Hedgehog Signaling in Mouse Mammary Tumor Stem Cells (FMMC 419II)
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Issue Date
2017
Authors
Sfoglia, Katherine '17
Degree
MS in Pharmaceutical Sciences
Advisor
Voigt, Jeffrey
Committee Members
Dearborn, Richard
Shi, Binshan
Shi, Binshan
Journal Title
Journal ISSN
Volume Title
Abstract
419II cells were originally isolated from mouse mammary tumors and are currently being used for cancer stem cell research. It is believed that the gene, Bmi-1, controls the tumorigenic potential of these cells, although other factors may contribute as well. The Hh pathway regulates proliferation and differentiation of stem cells during embryonic development. When unregulated, this pathway has been observed to contribute to some cancers. Since Hh signaling has a role in the regulation of stemness of human mammary tumor stem cells, it is possible that the hedgehog pathway regulates growth and gene expression in the 419II cells. Studies on the developing Drosophila visual system showed a decrease in VDUP1 expression in the presence of hedgehog activity during visual development. Treatment of MDA-231 cells with GANT61, a Gli inhibitor, increased VDUP1 protein expression. These observations suggest that the hedgehog pathway may regulate VDUP1 expression. This led to the hypothesis that inhibition of the hedgehog pathway will affect proliferation and gene expression of the 419II cells. GANT61, a Hh inhibitor, was effective in inhibiting the growth of the 419II cells. Flow cytometric analyses showed that the growth inhibitory effects of GANT61 were due to an induction of apoptosis. QPCR analysis of mRNA expression demonstrated that hedgehog signaling components (Gli1, Gli2 and SHh ligand), as well as a downstream target gene (Bmi-1) are expressed in 419II cells. GANT61 treatment decreased Gli-1 mRNA expression and Western blot results showed a decrease in Bmi-1 protein expression after GANT61 treatment. These finding provide proof of a functional Hh signaling pathway. A decrease in VDUP1 mRNA expression following GANT61 treatment was observed, but no change in protein expression was seen. This suggested that the Hh pathway regulates VDUP1 mRNA expression. In conclusion, the Hh pathway was found to be active in the 419II cells and inhibition of the pathway did affect growth and gene expression. In addition, VDUP1 is present in the 419II cells and its mRNA is regulated by Hh activity. This study provides valuable information about cancer stem cells that could contribute to creating more effective cancer therapies.
Citation
Sfoglia K. Hedgehog signaling in mouse mammary tumor stem cells (FMMC 419II) [thesis]. Ann Arbor (MI): Proquest LLC; 2017. 72 p.
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