NK Cell-Mediated Eradication of Ovarian Cancer Cells with a Novel Chimeric Antigen Receptor Directed against CD44.

Rüdiger Klapdor,Michael A Morgan,Hildegard Büning,Shuo Wang,Axel Schambach,Thilo Dörk,Peter Hillemanns,Katharina Zimmermann,Jens Hachenberg

doi:10.3390/biomedicines9101339

Rüdiger Klapdor, Michael A Morgan + Show 7 more

Open Access

https://doi.org/10.3390/biomedicines9101339

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Abstract

Ovarian cancer is the most common cause of gynecological cancer-related death in the developed world. Disease recurrence and chemoresistance are major causes of poor survival rates in ovarian cancer patients. Ovarian cancer stem cells (CSCs) were shown to represent a source of tumor recurrence owing to the high resistance to chemotherapy and enhanced tumorigenicity. Chimeric antigen receptor (CAR)-based adoptive immunotherapy represents a promising strategy to reduce the risk for recurrent disease. In this study, we developed a codon-optimized third-generation CAR to specifically target CD44, a marker widely expressed on ovarian cancer cells and associated with CSC-like properties and intraperitoneal tumor spread. We equipped NK-92 cells with the anti-CD44 CAR (CD44NK) and an anti-CD19 control CAR (CD19NK) using lentiviral SIN vectors. Compared to CD19NK and untransduced NK-92 cells, CD44NK showed potent and specific cytotoxic activity against CD44-positive ovarian cancer cell lines (SKOV3 and OVCAR3) and primary ovarian cancer cells harvested from ascites. In contrast, CD44NK had less cytotoxic activity against CD44-negative A2780 cells. Specific activation of engineered NK cells was also demonstrated by interferon-γ (IFNγ) secretion assays. Furthermore, CD44NK cells still demonstrated cytotoxic activity under cisplatin treatment. Most importantly, the simultaneous treatment with CD44NK and cisplatin showed higher anti-tumor activity than sequential treatment.

Highlights

After production of lentiviral vector, retronectin-mediated transduction was performed on human natural killer (NK)-92 cells
We describe a novel anti-CD44 third-generation Chimeric antigen receptor (CAR) directed against ovarian cancer
The expression of CD44 was shown to be more pronounced in the recurrent and metastatic ovarian cancer tissues, when compared with its primary counterparts

Summary

Introduction

Ovarian cancer remains the most lethal among gynecological cancers [1]. Because localized ovarian cancer is generally asymptomatic and screening tests have not been successfully implemented, 75% of patients present with advanced tumor stages (FIGO stages III–IV) at the time of diagnosis [2]. There is an urgent need for the development of novel and effective therapeutic strategies. It is well-known that the immune system plays an important role in monitoring tumor development and progression [3]. Compelling clinical evidence shows that the presence of tumor-infiltrating lymphocytes (TILs) is associated with a favorable prognosis in ovarian cancer [4,5,6,7].

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