DEVELOPMENT OF GUCY2C-TAC T CELLS FOR THE TREATMENT OF COLORECTAL CANCER

ABSTRACT

Background

Materials and Methods

The in vitro and in vivo data confirm strong and specific activity of humanized nanobody GUCY2C-targeted TACT cells against GUCY2C-expressing tumor cells.

Results

TAC SCIENCE

Conclusions

Key features of TAC technology:

• TAC functions independently of MHC

The membrane-bound TAC receptor interacts directly with the TCR-CD3 epsilon domain and...

• TAC activates T cells via the endogenous TCR

• TAC incorporates the co-receptor and recruits the TCR complex mimicking natural TCR activation

...binds directly to the targeted tumor antigen. Clustering of TAC-TCR complexes leads to recruitment of kinases (Lck) via the cytoplasmic co-receptor domain and...

... initiates T cell activation via the endogenous CD3-TCR complex.

Watch a short animation to understand the TAC mechanism.

This results in effective cell lysis of multiple tumor cells during multiple killing events.

Guanylate cyclase 2C (GUCY2C) is essential for intestinal fluid and ion homeostasis. In healthy, polarized epithelial cells, GUCY2C is only exposed to the intestinal lumen and inaccessible to immune cells. In a vast majority of colorectal cancers and several gastric and pancreatic cancers, GUCY2C is overexpressed and no longer restricted to the lumen, thus becoming a specific target for immune cell therapy. Figure created in BioRender.com.

Normalized Division Index

Proliferation of GUCY2C-TAC T cells against GUCY2C-positive cell lines

GUCY2C-TAC T cells demonstrate persistent cytotoxicity against tumor cells.

GUCY2C-TAC T cells were co-cultured with NALM 6 GUCY2C/eGFP target cells at a 3:1 E:T ratio. (A) Alternating rounds of 3 and 4 days of co-culture were used. At the end of each round, cytotoxicity was evaluated by GFP fluorescence and quantified by calculating the area under each GFP curve. The T cells were carried forward into a new round with fresh target cells at the same 3:1 E:T ratio. The assay was performed in a 96-well plate with initially 8 wells setup per condition. (B) The total amount of T cells retrieved after each round was graphed relative to the initial total cells seeded at the start of each round. GUCY2C-TAC T cells killed targets repeatedly up to 9 rounds, similar to CD19- TACT cell positive controls.

GUCY2C-TAC T cells demonstrate highly potent cytotoxicity.

GUCY2C-TAC T cells lack signs of terminal exhaustion.

GUCY2C-TAC T cells

GUCY2C-TAC T cells demonstrate efficacy at subtherapeutic dose levels in a liquid tumor model expressing GUCY2C.

GUCY2C-TAC T cells demonstrate efficacy in a solid tumor model expressing GUCY2C.

Mice were inoculated with $ N 8 7^{G U C Y2 C} $ tumors subcutaneously in hind flank. Treatment of tumor-bearing mice with $ 6 \times10^{6} $ GUCY2C-TAC T cells/mouse occurred on Day 0. Control animals had either no treatment (NT) or were administered non-transduced (NTD) T cells. Tumors were monitored weekly by caliper measurements.

Summary