Articles by Amelia J. Tesone in JoVE
Initiation of Metastatic Breast Carcinoma by Targeting of the Ductal Epithelium with Adenovirus-Cre: A Novel Transgenic Mouse Model of Breast Cancer Melanie R. Rutkowski*1, Michael J. Allegrezza*1, Nikolaos Svoronos1, Amelia J. Tesone1, Tom L. Stephen1, Alfredo Perales-Puchalt1, Jenny Nguyen1, Paul J. Zhang2, Steven N. Fiering3, Julia Tchou4,5,6, Jose R. Conejo-Garcia1 1Tumor Microenvironment and Metastasis Program, Wistar Institute, 2Department of Pathology and Lab Medicine, Perelman School of Medicine, University of Pennsylvania, 3Department of Microbiology and Immunology and Department of Genetics, Geisel School of Medicine at Dartmouth, 4Division of Endocrine and Oncologic Surgery, Department of Surgery, Perelman School of Medicine, University of Pennsylvania, 5Rena Rowan Breast Center, Abramson Cancer Center, University of Pennsylvania, 6Center for Advanced Medicine, University of Pennsylvania Activation of latent mutations with adenovirus-Cre into the mammary ductal system results in a clinically relevant metastatic breast cancer. Incorporation of a YFP promoter allows tracking of distal metastatic tumor cells. This model is useful to study latent metastasis, anti-tumor immunity, and for designing novel immunotherapies to treat breast cancer.
Other articles by Amelia J. Tesone on PubMed
5α-Reductase, an Enzyme Regulating Glucocorticoid Action in the Testis of Rhinella Arenarum (Amphibia: Anura) General and Comparative Endocrinology. May, 2012 | Pubmed ID: 22285601 The reduction of A-ring of glucocorticoids to produce 5α-dihydro-derivatives by 5α-reductases has been considered as a pathway of irreversible inactivation. However, 5α-reduced metabolites of corticosterone and testosterone have significant biological activity. In this paper, we investigated whether toad testicular 5α-reductase (5α-Red) is able to transform corticosterone into 5α-dihydrocorticosterone. Furthermore, we studied the role of 5α-reduced metabolite of corticosterone as a glucocorticoid receptor (GR) agonist. The activity of 5α-Red was assayed in subcellular fractions with [(3)H]corticosterone or [(3)H]testosterone as substrate. The enzyme localizes in microsomes and its optimal pH is between 7 and 8. The activity is not inhibited by finasteride. These results support the conclusion that toad 5α-Red resembles mammalian type 1 isoenzyme. Kinetic studies indicate that neither K(m) nor V(max) for both corticosterone and testosterone were significantly different among reproductive periods. The K(m) value for testosterone was significantly higher than that for corticosterone, indicating that the C-21 steroid is the preferred substrate for the enzyme. Studies of the binding capacity of 5α-dihydrocorticosterone (5α-DHB) to the testicular GR show that 5α-DHB is able to displace the binding of [(3)H]dexamethasone to testicular cytosol with a similar potency than corticosterone. The inhibition constant (Ki) values for corticosterone and 5α-DHB were similar, 31.33±2.9 nM and 35.24±2.3 nM, respectively. In vitro experiments suggest that 5α-DHB is an agonist of toad testicular GR, decreasing the activity of the key enzyme for androgen synthesis, the cytochrome P450 17-hydroxylase, C17,20-lyase.
Reprogramming Tumor-associated Dendritic Cells in Vivo Using MiRNA Mimetics Triggers Protective Immunity Against Ovarian Cancer Cancer Research. Apr, 2012 | Pubmed ID: 22307839 Modulating the activity of miRNAs provides opportunities for novel cancer interventions. However, low bioavailability and poor cellular uptake are major challenges for delivering miRNA mimetics specifically to tumor cells. Here, we took advantage of the spontaneous enhanced endocytic activity of ovarian cancer-associated dendritic cells (DC) to selectively supplement the immunostimulatory miRNA miR-155. In vivo processing of nanoparticles carrying oligonucleotide duplexes mimicking the bulged structure of endogenous pre-miRNA (but not siRNA-like oligonucleotides) dramatically augmented miR-155 activity without saturating the RNA-induced silencing complex. Endogenous processing of synthetic miR-155 favored Ago2 and, to a lesser extent, Ago4 loading, resulting in genome-wide transcriptional changes that included silencing of multiple immunosuppressive mediators. Correspondingly, tumor-infiltrating DCs were transformed from immunosuppressive to highly immunostimulatory cells capable of triggering potent antitumor responses that abrogated the progression of established ovarian cancers. Our results show both the feasibility and therapeutic potential of supplementing/replenishing miRNAs in vivo using nonviral approaches to boost protective immunity against lethal tumors. Thus, we provide a platform, an optimized design, and a mechanistic rationale for the clinical testing of nonviral miRNA mimetics.
Pathological Mobilization and Activities of Dendritic Cells in Tumor-Bearing Hosts: Challenges and Opportunities for Immunotherapy of Cancer Frontiers in Immunology. 2013 | Pubmed ID: 24339824 A common characteristic of solid tumors is the pathological recruitment of immunosuppressive myeloid cells, which in certain tumors includes dendritic cells (DCs). DCs are of particular interest in the field of cancer immunotherapy because they induce potent and highly specific anti-tumor immune responses, particularly in the early phase of tumorigenesis. However, as tumors progress, these cells can be transformed into regulatory cells that contribute to an immunosuppressive microenvironment favoring tumor growth. Therefore, controlling DC phenotype has the potential to elicit effective anti-tumor responses while simultaneously weakening the tumor's ability to protect itself from immune attack. This review focuses on the dual nature of DCs in the tumor microenvironment, the regulation of DC phenotype, and the prospect of modifying DCs in situ as a novel immunotherapeutic approach.