Harnessing natural killer cells for cellular immunotherapy against solid tumors - Project Summary/Abstract Despite recent advances in cancer therapy, cancer remains the second leading cause of death in the United States. The field of cancer immunotherapy has evolved to meet this challenge, but there is an ongoing need for treating metastatic and treatment-resistant solid tumors, particularly those of lung, breast, prostate, and colorectal origin. Cellular immunotherapies, such as chimeric antigen receptor (CAR) T-cell therapy, have shown success in treating blood cancers. However, they remain ineffective against solid tumors, and are often fraught with inherent toxicities such as cytokine release syndrome and attack of healthy tissues. In light of these challenges, this proposal aims to harness natural killer (NK) cells, which have broad anti-tumor activity and a superior safety profile, to generate CAR NK-cell therapy as an effective immunotherapy against solid tumors. CAR NK-cell therapy has recently shown remarkable success against blood cancers but remains challenging for use in solid tumors. The tumor microenvironment employs immune-evasive mechanisms to subvert NK-cell killing and limits their infiltration and survival. Our research proposal will address these obstacles by leveraging high-throughput, sequencing-based functional screens and innovative synthetic biology approaches that will shed light on fundamental NK-cell biology and enhance CAR NK-cell infiltration and killing of solid tumors. We will implement a genome-wide CRISPR screen in primary human NK cells to identify negative regulators (‘innate immune checkpoints’) of NK-cell cytotoxicity. Subsequently, we will identify homing and survival signals in tumor- infiltrating immune cells by mining single-cell RNA-sequencing databases. We will then introduce these genes into NK cells to enhance their infiltration and survival in in-vitro and in-vivo models of the tumor microenvironment. Finally, we will perform a high-throughput CARpool screen to simultaneously assess hundreds of NK cell-tailored CARs designed with native NK cell-receptor signaling machinery to maximize CAR NK-cell functioning. In summary, this proposed research introduces several innovative approaches to study fundamental NK-cell biology and engineer NK-cell based immunotherapies against solid tumors. Our project is poised to uncover new targets in NK cells for 'innate immune checkpoint blockade' as well as create the next-generation of CAR NK- cell therapy for treating metastatic and treatment-resistant cancers. Ultimately, we will establish a pipeline of technologies that can be applied to many cancer types in order to broaden the scope of immunotherapies against cancer and transform patient care to mitigate the devastating impact of this disease.
