Abstract: Objective To investigate the correlation of miR-7 and its downstream target specific protein 1(SP-1) with the radiosensitivity in non-small cell lung cancer (NSCLC) patients. Methods The tumor tissues, adjacent tissues and peripheral blood of 116 patients with primary NSCLC, admitted to the First Affiliated Hospital of Hunan Normal University from July 2018 to September 2020, were collected. The expression of miR-7 in tissue samples and peripheral blood serum were measured by real-time fluorescent quantitative PCR. The expression of SP-1 protein was detected by immunohistochemistry. The factors affecting the radiosensitivity of NSCLC patients were analyzed by the logistic regression model. Results The expression of miR-7 in tumor tissues of NSCLC patients was lower than that in adjacent tissues (P<0.001), while the positive expression rate of SP-1 protein was higher than that in adjacent tumor tissues (P<0.001). Pearson showed that serum miR-7 was positively correlated with the expression of miR-7 in tumor tissue (r=0.492, P<0.001), and serum miR-7 expression in NSCLC patients with positive SP-1 expression was lower than that in patients with negative SP-1 expression (P=0.005). The expression levels of miR-7 in serum and tissue of patients with T3-4 stage, TNM stageⅢA-B, smoking and radiation-induced lung injury were decreased (all P<0.05), and the positive rate of SP-1 was increased in cancer tissues (all P<0.05). Compared with the radiation sensitivity group, the relative expression of miR-7 in serum and tumor tissue of the radiation resistance group was decreased (all P<0.001), and the positive expression rate of SP-1 was increased (P<0.001). The receiver operating characteristic curve showed that the area under the curve of serum miR-7 to predict rodiotherapy resistance in NSCLC patients was 0.822 (95%CI: 0.746-0.897). Decreased serum miR-7 expression was a risk factor for radiotherapy sensitivity (P=0.009). Conclusions Serum miR-7 has a good efficacy in predicting radiotherapy resistance. miR-7 and its downstream targeted molecular SP-1 are potential radio sensitizing targets.

Key words: Non-small cell lung cancer, miR-7, SP-1, Radiotherapy sensitivity