Maa MC, Lee JC, Chen YJ, Chen YJ, Lee YC, Wang ST et al.. EPS8 facilitates cellular growth and motility of colon cancer cells by increasing the expression and activity of focal adhesion kinase. J Biol Chem 282: 19399-19409

Department of Public Health, National Cheng Kung University, 臺南市, Taiwan, Taiwan
Journal of Biological Chemistry (Impact Factor: 4.57). 07/2007; 282(27):19399-409. DOI: 10.1074/jbc.M610280200
Source: PubMed


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.

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    • "We conclude that although Eps8 shares overlapping functions with other family members during mammalian development, its role in cancer cell polarization and invasive migration cannot apparently be replaced by other Eps8 family members. Although it has been reported that Eps8 regulates colon cancer growth (Chen et al., 2008; Maa et al., 2007), we did not find proliferation to be dependent on Eps8 in SCCs from mouse or human tumors. We recently described that highly active Src is removed from focal adhesions and transported into intracellular puncta when FAK is absent from SCC cells (Sandilands et al., 2012a). "
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    ABSTRACT: Eps8 is an actin regulatory scaffold protein increased in Squamous Cell Carcinoma (SCC) cells. It forms a complex with both Focal Adhesion Kinase (FAK) and c-Src in SCC cells derived from the DMBA/TPA model of skin carcinogenesis. Here, we describe two new roles for Eps8. Firstly, it controls the spatial distribution of active c-Src in a FAK-dependent manner. Specifically, Eps8 participates in, and regulates, a biochemical complex with c-Src and drives c-Src's trafficking to autophagic structures that SCC cells use to cope with high levels of active c-Src when FAK is absent. Secondly, when FAK is expressed in SCC cells, so tethering active c-Src at focal adhesion complexes, Eps8 is also recruited to focal adhesions and is required for FAK-dependent polarization and invasion. Therefore, Eps8 is a critical mediator of Src/FAK-regulated processes; it participates in specific biochemical complexes and promotes actin re-arrangements that determine c-Src's spatial localization and Src/FAK functions in invasive migration.
    Journal of Cell Science 10/2014; DOI:10.1242/jcs.157560 · 5.43 Impact Factor
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    • "Sp1 and FOXM1 have been shown to transactivate promoters of c-myc synergistically [38]. Furthermore, EPS8 attenuation has been found to decrease levels of Src, Shc and FAK (also known as PTK2), an intracellular tyrosine kinase participating in cell adhesion and motility [39]. FOXO3A may also be regulated by the presence or absence of EPS8 through various pathways, either through PI3K/AKT/mTOR signaling [40] or via the Ras-Raf-MEK-ERK pathway [41]. "
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    ABSTRACT: Cisplatin, a commonly used chemotherapeutic, is associated with ototoxicity, renal toxicity and neurotoxicity, thus identifying means to increase the therapeutic index of cisplatin may allow for improved outcomes. A SNP (rs4343077) within EPS8, discovered through a genome wide association study of cisplatin-induced cytotoxicity and apoptosis in lymphoblastoid cell lines (LCLs), provided impetus to further study this gene. The purpose of this work was to evaluate the role of EPS8 in cellular susceptibility to cisplatin in cancerous and non-cancerous cells. We used EPS8 RNA interference to determine the effect of decreased EPS8 expression on LCL and A549 lung cancer cell sensitivity to cisplatin. EPS8 knockdown in LCLs resulted in a 7.9% increase in cisplatin-induced survival (P = 1.98×10(-7)) and an 8.7% decrease in apoptosis (P = 0.004) compared to control. In contrast, reduced EPS8 expression in lung cancer cells resulted in a 20.6% decrease in cisplatin-induced survival (P = 5.08×10(-5)). We then investigated an EPS8 inhibitor, mithramycin A, as a potential agent to increase the therapeutic index of cisplatin. Mithramycin A decreased EPS8 expression in LCLs resulting in decreased cellular sensitivity to cisplatin as evidenced by lower caspase 3/7 activation following cisplatin treatment (42.7%±6.8% relative to control P = 0.0002). In 5 non-small-cell lung carcinoma (NSCLC) cell lines, mithramycin A also resulted in decreased EPS8 expression. Adding mithramycin to 4 NSCLC cell lines and a bladder cancer cell line, resulted in increased sensitivity to cisplatin that was significantly more pronounced in tumor cell lines than in LCL lines (p<0.0001). An EGFR mutant NSCLC cell line (H1975) showed no significant change in sensitivity to cisplatin with the addition of mithramycin treatment. Therefore, an inhibitor of EPS8, such as mithramycin A, could improve cisplatin treatment by increasing sensitivity of tumor relative to normal cells.
    PLoS ONE 12/2013; 8(12):e82220. DOI:10.1371/journal.pone.0082220 · 3.23 Impact Factor
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    • "Interestingly, Eps8 has been shown to regulate the expression of FAK via the mTor/STAT3 pathway [11]. Eps8 overexpression leading to increased activity of FAK via this pathway has been shown to promote disease progression in colon cancer [11]. MAPKAP1 may be a physical link to this pathway. "
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    ABSTRACT: Eps8 is involved in both cell signalling and receptor trafficking. It is a known phosphorylation substrate for two proteins involved in the fibroblast growth factor receptor (FGFR) signalling pathway: the receptor itself and Src. Here we report a differential proteomic analysis of Eps8 aimed to identify specific FGFR and Src family kinase dependent phosphosites and co-associated phosphodependent binding partners. This study reveals a total of 22 Eps8 pTyr and pSer/Thr phosphorylation sites, including those that are dependent on Src family and FGFR kinase activity. Peptide affinity purification of proteins that bind to a selection of the pTyr phosphosites has identified a range of novel Eps8 binding partners including members of the intracellular vesicle trafficking machinery (clathrin and AP-2), proteins which have been shown to regulate activated receptor trafficking (NBR1 and Vav2), and proteins involved in receptor signalling (IRS4 and Shp2). Collectively this study significantly extends the understanding of Eps8 post-translational modification by regulated phosphorylation, identifies novel Eps8 binding partners implicated in receptor trafficking and signalling, and confirms the functions of Eps8 at the nexus of receptor signalling and vesicular trafficking.
    PLoS ONE 04/2013; 8(4):e61513. DOI:10.1371/journal.pone.0061513 · 3.23 Impact Factor
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