Eps8 facilitates cellular growth and motility of colon cancer cells by increasing the expression and activity of focal adhesion kinase.

Abstract

In an attempt to study the role of Eps8 in human carcinogenesis, we observe that ectopic overexpression of Eps8 in SW480 cells (low Eps8 expression) increases cell proliferation. By contrast, expressing eps8 small interference RNA in SW620 and WiDr cells (high Eps8 expression) reduces their proliferation rate. Interestingly, attenuation of Eps8 decreases Src Pi-Tyr-416, Shc Pi-Tyr-317, and serum-induced FAK Pi-Tyr-397 and Pi-Tyr-861. Remarkably, by virtue of mammalian target of rapamycin/STAT3 Pi-Ser-727, Eps8 modulates FAK expression required for cell proliferation. Within 62% of colorectal tumor specimens examined, >2-fold enhancement of Eps8 as compared with their normal counterparts is observed, especially for those from the advanced stage. In agreement with the modulation of FAK by Eps8, the concomitant expression of these two proteins in tumor specimens is observed. Notably, Eps8 attenuation also impedes the motility of SW620 and WiDr cells, which can be rescued by ectopically expressed FAK. This finding discloses the indispensability of Eps8 and FAK in cell locomotion. These results provide a novel mechanism for Eps8-mediated FAK expression and activation in colon cancer cells.

• Authors: Ming-Chei Maa, Jenq-Chang Lee, Yen-Jen Chen, Yun-Ju Chen, Yuch-Ching Lee, Shan-Tair Wang, Ching-Chung Huang, Nan-Haw Chow, Tzeng-Horng Leu
• Journal: The Journal of biological chemistry (J Biol Chem) Vol. 282 Issue 27 Pg. 19399-409 (Jul 06 2007) ISSN: 0021-9258 [Print] United States
• PMID: 17496330 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Adaptor Proteins, Signal Transducing
• EPS8 protein, human
• Intracellular Signaling Peptides and Proteins
• Neoplasm Proteins
• RNA, Small Interfering
• STAT3 Transcription Factor
• STAT3 protein, human
• Protein Kinases
• MTOR protein, human
• mTOR protein, mouse
• Focal Adhesion Protein-Tyrosine Kinases
• src-Family Kinases
• TOR Serine-Threonine Kinases

Topics

• Adaptor Proteins, Signal Transducing
• Animals
• Cell Line, Tumor
• Cell Movement (drug effects)
• Cell Proliferation (drug effects)
• Colonic Neoplasms (metabolism, pathology)
• Focal Adhesion Protein-Tyrosine Kinases (biosynthesis)
• Gene Expression Regulation, Enzymologic (drug effects)
• Gene Expression Regulation, Neoplastic (drug effects)
• Humans
• Intracellular Signaling Peptides and Proteins (antagonists & inhibitors, metabolism)
• Male
• Mice
• Mice, Inbred BALB C
• Mice, Nude
• Neoplasm Proteins (antagonists & inhibitors, metabolism)
• Protein Kinases (metabolism)
• RNA, Small Interfering (pharmacology)
• STAT3 Transcription Factor (metabolism)
• TOR Serine-Threonine Kinases
• src-Family Kinases (metabolism)