1.Pharmacokinetic properties of tandem d-peptides designed for treatment of Alzheimer's disease.
Leithold LH1, Jiang N2, Post J3, Niemietz N4, Schartmann E5, Ziehm T6, Kutzsche J7, Shah NJ8, Breitkreutz J9, Langen KJ10, Willuweit A11, Willbold D12. Eur J Pharm Sci. 2016 Apr 13. pii: S0928-0987(16)30119-1. doi: 10.1016/j.ejps.2016.04.016. [Epub ahead of print]
Peptides are more and more considered for the development of drug candidates. However, they frequently exhibit severe disadvantages such as instability and unfavourable pharmacokinetic properties. Many peptides are rapidly cleared from the organism and oral bioavailabilities as well as in vivo half-lives often remain low. In contrast, some peptides consisting solely of d-enantiomeric amino acid residues were shown to combine promising therapeutic properties with high proteolytic stability and enhanced pharmacokinetic parameters. Recently, we have shown that D3 and RD2 have highly advantageous pharmacokinetic properties. Especially D3 has already proven promising properties suitable for treatment of Alzheimer's disease. Here, we analyse the pharmacokinetic profiles of D3D3 and RD2D3, which are head-to-tail tandem d-peptides built of D3 and its derivative RD2. Both D3D3 and RD2D3 show proteolytic stability in mouse plasma and organ homogenates for at least 24h and in murine and human liver microsomes for 4h.
2.Design and synthesis of some novel 4-Chloro-N-(4-(1-(2-(2-cyanoacetyl)hydrazono)ethyl)phenyl) benzenesulfonamide derivatives as anticancer and radiosensitizing agents.
Ghorab MM1, Ragab FA2, Heiba HI3, Soliman AM3. Eur J Med Chem. 2016 Apr 6;117:8-18. doi: 10.1016/j.ejmech.2016.04.009. [Epub ahead of print]
A novel series of sulfonamide derivatives 4-21 have been synthesized starting from the strategic starting material (E)-4-Chloro-N-(4-(1-(2-(2-cyanoacetyl)hydrazono)ethyl)phenyl) benzenesulfonamide 4. Two series of hydrazone 5-9, and pyridone 10-21 derivatives bearing a sulfonamide moiety were obtained. All the newly synthesized compounds were evaluated for their in vitro cytotoxic activity against human liver cancer cell line (HepG2). Compounds 4-6, 8, 9, 10-14 and 16-18 showed higher activity compared to doxorubicin as a positive control. The radiosensitizing ability of the most promising compounds 4, 10 and 12 was studied which showed an increase in the cell killing effect of γ-radiation after combination with these derivatives. The molecular design was performed to predict the binding mode of the most promising compounds 4, 10 and 12 with the active site of hCA IX, that showed appropriate fitting with the relevant amino acids in the binding pocket on the basis of standard bond lengths, angles, S score and E conformation data.
3.Novel N-allyl/propargyl tetrahydroquinolines: Synthesis via three-component cationic imino Diels-Alder reaction, binding prediction and evaluation as cholinesterase inhibitors.
Rodríguez YA1, Gutiérrez M1, Ramírez D2, Alzate-Morales J2, Bernal CC3, Güiza FM3, Romero Bohórquez AR3. Chem Biol Drug Des. 2016 Apr 17. doi: 10.1111/cbdd.12773. [Epub ahead of print]
New N-allyl/propargyl 4-substituted 1,2,3,4-tetrahydroquinolines derivatives were efficiently synthesized using acid-catalyzed three components cationic imino Diels-Alder reaction (70-95%). All compounds were tested in vitro as dual acetylcholinesterase (AChE) and butyryl-cholinesterase (BChE) inhibitors and their potential binding modes, and affinity, were predicted by molecular docking and binding free energy calculations (∆G), respectively. The compound 4af (IC50 = 72 μM) presented the most effective inhibition against AChE despite its poor selectivity (SI= 2), while the best inhibitory activity on BChE was exhibited by compound 4ae (IC50 = 25.58 μM) with considerable selectivity (SI=0.15). Molecular docking studies indicated that the most active compounds fit in the reported AChE and BChE active sites. Moreover, our computational data indicated a high correlation between the calculated ∆G and the experimental activity values in both targets.
4.The mutation spectrum in genomic late replication domains shapes mammalian GC content.
Kenigsberg E1, Yehuda Y2, Marjavaara L3, Keszthelyi A3, Chabes A4, Tanay A5, Simon I6. Nucleic Acids Res. 2016 Apr 16. pii: gkw268. [Epub ahead of print]
Genome sequence compositions and epigenetic organizations are correlated extensively across multiple length scales. Replication dynamics, in particular, is highly correlated with GC content. We combine genome-wide time of replication (ToR) data, topological domains maps and detailed functional epigenetic annotations to study the correlations between replication timing and GC content at multiple scales. We find that the decrease in genomic GC content at large scale late replicating regions can be explained by mutation bias favoring A/T nucleotide, without selection or biased gene conversion. Quantification of the free dNTP pool during the cell cycle is consistent with a mechanism involving replication-coupled mutation spectrum that favors AT nucleotides at late S-phase. We suggest that mammalian GC content composition is shaped by independent forces, globally modulating mutation bias and locally selecting on functional element. Deconvoluting these forces and analyzing them on their native scales is important for proper characterization of complex genomic correlations.