Control tumors had a significantly lower apoptotic index than the treated (P<

Control tumors had a significantly lower apoptotic index than the treated (P< .01). mg/kg) treatment group and a control group given saline. MRI/MRS was performed 1 day before treatment and 1, 3, and 6 days after treatment. Parametric images of the extracellular extravascular volume fraction (ve) transfer constant (Ktrans) and the apparent diffusion coefficient (ADC) were calculated from the DCE-MRI and DW-MRI data. Biopsies were analyzed by HR MAS MRS, and histopathology and gene expression profiles were determined (Illumina). A significant increase in the ADC 3 and 6 days after treatment and a significant decrease in total choline and a highervewere found in treated tumors 6 days after treatment. No significant difference was found in theKtransbetween the two groups. Our results show that docetaxel induces apoptosis and decreases proliferation in MCF7 xenografts. Further, these phenomena can be monitored byin vivoMRS, DW-MRI, and gene expression. == Introduction == More than 1 million women worldwide are diagnosed with breast cancer annually [1]. Recent advances in cancer therapy have aimed to optimize treatment strategies individually. Docetaxel is used clinically for neoadjuvant treatment of advanced breast carcinomas [2] to decrease tumor size before surgery and improve the effectiveness of systemic treatment by fighting micro metastatic disease at an early stage [2,3]. Clinical assessment of tumor sensitivity to neoadjuvant chemotherapy is performed within 3 to 4 4 months (i.e., Monensin sodium after three to four cycles given each 3 weeks) by assessing changes in tumor volume [4]. New methods having the possibility to predict tumor response earlier render earlier optimized treatment strategies. This would reduce health costs and unnecessary adverse effects and increase patient survival. Docetaxel is a microtubule-stabilizing agent that induces polymerization of tubulin monomers [5], leading to mitotic arrest in the cell cycle. Choline (Cho) metabolites have been investigated as biomarkers for cell proliferation and tumor metabolism [69].In vivomagnetic resonance spectroscopy (MRS) provides quantitative metabolite information and is thus a promising tool for monitoring changes induced by treatment. By using high-resolution magic angle spinning (HR MAS) MRS on intact tissue samples, more detailed metabolite profiles can be obtained. Various studies have revealed an increased Cho uptake, an upregulated activity of choline kinase and an increased level of phosphocholine (PCho) in cancer cells [1012]. A previous study in our laboratory observed decreased choline metabolite levels in docetaxel-treated tumors usingin vivoMRS andex vivoHR MAS MRS [6]. After mitotic arrest induced by treatment, tumor cells generally enter apoptosis or undergo mitotic catastrophe cell death [13,14]. The motion of water molecules is restricted by cell membranes and macromolecules. Because of this, changes in diffusion-weighted (DW) MRI may be an effective early biomarker for monitoring docetaxel treatment effects. Successful anticancer therapies have been observed to cause early increases in the tumor apparent diffusion coefficient (ADC) in both animals and humans [1518]. DW-MRI may monitor docetaxel effects in subtumor areas and differentiate necrotic and viable tissue [19]. In addition to induced cell death, docetaxel inhibits several endothelial cell functions, impairing the development of essential tumor vasculature [20]. Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) is a widely used tool for evaluating tumor vasculature. Contrast enhancement in tumor tissue depends on factors such as tumor vasculature, tissue perfusion, vessel permeability, and the volume of the extracellular extravascular space. The contrast enhancement curves can be analyzed either empirically [21] or with model-based quantitative methods [6,22]. Several studies have shown decreased contrast enhancement [21,23,24] and a decreasedKtrans[18,25] after successful treatment. Jensen et al. [6] showed a slight decrease inKtransin MCF7 xenografts due to docetaxel treatment. When a tumor responds to therapy, a cascade of different incidents is actuated. The cytostatic effect of docetaxel will affect the tumor microenvironment, which, in turn, might affect the tumor gene expression profile. Gene expression analysis gives information about processes controlled at the messenger RNA level and might therefore add valuable information Mouse monoclonal antibody to TBL1Y. The protein encoded by this gene has sequence similarity with members of the WD40 repeatcontainingprotein family. The WD40 group is a large family of proteins, which appear to have aregulatory function. It is believed that the WD40 repeats mediate protein-protein interactions andmembers of the family are involved in signal transduction, RNA processing, gene regulation,vesicular trafficking, cytoskeletal assembly and may play a role in the control of cytotypicdifferentiation. This gene is highly similar to TBL1X gene in nucleotide sequence and proteinsequence, but the TBL1X gene is located on chromosome X and this gene is on chromosome Y.This gene has three alternatively spliced transcript variants encoding the same protein for understanding treatment effects detected by MRS, DCE-MRI, and DW-MRI. Because early treatment monitoring may provide Monensin sodium important information about patient management, the purpose of this study was to evaluate DCE-MRI, DW-MRI,in vivoMRS, andex vivoHR MAS MRS as Monensin sodium tools for detecting early effects of docetaxel treatment. Gene expression analysis using Illumina microarray (Illumina, Inc, San Diego, CA) was performed to study the underlying molecular mechanisms. Proliferation and apoptotic index, determined by histopathology, were used as measures for docetaxel treatment effects. == Materials and Methods == == Mice and Tumors == Human MCF-7 (ATCC-HTB-22; American Type Culture Collection, Manassas, VA) breast cancer cells were cultured as recommended by the supplier. Female 6-week-old athymic mice (BalbC/cnu/nu; Mllergrd, Denmark; mean weight, 20 g) were allowed to acclimatize for 1 week and cared.