Please use this identifier to cite or link to this item: http://dx.doi.org/10.18419/opus-8262
Olayioye, Monilola A.
|Title:||EGFR-targeted TRAIL and a Smac mimetic synergize to overcome apoptosis resistance in KRAS mutant colorectal cancer cells|
|metadata.ubs.publikation.source:||PLoS one 9 (2014), issue 9, e107165. URL http://dx.doi.org./10.1371/journal.pone.0107165|
|Abstract:||TRAIL is a death receptor ligand that induces cell death preferentially in tumor cells. Recombinant soluble TRAIL, however, performs poorly as an anti-cancer therapeutic because oligomerization is required for potent biological activity. We previously generated a diabody format of tumor-targeted TRAIL termed Db<sub>Î±EGFR</sub>-scTRAIL, comprising single-stranded TRAIL molecules (scTRAIL) and the variable domains of a humanized variant of the EGFR blocking antibody Cetuximab. Here we define the bioactivity of Db<sub>Î±EGFR</sub>-scTRAIL with regard to both EGFR inhibition and TRAIL receptor activation in 3D cultures of Caco-2 colorectal cancer cells, which express wild-type K-Ras. Compared with conventional 2D cultures, Caco-2 cells displayed strongly enhanced sensitivity toward Db<sub>Î±EGFR</sub>-scTRAIL in these 3D cultures. We show that the antibody moiety of Db<sub>Î±EGFR</sub>-scTRAIL not only efficiently competed with ligand-induced EGFR function, but also determined the apoptotic response by specifically directing Db<sub>Î±EGFR</sub>-scTRAIL to EGFR-positive cells. To address how aberrantly activated K-Ras, which leads to Cetuximab resistance, affects Db<sub>Î±EGFR</sub>-scTRAIL sensitivity, we generated stable Caco-2tet cells inducibly expressing oncogenic K-Ras<sup>G12V</sup>. In the presence of doxycycline, these cells showed increased resistance to Db<sub>Î±EGFR</sub>-scTRAIL, associated with the elevated expression of the anti-apoptotic proteins cIAP2, Bcl-xL and Flip<sub>S</sub>. Co-treatment of cells with the Smac mimetic SM83 restored the Db<sub>Î±EGFR</sub>-scTRAIL-induced apoptotic response. Importantly, this synergy between Db<sub>Î±EGFR</sub>-scTRAIL and SM83 also translated to 3D cultures of oncogenic K-Ras expressing HCT-116 and LoVo colorectal cancer cells. Our findings thus support the notion that Db<sub>Î±EGFR</sub>-scTRAIL therapy in combination with apoptosis-sensitizing agents may be promising for the treatment of EGFR-positive colorectal cancers, independently of their KRAS status.|
|Appears in Collections:||15 Fakultätsübergreifend / Sonstige Einrichtung|
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|001_journal.pone.0107165.pdf||Article||1,35 MB||Adobe PDF||View/Open|
|01_Figure_S1.pdf||Supplementary figure 1||214,21 kB||Adobe PDF||View/Open|
|02_Figure_S2.pdf||Supplementary figure 2||134,92 kB||Adobe PDF||View/Open|
|03_Figure_S3.pdf||Supplementary figure 3||95,52 kB||Adobe PDF||View/Open|
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