Imaging multidrug resistance and modulation in breast CA

Imaging multidrug resistance and modulation in breast CA

ABSTRACTS OF NIH GRANTS Academic Radiology, Vol 11, No 1, January 2004 stimuli converge on a process of activation of a family of cysteine proteases...

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ABSTRACTS OF NIH GRANTS

Academic Radiology, Vol 11, No 1, January 2004

stimuli converge on a process of activation of a family of cysteine proteases known as the caspases (cysteine aspartases). Activation of members of the caspase family have been shown to be necessary for programmed cell death in a number of biological systems and evidence strongly points to caspase-3 as standing at the center of the execution pathway of the cell death program. While existing in a non-active pro-enzyme form in the cytosol of resting cells, caspase-3 is one key “effector” protease when activated. Thus, to monitor the final commitment of tumor cells to death pathways, the need exists to directly quantify the enzymatic activity of caspase-3 in vivo. To meet this challenge, we have designed and synthesized a prototype of an entirely new class of peptide based imaging agents that can permeate the cell membrane. Incorporating permeation motifs of viral proteins, these prototypic membrane permeant peptide conjugates are capable of translocating across the cell membrane to the cytosolic compartment. Engineered with substrate recognition sequences and appropriate peptide-based motifs for chelating radionuclides such as technetium-99m (Tc-99m), these agents will enable imaging of caspase-3 activity in vivo. Enzyme-dependent signal amplification should result in high quality enzyme-specific molecular images. In this way, focal retention of radioactivity, a “hot spot”, will be generated on tumor images where there exists enzymatically active caspase-3. We propose to define the structural determinants of the viral protein cell membrane permeation sequences for use in peptide imaging conjugates, use a degenerate peptide combinatorial library to determine the preferred recognition sequences of the peptide imaging substrates, define the structural determinants and charge of the chelation moiety of our peptide conjugates that will confer favorable cellular retention properties to the imaging fragments, and perform preclinical evaluation of Tc-99m labeled peptide chelation conjugates in order to study the time course of activation of caspase-dependent apoptosis in tumor models grown in nude mice. Studies with these novel imaging tools will assist interrogation of the efficacy of new therapies, including gene therapy and new molecular targeted chemotherapy in cancer. Thesaurus Terms: bioengineering/biomedical engineering, cell membrane, chelating agent, cysteine endopeptidase, enzyme activity, membrane permeability, peptide, radionuclide imaging/scanning apoptosis, chemical conjugate, contrast media, cytoplasm, disease/disorder model, neoplastic cell, protein sequence, technetium MCF7 cell, athymic mouse, bioimaging/biomedical imaging, fluorescence microscopy, laboratory rat, radionuclide, tissue/cell culture

Institution:

Fiscal Year: Department:

Washington University Lindell And Skinker Blvd St. Louis, MO 63130 2002 Radiology

Project Start: Project End: ICD: IRG:

01-Jul-1999 30-Apr-2004 National Cancer Institute RNM

IMAGING MULTIDRUG RESISTANCE AND MODULATION IN BREAST CA Grant Number: PI Name:

5R01CA083059-04 Piwnica-Worms, David R.

Abstract: In the United States, breast cancer is the most common malignancy in women. Although most women with advanced disease initially respond to chemotherapy, most die of recurrent and refractory disease. Emergence of multi-drug resistance (MDR) in breast cancer mediated by the MDR1 P-glycoprotein has been associated with poor response to chemotherapy and a shorter overall survival. P-glycoprotein acts as an efflux transporter reducing the intracellular accumulation of many chemotherapeutic drugs. The multi-drug resistance-associated protein (MRP), a homologue of P-glycoprotein, may also have a role in therapeutic response in breast cancer, but this is less well defined. Recently, several novel MDR antagonists (modulators) highly selective for Pglycoprotein have been commercially developed with nanomolar potency. Thus, functional identification of P-glycoprotein, and perhaps MRP, at the time of presentation could provide important information that could direct the choice of chemotherapeutic options. We have discovered that Tc-99mSestamibi, a commercially available radiopharmaceutical, is recognized as a transport substrate by the human MDR1 Pglycoprotein in vitro and in vivo and may be recognized by MRP, thus enabling functional identification of transportermediated resistance by scintigraphy. We propose to test the hypothesis that dynamic imaging of breast tumors with Tc99m-Sestamibi will predict treatment failure in women with advanced breast carcinoma and determine whether P- glycoprotein and MRP together or independently impact Tc-99mSestamibi pharmacokinetics in breast tumors in vivo. These imaging studies will be integrated with a Phase II clinical trial of LY335979 (Eli Lilly and Co.), a potent new MDR modulator selective for inhibition of P-glycoprotein. Patients with advanced breast carcinoma will be imaged before and after administration of LY335979 as a pharmacokinetic endpoint to aid drug development. Functional imaging of the MDR phenotype with radiopharmaceuticals may provide a novel tool to rapidly characterize clinically relevant MDR in human tumors in vivo, target MDR modulators in vivo, and ultimately provide a means to direct patients to molecularspecific cancer therapies. Thesaurus Terms: P glycoprotein, autoradiography, breast neoplasm, multi-drug resistance, neoplasm/cancer radiodiag-

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ABSTRACTS OF NIH GRANTS

nosis, radiopharmacology, technetium breast neoplasm/cancer diagnosis, gene expression, human therapy evaluation, neoplasm/cancer chemotherapy, pharmacokinetics, tumor progression bioimaging/biomedical imaging, biopsy, clinical research, female, human subject, immunocytochemistry, laboratory mouse, positron emission tomography, scanning electron microscopy, women’s health

Institution:

Fiscal Year: Department: Project Start: Project End: ICD: IRG:

Washington University Lindell And Skinker Blvd St. Louis, MO 63130 2002 Radiology 01-Sep-1999 30-Jun-2004 National Cancer Institute ZCA1

WASHINGTON UNIVERSITY MOLECULAR IMAGING CENTER Grant Number: PI Name:

1P50CA094056-01 Piwnica-Worms, David R.

Abstract: Description (provided by applicant): Washington University Medical School’s concept of an In Vivo Cellular and Molecular Imaging Center (ICMIC) envisions a process that will permit the Center to become the focal point for the development of novel in vivo molecular imaging initiatives on campus. This involves further expanding and reinforcing collaborations and enhancing the productivity of multidisciplinary programs in basic cancer cell biology and molecular imaging research. The ultimate objective of the proposed P50 Program is to combine the institutional expertise of Washington University in the basic sciences of molecular oncology, immunology, molecular genetics and signal transduction with our well-developed infrastructure in medical imaging under the formal configuration of an ICMIC. We are strategically positioned to focus the majority of our ICMIC resources on the advancement of novel interactive and collaborative oncologic molecular imaging projects. To meet these goals, an organizational structure with three molecular imaging cores, four multidisciplinary ICMIC research projects, four developmental research projects, an educational program and a training/career development program are proposed. The four projects, representing innovative and exciting new initiatives on campus are: 1) In Vivo Imaging of Gene Expression in Prostate Cancer, 2) Non-Invasive Monitoring of T Cell-Mediated Tumor Ablation, 3) Imaging Cancer Viruses with Tat Transducible Peptides, 4) Imaging MDRI P-glycoprotein Transport Activity In Vivo with Tc94m-Sestamibi PET to Predict Response to Chemotherapy in

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Academic Radiology, Vol 11, No 1, January 2004

Extensive Stage Small Cell Lung Cancer. An organizational structure for an ICMIC has been established and all milestones achieved with our active P20 planning grant. The P50 Center grant will now promote excellence in molecular imaging in cancer research by providing a formal conduit for interdisciplinary multi-modality collaborations. Thesaurus Terms: human therapy evaluation, magnetic resonance imaging, neoplasm/cancer chemotherapy, positron emission tomography, prognosis bioimaging/biomedical imaging, clinical research, human subject

Institution:

Fiscal Year: Department: Project Start: Project End: ICD: IRG:

Washington University Lindell And Skinker Blvd St. Louis, MO 63130 2002 Radiology 31-May-2002 31-Mar-2007 National Cancer Institute ZCA1

BREAST CANCER TREND ANALYSIS USING STOCHASTIC SIMULATION Grant Number: PI Name:

5U01CA088248-03 Plevritis, Sylvia K.

Abstract: The goals of this NCI cooperative research program (CISNET) are to explain the US breast cancer incidence and mortality trends, and to predict changes in the trends with new interventions. We will collaboratively with CISNET investigators toward developing validated computer-based simulation analyses that will attain these goals. In addition, we will contribute to CISNET novel research ideas and validated methods to quantify the impact of biological factors on breast cancer trends. The specific aims of this research effort will be: (1) to develop a stochastic model of the natural history of breast cancer that describes the growth rate of the primary tumor, the size of the primary tumor when it sheds its first metastatic cell, and the growth rate of metastases; (2) to simulate the progression of breast cancer in the US population using a natural history model of breast cancer; (3) to explain and predict US breast cancer trends with validated computer simulation tools that incorporate a natural history model of the disease. Awareness of biological factors on the breast cancer trends may provide new insights for more effectively targeting future breast cancer control programs. Thesaurus Terms: breast neoplasm, mathematical model, model design/development, neoplasm/cancer epidemiology,