<i>Toxoplasma gondii</i> GRA8-derived peptide immunotherapy improves tumor targeting of colorectal cancer
Jae‐Sung Kim, Daeun Lee, Dong-Gyu Kim, Seok‐Jun Mun, Euni Cho, Wooic Son, Chul‐Su Yang
Abstract
// Jae-Sung Kim 1 , 2 , Daeun Lee 1 , Donggyu Kim 1 , Seok-Jun Mun 1 , 2 , Euni Cho 1 , 2 , Wooic Son 1 and Chul-Su Yang 1 , 2 1 Department of Molecular and Life Science, Hanyang University, Ansan 15588, S. Korea 2 Department of Bionano Technology, Hanyang University, Seoul 04673, S. Korea Correspondence to: Chul-Su Yang, email: [email protected] Keywords: Toxoplasma gondii GRA8 peptide; mitochondria; tumor-targeting; metabolism Received: October 17, 2019     Accepted: December 19, 2019     Published: January 07, 2020 ABSTRACT Targeted tumor and efficient, specific biological drug delivery in vivo has been one of the main challenges in protein-based cancer-targeted therapies. Mitochondria are potential therapeutic targets for various anti-cancer drugs. We have previously reported that protein kinase Cα-mediated phosphorylation of Toxoplasma gondii GRA8 is required for mitochondrial trafficking and regulating the interaction of the C-terminal of GRA8 with ATP5A1/SIRT3 in mitochondria. Furthermore, SIRT3 facilitates ATP5A1 deacetylation, mitochondrial activation, and subsequent antiseptic activity in vivo . Herein we developed a recombinant acidity-triggered rational membrane (ATRAM)-conjugated multifunctional GRA8 peptide (rATRAM-G8-M/AS) comprising ATRAM as the cancer-targeting cell-penetrating peptide, and essential/minimal residues for mitochondrial targeting or ATP5A1/SIRT3 binding. This peptide construct showed considerably improved potency about cancer cell death via mitochondria activity and biogenesis compared with rGRA8 alone in HCT116 human carcinoma cells, reaching an IC 50 value of up to 200-fold lower in vitro and 500-fold lower in vivo . Notably, rATRAM-G8-M/AS treatment showed significant therapeutic effects in a mouse xenograft model through mitochondrial metabolic resuscitation, and it produced negligible immunogenicity and immune responses in vivo . Thus, these results demonstrate that rATRAM-G8-M/AS represents a useful therapeutic strategy against tumors, particularly colon cancer. This strategy represents an urgently needed paradigm shift for therapeutic intervention.