Conformationally constrained analogues of diacylglycerol (DAG). 31. Modulation of the biological properties of diacylgycerol lactones (DAG-lactones) containing rigid-rod acyl groups separated from the core lactone by spacer units of different lengths

Diacylglycerol lactones built with a rigid 4-[(methylphenyl)ethynyl]phenyl rod that is separated from the exocyclic acylcarbonyl of the DAG-lactone core by a spacer unit of variable length were synthesized and studied. Binding affinities for a panel of classical and novel PKC isozymes in two different phospholipid environments, one corresponding to the plasma membrane of cells, were determined. The kinetics and site of translocation for the PKC isozymes α and δ upon treatment with the compounds were also studied as well as the early response of ERK phosphorylation and the late response of induction of apoptosis in the human prostatic carcinoma cell line LNCaP. Finally, the compounds were evaluated in terms of their interaction with biomimetic lipid/polydiacetylene membranes by the associated chromatic response. The different spatial disposition of the rigid structural motif on the DAG-lactones contributes to differential activity.