Toxoplasma gondii GRA8-derived peptide immunotherapy improves tumor targeting of colorectal cancer

Area of Science:

• Biochemistry
• Molecular Biology
• Cancer Therapy

Background:

• Targeted drug delivery to tumors remains a challenge in protein-based cancer therapies.
• Mitochondria are key targets for anti-cancer drugs.
• Previous work identified the role of Toxoplasma gondii GRA8 in mitochondrial trafficking and interaction with ATP5A1/SIRT3.

Purpose of the Study:

• To develop a novel peptide construct for targeted cancer therapy.
• To enhance the delivery and efficacy of anti-cancer drugs by targeting mitochondria.
• To evaluate the therapeutic potential of the engineered peptide in cancer models.

Main Methods:

• Development of a recombinant peptide (rATRAM-G8-M/AS) conjugating an acidity-triggered rational membrane (ATRAM) with a GRA8 peptide.
• Incorporation of essential residues for mitochondrial targeting and binding to ATP5A1/SIRT3.
• In vitro and in vivo evaluation of the peptide's efficacy in HCT116 human carcinoma cells and a mouse xenograft model.

Main Results:

• The rATRAM-G8-M/AS peptide demonstrated significantly enhanced potency in inducing cancer cell death compared to rGRA8 alone (200-fold lower IC50 in vitro, 500-fold lower in vivo).
• Treatment with rATRAM-G8-M/AS resulted in significant therapeutic effects in a mouse xenograft model via mitochondrial metabolic resuscitation.
• The peptide construct exhibited negligible immunogenicity and immune responses in vivo.

Conclusions:

• The rATRAM-G8-M/AS peptide represents a promising therapeutic strategy for tumors, especially colon cancer.
• This approach offers a paradigm shift for therapeutic intervention by effectively targeting cancer cell mitochondria.
• The study highlights the potential of engineered peptides for targeted cancer therapy with improved safety profiles.