In this study, we investigated the mechanisms of HDGF on cell migration in non-transformed NIH/3T3 cells. HDGF promoted the migration and the formation of dorsal ruffles and podosome rosettes. Besides, HDGF supply increased the PI3K expression, Akt phosphorylation and PTEN phosphorylation as well as stimulated the RhoA, Rac1, and Cdc42 activities. Furthermore, Adenoviral gene transfer of PTEN attenuated migration and PI3K/Akt/Rho GTPases signaling in HDGF-overexpressing transfectants. Pharmaceutical intervention using the PI3K inhibitor, LY294002, potently reversed HDGF-stimulated cell migration, dorsal ruffles formation and podosome formation as well as the RhoA, Rac1, and Cdc42 activities. Thus, HDGF elicits the activation of PI3K/Akt /Rho GTPases signaling cascade and promotes cytoskeleton remodeling to stimulate cellular migration. Moreover, we investigate the expression proļ¬le of HDGF during breast carcinogenesis. Immunohistochemical studies revealed elevated HDGF expression in human breast cancer. Nuclear HDGF labelling index was positively correlated with tumour grade, stage and proliferation index, but negatively correlated with survival rate in breast cancer patients. Our data also showed that HDGF over-expression was associated with lymph node metastasis and represented an independent prognostic factor for tumor recurrence. Furthermore, Immunoblot study revealed that elevated HDGF expression significantly higher in breast cancer cells (MDA-MB-231 cells) than that in non-transformed breast cells (MCF-7 cells). Consistently, higher invasive potency and colony formation also observed in MDA-MB-231 cells than in MCF-7 cells. Adenovirus-mediated HDGF over-expression and exogenous HDGF treatment stimulated the invasiveness and colony formation as well as E-cadherin down-regulation and Vimentin up-regulation. Conversely, either HDGF knockdown by RNA interference, HDGF antibody neutralization or BITC-induced EMT suppression in MDA-MB-231 cells attenuated the malignant behavior and elicited EMT reversal by enhancing E-cadherin expression while depleting Vimentin expression.
In summary, HDGF elicits the activation of PI3K/Akt/Rho GTPases signaling cascade, thereby promoting cytoskeleton remodeling to stimulate cellular migration. Moreover, the formation of podosome rosettes is correlated with cell invasion, the podosome-stimulating capability of HDGF is consistent with HDGF regulates the metastasis of breast cancer through modulating of epithelial-mesenchymal transition. Therefore, our results provide not only novel insights into the role of the HDGF in cell migration and tumor metastasis, but also validate a novel prognostic indicator for breast cancer.
Key words: Hepatoma-derived growth factor, PI3K, Akt, epithelal-mesenchemal transition, E-cadherin, Vimentin
| Identifer | oai:union.ndltd.org:NSYSU/oai:NSYSU:etd-0804112-214405 |
| Date | 04 August 2012 |
| Creators | Kung, Mei-Lang |
| Contributors | Ming-Hong Tai, Yi-Ren Hong, Jong-Kang Liu, Tsung-Hui Hu, Hoi-Hung Chan |
| Publisher | NSYSU |
| Source Sets | NSYSU Electronic Thesis and Dissertation Archive |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0804112-214405 |
| Rights | user_define, Copyright information available at source archive |
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