Anti-tumor effects of CD133-targeted CAR-NK92MI cells in colorectal cancer.

BACKGROUND AIMS: Colorectal cancer (CRC), a highly aggressive malignancy, continues to threaten many lives. Chimeric antigen receptor-natural killer cell (CAR-NK) therapy has emerged as a promising therapeutic approach for CRC. CD133 is an important marker in many solid tumors, especially CRC.

METHODS

In this study, we generated CD133-targeted CAR-NK92MI cells using a lentiviral system and analyzed CAR expression by flow cytometry. The proliferation of NK92MI cells after CAR introduction was evaluated by CCK-8 assay. In vitro cytotoxicity against target cells was assessed by LDH release, Calcein-AM/PI staining, and TUNEL staining, and effector cell activation was evaluated by measuring IFN-γ secretion. The effects of CAR-NK92MI cells on target-cell invasion and migration were further assessed by Transwell invasion assays, wound-healing assays, and a 3D tumor-spheroid system. In vivo antitumor activity was also evaluated.

RESULTS

CAR was successfully expressed in NK92MI cells without significantly affecting cell proliferation. In vitro, CAR-NK92MI cells showed enhanced killing activity against target cells and increased IFN-γ secretion. CAR-NK92MI cells also suppressed target-cell invasion and spheroid growth. The in vivo findings were consistent with the in vitro results.

CONCLUSION

CD133-targeted CAR-NK92MI cells showed promising antitumor activity against colorectal cancer and may provide a potential strategy for developing an off-the-shelf cell therapy product for CRC.