OBJECTIVE: To explore the molecular mechanism by which microRNA let-7g-3p regulates biological behaviors of bladder cancer cells. METHODS: The expression levels of let-7g-3p in bladder cancer and adjacent tissues, normal bladder epithelial cells (HUC cells) and bladder cancer cells (T24, 5637 and EJ cells) were detected using qRT- PCR. T24 cells were transfected with let-7g-3p mimic or inhibitor, and the changes in cell proliferation, migration, invasion, and apoptosis were examined. Transcriptome sequencing was carried out in cells overexpressing let-7g-3p, and the results of bioinformatics analysis, double luciferase reporter gene assay, qRT-PCR and Western blotting confirmed that HMGB2 gene was the target gene of let-7g-3p. The expression of HMGB2 was examined in HUC, T24, 5637 and EJ cells, and in cells with HMGB2 knockdown, the effect of let-7g-3p knockdown on the biological behaviors were observed. RESULTS: qRT-qPCR confirmed that let-7g-3p expression was significantly lower in bladder cancer tissues and cells (P < 0.01). Overexpression of let-7g-3p inhibited cell proliferation, migration and invasion, and promoted cell apoptosis, while let-7g-3p knock-down produced the opposite effects. Bioinformatics and transcriptome sequencing results showed that HMGB2 was the key molecule that mediate the effect of let-7g-3p on bladder cancer cells. Luciferase reporter gene assay, qRT-PCR and Western blotting all confirmed that HMGB2 was negatively regulated by let-7g-3p (P < 0.01). Knocking down HMGB2 could partially reverse the effect of let-7g-3p knockdown on the biological behaviors of the bladder cancer cells. CONCLUSION The microRNA let-7g-3p can inhibit the biological behavior of bladder cancer cells by negatively regulating HMGB2 gene.
Apoptosis ; Cell Line, Tumor ; Cell Movement/physiology* ; Cell Proliferation ; Epithelial Cells/metabolism* ; Gene Expression Regulation, Neoplastic ; HMGB2 Protein/metabolism* ; Humans ; MicroRNAs/metabolism* ; Urinary Bladder ; Urinary Bladder Neoplasms/genetics*

Individuals affected with Swyer syndrome are phenotypic females with 46, XY karyotype, sexual infantilism, mullerina derivatives, and bilateral streak gonads that may undergo neoplastic transformation. The pathogenesis of this syndrome is uncertain, but may be related to a defect in the regulation or expression of the testicular determining factor which is believed to be located on the short arm of the Y chromosome. Recently, a region termed "SRY", a single copy gene of the Y chromosome was identified as belonging to a testis-determining gene. This gene is Y-specific, highly conserved among mammals, and transcribed only in testis. The predicted amino acid sequence of SRY shares homology with DNA-binding domains of transcription factors such as chromatinassociated, nonhistone proteins HMG 1 and HMG 2. Hence, it was thought that there may be some change in SRY gene of the patients with Swyer syndrome. And it was reported in some cases that there was deletion or mutation in the gene, but no abnormality of SRY gene was observed in other cases. So, it is a new approach to understand the mechanism of the human sexual differentiation to investigate this syndrome in terms of DNA sequence of SRY gene. To verify the presence or absence of SRY, or the change in SRY, we performed polymerase chain reaction and DNA sequencing of the conserved region of SRY gene from four patients with Swyer syndrome and their family members. The results are as follows. 1) Four patients with Swyer syndrome, their father, and two normal male control were positive whereas two female control were negative for the band that represents the coding sequence of SRY. 2) The DNA sequences of SRY gene from four patients with Swyer syndrome, their father, and two normal male control were the same, and there was no deletion or mutation in the gene. In conclusion, there may be complex sex determining cascade including other genes not only on the Y chromosome, but also on the X chromosome or even autosome in human sexual differentiation.
Amino Acid Sequence ; Arm ; Base Sequence ; Clinical Coding ; Fathers ; Female ; Genes, sry* ; Gonadal Dysgenesis, 46,XY* ; Gonads ; HMGB2 Protein ; Humans ; Karyotype ; Male ; Mammals ; Polymerase Chain Reaction ; Sequence Analysis, DNA ; Sex Differentiation ; Sex-Determining Region Y Protein ; Sexual Infantilism ; Testis ; Transcription Factors ; X Chromosome ; Y Chromosome