9-cis-retinoic acided mediated endothelial transdifferentiation in breast cancer cells
Thesis (Ph.D.)--Georgetown University, 2008.; Includes bibliographical references.; Text (Electronic thesis) in PDF format. Retinoic acid is a vitamin A derivative that has growth inhibitory and differentiating effects. For these reasons, it was thought that retinoic acid could function as a chemopreventative and a chemotherapeutic agent. However, clinical trials have shown mixed results - it is beneficial to some patients and harmful to others. We studied the effects of 9-cis-retinoic acid on breast cancer in vitro. In this work I show that retinoic acid treatment of SKBR-3 cells has growth inhibitory and differentiating effects; however, instead of differentiating into epithelial cells, retinoic acid treated SKBR-3 cells differentiate into endothelial-like cells. These results may explain the failure of retinoic acid treatment in clinical trials in a subset of the population. Previous data in the laboratory indicates that SOX9 and ER81 expression are necessary but not sufficient for inducing the expression of VE-cadherin. The use of two pan-kinase inhibitors, Genistein and SD705702, demonstrates that VE-cadherin expression is dependent on kinase activity; however, the active kinase is not a receptor tyrosine kinase since retinoic acid treatment results in the loss of tyrosine kinase activity. The TGF-beta-R1 kinase inhibitor, SB431542, has the ability to inhibit VE-cadherin expression.; Retinoic acid also induces profound morphological changes in SKBR-3 cells, reminiscent of vasculogenic mimicry, an alternative form of tumor vascularization. When retinoic acid treated SKBR-3 cells are grown on Matrigel, they form endothelial like networks with hollowed out balls resulting from cell fusion. VE-cadherin siRNA and SB431542 treatment result in the loss of cell fusion, but not network formation in retinoic acid treated cells. On the other hand, COUP-TFII siRNA does not affect cell fusion, but inhibits network formation.; Functionally, retinoic acid treated SKBR-3 cells are able to interact with HUVECs in Matrigel. Untreated SKBR-3 cells grow on top of established HUVEC networks. On the other hand, retinoic acid treated SKBR-3 cells fuse together and form the nodal points into which HUVEC networks grow into and out of. This arrangement might allow a channel lined by tumor cells to conduct nutrients deep into the tumor.; In conclusion, VE-cadherin expression in retinoic acid treated SKBR-3 cells is mediated by 3 necessary but not sufficient factors - SOX9, ER81, and a TGF-beta pathway. The cell fusion portion of vasculogenic mimicry is mediated by VE-cadherin, while network formation is mediated by COUP-TFII. Given the poor prognosis associated with vasculogenic mimicry, it is important to understand the mechanism of vitamin A induced endothelial transdifferentiation to help tailor a patient's treatment.
Showing items related by title, author, creator and subject.
A Phase I Study of Adenovirus Mediated Gene Transfer of Interleukin 2 cDNA into Metastatic Breast Cancer or Melanoma Stewart, A. K.; Lassam, N. J.; Graham, F. L.; Gauldie, J.; Addison, C. L.; Bailey, D. J.; Dessurealt, S.; Dube, I. D.; Gallenger, S.; Krajden, M.; Rotstein, L. E.; Quirt, I. C.; Moen R. (1997-07-20)
TRANSCRIPTIONAL REPRESSION OF THE NUCLEAR RECEPTOR COACTIVATOR AIB1 BY FOXG1 LEADS TO APOPTOSIS IN BREAST CANCER CELLS Li, Jordan V. (Georgetown University, 2013)The oncogene nuclear receptor coactivator amplified in breast cancer 1 (AIB1) is a transcriptional coactivator that is overexpressed in various types of human cancers. However, the molecular mechanisms controlling AIB1 ...
Laminin-1 mediates epigenetic control of the epithelial cadherin for breast cancer cells in three-dimensional culture Benton, Gabriel Jon. (Georgetown University, 2010)