stilbenes and Carcinoma--Ductal--Breast

Normal cellular phenotypes that serve an oncogenic function during tumorigenesis are potential candidates for cancer targeting drugs. Within a subset of invasive primary breast carcinoma, we observed relatively abundant expression of Tetherin, a cell surface protein encoded by the Bone Marrow Stromal Cell Antigen (BST2) known to play an inhibitory role in viral release from infected immune cells of the host. Using breast cancer cell lines derived from low and intermediate histopathologic grade invasive primary tumors that maintain growth-suppressive TGFβ signaling, we demonstrate that BST2 is negatively regulated by the TGFβ axis in epithelial cells. Binding of the transcription factor AP2 to the BST2 promoter was attenuated by inhibition of the TGFβ pathway thereby increasing BST2 expression in tumor cells. In contrast, inherent TGFβ resistance characteristic of high grade breast tumors is a key factor underlying compromised BST2 regulation, and consequently its constitutive overexpression relative to non-malignant breast epithelium, and to most low and intermediate grade cancer cells. In both 2-dimensional and 3-dimensional growth conditions, BST2-silenced tumor cells displayed an enhancement in tamoxifen or staurosporine-induced apoptotic cell death together with a reduction in the S-phase fraction compared to BST2 overexpressing counterparts. In a subset of breast cancer patients treated with pro apoptotic hormonal therapy, BST2 expression correlated with a trend for poor clinical outcome, further supporting its role in conferring an anti apoptotic phenotype. Similar to the effects of gene manipulation, declining levels of endogenous BST2 induced by the phytoalexin - resveratrol, restored apoptotic function, and curbed cell proliferation. We provide evidence for a direct approach that diminishes aberrant BST2 expression in cancer cells as an early targeting strategy to assist in surmounting resistance to pro apoptotic therapies.

Topics: Antigens, CD; Antineoplastic Agents, Hormonal; Apoptosis; Base Sequence; Binding Sites; Breast Neoplasms; Carcinoma, Ductal, Breast; Cell Line, Tumor; Cell Proliferation; Drug Synergism; Fatty Acid-Binding Proteins; Female; Gene Expression; Gene Expression Regulation, Neoplastic; GPI-Linked Proteins; Humans; Kaplan-Meier Estimate; Molecular Sequence Data; Promoter Regions, Genetic; Proportional Hazards Models; Protein Binding; Resveratrol; Stilbenes; Tamoxifen; Transforming Growth Factor beta

Natural compounds have been studied as a source of countless bioactive compounds with diverse activities. Among them, many dietary phytochemicals have been thoroughly studied for their cytotoxic or apoptotic effects in several cellular models in order to explain their anticancer capacity. Curcumin and resveratrol are two natural compounds with a large body of evidence showing their cytotoxic activity against a wide variety of cancer cells; however, their poor absorption, bioavailability, and low selectivity have limited their clinical use. With the aim of improving bioavailability and selectivity, the antiproliferative effects of free-, liposomed-, and immunoliposomed-curcumin and/or resveratrol formulations have been compared in two human breast cancer cell lines with different HER2 expression levels. The results demonstrate that when HER2-targeted immunoliposomes are coupled to trastuzumab there is a dramatic increase in the antiproliferative effects of curcumin and resveratrol in HER2 positive human breast cancer cells in comparison to regular liposomed or free forms, indicating an increase of its therapeutic effect. The enhancement of the cytotoxic effects was also correlated to the uptake of curcumin at intracellular level, as shown by using ImageStream technique. The striking efficacy of the immunoliposomed formulation containing both resveratrol and curcumin suggests a multitargeted mechanism of action that deserves further study. These findings show the potential of HER2-targeted nanovesicles to develop new drug delivery systems for cancer therapy based on these compounds and justify further preclinical trials.

Topics: Antibodies, Monoclonal, Humanized; Anticarcinogenic Agents; Antineoplastic Agents; Biological Availability; Biological Products; Breast Neoplasms; Carcinoma, Ductal, Breast; Cell Division; Cell Line, Tumor; Cholesterol; Chromatography, High Pressure Liquid; Curcumin; Drug Compounding; Drug Screening Assays, Antitumor; Female; Gene Expression Regulation, Neoplastic; Genes, erbB-2; Humans; Immunoconjugates; Liposomes; Neoplasm Proteins; Particle Size; Phosphatidylcholines; Phosphatidylethanolamines; Receptor, ErbB-2; Resveratrol; Stilbenes; Trastuzumab

Trans-3,4',5-trihydroxystilbene (resveratrol), a phytoalexin present in grapes and grape products such as wine, has been identified as a chemopreventive agent. Recent studies performed with MCF-7 human breast cancer cells have demonstrated superestrogenic effects with resveratrol. In contrast, studies performed using estrogen receptor-transfected cell lines have shown that resveratrol acts as a mixed agonist/antagonist. The major objective of this study was to characterize the estrogen-modulatory effects of resveratrol in a variety of in vitro and in vivo mammary models. Thus, the effect of resveratrol alone and in combination with 17beta-estradiol (E2) was assessed with MCF-7, T47D, LY2, and S30 mammary cancer cell lines. With cells transfected with reporter gene systems, the activation of estrogen response element-luciferase was studied, and using Western blot analysis, the expression of E2-responsive progesterone receptor (PR) and presnelin 2 protein was monitored. Furthermore, the effect of resveratrol on formation of preneoplastic lesions (induced by 7,12-dimethylbenz(a)anthracene) and PR expression (with or without E2) was evaluated with mammary glands of BALB/c mice placed in organ culture. Finally, the effect of p.o. administered resveratrol on N-methyl-N-nitrosourea-induced mammary tumors was studied in female Sprague Dawley rats. As a result, in transient transfection studies with MCF-7 cells, resveratrol showed a weak estrogenic response, but when resveratrol was combined with E2 (1 nM), a clear dose-dependent antagonism was observed. Similar mixed estrogenic/antiestrogenic effects were noted with S30 cells, whereas resveratrol functioned as a pure estrogen antagonist with T47D and LY2 cells. Furthermore, in MCF-7 cells, resveratrol induced PR protein expression, but when resveratrol was combined with E2, expression of PR was suppressed. With T47D cells, resveratrol significantly down-regulated steady-state and E2-induced protein levels of PR. With LY2 and S30 cells, resveratrol down-regulated presnelin 2 protein expression. Using the mouse mammary organ culture model, resveratrol induced PR when administered alone, but expression was suppressed in the presence of E2 (1 nM). Furthermore, resveratrol inhibited the formation of estrogen-dependent preneoplastic ductal lesions induced by 7,12-dimethylbenz(a)anthracene in these mammary glands (IC50 = 3.2 microM) and reduced N-methyl-N-nitrosourea-induced mammary tumorigenesis when administered to fe

Topics: Animals; Anticarcinogenic Agents; Carcinogens; Carcinoma, Ductal, Breast; Estrogens; Female; Humans; Luciferases; Mammary Glands, Animal; Mammary Neoplasms, Experimental; Methylnitrosourea; Mice; Mice, Inbred BALB C; Organ Culture Techniques; Protein Biosynthesis; Proteins; Rats; Rats, Sprague-Dawley; Receptors, Estrogen; Receptors, Progesterone; Response Elements; Resveratrol; Selective Estrogen Receptor Modulators; Stilbenes; Trefoil Factor-1; Tumor Cells, Cultured; Tumor Suppressor Proteins