Abstract B066: Identifying novel effectors of the gut microbiota that modulate cancer cell killing by CTLs using functional metagenomics

Abstract

Listen

Translate article

Abstract The immune system, which is profoundly affected by the microbiota composition and activity, plays an anti-tumorigenic role by surveying for and killing cancer cells. Indeed, recent studies found the microbiota to be essential for the success of cancer immunotherapy treatments in mice, while the bacterial effectors remain unknown. We developed an innovative high throughput screening system to isolate microbiota-derived effectors that modulate the ability of immune cells to kill cancer cells. We utilize the mouse CT26 colon carcinoma cell line as targeT-cells and the GSW11 specific CCD2Z T-cell hybridoma cell line as the effector cells. Bacterial DNA extracted from fecal contents of mice bearing colorectal tumors served for generation of metagenomics libraries. Supernatnants of the metagenomic clones were added to the CT26-CCD2Z co-culture and CCD2Z activation was measured using a LacZ reporter, regulated by NFAT. We identified about 40 clones that activate CCD2Z cells. We performed secondary screens and tested the activation of CD8+ T-cells sorted from mouse spleens. We sequenced the metagenomic DNA of several clones and analyzed the coding sequences. Currently, we are sub-cloning the clones to find the microbial genes responsible for CD8+ T-cell activation and design strategies for isolation of active molecules from these bacterial supernatnats. Finally, we hope that our future results could be taken to the clinic and serve for diagnosis, prognosis and therapeutics. Citation Format: Lior Lobel, Wendy S. Garrett. Identifying novel effectors of the gut microbiota that modulate cancer cell killing by CTLs using functional metagenomics [abstract]. In: Proceedings of the Fourth CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; Sept 30-Oct 3, 2018; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2019;7(2 Suppl):Abstract nr B066.