The function of membrane-associated molecules in acquired resistance to antiestrogens in breast cancer

Long-term clinical adjuvant antihormone therapy for breast cancer has significantly improved survival of estrogen receptor (ER)-positive breast cancer patients, but acquired resistance to antiestrogens is a major challenge in clinic. The evolution of acquired resistance to selective estrogen receptor modulators (SERMs) is unique because the growth of resistant tumors is dependent on SERMs. Thus, it appears that acquired resistance to SERMs is initially able to utilize either estrogen (E2) or a SERM as the growth stimulus in the ER-positive SERM-resistant breast tumors. However, no mechanism has been established to explain this paradox. Our newly established cell model MCF-7: PF, for the first time, replicates Phase I acquired resistance to SERMs in vitro. The cells are stimulated to grow robustly with E2 and SERMs through the ER which is confirmed by the evidence that pure antiestrogen ICI 182,780 (ICI) completely blocks the stimulation induced by E2 or SERMs. In contrast to E2 that activates classical ER-target genes, SERMs continue to function as effective antiestrogens to inhibit classical ER-target genes, even at the time of growth stimulation. A significant alteration of ER function observed in SERM-resistant cells is the enhancement of the non-genomic pathway of ER and the activation of multiple membrane function-associated molecules including focal adhesion molecules and adapter proteins to further increase phosphorylation of insulin-like growth factor-1 receptor (IGF-1R). Inhibition of membrane-associated signaling, IGF-1R and focal adhesion kinase (FAK), completely abolishes 4-OHT-stimulated cell growth. Overall, the constant nuclear pressure causes broad activation of membrane-associated signaling to aid breast cancer cell survival during the selection process required for acquired SERM resistance. The targeting of these membrane function-associated pathways and seeking new unanticipated combination therapies may have further clinical potential to decipher and treat endocrine-resistant breast cancer

Polyoxometalate multi-electron-transfer catalytic systems for water splitting

The viable production of solar fuels requires a visible-light-absorbing unit, a H2O (or CO2) reduction catalyst (WRC), and a water oxidation catalyst (WOC) that work in tandem to split water or reduce CO2 with H2O rapidly, selectively, and for long periods of time. Most catalysts and photosensitizers developed to date for these triadic systems are oxidatively, thermally, and/or hydrolytically unstable. Polyoxometalates (POMs) constitute a huge class of complexes with extensively tunable properties that are oxidatively, thermally, and (over wide and adjustable pH ranges) hydrolytically stable. POMs are some of the fastest and most stable WOCs to date under optimal conditions. This Microreview updates the very active POM WOC field; it reports the application of POMs as WRCs and initial self-assembling metal oxide semiconductor–photosensitizer–POM catalyst triad photoanodes. The complexities of investigating these POM systems, including but not limited to the study of POM-hydrated metal-ion–metal-oxide speciation processes, are outlined. The achievements and challenges in POM WOC, WRC, and triad research are outlined

Cellular Arrays (US Patent Application)

The present invention relates to characterizing transcription within cells. In particular, the present invention provides transfected cell arrays (e.g., two-dimensional and/or three-dimensional arrays) and systems, kits and methods utilizing the same (e.g., for transcriptional activity characterization). Compositions and methods of the present invention find use in, among other things, research, drug discovery and clinical (e.g., diagnostic, preventative and therapeutic) applications

Bioluminescence Imaging for Assessment and Normalization in Transfected Cell Arrays

Transfected cell arrays (TCAs) represent a high-throughput technique to correlate gene expression with functional cell responses. Despite advances in TCAs, improvements are needed for the widespread application of this technology. We have developed a TCA that combines a two-plasmid system and dual-bioluminescence imaging to quantitatively normalize for variability in transfection and increase sensitivity. The two-plasmids consist of: (i) normalization plasmid present within each spot, and (ii) functional plasmid that varies between spots, responsible for the functional endpoint of the array. Bioluminescence imaging of dual-luciferase reporters (renilla, firefly luciferase) provides sensitive and quantitative detection of cellular response, with minimal post-transfection processing. The array was applied to quantify estrogen receptor α (ERα) activity in MCF-7 breast cancer cells. A plasmid containing an ERα-regulated promoter directing firefly luciferase expression was mixed with a normalization plasmid, complexed with cationic lipids and deposited into an array. ER induction mimicked results obtained through traditional assays methods, with estrogen inducing luciferase expression 10-fold over the antiestrogen fulvestrant or vehicle. Furthermore, the array captured a dose response to estrogen, demonstrating the sensitivity of bioluminescence quantification. This system provides a tool for basic science research, with potential application for the development of patient specific therapies

Bioluminescence Imaging for Assessment and Normalization in Transfected Cell Arrays

Transfected cell arrays (TCAs) represent a high-throughput technique to correlate gene expression with functional cell responses. Despite advances in TCAs, improvements are needed for the widespread application of this technology. We have developed a TCA that combines a two-plasmid system and dual-bioluminescence imaging to quantitatively normalize for variability in transfection and increase sensitivity. The two-plasmids consist of: (i) normalization plasmid present within each spot, and (ii) functional plasmid that varies between spots, responsible for the functional endpoint of the array. Bioluminescence imaging of dual-luciferase reporters (renilla, firefly luciferase) provides sensitive and quantitative detection of cellular response, with minimal post-transfection processing. The array was applied to quantify estrogen receptor α (ERα) activity in MCF-7 breast cancer cells. A plasmid containing an ERα-regulated promoter directing firefly luciferase expression was mixed with a normalization plasmid, complexed with cationic lipids and deposited into an array. ER induction mimicked results obtained through traditional assays methods, with estrogen inducing luciferase expression 10-fold over the antiestrogen fulvestrant or vehicle. Furthermore, the array captured a dose response to estrogen, demonstrating the sensitivity of bioluminescence quantification. This system provides a tool for basic science research, with potential application for the development of patient specific therapies

Most Plastic Products Release Estrogenic Chemicals: A Potential Health Problem That Can Be Solved

Background: Chemicals having estrogenic activity (EA) reportedly cause many adverse health effects, especially at low (picomolar to nanomolar) doses in fetal and juvenile mammals