I came across  3  quite substantial papers on PubMed central:

PLoS One. 2012;7(6):e37736. doi: 10.1371/journal.pone.0037736. Epub 2012 Jun 29.

Polyphenols sensitization potentiates susceptibility of MCF-7 and MDA MB-231

cells to Centchroman.

Singh N(1), Zaidi D, Shyam H, Sharma R, Balapure AK.

Polyphenols as "sensitizers" together with cytotoxic drugs as "inducers"

cooperate to trigger apoptosis in various cancer cells. Hence, their combination

having similar mode of mechanism may be a novel approach to enhance the efficacy

of inducers. Additionally, this will also enable to achieve the physiological

concentrations facilitating significant increase in the activity at

concentrations which the compound can individually provide. Here we propose that

polyphenols (Resveratrol (RES) and Curcumin (CUR)) pre-treatment may sensitize

MCF-7/MDA MB-231 (Human Breast Cancer Cells, HBCCs) to Centchroman (CC,

antineoplastic agent). 6 h pre-treated cells with 10 µM RES/CUR and 100 µM RES/30 µM CUR doses, followed by 10 µM CC for 18 h were investigated for Ser-167 ER-phosphorylation, cell cycle arrest, redox homeostasis, stress activated

protein kinase (SAPKs: JNK and p38 MAPK) pathways and downstream apoptosis effectors. Low dose RES/CUR enhances the CC action through ROS mediated JNK/p38 as well as mitochondrial pathway in MCF-7 cells. However, RES/CUR sensitization enhanced apoptosis in p53 mutant MDA MB-231 cells without/with involvement of ROS mediated JNK/p38 adjunct to Caspase-9. Contrarily, through high dose sensitization in CC treated cells, the parameters remained unaltered as in

polyphenols alone. We conclude that differential sensitization of HBCCs with low

dose polyphenol augments apoptotic efficacy of CC. This may offer a novel

approach to achieve enhanced action of CC with concomitant reduction of side

effects enabling improved management of hormone-dependent breast cancer.

J Mol Med (Berl). 2011 Feb;89(2):181-91. doi: 10.1007/s00109-010-0698-y. Epub

2010 Nov 23.

Mammalian MST2 kinase and human Salvador activate and reduce estrogen receptor

alpha in the absence of ligand.

Park Y(1), Park J, Lee Y, Lim W, Oh BC, Shin C, Kim W, Lee Y.

Mammalian MST2 kinase plays an important role in cell proliferation, survival,

and apoptosis. In search of interacting proteins of MST2, we found that estrogen

receptor α (ERα) co-immunoprecipitates with MST2 and its adaptor protein human

Salvador (hSAV). Using reporter assays, we observed that overexpression of MST2

and hSAV leads to ligand-independent activation of ERα in human breast cancer

MCF-7 cells, which was attenuated by the knockdown of hSAV. Furthermore, using

truncated mutants of hSAV, we observed that the C terminus of hSAV is necessary

and sufficient for the induction of ERα transactivation. The expression of hSAV

and MST2 results in the phosphorylation of ERα at serine residues 118 and 167 and represses ERα expression. We then investigated the incidence of MST2 and ERα expression with other tumor biomarkers using commercially available tissue

microarrays. Among 40 breast cancer samples analyzed, 60% (24 out of 40)

expressed MST2. Nineteen among the 40 cases were MST2-positive and ERα-negative, implying a correlation between expressions of MST2 with loss of ERα in breast tumor samples. This study suggests that MST and hSAV act as novel co-regulators of ERα and may play an important role in breast cancer pathogenesis.

Int J Cancer. 2004 Mar 20;109(2):167-73.

Resveratrol modulates the phosphoinositide 3-kinase pathway through an estrogen

receptor alpha-dependent mechanism: relevance in cell proliferation.

Pozo-Guisado E(1), Lorenzo-Benayas MJ, Fernández-Salguero PM.

Resveratrol (RES), a natural phytoalexin, has antiproliferative activity in

human-derived cancer cells and in rodent models of tumor development. We have

previously shown that RES induced apoptotic death in estrogen-responsive MCF-7

human breast cancer cells. Recent data have indicated that the estrogen

receptor-alpha (ERalpha), through interaction with p85, regulates

phosphoinositide 3-kinase (PI3K) activity, revealing a physiologic, nonnuclear

function of the ERalpha potentially relevant in cell proliferation and apoptosis.

In our study, using MCF-7, we have analyzed the ability of RES to modulate the

ERalpha-dependent PI3K pathway. Immunoprecipitation and kinase activity assays

showed that RES increased the ERalpha-associated PI3K activity with a maximum

stimulatory effect at concentrations close to 10 microM; concentrations >50

microM decreased PI3K activity. Stimulation of PI3K activity by RES was

ERalpha-dependent since it could be blocked by the antiestrogen ICI 182,780. RES

did not affect p85 protein expression but induced the proteasome-dependent

degradation of the ERalpha. Nevertheless, the amount of PI3K immunoprecipitated

by the ERalpha remained unchanged in presence of RES, indicating that ERalpha

availability was not limiting PI3K activity. Phosphoprotein kinase B (pPKB/AKT)

followed the pattern of PI3K activity, whereas RES did not affect total PKB/AKT

expression. PKB/AKT downstream target glycogen synthase kinase 3 (GSK3) also

showed a phosphorylation pattern that followed PI3K activity. We propose a

mechanism through which RES could inhibit survival and proliferation of

estrogen-responsive cells by interfering with an ERalpha-associated PI3K pathway,

following a process that could be independent of the nuclear functions of the

ERalpha.

This article (below) has been retracted!!!

IKKepsilon phosphorylation of estrogen receptor alpha Ser-167 and contribution to tamoxifen resistance in breast cancer.

Guo JP, Shu SK, Esposito NN, Coppola D, Koomen JM, Cheng JQ.

J Biol Chem. 2010 Feb 5;285(6):3676-84

thanks alot respected

olga sukocheva