Downregulation of STAT3/NF-κB potentiates gemcitabine activity in pancreatic cancer cells.

There is an unmet need to develop new agents or strategies against therapy resistant pancreatic cancer (PanCA). Recent studies from our laboratory showed that STAT3 negatively regulates NF-κB and that inhibition of this crosstalk using Nexrutine® (Nx) reduces transcriptional activity of COX-2. Inhibition of these molecular interactions impedes pancreatic cancer cell growth as well as reduces fibrosis in a preclinical animal model.

KDAC8 with High Basal Velocity Is Not Activated by N-Acetylthioureas.

Lysine deacetylases (KDACs) are enzymes that reverse the post-translational modification of lysine acetylation. Recently, a series of N-acetylthioureas were synthesized and reported to enhance the activity of KDAC8 with a fluorogenic substrate. To determine if the activation was general, we synthesized three of the most potent N-acetylthioureas and measured their effect with peptide substrates and the fluorogenic substrate under multiple reaction conditions and utilizing two enzyme purification approaches.

Tetrahydroberberine, a pharmacologically active naturally occurring alkaloid.

Tetrahydroberberine (systematic name: 9,10-dimethoxy-5,8,13,13a-tetrahydro-6H-benzo[g][1,3]benzodioxolo[5,6-a]quinolizine), C20H21NO4, a widely distributed naturally occurring alkaloid, has been crystallized as a racemic mixture about an inversion center. A bent conformation of the molecule is observed, with an angle of 24.72 (5)° between the arene rings at the two ends of the reduced quinolizinium core.

Weak C-H···X (X = O, N) hydrogen bonds in the crystal structure of dihydroberberine.

Dihydroberberine (systematic name: 9,10-dimethoxy-6,8-dihydro-5H-1,3-dioxolo[4,5-g]isoquinolino[3,2-a]isoquinoline), C20H19NO4, a reduced form of pharmacologically important berberine, crystallizes from ethanol without interstitial solvent. The molecule shows a dihedral angle of 27.94 (5)° between the two arene rings at the ends of the molecule, owing to the partial saturation of the inner quinolizine ring system.