translation persistent in breast CSCs. Translation initiation factor eIF4E1 is significantly enhanced in breast CSCs in comparison to non-CSC breast cancer cells. 4EGI-1 presents increased cytotoxicity to breast CSCs compared to non-CSC breast cancer cells. 4EGI-1 promotes breast CSC differentiation and represses breast CSC induced tube-like structure formation of human umbilical vein endothelial cells (HUVECs). 4EGI-1 isomers suppress breast CSC tumorangiogenesis and tumor growth in vivo. In addition, 4EGI-1 decreases proliferation in and induces apoptosis into breast CSC tumor cells. Furthermore, 4EGI-1 selectively inhibits translation of mRNAs encoding NANOG, OCT4, CXCR4, c-MYC and VEGF in breast CSC tumors. Our study demonstrated that 4EGI-1 targets breast CSCs through selective inhibition of translation critical for breast CSCs, suggesting that selective translation initiation interference might be an avenue targeting CSCs within tumors.

In a previous preliminary study, we found that a cyclic five-member ring beta-keto ester (lactone) reacts with one molecule of urea and two of aldehyde to give a new family of spiro heterobicyclic aliphatic rings in good yields with no traces of the expected dihydropyrimidine (Biginelli) products. The reaction is driven by a regiospecific condensation of two molecules of aldehyde with urea and beta-keto-gamma-lactone to afford only products harboring substitutions exclusively in a syn configuration (Byk, G.; Gottlieb, H. E.; Herscovici, J.; Mirkin, F. J. Comb. Chem. 2000, 2, 732-735). In the present work ((a) Presented in part at ISCT Combitech, October 15, 2002, Israel, and Eurocombi-2, Copenhagen 2003 (oral and poster presentation). (b) Also in American Peptide Society Symposium, Boston, 2003 (poster presentation). (c) Abstract in Biopolymers 2003, 71 (3), 354-355), we report a large and exciting extension of this new reaction utilizing parallel organic synthesis arrays, as demonstrated by the use of chiral beta-keto-gamma-lactams, derived from natural amino acids, instead of tetronic acid (beta-keto-gamma-lactone) and the potential of the spirobicyclic products for generating "libraries from libraries". Interestingly, we note an unusual and important anisotropy effect induced by perpendicular interactions between rigid pi systems and different groups placed at the alpha position of the obtained spirobicyclic system. Stereo/regioselectivity of the aldehyde condensation is driven by the nature of the substitutions on the starting beta-keto-gamma-lactam. Aromatic aldehydes can be used as starting reagents with good yields; however, when aliphatic aldehydes are used, the desired products are obtained in poor yields, as observed in the classical Biginelli reaction. The possible reasons for these poor yields are addressed and clarify, to some extent, the complexity of the Biginelli multicomponent reaction mechanism and, in particular, the mechanism of the present reaction. Finally, we have investigated and proposed a mechanism for this new reaction by intercepting several intermediates.

The interaction of the eukaryotic translation initiation factor eIF4E with the initiation factor eIF4G recruits the 40S ribosomal particle to the 5′ end of mRNAs, facilitates scanning to the AUG start codon, and is crucial for eukaryotic translation of nearly all genes. Efficient recruitment of the 40S particle is particularly important for translation of mRNAs encoding oncoproteins and growth-promoting factors, which often harbor complex 5′ UTRs and require efficient initiation. Thus, inhibiting the eIF4E/eIF4G interaction has emerged as a previously unpursued route for developing anticancer agents. Indeed, we discovered small-molecule inhibitors of this eIF4E/eIF4G interaction (4EGIs) that inhibit translation initiation both in vitro and in vivo and were used successfully in numerous cancer–biology and neurobiology studies. However, their detailed molecular mechanism of action has remained elusive. Here, we show that the eIF4E/eIF4G inhibitor 4EGI-1 acts allosterically by binding to a site on eIF4E distant from the eIF4G binding epitope. Data from NMR mapping and high-resolution crystal structures are congruent with this mechanism, where 4EGI-1 attaches to a hydrophobic pocket of eIF4E between β-sheet2 (L60-T68) and α-helix1 (E69-N77), causing localized conformational changes mainly in the H78-L85 region. It acts by unfolding a short 310-helix (S82-L85) while extending α-helix1 by one turn (H78-S82). This unusual helix rearrangement has not been seen in any previous eIF4E structure and reveals elements of an allosteric inhibition mechanism leading to the dislocation of eIF4G from eIF4E.

A novel γ-cyclodextrin (γ-CD) based carrier for molecular encapsulation of cancer chemotherapeutic agent doxorubicin (DOX) was synthesized and fully characterized by various analytical approaches. The γ-CD derivative, with a β-naphthyl alanine residue attached in its primary face, exhibits potent binding capacity with DOX. The encapsulation efficiency was assessed under various temperatures and pHs and it was demonstrated that the carrier-DOX inclusion complex is highly stable under a wide range of acidic conditions (pH 1.0-7.0); however, the encapsulated drug is slowly released under hyperthermic conditions (up to 50°C). Cell culture studies showed that the complexation of DOX with the carrier protected the drug from being uptaken by the cells and also greatly reduced its toxicity. Thermo-triggered DOX release was validated and the increase in cellular uptake was observed in in-vitro experiments. We concluded that this novel γ-CD derivative is able to effectively encapsulate DOX and the inclusion is responsive to temperature change, hence renders it a potential encapsulating agent for DOX delivery in combination with hyperthermia treatments.

The synthesis of new fluorescent nucleotides is described. This synthesis comprises two parallel reactions, the Kornblum oxidation and imidazole formation, which lead to 8-(aryl)-3-β-D-ribofuranosylimidazo[2,1-i]purine 5′-phosphates 2 from AMP or ATP. A detailed mechanism is proposed based on monitoring the reaction by 1H- and 13C-NMR spectroscopy, MS, FAB, HPLC, and pH meter. The spectral and fluorescent properties of the new derivatives at various pH values are described Excitation and emission maxima for 3 were observed at 290 and 420 nm, respectively, in both basic and neutral media. In acidic media, the emission maximum shifted to 410 nm, however, the fluorescence intensity increased 1.5-fold. ATP analogues 2b and 3b exhibited relative stability regarding hydrolysis by type II ATPDase. Compound 3b is relatively chemically stable at pH 10.4 and 7.4.

Translation initiation factors are over-expressed and/or activated in many human cancers and may contribute to their genesis and/or progression. Removal of physiologic restraints on translation initiation causes malignant transformation. Conversely, restoration of physiological restrains on translation initiation reverts malignant phenotypes. Here, we extensively characterize the anti-cancer activity of two small molecule inhibitors of translation initiation: #1181, which targets the eIF2∙GTP∙Met-tRNA i ternary complex, and 4EGI-1, which targets the eIF4F complex. In vitro, both molecules inhibit translation initiation, abrogate preferentially translation of mRNAs coding for oncogenic proteins, and inhibit proliferation of human cancer cells. In vivo, both #1181 and 4EGI-1 strongly inhibit growth of human breast and melanoma cancer xenografts without any apparent macroscopic- or microscopictoxicity. Mechanistically, #1181 phosphorylates eIF2α while 4EGI-1 disrupts eIF4G/ eIF4E interaction in the tumors excised from mice treated with these agents. These data indicate that inhibition of translation initiation is a new paradigm in cancer therapy.

The preparation of a new family of lipothiourea is reported using an automatic synthetic workstation. In these compounds the headgroups were made from single thiourea derivatives. The physicochemical properties and the transfection efficiency of several members of the family were studied. It was found that in the presence of DMPC small lipoplexes could be prepared. In opposite to the previously described di- and tri-lipothioureas most of these liposomes are unstable overtime. In addition, even the stable ones show no transfecting efficiency. All these data demonstrate that at least two thiourea groups are necessary to produce stable lipoplexes, to condense DNA and to give efficient transfection.

Herein, we describe a solid-supported stereoselective multicomponent reaction. One of the components, a β-keto-γ-lactam derived from alanine is generated in situ on the solid support and the addition of two equivalents of an aromatic aldehyde and one equivalent of urea generates a spiro-bicyclic γ-lactam bearing three asymmetric carbons in a totally stereoselective manner resulting in a single product. The same reaction performed in solution displayed moderate stereoselectivity.