Background: Glioma is the most common human central nervous system tumour with a high degree
of malignancy. Some Rab GTPases have significant effects on glioma.
Objective: This study aimed to investigate the effect of Rab3b (Rab GTPase3b) on human glioma cell proliferation
and apoptosis by silencing Rab3b and to initially verify the value of Rab3b expression for the diagnosis
and progression in human glioma.
Methods: Rab3b was silenced by siRNA transfection. Human glioma tissues and normal brain tissues adjacent
to glioma were obtained by surgery. Rab3b, P53, Caspase 7, Bax, and Bim mRNA and protein expression levels
were detected by quantitative real-time polymerase chain reaction (qRT-PCR) and Western blotting. Cell
proliferation was detected by the cell counting kit-8 assay, and the cell cycle and apoptosis were analysed using
Results: Rab3b mRNA and protein expression in human glioma U251 and U87 cells were significantly downregulated
after Rab3b silencing. Rab3b silencing inhibited glioma cell proliferation by promoting cell cycle arrest
and induced apoptosis by upregulating the expression of apoptosis-related proteins. Rab3b expression in human
glioma (n = 33) was significantly higher than that in normal brain tissues adjacent to glioma (n = 15). In addition,
Rab3b expression levels in high-grade gliomas (WHO III-IV, n = 19) were also significantly higher than
those in low-grade gliomas (WHO I-II, n = 14).
Conclusion: Rab3b expression levels are significantly related to the progression of gliomas. Moreover, Rab3b
silencing not only significantly inhibits cell proliferation in gliomas via cell cycle arrest but also promotes cell
apoptosis by upregulating the expression levels of apoptosis-related proteins; however these preliminary in
vitro results warrant validation on in vivo studies.