miR-30a-3p inhibits the proliferation of liver cancer cells by targeting DNMT3a through the PI3K/AKT signaling pathway.

MicroRNAs (miRNAs or miRs) are crucial for normal development and maintenance of homeostasis. Dysregulated miRNA expression contributes to numerous pathological conditions, including cancer tumorigenesis. However, a limited number of studies have examined the regulatory effects of miR-30a-3p in tumorigenesis. Therefore, the present study investigated the mechanistic process of tumorigenesis in liver cancer. The results revealed a high expression of DNA methyltransferase 3a (DNMT3a) and a low expression of miR-30a-3p in HepG2 cells compared with that in the L02 cell line. A luciferase reporter assay demonstrated that DNMT3a is a direct target of miR-30a-3p. In addition, DNMT3a overexpression significantly enhanced cell proliferation, which was reversed by a miR-30a-3p mimic. Similarly, the miR-30a-3p mimic blocked DNMT3a-triggered cell cycle processes and apoptosis by attenuating active p-AKT and p-PI3K in HepG2 cells. In summary, the results of the present study demonstrate that miR-30a-3p is essential for cell proliferation regulation via its association with AKT/PI3K signaling in liver cancer. These results provide insight into the molecular mechanism by which miR-30a-3p inhibits liver cancer cell proliferation and provides a foundation for its clinical development and application.

[Association of mammalian target of rapamycin gene polymorphisms with the risk of pediatric epilepsy].

OBJECTIVE: To study the association between two single nucleotide polymorphisms (SNP), rs2295080 and rs2536, in mammalian target of rapamycin (mTOR) gene and the susceptibility to pediatric epilepsy. METHODS: A case- control study was performed on 480 children with epilepsy (116 cases of refractory epilepsy) and 503 healthy children. SNP rs2295080 and rs2536 in the mTOR gene were detected by polymerase chain reaction restriction and fragment length polymorphisms (PCR-RFLP). Genotype and allele frequencies of SNP rs2295080 and rs2536 were compared between the children with epilepsy and healthy controls. RESULTS: There were no significant differences in the genotype and allele frequencies of SNP rs2295080 between the children with epilepsy and healthy controls. There were no significant differences in the genotype frequencies of SNP rs2536 between the two groups either, but the frequency of G allele of SNP rs2536 was higher in children with epilepsy than that in healthy controls (P=0.042, OR=1.344, 95%CI: 1.010-1.789). CONCLUSIONS: SNP rs2536 of mTOR gene may be associated with the risk of pediatric epilepsy.

[Clinical features and MECP2 mutations in children with Rett syndrome].

OBJECTIVE: To study the clinical features and mutations in methyl-CpG-binding protein 2 (MECP2) gene among children with classical Rett syndrome in China. METHODS: PCR and direct sequencing were employed to analyze the three exons of MECP2 gene in 9 children recently diagnosed with Rett syndrome and their parents. RESULTS: Heterozygous mutations were identified in 5 out of 9 patients, with a mutation rate of over 50%; there was one case of insert mutation (c.913insT) and 4 cases of missense mutation (exon 3: c.316C>T (R106W); exon 4: c.502C>T (R168X), c.808C>T (R270X), and c.1126C>T (P376S). A new mutation (c.913insT) was found. No mutations were detected in their parents. Two patients had MECP2 mutations in the transcriptional repression domain (TRD). They had almost lost language functions and were found to have significantly delayed development compared with other patients. CONCLUSIONS: Mutations in MECP2 gene were detected in 5 confirmed cases of Rett syndrome, and most of them were on exon 4. Mutations in the TRD of MECP2 protein may affect the language ability and development in children with Rett syndrome.