关键词: BMS1, 神经母细胞瘤, 细胞增殖, p53, MYCN

Abstract: Objective  To elucidate the functional role and underlying mechanisms of the ribosome biogenesis factor BMS1 in neuroblastoma (NB) cellular proliferation. Methods  We utilized the R2 genomics analysis and visualization platform to analyze the correlation between BMS1 expression levels and clinical characteristics of NB children. The BMS1 mRNA level in three human neuroblastoma cells SK-N-BE(2), BE(2)-C, IMR-32 and two normal cells hTERT RPE-1, IMR-90 was detected by real-time quantitative polymerase chain reaction (RT-qPCR). Two distinct small interfering RNA (siRNA) sequences were used to target BMS1 mRNA in NB cells SK-N-BE(2) and BE(2)-C, with normal cells hTERT RPE-1 serving as controls. We used RT-qPCR to quantify the mRNA levels of BMS1 and two key neuroblastoma-associated molecules (MYCN and p53). After transfection with siRNA, cellular proliferation was detected by various experimental approaches: crystal violet staining, real-time cell analysis (RTCA), colony-forming unit assay and immunofluorescence. Results  By analyzing two independent neuroblastoma clinical cohorts (GSE85047/NRC-283 and Westermann-144 datasets), it was found that the BMS1 mRNA level in MYCN-amplified NB was significantly higher than that in MYCN-non-amplified NB (P<0.05). Furthermore, the overall survival rate of NB children in the BMS1 high-expression group was decreased (P<0.05). Consistent with these clinical observations, the BMS1 mRNA level in NB cells SK-N-BE(2), BE(2)-C and IMR-32 was significantly higher than that in normal cells hTERT RPE-1, IMR-90 (P<0.05).  The targeted transient knockdown of BMS1 in NB cell lines SK-N-BE(2) and BE(2)-C resulted in decreased intracellular MYCN mRNA expression levels (P<0.05), significantly reduced cell proliferation capacity and colony-forming ability (P<0.05). Immunofluorescence revealed that the expression of Ki-67, a proliferation marker, was decreased (P<0.05). At the molecular level, RT-qPCR showed that  the p53 mRNA level was significantly elevated in the BMS1-knockdown groups (siBMS1-1# and siBMS1-2#) compared with the control group (P<0.05). However, transient knockdown of BMS1 had no significant impact on the proliferative capacity of normal cells hTERT RPE-1. Conclusion  BMS1 expression was up-regulated in MYCN-amplified NB and negatively correlated with the prognosis of the NB children. Mechanistically, interfering with BMS1 expression may transcriptionally activate p53 in NB cells, thereby inhibiting their proliferative ability, while having minimal impact on normal cells growth kinetics. These findings suggest that BMS1 serves as an important proliferation driver in NB and is expected to be a promising therapeutic target for NB children, particularly MYCN-amplified pediatric patients.

Key words: BMS1, neuroblastoma, cell proliferation, p53, MYCN