| Summary: | 碩士 === 國立交通大學 === 生物科技學系 === 104 === Thermostable direct hemolysin (TDH) is a pore-forming toxin produced by Grimontia hollisae. However, this toxin protein lacks selective cytotoxicity. To specify the anti-tumor activity and reduce side effects, we tried to prepare TDH-tumor targeting toxin protein as a suitable immunotoxin.
Because the Gh-TDHR46E mutation reduced bioactivities and side reactions, it has potential as an anticancer agent. In this study we used THD-based protein TDHR46E to design the corresponding TDH-tumor targeting proteins. At TDH R46E, C-terminal was added with targeting peptides. To target TDHR46E precisely to tumor cells, aminopeptidase P (APaseP) and neuropilin-1(Nrp1) receptor such as PEGA (P5), iRGD (P6) were selected as peptides that targeted breast cancer.
The cytotoxic activity of Gh-TDHR46E-P5 and Gh-TDHR46E-P6 was evaluated using receptor-positive cell lines such as MDA-MB-231 and MCF7; receptor-negative tumor cell line such as BT474. The results showed apparent cytotoxic on MDA-MB-231and MCF7 cells but not on BT474 cells. In contrast, Gh-TDHR46E treatment was non-cytotoxic on all tumor cell lines, indicating enhanced cytotoxic efficacy of Gh-TDHR46E by combination of P5 and P6 peptides to Gh-TDHR46E. Furthermore, P6 can increase internalization to increase treatment effects significantly. These data may open new avenues for breast cancer therapy.
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