Cetuximab combination with cytokine induced killer cells effectively inhibit conjunctival squamous cell carcinoma in vitro

We explored the potential effects of the anti-EGFR monoclonal antibody Cetuximab when combined with activated cytokine-induced killer cells (CIKs) as a novel treatment strategy for human conjunctival squamous cell carcinoma (CSCCs) in vitro. The CSCC used in our study was obtained from an explant of a patient diagnosed with the condition. After molecular and pathological confirmations, the CSCC was established as proliferating and confluent cultures and was exposed continuously for seven days to different concentrations of Cetuximab (10 –3 -10 3 µg/mL) and different ratios of CIKs. CIK cells were cultured with a high dose of IL-2 and the cell population contained activated CD3 + , CD16 + , and CD56 + cells. CIK cells alone exhibited cytotoxicity toward EGFR-positive CSCC whereas Cetuximab alone exhibited limited cytotoxic efficacy. Final counts of CSCC measured on days 1 and 7 after exposure demonstrated over 95% suppression of proliferating CSCC at a Cetuximab concentration of 10 2 µg/mL, with a CIKs ratio of 50:01 (Effector:Target). Meanwhile, the confluent normal limbal stem cells were largely unaffected. This particular anti-EGFR monoclonal antibody could be beneficial in treating proliferative ocular epithelial conditions, including squamous cell carcinoma of the ocular surface.