Influence of cholesterol derivatives on cytoskeletal organization of human carcinoma cells

Growth inhibition of MCF-7 and MCF-10A human breast cells by alpha-tocopheryl hemisuccinate, cholesteryl hemisuccinate and their ether analogs

The growth inhibitory properties of alpha-tocopheryl hemisuccinate (vitamin E succinate) and related compounds were examined in MCF-7 human breast tumor cells and MCF-10A normal-like human breast cells since they have been suggested to be an effective antitumor compound. The data showed that both alpha-tocopherol hemisuccinate and a structurally-similar compound, cholesteryl hemisuccinate, inhibited the growth of MCF-7 and MCF-10A cells, while alpha-tocopherol, cholesterol, cholesteryl sulfate and Tris succinate had little effect on cell growth. The ether analogs of the succinate esters, alpha-tocopheryloxybutyric acid and cholesteryloxybutyric acid, also inhibited growth of MCF-7 and MCF-10A cells, indicating that hydrolysis of the succinate esters by esterases is not required for the antiproliferative effects. The antiproliferative effects of these succinate esters and ethers may be related to their physiochemical properties that allow incorporation into cell membranes.

Alterations in apolipoprotein E expression during aging and neurodegeneration

Apolipoprotein E (apoE) is a 34 kDa protein that plays an important role in cholesterol transport, uptake and redistribution. Within the nervous system, apoE might be involved in maintaining synaptic integrity after injury and during aging. ApoE might help maintain the integrity of the synaptodendritic complex by several different mechanisms. Among them, recent studies have suggested that apoE: (1) stabilizes the neuronal cytoskeleton; (2) plays an important role in transporting esterified cholesterol to neurons undergoing reinnervation where it is taken up by the low density lipoprotein receptor-related protein pathway and used as a precursor for the synthesis of new synaptic terminals; (3) regulates interactions between neurons and the extracellular matrix (e.g. laminin); and (4) regulates levels of intracellular calcium. The main objective of the manuscript is to review the current progress in understanding the functions of apoE in the nervous system and how malfunctioning of this molecule might result in neurodegenerative disorders such as Alzheimer's disease.