Studying the role of WWP2 in Eps8-promoted cell proliferation in HeLa cells

• Main Authors: Yu-HsiuTung, 童郁琇
• Other Authors: Tzeng-Horng Leu
• Format: Others
• Language: zh-TW
• Published: 2012
• Online Access: http://ndltd.ncl.edu.tw/handle/58590494121833835151

碩士 === 國立成功大學 === 藥理學研究所 === 100 === Protein ubiquitination is an important post-translational modification that regulates numerous biological functions. Although the HECT type E3 ubiquitin ligases had been correlated with cancer development, the role of WWP2 in cancer formation remains to be solved. EPS8 (EGF receptor pathway substrate No.8) is a common substrate of EGF receptor and Src. Here, we demonstrated that EPS8 associated with WWP2 and was ubiquitinated in SW620 cellls. We wondered whether WWP2 affected EPS8 expression and participated in cell growth. Our data indicated that transient overexpression of WWP2 does not affect Eps8 expression but inhibits Pi-S473 AKT, CyclinD1 expression, and decreased cell proliferation in both culture dishes and soft agar in HeLa cells. In contrast, transient overexpression of WWP2 in Eps8-attenuated HeLa cells elevates FAK Pi-Y861, AKT Pi-S473, and Src Pi-Y416 resulted in the increase of cell proliferation. Similar results were observed in stably WWP2-overexpressing Eps8-attenuated cells. Further study indicated that WWP2 overexpression did not affect FAK mRNA level in HeLa cells. Since treatment with MG132 could not restore FAK expression in these cells, WWP2-mediated FAK expression probably was not through proteosome-dependent pathway. Finally, we demonstrated that attenuation of WWP2 deceased FAK Pi-Y861, Src Pi-Y416, AKT Pi-Y473 expression and suppressed cell proliferation in SW620 cells. Taken together, our results indicated that WWP2 may affect the cell growth by Src/FAK and PI3K/AKT pathways depending on the cellular context.