Study On The P53-related MiRNAs In Breast Cancer

As an important tumor suppressor, p53 plays a pivotal role in the DNA damage and oncogene signaling pathway, mainly functioning as a transcription factor. When suffering from DNA damage, stimuli of oncogenic and hypoxia, the activated p53 protein can transcriptionally regulate a series of genes, resulting in arrest of cell cycle, apoptosis, DNA repair or senescence. miRNAs are a class of endogenous non-coding RNA, which can bind the target mRNA through complementary base pairing, form RNA induced silencing complex(RISC), and lead to degradation or translation inhibition of their target mRNAs. Numerous miRNAs have been found to be involved in the regulation of the p53 signaling pathway. Conversely, p53 regulates the transcription or processing of mi RNAs. Given that complexities in the association between p53 and mi RNAs exist, and due to the rapidly increasing amount of literature regarding the interactions between p53 and miRNAs, the present study systematically analyzed the associations between miRNAs and p53 in breast cancer using a literature-based discovery approach and next generation sequencing.Using a literature-based discovery approach, natural language processing, we found that a total of 22 miRNAs were associated with p53 in the breast cancer. Next, three popular online tools(PicTar, mi Randa and TargetScan) were used to predict the targets of each miRNA, and certain targets were validated by experiments. Gene Ontology annotation and network analysis demonstrated that the majority of the targets of the p53-related miRNAs were enriched in the cell cycle process and axonal guidance signaling.In addition, the breast cancer cell line MCF-7 was infected with lentiviral p53 shRNA and empty vector lentivirus. At 72 hours after infection, puromycin were used to screen for stable cell lines. Then, we analyzed the small RNA expression profiles by the second-generation sequencing, and found that p53 interference significantly decreased expression of 12 miRNAs. Realtime PCR analysis showed that overexpression of p53 gene in Hek293 cells significantly enhanced the expression of 5 mi RNAs. Using PicTar, miRanda and TargetScan, we predicted a total of 464 target genes. Using ingenuity pathway analysis software, we found that these genes were mainly enriched in the axon guidance signaling pathway, followed by cell growth and proliferation.This study reveals a new mechanism of p53 regulation that, in addition to regulating the transcription of genes involved in cell cycle and axon guidance signaling pathway, p53 also indirectly modulates the cell cycle and axon guidance signaling via mi RNAs.