Cynthia Miranti

Cynthia Miranti

Professor, Cellular and Molecular Medicine
Chair, Cancer Biology - GIDP
Co-Program Leader, Cancer Biology Research Program
Member of the Graduate Faculty
Professor, BIO5 Institute
Primary Department
Contact
(520) 626-2269

Research Interest

Research Interests Our objective is to define how integrin interactions within the tumor microenvironment impact prostate cancer development, hormonal resistance, and metastasis. Our approach is to understand the normal biology of the prostate gland and its microenvironment, as well as the bone environment, to inform on the mechanisms by which tumor cells remodel and use that environment to develop, acquire hormonal resistance, and metastasize. Our research is focused in three primary areas: 1) developing in vitro and in vivo models that recapitulate human disease based on clinical pathology, 2) identifying signal transduction pathway components that could serve as both clinical markers and therapeutic targets, and 3) defining the genetic/epigenetic programming involved in prostate cancer development.

Publications

Wang, X., Zhu, J., Zhao, P., Jiao, Y., Xu, N., Grabinski, T., Liu, C., Miranti, C. K., Fu, T., & Cao, B. B. (2007). In vitro efficacy of immuno-chemotherapy with anti-EGFR human Fab-Taxol conjugate on A431 epidermoid carcinoma cells. Cancer biology & therapy, 6(6), 980-7.

The aims of this study were to generate a human Fab fragment against EGFR; conjugate it to paclitaxel (Taxol) as an immuno-chemotherapy agent; and investigate its in vitro anti-tumor efficacy on A431 epidermoid carcinoma cells. A431 cells (EGFR-positive), NIH 3T3 cells (EGFR-negative), and purified EGFR were used for subtractive panning on a human naïve Fab phage library to generate a human anti-EGFR Fab fragment that binds the EGFR extracellular domain in native conformation and subsequently internalizes it into the cytosol. The Fab was then conjugated with the chemotherapeutic Taxol, and cell proliferation inhibition and apoptosis (TUNEL) assays were conducted to determine the effect of this Fab-drug conjugate on A431 cells. The specificity and internalization property of this Fab were characterized by immunoprecipitation, fluorescence staining, flow cytometry, and Hum-Zap assay. The binding affinity to purified EGFR was 30 nM. The Fab-Taxol conjugate inhibited A431 cell proliferation at low concentrations and in a dose-responsive manner; more than 70% inhibition was observed at 52 pM. Furthermore, almost 100% of cells underwent apoptosis after treatment with Fab-Taxol at 26 pM for 48 hours. Our findings suggest that this Fab-Taxol conjugate could be a potential immuno-chemotherapeutic drug for clinical treatment of EGFR-overexpressing tumors.

Bill, H. M., Knudsen, B., Moores, S. L., Muthuswamy, S. K., Rao, V. R., Brugge, J. S., & Miranti, C. K. (2004). Epidermal growth factor receptor-dependent regulation of integrin-mediated signaling and cell cycle entry in epithelial cells. Molecular and cellular biology, 24(19), 8586-99.

Integrin-mediated adhesion of epithelial cells to extracellular matrix (ECM) proteins induces prolonged tyrosine phosphorylation and partial activation of epidermal growth factor receptor (EGFR) in an integrin-dependent and EGFR ligand-independent manner. Integrin-mediated activation of EGFR in epithelial cells is required for multiple signal transduction events previously shown to be induced by cell adhesion to matrix proteins, including tyrosine phosphorylation of Shc, Cbl, and phospholipase Cgamma, and activation of the Ras/Erk and phosphatidylinositol 3'-kinase/Akt signaling pathways. In contrast, activation of focal adhesion kinase, Src, and protein kinase C, adhesion to matrix proteins, cell spreading, migration, and actin cytoskeletal rearrangements are induced independently of EGFR kinase activity. The ability of integrins to induce the activation of EGFR and its subsequent regulation of Erk and Akt activation permitted adhesion-dependent induction of cyclin D1 and p21, Rb phosphorylation, and activation of cdk4 in epithelial cells in the absence of exogenous growth factors. Adhesion of epithelial cells to the ECM failed to efficiently induce degradation of p27, to induce cdk2 activity, or to induce Myc and cyclin A synthesis; subsequently, cells did not progress into S phase. Treatment of ECM-adherent cells with EGF, or overexpression of EGFR or Myc, resulted in restoration of late-G(1) cell cycle events and progression into S phase. These results indicate that partial activation of EGFR by integrin receptors plays an important role in mediating events triggered by epithelial cell attachment to ECM; EGFR is necessary for activation of multiple integrin-induced signaling enzymes and sufficient for early events in G(1) cell cycle progression. Furthermore, these findings suggest that EGFR or Myc overexpression may provoke ligand-independent proliferation in matrix-attached cells in vivo and could contribute to carcinoma development.

Kahn, N. S., Feliu, M., Lord, A. K., Lukason, D., Tam, J. M., Kasperkovitz, P. V., Reedy, J. L., Negoro, P. E., Dagher, Z., Vyas, T. D., Xu, S., Brinkmann, M. M., Ploegh, H. L., Kim, Y., Latz, E., Mansour, M. K., Levitz, S. M., Miranti, C., & Vyas, J. (2018). CD82 controls CpG-dependent TLR9 signaling. PNAS.
Lamb, L. E., Knudsen, B. S., & Miranti, C. K. (2010). E-cadherin-mediated survival of androgen-receptor-expressing secretory prostate epithelial cells derived from a stratified in vitro differentiation model. Journal of cell science, 123(Pt 2), 266-76.

The androgen receptor (AR) is expressed in differentiated secretory prostate epithelial cells in vivo. However, in the human prostate, it is unclear whether androgens directly promote the survival of secretory cells, or whether secretory cells survive through androgen-dependent signals from the prostate stroma. Biochemical and mechanistic studies have been hampered by inadequate cell-culture models. In particular, large-scale differentiation of prostate epithelial cells in culture has been difficult to achieve. Here, we describe the development of a differentiation system that is amenable to functional and biochemical analysis and its application to deciphering the survival pathways in differentiated AR-expressing epithelial cells. Confluent prostate epithelial cell cultures were treated with keratinocyte growth factor (KGF) and dihydrotestosterone. After 2 weeks, a suprabasal cell layer was formed in which cells no longer expressed alpha2, alpha3, alpha6, alphav, beta1 or beta4 integrins or p63, K5, K14, EGFR, FGFR2IIIb or Bcl-2, but instead expressed AR and androgen-induced differentiation markers, including K18, K19, TMPRSS2, Nkx3.1, PMSA, KLK2 and secreted prostate-specific antigen (PSA). Differentiated prostate cell survival depended on E-cadherin and PI3K, but not KGF, androgen, AR or MAPK. Thus survival of differentiated prostate epithelial cells is mediated by cell-cell adhesion, and not through androgen activity or prostate stroma-derived KGF.

Bergsma, A., Dick, D., Williams, B. O., & Miranti, C. K. (2018). Global deletion of Tetraspanin CD82 attenuates bone growth and enhances bone marrow adipogenesis.. Bone.