Jean Gariépy's Laboratory

Molecular Targeting and Therapeutics

How to potentially use gas vesicles ?

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Introducing a tumor targeting function on their surface would enhance their tumor imaging and therapeutic value. Herein, we have developed a non-covalent strategy to universally target Halobacterium salinarum GVs, weaponized with the photoreactive agent chlorin e6 (Ce6-GVs) to guide their delivery to tumor cells.

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Specifically, four murine monoclonal antibodies were generated that bind tightly to GvpA, the major protein component forming the GV shell. A bispecific adapter protein, termed MFE-23-ZZ, was also constructed incorporating MFE-23, a murine scFv fragment that recognizes the cancer-associated human carcinoembryonic antigen (CEA) with high affinity fused to a Protein ZZ domain, which binds to the Fc region of murine and human IgGs. The adapter protein MFE-23-ZZ readily formed complexes with anti-GvpA-decorated Ce6-GVs.

 

The resulting tripartite complexes termed MFE-23-ZZ-mAb2B10-1-Ce6-GVs enhanced the intracellular uptake of Ce6-GVs into murine MC38.CEA colon carcinoma cells expressing human CEA relative to the CEA-parental cell line MC38, as monitored by flow cytometry. Furthermore, MC38.CEA cells exposed to MFE-23-ZZ-mAb2B10-1-Ce6-GV complexes were one order of magnitude more sensitive to light exposure (660 nm) and displayed higher levels of reactive oxygen species due to chlorin e6 activation than the parental CEA- MC38 cells.

 

Collectively, these results suggest that the surface of nanoparticles such as gas vesicles can be rapidly and non-covalently functionalized to target tumor cells, increasing their potential as both therapeutic and diagnostic agents. Similarly, more common nanoparticles such as PEGylated liposomes can also be non-covalently modified with a bispecific adapter protein incorporating an anti-PEG scFv and a ZZ domain to target them to tumor antigens.