Abstract
Novel therapeutic approaches against ovarian cancer (OC) are urgently needed because of its high rate of recurrence even after extensive surgery and multi-agent chemotherapy. We aimed to develop a novel anti-CD24 chimeric antigen receptor (CAR) as an immunotherapeutic approach against OC cells and cancer stem cells (CSC). CSC represents a subpopulation of the tumor characterized by enhanced chemoresistance as well as the increased capability of self-renewal and metastasis. We designed a codon-optimized third-generation CAR containing the highly active single chain variable fragment (scFv) “SWA11” against CD24. We equipped the human NK-cell line NK-92 with the anti-CD24 CAR and an anti-CD19 control CAR using lentiviral transduction. Engineered NK-92 cells showed high cytotoxic activity against CD24-positive OC cell lines (SKOV3, OVCAR3). This effect was restricted to CD24-expressing cells as shown after lentiviral transduction of CD24-negative cell lines (A2780, HEK-293T) with CD24 transmembrane proteins. Additionally, NK-92 cells equipped with our novel anti-CD24 CAR were highly effective against patient-derived primary ovarian cancer cells. The activation of NK cells was shown by specific IFNγ secretion upon antigen stimulation. To further reduce possible off-target effects in vivo, we applied a dual-CAR approach using an anti-CD24-CD28-41BB fusion protein linked via a 2A sequence to an anti-mesothelin-CD3ζ-CAR. The dual-CAR was simultaneously active against CD24 and mesothelin expressing cells. Our novel anti-CD24-CAR showed a highly cytotoxic effect against OC cell lines and primary OC cells and will be evaluated in future in vivo trials as a promising immunotherapeutic approach against OC.
Highlights
Among gynecologic malignancies, ovarian cancer (OC) has the highest mortality
We developed a novel CD24 specific third-generation chimeric antigen receptor (CAR), which we characterized and analyzed for its functionality in OC cell lines and primary patient-derived OC cells
The scFv of the monoclonal antibody SWA11, which is specific for the LAP epitope of the protein core of human CD24, was selected for our anti-CD24 CAR [12]
Summary
Ovarian cancer (OC) has the highest mortality. Despite the use of ultrasounds, tumor markers or regular gynecologic examinations, OC is mostly detected at advanced tumor stages with tumor spread over the entire abdominal cavity. Current research in this direction focuses on cell- or antibody-based immunotherapeutic approaches due to the possibilities of targeting tumor cells of interest. Cancer stem cells (CSC) represent a very interesting target for immunotherapy, since these cells are characterized by high resistance against chemotherapy and an increased capability of self-renewal [3,4,5]. Frequently described CSC markers in OC are CD133, CD44, CD24, CD117, and their elevated expression, especially for CD44, CD24 or CD133, was shown to be associated with poor clinical outcome in OC patients [3]. CD24 is expressed in a variety of human cancers and is associated with poor survival [6,7,8]. We selected the single chain variable fragment (scFv) from this antibody for our newly designed chimeric antigen receptor (CAR) against CD24
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
