48 research outputs found
In-vitro NMR Studies of Prostate Tumor Cell Metabolism by Means of Hyperpolarized [1-13C]Pyruvate Obtained Using the PHIP-SAH Method
Targeting of the adaptor protein Tab2 as a novel approach to revert tamoxifen resistance in breast cancer cells.
Genome-wide activity of unliganded estrogen receptor-\u3b1\ua0 in breast cancer cells
Estrogen receptor-\u3b1 (ER\u3b1) has central role in hormone-dependent
breast cancer and its ligand-induced functions have been extensively
characterized. However, evidence exists that ER\u3b1 has functions that
are independent of ligands. In the present work, we investigated the
binding of ER\u3b1 to chromatin in the absence of ligands and its functions
on gene regulation. We demonstrated that in MCF7 breast cancer
cells unliganded ER\u3b1 binds to more than 4,000 chromatin sites.
Unexpectedly, although almost entirely comprised in the larger group
of estrogen-induced binding sites, we found that unliganded-ER\u3b1
binding is specifically linked to genes with developmental functions,
compared with estrogen-induced binding. Moreover, we found that
siRNA-mediated down-regulation of ER\u3b1 in absence of estrogen is
accompanied by changes in the expression levels of hundreds of
coding and noncoding RNAs. Down-regulatedmRNAs showed enrichment
in genes related to epithelial cell growth and development.
Stable ER\u3b1 down-regulation using shRNA, which caused cell growth
arrest, was accompanied by increased H3K27me3 at ER\u3b1 binding
sites. Finally, we found that FOXA1 and AP2\u3b3 binding to several sites
is decreased upon ER\u3b1 silencing, suggesting that unliganded ER\u3b1
participates, together with other factors, in the maintenance of the
luminal-specific cistrome in breast cancer cell
Gene expression of growth factor BMP15, GDF9, FGF2 and their receptors in bovine follicular cells
Introduction. Growth and follicular maturation involve transformations of various components of the follicle, such as the oocyte, granulosa and techa cells. Several growth factors, including differentiation growth factor 9 (GDF9), bone morphogenic protein 15 (BMP15) and basic fibroblast growth factor (FGF2) are important for follicular development and oocyte maturation, by its ability to increase the proliferation of granulosa, techa cells and the ovarian stroma. Objetive. Evaluate mRNA expression of GDF9, BMP15, FGF2 and their main receptors, transforming growth factor beta receptor 1 (TGFβ-R1), bone morphogenetic protein receptor, type IB (BMPR-IB) and fibroblast growth factor receptor 2 (FGFR2) in bovine follicular cells. Materials and methods. Total RNA was isolated from pooled samples of oocytes (OOs), cumulus cells (CCs) of cumulus oocyte complexes (COCs) and follicular cell pellets (PCs) of 70 ovaries obtained from 96 beef heifers, collected at a local abattoir. The expression pattern of growth factors and their receptors in follicular bovine cells was evaluated by reverse transcriptase polymerase chain reaction (RT-PCR). Results. The mRNA transcripts encoding GDF9, BMP15, FGF2, TGFβ-R1, BMPR-IB and FGFR2 genes were detected, by RT-PCR, in all studied cells. This is the first time that the expression of TGFβ-R1 and BMPR-IB receptors is reported in bovine oocytes. Conclusions. The presence of growth factors and receptor transcripts in the studied cells indicate that these factors could act as paracrine and autocrine regulators of folliculogenesis
Metabolic Studies of Tumor Cells Using [1- 13 C] Pyruvate Hyperpolarized by Means of PHIP-Side Arm Hydrogenation
Effect of the hydrogenation solvent in the PHIP-SAH hyperpolarization of [1-13C]pyruvate
ParaHydrogen Polarized Ethyl-[1-13C]pyruvate in Water, a Key Substrate for Fostering the PHIP-SAH Approach to Metabolic Imaging
An efficient synthesis of vinyl-[1-13C]pyruvate has been reported, from which 13C hyperpolarized (HP) ethyl-[1-13C]pyruvate has been obtained by means of ParaHydrogen Induced Polarization (PHIP). Due to the intrinsic lability of pyruvate, which leads quickly to degradation of the reaction mixture even under mild reaction conditions, the vinyl-ester has been synthesized through the intermediacy of a more stable ketal derivative. 13C and 1H hyperpolarizations of ethyl-[1-13C]pyruvate, hydrogenated using ParaHydrogen, have been compared to those observed on the more widely used allyl-derivative. It has been demonstrated that the spin order transfer from ParaHydrogen protons to 13C, is more efficient on the ethyl than on the allyl-esterdue to the larger J-couplings involved. The main requirements needed for the biological application of this HP product have been met, i. e. an aqueous solution of the product at high concentration (40 mM) with a good 13C polarization level (4.8 %) has been obtained. The in vitro metabolic transformation of the HP ethyl-[1-13C]pyruvate, catalyzed by an esterase, has been observed. This substrate appears to be a good candidate for in vivo metabolic investigations using PHIP hyperpolarized probes