TAZ是一個WW結構域的蛋白質，在人體是由WWTR1基因編碼。它是一種由河馬腫瘤抑制途徑負調節的轉錄輔激活因子。在最近的研究中，Siew Wee Chan還發現，TAZ做為一種新的標靶，用於檢測和治療乳腺癌，因為它在~20%的乳腺癌中是過度表達的，並在其遷移，侵入和腫瘤生成中扮演重要的角色。在乳腺癌細胞中，Nuo Yang發現TAZ可以藉由活化EGFR的配體，Amphiregulin來促進EGFR訊號途徑並且促使腫瘤生成和轉移。然而，TAZ在前列腺癌中的作用從未被檢驗。
我們觀察到與正常前列腺上皮細胞RWPE-1相比，雄激素依賴的前列腺癌細胞LNCaP的TAZ表達被下調。相反地，在雄激素非依賴性細胞PC-3和DU145中， TAZ的表達被恢復，甚至比RWPE-1細胞更高。有趣的是，阻斷TAZ基因的表達強烈抑制細胞的增殖和遷移。此外，siRNA抑制TAZ的表達導致抑制PDK1，S6K和S6的磷酸化，並且降低caveolin-1，caveolin-2和KDM4C的表達。
熊果酸之前被報導過具有抗癌的活性。包含了促進細胞凋亡、抑制增殖和轉移。有趣的是在DU145細胞中，UA會降低TAZ的蛋白質水平。
因此，TAZ可能是前列腺癌的一種生物標記，並可能可以做為前列腺癌的治療的一個新的治療靶點。

Transcriptional co-activator with PDZ-binding motif (TAZ) is a WW domain -containing protein in human and encoded by the WWTR1 gene. It is a transcriptional coactivator negatively regulated by the Hippo tumor suppressor pathway. In a recent study, Siew Wee Chan has found that TAZ presents a novel target for detecting and treating breast cancer, because it is overexpressed in ~20% of breast cancer and plays a role in migration, invasion, and tumorigenesis. In breast cancer, Nuo Yang has found that TAZ through the EGFR ligand, amphiregulin, stimulates the EGFR signaling pathway and promotes tumorigenesis and metastasis. However, the role of TAZ in prostate cancer has never been examined.
We observed that compared to the normal prostate epithelial cell line, RWPE-1, the expression of TAZ is down regulated in the androgen-dependent LNCaP cells. In contrast, the expression of TAZ in androgen-independent cell lines, PC-3 and DU 145, is restored and even higher than that in RWPE-1 cells. Interestingly, the blockage of TAZ gene expression strongly suppresses proliferation and migration. Furthermore, inhibition of TAZ expression by small interfering RNA leads to inhibition of PDK1, S6K and S6s’ phosphorylation, and decrease of caveolin-1, caveolin-2 and KDM4C expression.
Ursolic acid (UA) has been reported to have anticancer activities by promoting apoptosis, suppressing proliferation and enhancing metastasis. Interestingly, we found that UA reduced protein levels of TAZ in DU145 cells.
Therefore, TAZ may serve as a biomarker for prostate cancer and represent a novel therapeutic target for the treatment of prostate cancer.

Catalog
INTRODUCTION 1
1. Prostate cancer 1
2. Transcriptional co-activator with PDZ-binding motif (TAZ) 3
3. Amphiregulin (AREG) 4
4. Ursolic Acid (UA) 5
MATERIALS AND METHODS 6
2.1 Cell lines 6
2.2 Lentivirus production and infection 6
2.3 Cell proliferation assay 7
2.4 Cell viability assay 8
2.5 Scratch wound-healing assay 9
2.6 Transwell invasion assay 9
2.7 Western Blotting 10
2.8 Total RNA extraction and Reverse transcriptase polymerase chain reaction (RT-PCR) 11
2.9 Statistics 14
RESULTS 15
TAZ expression levels in different prostate cancer cell lines 15
TAZ knockdown suppressed DU145 proliferation and migration 15
AREG as a secreted growth factor induced by TAZ and activates EGFR 16
Knockdown of TAZ suppresses some metastasis related oncogenes 17
UA suppresses the expression of TAZ protein in DU145 prostate cancer cell line. 17
Disscussion 19
REFERENCES 21
Figures and figure legends 33
Figure 1. The chemical structure of ursolic acid 33
Figure 2. TAZ is overexpressed in androgen independent prostate cancer cells. 34
Figure 3. The expression level of TAZ in TAZ knockdown DU145 cells. 35
Figure 4. TAZ knockdown in DU145 cells inhibit proliferation. 36
Figure 5. TAZ knockdown in DU145 cells inhibit migration. 37
Figure 5. TAZ knockdown in DU145 cells inhibit migration. 38
Figure 6. TAZ knockdown in DU145 cells don’t affect cell invasion. 39
Figure 7. Knock down TAZ reduces amphiregulin expression and tyrosine phosphorylation (activation) of EGFR. 40
Figure 8. TAZ does not signal through PTEN/PI3K/AKT and MAPK pathway to affect cell migration and proliferation. 41
Figure 9. TAZ signal through PI3K/PDK1-dependent, Akt-independent, mechanism to affect protein synthesis, cell proliferation and tumorigenesis. 42
Figure 10. TAZ is related with metastasis. 43
Figure 11. Ursolic acid suppresses DU145 cell survival depending on concentration and time. 44
Figure 12. Ursolic acid suppresses DU145 cell survival depending on concentration and time. 45
Figure 13. Ursolic acid suppresses cell migration in DU145 cells. 46
Figure 14. Ursolic acid suppress TAZ protein expression in DU145 cells. 47
Table 1. Primer sequences used for RT-PCR analyses. 48
Table 2. The PCR reaction conditions of genes. 49

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