Developing 3-Hydroxyflavone Derivatives as Fluorescence Probes for MCF-7 Cells: Synthesis, Photophysical Properties and Morphology Studies
Date Issued
2009
Date
2009
Author(s)
Yu, Jou-Ching
Abstract
The aims of this thesis are to synthesize a series of estradiol-3-hydroxyflavone fluorescent probes and study the feasibility of using these probes for cellular trafficking of estradiol in MCF-7 cells. t was shown that estrogen plays an important role of growth, development and physiological balance. Furthermore, it has a vital character in the regulation of intracellular signaling pathway. This classical pathway of estrogen involves the formation of preinitiation complex (estrogen-ER complex) and the subsequent binding of this complex to estrogen response element (ERE) sequences of estrogen-responsive genes in nucleus, which leads to the production of associated proteins and finally a physiological response. Thus we design and synthesize a series of fluorescent probes by conjugation of 3-hydroxyflavone fluorophore with estradiol: HF-EDIOL, HF-7α-EDIOL, HF-EDINH2, and HF-EDISO4H. The fluorescent molecular probe features the estradiol derivative and a fluorophore, which is 3-hydroxyflavone, bridged by a hydrocarbon linker. The structural difference between HF-EDIOL and HF-7α-EDIOL is the linkage site, the derivatization at either 3 or 7α of the estradiol. The effect of positive and negative character in estradiol is probed by HF-EDINH2 and HF-EDISO4H. 3-Hydroxyflavone exhibits remarkable dual emission and possesses high sensitivity to different microenvironmental polarity in fluorescent wavelength of ESICT/ESIPT ratio change. Taking advantage of this unique photoproperties, the probe potentially can detect not only the location of estrogen receptor but provide direct tracking of its binding pathway in real time. In the studies of fluorescence spectra, as the ratio of DMSO and water solution increases, we obtained that fluorescence probes could self-assembly to certain kinds of aggregations. By utilizing DLS, zeta potential, TEM, and SEM technology, we can confirm the structure of these aggregations. In the cell imaging experiments, it reveals that HF-EDIOL can only be found in the cytoplasm while HF-7α-EDIOL distributed in both cytoplasm and nucleus with different ratios of ESICT and ESIPT emissions, displaying the location dependence.
Subjects
estrogen receptor
fluorescence probe
3-hydroxyflavone
ESICT
ESIPT
Type
thesis
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