Currently, there is an urgent need to integrate imaging and therapy for the detection and treatment of breast cancer. Of particular concern is the aggressive triple negative subtype which lacks the progesterone and estrogen receptors and epidermal growth factor type 2 receptor (Her-2/neu) and accounts for approximately half of all breast cancer deaths. To this end, we propose developing a molecular image based therapy to assess the localization and extent of breast cancer based on epithelial protein-2 (EMP2) expression. EMP2 is a novel biomarker highly expressed in the majority (63%;n=97) of invasive breast cancer tumors examined compared to healthy mammary epithelium. Its expression is independent of ER, PR, and HER2/neu expression, and high EMP2 expression is observed in over 70% of triple negative breast cancer cases examined. As engineered recombinant antibodies hold great promise for cancer diagnostics and therapy, we have carefully assembled a research team centered at UCLA to develop recombinant EMP2 antibody fragments for both imaging using PET and therapy. We have previously shown that recombinant antibody fragments (diabodies) against EMP2 promote apoptosis both in vitro and in vivo in a number of EMP2 positive tumors, and we have new data that radiolabeled minibodies specificially recognize EMP2 positive tumors using microPET. Moreover, new preliminary data clearly indicate that systemic administration of the EMP2 IgG1 reduces tumor load in human xenograft and orthotopic, syngeneic mouse model systems. In this proposal, with the explicit goal of creating a product to advance for clinical testing, we will determine the optimum full-length antibody and antibody fragment for use in therapy and imaging, respectively. We have already generated a number of these reagents, and our EMP2 antibodies and antibody fragments exhibit human and murine cross-reactivity. In this study, we will define a more complete toxicity profile, including pK, pD, and maximum tolerated dosage of these reagents to validate their usage. As a step towards using engineered EMP2 antibody fragments as an imaging agent, we propose engineering two antibody fragment formats with different pharmacokinetic and clearance characteristics to allow maximization of expression and binding. For therapy, we have created two unique fully human IgG1 antibodies that recognize the second extracellular loop of EMP2. Following validation of the specificity and sensitivity of these fragments in defined human breast cancer model systems, we will integrate therapy of breast cancer using a-EMP2 antibodies or neoadjuvant chemotherapy. Successful completion of the work proposed in this grant submission will identify the optimum strategy for imaging and therapy of breast cancer using EMP2. Given its high expression in a number of gynecological tumors including ovarian and endometrial, these studies will be important to position EMP2 as a viable target for cancers in women.

Public Health Relevance

Despite significant advances in biology and medicine, the incidence and mortality due to breast cancer world- wide is still unacceptably high. Breast cancer remains the 5th most common cause of death in women. Recently, we have identified a protein epithelial membrane protein-2 (EMP2) that is upregulated in 68% of all breast cancer tumors and 73% of triple negative tumors tested. In the studies proposed here, we present a novel and exciting imaging guided therapeutic approach through the targeting of EMP2 in breast cancer.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Research Project (R01)
Project #
1R01CA163971-01A1
Application #
8372999
Study Section
Special Emphasis Panel (ZRG1-SBIB-Q (04))
Program Officer
Tandon, Pushpa
Project Start
2012-07-09
Project End
2017-04-30
Budget Start
2012-07-09
Budget End
2013-04-30
Support Year
1
Fiscal Year
2012
Total Cost
$319,550
Indirect Cost
$112,050
Name
University of California Los Angeles
Department
Pathology
Type
Schools of Medicine
DUNS #
092530369
City
Los Angeles
State
CA
Country
United States
Zip Code
90095
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Williams, Carmen J; Chu, Alison; Jefferson, Wendy N et al. (2017) Epithelial membrane protein 2 (EMP2) deficiency alters placental angiogenesis, mimicking features of human placental insufficiency. J Pathol 242:246-259
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Ashki, Negin; Gordon, Lynn; Wadehra, Madhuri (2015) Review of the GAS3 Family of Proteins and their Relevance to Cancer. Crit Rev Oncog 20:435-47
Qin, Yu; Mohandessi, Shabnam; Gordon, Lynn et al. (2015) Regulation of FAK Activity by Tetraspan Proteins: Potential Clinical Implications in Cancer. Crit Rev Oncog 20:391-405
Lugassy, Claire; Zadran, Sohila; Bentolila, Laurent A et al. (2014) Angiotropism, pericytic mimicry and extravascular migratory metastasis in melanoma: an alternative to intravascular cancer dissemination. Cancer Microenviron 7:139-52
Fu, Maoyong; Maresh, Erin L; Helguera, Gustavo F et al. (2014) Rationale and preclinical efficacy of a novel anti-EMP2 antibody for the treatment of invasive breast cancer. Mol Cancer Ther 13:902-15
Qin, Yu; Fu, Maoyong; Takahashi, Masamichi et al. (2014) Epithelial membrane protein-2 (EMP2) activates Src protein and is a novel therapeutic target for glioblastoma. J Biol Chem 289:13974-85

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