Paclitaxel inhibits natural killer cell binding to target cells by down-regulating adhesion molecule expression

Background: Chemotherapy with paclitaxel is associated with impaired natural killer (NK) cell function. The purpose of this study was to determine the effect of paclitaxel treatment on NK cell adherence to target cells. Materials and Methods: Human NK-like YT cells or NK-sensitive K562 cells were exposed to submaximal cytotoxic concentrations (EC₁₀ and EC ₃₀) of paclitaxel. The ability of surviving YT or K562 cells to adhere to untreated K562 cells or YT cells, respectively, was assessed in a conjugation assay. The effect of paclitaxel on adhesion molecule expression was determined by flow cytometry. Results: Paclitaxel treatment resulted in decreased conjugate formation, as well as decreased α₄ α_L, and β₇ integrin expression by YT cells and decreased ICAM-1 expression by K562 cells. Conclusions: Paclitaxel inhibition of adhesion molecule expression resulted in impaired NK cell binding to target cells, which may have a negative impact on immune surveillance.