Abstract:
Objective This study aimed to investigate the relationship between miR-29a and CDC42 expressions in glioma cells.This study also aimed to determine the effect of miR-29a on CDC42 expression as well as tumor cell migration and invasion.
Methods The expression levels of miR-29a in 10 cases with non-tumor control brain tissues and 60 cases with glioma tissues of four pathological grades were detected by tissue microarray and locked-oligonucleotide-probe in situ hybridization.The expression levels of miR-29, CDC42 mRNA, and protein, the migratory and invasive abilities of U251, and also its corresponding miR-29a and scrambled sequences which overexpress the sub-cell lines U251-miR-29a and U251-scr, were determined by quantitative reverse transcription-polymerase chain reaction, Western blot, and Transwell assay.The relationships among these indexes were also analyzed.
Results miR-29a was significantly downregulated in all of the glioma samples and continuously decreased as the malignant grade of the tumors increased.All of the differences between each pair of the four groups were statistically significant(P < 0.01).U251-miR-29a expressed a significantly higher level of miR-29a(P < 0.001) and lower levels of CDC42 mRNA and protein(P < 0.05) than U251 and U251-scr.The expression level of CDC42 mRNA was negatively correlated with that of miR-29a(r=-0.979, P < 0.01), but this expression level was positively correlated with that of CDC42 protein(r=0.834, P < 0.01).The highest migratory and invasive abilities were observed in U251-miR-29a.Such abilities were positively correlated with CDC42 expression level(r=0.828, P < 0.01).
Conclusion miR-29a could be used as an important marker to assess the malignant degree of gliomas.The aberrant decrease in miR-29a expression resulted in CDC42 upregulation.This decrease also facilitated the migration and invasion of glioma cells.The overexpression of miR-29a could effectively block CDC42 expression and substantially inhibit the migration and invasion of glioma cells, indicating the importance of miR-29a in gene therapy of malignant gliomas.