Correlation study of biological characteristics of non-small cell lung cancer A549 cells after transfecting plasmid by microbubble ultrasound contrast agent

Objective: To explore the role of the abnormal expression of miRNAs in the development process of non-small cell lung cancer and the feasibility of ultrasound microbubble-mediated gene therapy after transfecting antisense miRNA-224 and miRNA-122a plasmids into non-small cell lung cancer A549 cells. Methods: Antisense miRNA-224 and miRNA-122a plasmids were transfected into nonsmall cell lung cancer A549 cells on the optimal ultrasound microbubble-mediated condition. We set up a control group. The cell proliferation activity, apoptosis, invasion ability were detected by MTT assay, Annexin V-PE, Transwell invasion experiment and colony formation assay, respectively. Results: The expression of miRNA-224 decreased and the expression of miRNA-122a rose after the plasmids of target genes were transfected into non-small cell lung cancer A549 cells, and there were significant differences when compared with those of the control group (P < 0.05). After the plasmids of target genes were transfected into A549 cells, the growth of antisense miRNA-224 and miRNA-122a were inhibited, and the differences were significant as compared with the control group (P < 0.05). Besides, the inhibition of miRNA-122a group was the most significant and there was statistically significant difference as compared with miRNA-224 group (t = -4.694, P = 0.009). After the plasmids of target genes were transfected into A549 cells, the proportion of apoptotic cells increased, the invasive cells were decreased and the clone ability reduced, and also there was a significant difference as compared with those of the control group (P < 0.05). What's more, the apoptotic peak appeared in miRNA-122a group. Its invasion ability decreased most obviously (40.25 +/- 3.97/visual field), the number of clone ability was 104.93 +/- 4.87 and the inhibitory effect was the most obviously. There was statistically significant difference as compared with other groups (P < 0.05). Conclusions: A549 cells transfected by ultrasound microbubble-mediated antisense miRNA-224 and miRNA-122a plasmids possessed good transfection efficiency. The cell growth, invasion and colony-forming abilities of transfected A549 cells were suppressed, which laid a solid foundation for the gene therapy of non-small cell lung cancer.