3-5-bis(2-fluorobenzylidene)piperidin-4-one and Breast-Neoplasms

Protein disulfide isomerase (PDI), an important endoplasmic reticulum-resident oxidoreductase chaperone can bind to estrogens as well as intact with its receptor proteins [i.e. estrogen receptors (ER) α and β]. It has been postulated that PDI also acts as an intracellular 17β-estradiol (E2)-binding protein that transports and accumulates E2 in live cells. Drop in E2 level promotes dissociation of E2 from PDI and released in cytosol; the released E2 can augment estrogen receptor-mediated transcriptional activity and mitogenic action in cultured cells by modulating the ERβ/ERα ratio. In this study, we observed rotenone-induced damage to PDI leads to significant increase in ERβ/ERα ratio by down-regulating ERα and up-regulating ERβ. We demonstrated that nitrosative stress induced disruption of the cellular estrogenic status can be prevented through diphenyl difluoroketone (EF24, curcumin analog) intervention by protecting PDI from reactive oxygen species (ROS)-induced damage. Together, our study suggests that both PDI and EF24 can play a vital role in maintaining cellular estrogenic homeostasis.

Topics: Benzylidene Compounds; Breast Neoplasms; Down-Regulation; Estradiol; Estrogen Receptor alpha; Estrogen Receptor beta; Female; HEK293 Cells; HeLa Cells; Humans; MCF-7 Cells; Microscopy, Confocal; Oxidative Stress; Piperidones; Protein Disulfide-Isomerases; Reactive Oxygen Species; Rotenone; Up-Regulation

A series of novel curcumin analogs, symmetrical dienones, were previously shown to possess cytotoxic, anti-angiogenic and anti-tumor activities. Analogs 1 (EF24) and 2 (EF31) share the dienone scaffold and serve as Michael acceptors. We propose that the anti-cancer effects of 1 and 2 are mediated in part by redox-mediated induction of apoptosis. In order to support this concept, 1 and 2 were treated with L-glutathione (GSH) and cysteine-containing dipeptides under mild conditions to form colorless water-soluble adducts, which were identified by LC/MS. Comparison of the cytotoxic action of 1, 2 and the corresponding conjugates, 1-(GSH)(2) and 2-(GSH)(2), illustrated that the two classes of compounds exhibit essentially identical cell killing capabilities. Compared with the yellow, somewhat light sensitive and nearly water insoluble compounds 1 and 2, the glutathione conjugates represent a promising new series of stable and soluble anti-tumor pro-drugs.

Topics: Antineoplastic Agents; Breast Neoplasms; Cell Line, Tumor; Cell Proliferation; Curcumin; Drug Screening Assays, Antitumor; Humans; Molecular Structure; Oxidation-Reduction; Stereoisomerism