ALK Inhibitors Do Not Increase Sensitivity to Radiation in EML4-ALK Non-small Cell Lung Cancer.

BACKGROUND/AIM ALK inhibitors like Crizotinib, Ceritinib and Alectinib are targeted therapies used in patients with anaplastic lymphoma kinase (ALK)-positive, advanced non-small cell lung cancer (NSCLC). Since in this tumor entity radiotherapy is employed sequentially or concomitantly, potential synergistic effects were investigated, which may support the hypothesis of induced radiosensitization by using ALK inhibitors. MATERIALS AND METHODS Two cell lines expressing wild-type (WT) or echinoderm microtubule-associated protein-like 4 (EML4)-ALK were treated with ALK inhibitors, followed by irradiation. Cell survival, cell death, cell cycle and phosphorylation of H2A histone family, member X (H2AX) were examined. RESULTS Combined treatment with ALK-inhibitors plus 10 Gy-irradiation led to effects similar to those of sole radiotherapy, but was more effective than sole drug treatment. CONCLUSION There is no clear evidence of sensitization to radiation by treating EML4-ALK mutated cells with ALK inhibitors.