Designed miR-19a/b sponge induces apoptosis in lung cancer cells through the PI3K-PTEN-Akt pathway regulation.

BACKGROUND: MicroRNAs (miRNAs) are one of the main factors in cancer development and can alter the activity of proto-oncogenic or tumor suppressor genes. The miR-17-92 cluster, which comprises miR-17, miR-18a, miR-19a/b, miR-20a, and miR-92a, has been identified as a biomarker in a variety of cancer types. Among them, miR-19a/b exerts an oncogenic effect by suppressing tumor suppressor genes, including PTEN and TP53INP1in numerous types of cancers, including NSCLC. An miRNA sponge is an mRNA with multiple repetitive sequences that prevents miRNAs from interacting with their targets, thereby inhibiting their action. METHODS AND RESULTS: In this study, we designed an miR-19a/b sponge plasmid and transfected it into A549 lung cancer cell lines and analyzed its effects on PTEN and TP53INP1 gene expression as the main miR-19a/b target and apoptosis rate in these cell lines. CONCLUSIONS: The findings revealed that miR-19a/b sponge significantly increased PTEN and TP53INP1 mRNA expression. The effect of the sponge on TP53INP1 was much greater than that on PTEN. This is because TP53INP1 is directly (sponge effect) and indirectly (AKT pathway is affected by the P53 gene) affected by this sponge. In addition, compared with the control group, the percentage of primary and secondary apoptosis increased significantly (P value < 0.0001).