Sensitisation of human lung adenocarcinoma A549 cells to radiotherapy by Nimotuzumab is associated with enhanced apoptosis and cell cycle arrest in the G2/M phase.

The epidermal growth factor receptor (EGFR) plays an important role in tumorigenesis and maintenance of cancers, making it a possible therapeutic target for cancer treatment. Nimotuzumab (h-R3), a humanised monoclonal antibody against EGFR, sensitises human lung adenocarcinoma A549 cells to radiotherapy. We have investigated the underlying molecular mechanism by treating A549 cells with Nimotuzumab (100 μg/mL) alone or in combination with a single dose of 2 Gy irradiation, and analysing apoptosis and cell cycle distribution by flow cytometry. Nimotuzumab significantly enhanced radiation-induced apoptosis of A549 cells as evidenced by increased cell apoptosis (7.15 ± 0.30%) compared with the control group (1.08 ± 0.25%), Nimotuzumab alone group (4.89 ± 0.30%) and irradiation alone group (5.90 ± 0.15%). Combining Nimotuzumab with irradiation significantly arrested cells in the G2/M phase (43. ± 0.36%) compared radiotherapy alone (18.7 ± 0.35%) and single Nimotuzumab treatment (27.2 ± 0.17%). A combination of Nimotuzumab with radiation increased apoptosis and G2/M phase arrest in human lung adenocarcinoma A549 cells, suggesting potential development of combinatorial therapy of Nimotuzumab with radiotherapy for lung cancer.