Cell Cycle Regulation by Ca2+-Activated K⁺ (BK) Channels Modulators in SH-SY5Y Neuroblastoma Cells.

The effects of Ca2+-activated K⁺ (BK) channel modulation by Paxilline (PAX) (10-7⁻10-4 M), Iberiotoxin (IbTX) (0.1⁻1 × 10-6 M) and Resveratrol (RESV) (1⁻2 × 10-4 M) on cell cycle and proliferation, AKT1pSer473 phosphorylation, cell diameter, and BK currents were investigated in SH-SY5Y cells using Operetta-high-content-Imaging-System, ELISA-assay, impedentiometric counting method and patch-clamp technique, respectively. IbTX (4 × 10-7 M), PAX (5 × 10-5 M) and RESV (10-4 M) caused a maximal decrease of the outward K⁺ current at +30 mV (Vm) of -38.3 ± 10%, -31.9 ± 9% and -43 ± 8%, respectively, which was not reversible following washout and cell depolarization. After 6h of incubation, the drugs concentration dependently reduced proliferation. A maximal reduction of cell proliferation, respectively of -60 ± 8% for RESV (2 × 10-4 M) (IC50 = 1.50 × 10-4 M), -65 ± 6% for IbTX (10-6 M) (IC50 = 5 × 10-7 M), -97 ± 6% for PAX (1 × 10-4 M) (IC50 = 1.06 × 10-5 M) and AKT1pser473 dephosphorylation was observed. PAX induced a G1/G2 accumulation and contraction of the S-phase, reducing the nuclear area and cell diameter. IbTX induced G1 contraction and G2 accumulation reducing diameter. RESV induced G2 accumulation and S contraction reducing diameter. These drugs share common actions leading to a block of the surface membrane BK channels with cell depolarization and calcium influx, AKT1pser473 dephosphorylation by calcium-dependent phosphatase, accumulation in the G2 phase, and a reduction of diameter and proliferation. In addition, the PAX action against nuclear membrane BK channels potentiates its antiproliferative effects with early apoptosis.

Effect of mofezolac-galactose distance in conjugates targeting cyclooxygenase (COX)-1 and CNS GLUT-1 carrier.

Neuroinflammation is the earliest stage of several neurological and neurodegenerative diseases. In the case of neurodegenerative disorders, it takes place about 15-20 years before the appearance of specific neurodegenerative clinical symptoms. Constitutive microglial COX-1 is one of the pro-inflammatory players of the neuroinflammation. Novel compounds 3, 14 and 15 (Galmof0, Galmof5 and Galmof11, respectively) were projected, and their synthetic methodologies developed, by linking by an ester bond, directly or through a C5 or C11 unit linker the highly selective COX-1 inhibitor mofezolac (COXs selectivity index > 6000) to galactose in order to obtain substances capable to cross blood-brain barrier (BBB) and control the CNS inflammatory response. 3, 14 and 15 (Galmofs) were prepared in good to fair yields. Galmof0 (3) was found to be a selective COX-1 inhibitor (COX-1 IC50 = 0.27 µM and COX-2 IC50 = 3.1 µM, selectivity index = 11.5), chemically and metabolically stable, and capable to cross Caco-2 cell monolayer, resembling BBB, probing that its transport is GLUT-1-mediated. Furthermore, Galmof0 (3) powerfully inhibits PGE2 release higher than mofezolac (1) in LPS-stimulated mouse BV2 microglial cell line, a worldwide recognized neuroinflammation model. In addition, Fingerprints for Ligands and Proteins (FLAP) was used to explain the different binding interactions of Galmofs with the COX-1 active site.

Investigating Structural Requirements for the Antiproliferative Activity of Biphenyl Nicotinamides.

A number of trimethoxybenzoic acid anilides, previously studied as permeability glycoprotein (P-gp) modulators, were screened with the aim of identifying new anticancer agents. One of these compounds, which showed antiproliferative activity against resistant MCF-7 cell line, was selected as the hit structure. Replacement of the trimethoxybenzoyl moiety with a nicotinoyl group, in order to overcome solubility issues, led to a new series of N-biphenyl nicotinoyl anilides, among which a nitro derivative, N-(3',5'-difluoro-3-nitro-[1,1'-biphenyl]-4-yl)nicotinamide (3), displayed antiproliferative activity against MCF-7 and MDA-MB-231 cells in the nanomolar range. The search for a bioisostere of the nitro group led to nitrile analogue N-(3-cyano-4'-fluoro-[1,1'-biphenyl]-4-yl)nicotinamide (36), which shows a strong increase in activity against MCF-7 and MDA-MB-231 cells. Compound 36 induced a dose-dependent accumulation of G2 - and M-phase MCF-7 cell populations, and a decrease in S-phase cells. Relative to vinblastine, a well-known potent antimitotic agent, compound 36 also induced G1 -phase arrest at low doses (20-40 nm), but did not inhibit in vitro tubulin polymerization.