Syngeneic Mouse Models of Oral Cancer are Effectively Targeted by anti-CD44-based NIR-PIT
Menée in vitro et à l'aide de modèles murins syngéniques de carcinome épidermoïde de la cavité buccale, cette étude met en évidence l'intérêt thérapeutique d'une immunophotothérapie en proche infrarouge utilisant un anticorps monoclonal anti-CD44 conjugué au photosensibilisant IR700DX
Oral cavity squamous cell carcinoma (OSCC) is considered one of the most aggressive subtypes of cancer. Anti-CD44 monoclonal antibodies (mAbs) are a potential therapy against CD44 expressing OSCC, however, to date the therapeutic effects have been disappointing. Here, a new cancer treatment is described, near-infrared photoimmunotherapy (NIR-PIT), that uses anti-CD44 mAbs conjugated to the photoabsorber, IR700DX. This conjugate is injected into mice harboring one of three CD44 expressing syngeneic murine oral cancer cell (MOC) lines, MOC1 (immunogenic), MOC2 mKate2 (moderately immunogenic), and MOC2-luc (poorly immunogenic). Binding of the anti-CD44-IR700 conjugate was shown to be specific and cell-specific cytotoxicity was observed after exposure of the cells to NIR in vitro. The anti-CD44-IR700 conjugate, when assessed in vivo, demonstrated deposition within the tumor with a high tumor-to-background ratio. Tumor-bearing mice were separated into four cohorts: no treatment; 100µg of anti-CD44-IR700 i.v. only; NIR light exposure only; and 100µg of anti-CD44-IR700 i.v. with NIR light exposure. NIR-PIT therapy, compared with the other groups, significantly inhibited tumor growth and prolonged survival in all three cell model systems. In conclusion, these data reveal that anti-CD44 antibodies are suitable as mAb-photoabsorber conjugates for NIR-PIT in MOC cells. Implications:This study using syngeneic mouse models, which better model the disease in humans than conventional xenografts, suggests that NIR-PIT with anti-CD44-IR700 is a potential candidate for the treatment of OSCC.