Abstract 891: CD70-targeting CAR-T and CAR-NK cells demonstrate potent activity against NSCLC drug-tolerant persister cells
Authors: Yang Yan , Nilsson Monique , Patel Sonia , Yu Xiaoxing , Poteete Alissa , Huang Qian , Heeke Simon , Heymach John 
Published: April 2023

Abstract
Non-small cell lung cancer (NSCLC) is the leading cause of cancer-related deaths in the US. Targeted agents, such as EGFR tyrosine kinase inhibitors (TKIs) and KRAS G12C inhibitors, have provided clinical benefits for patients and can yield significant tumor shrinkage. Inevitably, however, there remain residual tumors that harbor drug-tolerant persister cells (DTPCs) not killed by initial treatment, leading to emerging of drug-resistant cells (DRCs) and tumor recurrence. The identification of effective treatment strategies to target DTPCs is a critical and unmet need. We hypothesized that DTPCs can be targeted using chimeric antigen receptor (CAR)-based cellular therapy approaches directed at cell surface proteins expressed on DTPCs and that the combination of such approaches with targeted agents will more effectively delay the emergence of fully drug-resistant cells than targeted agents alone. To this end, we first performed luciferase-based killing assays and observed that EGFR-targeting CAR-T and CAR-NK cells displayed potent cytotoxicity against DTPCs of osimertinib-treated EGFR mutant NSCLC cells. Moreover, osimertinib DTPCs showed increased sensitivity to EGFR CAR-T and CAR-NK cells compared to their parental cells, likely due to the upregulation of EGFR on the cell surface following osimertinib treatment. In a patient-derived xenograft model of HER2YVMA mutant lung cancer, we observed that HER2 CAR-NK cells showed enhanced antitumor activity in mice treated with the HER2 inhibitor, poziotinib, for two weeks, compared to CAR-NK cells only, poziotinib only, or mice treated upfront with HER2 CAR-NK cells plus poziotinib. These in vitro and in vivo data support that CAR-based cellular therapy can effectively eliminate DTPCs. To identify additional candidate cell surface proteins expressed on DTPCs that could be targeted by CAR-based cell therapy approaches, we interrogated RNA expression from our panel of DTPCs as well as public datasets containing DTPCs of targeted agents. Likewise, we investigated the expression of cell surface proteins using datasets of parental and DRCs to identify the common candidate targets that could be exploited on both DTPCs and DRCs. Our analysis identified CD70 as being consistently upregulated in both EGFR TKI-resistant cells and DTPCs of osimertinib-treated EGFR mutant NSCLC. Moreover, we observed CD70 upregulation in DTPCs and DRCs of other targeted agents, including KRAS, ALK, and RET inhibitors, suggesting that CD70 may be a common target in DTPCs across oncogenic drivers. Furthermore, we determined that CD70-targeting CAR-T and CAR-NK cells showed promising in vitro activity against the DTPCs of osimertinib-treated EGFR mutant NSCLC. These results demonstrate CAR-based cellular therapy as an effective approach to target DTPCs and identify CD70 as a novel therapeutic target for combatting DTPCs in NSCLC.
Citation Format: Yan Yang, Monique Nilsson, Sonia Patel, Xiaoxing Yu, Alissa Poteete, Qian Huang, Simon Heeke, John Heymach. CD70-targeting CAR-T and CAR-NK cells demonstrate potent activity against NSCLC drug-tolerant persister cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 891.