Expression of miR-520d-3p in X-rays irradiated A549 cells and serum samples of non-small cell lung cancer patients and its significance

Abstract

Objective To investigate the expression of miR-520d-3p in 2 and 4 Gy X-ray irradiated A549 cells, serum samples of non-small cell lung cancer (NSCLC) patients and its significance. Methods Real time quantitative PCR (RT-qPCR) was employed to detect the expression miR-520d-3p in 2 and 4 Gy X-ray irradiated A549 cells in vitro. Besides, 0, 2 and 4 Gy X-ray irradiated A549 cells were used to prepare animal model of nude mice lung metastasis through mainline. The expressions of miR-520d-3p and lung tissue of nude mice were detected, and the serum samples of NSCLC patients were collected to test the expression of miR-520d-3p. Results Compared with the control group (0 Gy), the expression of miR-520d-3p was up-regulated significantly in 2 and 4 Gy X-ray irradiated A549 cells after 48 hours (1.00±0.03, 1.47±0.10, 1.84±0.09 respectively), and there was a significant difference (F= 94.350, P= 0.000). Furthermore, compared the control group with injection after 10 weeks, the expressions of miR-520d-3p in nude mice lung tissue in 0, 2 and 4 Gy X-ray irradiated groups were increased (2.33±0.13, 8.24±0.25, 3.46±0.14, respectively) (F= 1.787, P= 0.227), and the expressions in serum were increased (11.43±2.30, 10.22±4.62, 8.99±3.67, respectively) (F= 1.547, P= 0.246). Out of 20 serum samples of NSCLC patients (including 10 cases of adenocarcinoma, 10 cases of squamous carcinoma), 11 cases (55 %) were detected with up-regulated miR-520d-3p expression. Conclusions 2 and 4 Gy X-ray could increase the expression of miR-520d-3p of A549 cells in vitro and in vivo, which might be correlated with the enhanced invasion and metastasis of A549 cells induced by X-ray in vitro and in vivo. Furthermore, the expressions of miR-520d-3p were increased significantly in over 50 % serum samples of NSCLC patients, which might be a new marker for the diagnosis of NSCLC. Key words: Carcinoma, non-small-cell lung; Radiation; MicroRNAs; Neoplasm invasiveness