CREM is a regulatory checkpoint of CAR and IL-15 signaling in NK cells — ASN Events
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  3. CREM is a regulatory checkpoint of CAR and IL-15 signaling in NK cells

CREM is a regulatory checkpoint of CAR and IL-15 signaling in NK cells (#279)

Hind Rafei 1 , Rafet Basar 1 , Sunil Acharya 1 , Yu-Sung Hsu 1 , Pinghua Liu 1 , Deqiang Zhang 1 , Qingnan Liang 1 , Vakul Mohanty 1 , Ranjan Upadhyay 1 , Ping Li 1 , Pravin Phadatare 1 , Merve Dede 1 , Donghai Xiong 1 , Huihui Fan 1 , Corry Mathew Jones 1 , May Daher 1 , Ana Karen Nunez Cortes 1 , Mayra Shanley 1 , Bin Liu 1 , Sadie Mae Moseley 1 , Patrick Zhang 1 , Dexing Fang 1 , Pinaki Banerjee 1 , Nadima Uprety 1 , Ye Ethan Li 1 , Rejeena Shrestha 1 , Xinhai Wan 1 , Hong Shen 1 , Vernikka Woods 1 , April Gilbert 1 , Seema Rawal 1 , Jinzhuang Dou 1 , Yukun Tan 1 , Jeong-Min Park 1 , Francia Reyes 1 , Alexander Biederstaedt 1 , Mecit Kaplan 1 , Xin Ru Jiang 1 , Inci Biederstaedt 1 , Silvia Tiberti 1 , Madison Moore 1 , Jingling Jin 1 , Ryan Yang 1 , Luis Muniz 1 , Samuel Rosemore 1 , Paul Lin 1 , Gary Deyter 1 , Natalie Wall Fowlkes 1 , Abhinav Jain 1 , David Marin 1 , Ken Chen 1 , Elizabeth Shpall 1 , Katy Rezvani 1
  1. The University of Texas MD Anderson Cancer Center, Missouri City, TX, United States

CAR-NK cell immunotherapy is a promising approach against cancer. However, the mechanisms governing CAR-NK cell activity remain poorly understood. Here, we identified the transcription factor cAMP response element modulator (CREM) as a pivotal regulator of CAR-NK cell function. ScRNA-seq in a Raji model revealed a marked upregulation of CREM in CAR-NK cells during peak anti-tumor activity, correlating with a transcriptional profile of both activation and upregulation of checkpoints.

In CD70-targeting CAR-NK cells, CREM was induced following CAR ligation to its cognate antigen CD70, but only when CAR signaling via ITAMs was functional, underscoring its dependence on CAR signaling. We also demonstrated that IL-15 induced CREM in a dose-dependent manner. The combination of CAR and IL-15 stimulation synergistically enhanced CREM expression. CREM-high CAR/IL-15 NK cells exhibited a phenotype suggestive of activation-induced exhaustion.

Mechanistically, we demonstrated that CREM is induced via the PKA-CREB axis downstream of CAR and IL-15 signaling. pCREB, driven by PKA and calcium mobilization, directly promoted CREM transcription, as confirmed by ChIP-qPCR. IL-15 amplified this pathway by upregulating PKA catalytic subunits.

Notably, CREM KO in CAR-NK cells significantly enhanced their cytotoxicity, cytokine production, resistance to tumor-induced immunosuppression, and anti-tumor efficacy across hematologic and solid tumor models, including CD70- and TROP2-targeting CAR-NK cells. In vivo, CREM KO improved NK cell proliferation, persistence, tumor infiltration, tumor control, and survival of mice in multiple tumor models including metastatic breast cancer, orthotopic pancreatic cancer, and Raji lymphoma.

ChIP-seq and ATAC-seq revealed that CREM acts as a dual-function transcriptional regulator, repressing genes involved in NK cell activation while upregulating exhaustion-associated genes. CREM KO enhanced chromatin accessibility of effector genes, enriching motifs for AP-1, CEBP, and STATs, thereby promoting NK cell activation.

Our data establish CREM as a critical checkpoint in CAR-NK cells and thus a compelling target for improving CAR NK cell immunotherapies.