UNDERSTANDING THE EFFECTS OF HYPOXIA AND HYPOXIA-MIMETIC AGENTS IN THE HUMAN PROSTATE CARCINOMA CELLS
| Autor: | Li-chuan Chung, 鍾麗娟 |
|---|---|
| Rok vydání: | 2011 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 100 L-mimosine and dimethyloxalylglycine (DMOG) are prolyl 4-hydroxylase inhibitors stabilizing the hypoxia-inducible factor-1α (HIF-1α) and are used to mimic the effects of hypoxia in vivo and in vitro. The B-cell translocation gene 2 (BTG2) regulates the G1/S transition phases of the cell cycle. N-myc downstream-regulated gene 1 (NDRG1) is a differentiation-inducing gene upregulated by hypoxia. Prostate-specific antigen (PSA) is a well-known biomarker for diagnosing and evaluating the status of prostate cancer. Studies of this dissertation are to evaluate the effects of hypoxia and hypoxia mimetics on prostate carcinoma cells. The 3H-thymidine incorporation and flow cytometry assays revealed that the L-mimosine arrested the cell cycle at the G1 phase in PC-3 cells and at S phase in LNCaP cells, thus attenuating cell proliferation. Immunoblot assays indicated that hypoxia and L-mimosine stabilized HIF-1α and induced BTG2 and NDRG1 protein expression, but downregulated protein levels of cyclin A in both PC-3 and LNCaP cells. The transient gene expression assay revealed that L-mimosine treatment or co-transfection with HIF-1α expression vector enhanced the promoter activities of BTG2 and NDRG1 genes. Knockdown of HIF-1α attenuated the increasing protein levels of both BTG2 and NDRG1 by hypoxia or L-mimosine in LNCaP cells. Immunoblot and enzyme-linked immunosorbent (ELISA) assays indicated that L-mimosine and DMOG stabilized HIF-1α and induced PSA gene expression in LNCaP cells. Further studies indicated that induction of the PSA expression by hypoxia is both HIF-1α- and AR-dependent. Immunoblot assays revealed that a curcumin treatment decreased the protein level of AR but did not significantly affect the protein levels of HIF-1α and vascular endothelial growth factor (VEGF) which were induced by hypoxia. ELISA and transient gene expression assays indicated that curcumin blocked the activation of L-mimosine or DMOG treatment on PSA expression. In conclusion, results of this dissertation indicated that hypoxia and L-mimosine modulated BTG2 and NDRG1 at the transcriptional level, which is dependent on HIF-1α. L-mimosine enhanced expression of BTG2 and NDRG1, which attenuated cell proliferation of the PC-3 and LNCaP prostate carcinoma cells. L-mimosine and DMOG stabilized HIF-1α and induced PSA gene expression. The curcumin blocked the AR protein expression, which attenuated the enhanced effect of PSA expression by L-mimosine and DMOG that induce hypoxia condition. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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