Improving the effect of radiation therapy by inducing reoxygenation of lung cancer cells through aerobic exercise

AbstractIn the field of radiation therapy, the oxygen effect is the most important key factor in increasing the treatment efficiency. Many researchers have studied methods for causing reoxygenation inside tumor cells. This study was conducted to determine whether reoxygenation is induced through relatively accessible aerobic exercise. The animals were injected with 5×105A549 cells in the flank and tumors were allowed to develop. Upon identification of a palpable tumor (tumor volume of 200 mm3), radiation and aerobic exercise combined treatment was administered for 2 weeks. Radiation was irradiated immediately after performing aerobic exercise. Radiation was irradiated with 2 Gy to the tumor and aerobic exercise was performed at a speed of 8.0 for 30 minutes. Next, 4–6 µm sections were prepared and stained with hematoxylin and eosin (H&E) following standard procedures. For Ki-67 and CA IX, HIF-1α, 4-hydroxynonenal & nitrotyrosine immunohistochemistry. We confirmed that lung cancer cell growth was suppressed when aerobic exercise was combined with radiotherapy throughin vivoxenograft studies. In addition, the effect of aerobic exercise on the radiation therapy effect through reoxygenation in tumor cells was confirmed. We also confirmed that HIF-1α and CA IX expressions were significantly increased in the combination treatment group. Lastly, we performed transcriptome analysis to discover the key factors that aerobic exercise induces reoxygenation. Taken together, the results suggest that the effect of radiation therapy is enhanced through aerobic exercise, which is relatively easy to apply.