Radiotherapy alters the polarization of tumor-associated macrophage to suppress lung cancer progression via up-regulation of lincRNA-p21

Objective : It has been reported that high tumor-associated macrophages (TAMs) numbers in tumors were correlated with poor tumor responses to irradiation. However, few studies have attempted to demonstrate the roles of TAMs in radiotherapy for suppressing the progression of lung cancer. Methods : TAMs were separated from C57BL/6 mice which were inoculated Lewis lung cancer cells and exposed to radiation therapy, then the expression of maker genes of polarized macrophages and lincRNA-p21 were analyzed using qPCR. Cell viability and invasion of Lewis cells cultured with TAMs exposed to radiation therapy were detected with CKK-8 assay and cell invasion assay, respectively. Ad-LincRNA-p21 and Ad-Si-LincRNA-p21 were used to examine the effect of lincRNA-p21 on TAMs. Results : Radiotherapy effectively suppressed the tumor growth in C57BL/6 mice transplanted with Lewis lung cancer cell. Radiotherapy promoted the polarized of TEMs into M1 macrophage and up-regulated the level of lincRNA-p21 in TEMs. Moreover, TEMs transfected with Ad-LincRNA-p21 presented anti-tumor effect and Ad-Si-LincRNA-p21 might reverse the effect of radiotherapy on tumor growth. Conclusion : Our results suggest that radiotherapy promotes the polarization of TEMs into M1 macrophage to suppress lung cancer progression and lincRNA-p21 plays an important role in the radiotherapy treatment for lung cancer. Keywords:  radiotherapy; polarization; tumor-associated macrophage; lung cancer; lincRNA-p21