Investigating Effective Combinations of Anti-cancer Drugs and Radiation Therapy for Treating Non-small Cell Lung Cancer with Using Two Cell Lines

ABSTRACT

PURPOSE: Radiotherapy had been used for treating unresectable locally advanced non-small cell lung cancer (NSCLC). However, the survival rate after radiotherapy alone is low and this primarily due to the failure of local disease control and distant metastasis. For achieving better disease control, radiotherapy has recently been combined with chemotherapy in various ways. In this study, we aimed to find the most effective combination of chemotherapy and radiotherapy for treating NSCLC. MATERIALS AND METHODS: Two human lung cancer cell lines (NCI-H520 and A549) and various chemotherapeutic agents (paclitaxel, docetaxel, gemcitabine and cisplatin) were used for this study. The radiation doses were 0, 2, 4 and 8 Gy. After processing various combinations according to the radiation doses and the concentrations of thechemotherapeutic agents, cell survival was quantified by MTT (3-(4,5-Dimethylhiazol- 2-yl)-2,5-diphenyltetrazoliumbromide) assay. For the evaluation of synergism between chemotherapy and radiotherapy, we used a combination index that as calculated by Chou and Talalay's method and with using Calcusyn software. RESULTS: Among the various combinations of chemotherapeutic agents and radiation doses, concurrent chemoradiation therapy (CCRT) led to the highest apoptosis rate and it showed frequent synergism. When taxane was administrated as a chemotherapeutic agent, chemotherapy followed by radiotherapy was the most effective combination. When high-dose chemotherapeutic agents were added to CCRT, induction chemotherapy resulted in a higher apoptosis rate and more frequent synergism than did consolidation chemotherapy. CONCLUSION: When radiotherapy is combined with chemotherapy for treating the NCI-H520 and A549 cell lines, CCRT is the most effective combination. If a high-dose chemotherapeutic agent is added to CCRT, then induction chemotherapy is more effective than consolidation chemotherapy.