EpCAM expression was evaluated by real-time polymerase chain reaction and flow cytometry. Sensitivity to MT201 antibody-dependent cell-mediated cytotoxicity (ADCC) and complement-dependent cytotoxicity was tested in 4-hour chromium-release assays. The effect of interleukin-2 on MT201 ADCC was also studied.
High messenger RNA expression by real-time polymerase chain reaction and high EpCAM surface expression by flow cytometry was detected in 71 % of ovarian cancers (5 of 7 cell lines). Although these cell lines were highly resistant to complement-dependent cytotoxicity and natural killer-dependent cytotoxicity in vitro (range of killing, 0–7 % ), EpCAM-positive cell lines showed high sensitivity to MT201 ADCC (range of killing, 27–66 % ). Incubation with interleukin-2 further increased the cytotoxic activity against EpCAM-positive ovarian cancer cell lines.
MT201 may represent a novel, potentially highly effective treatment option for patients with ovarian carcinoma whose body is harboring disease refractory to chemotherapy.