Objective To explore the function of olfactomedin domain family protein 3(OLFM3)in neuroblastoma(NB).Methods The relationship between the expression of OLFM3 mRNA and v-myc avian myelocytomatosis viral oncogene neuroblastoma derived homolog(MYCN)amplification status and the prognosis of patients in NB clin-ical samples were clarified by using R2 Genomics Analysis and Visualization Platform.Depmap database was used to examine the expression level of OLFM3 in different tumors cell lines and to identify the correlation between OLFM3 expression and MYCN amplification status in various NB cell lines.RT-qPCR and Western blot were used to detect the knockdown level of OLFM3.Cell proliferation was monitored using crystal violet staining and real?time cellular analysis.The colony formation ability of NB cells was assessed using colony?forming unit assay.Results Analysis of R2 database revealed higher level of OLFM3 expression in MYCN?amplified NB clinical samples(P<0.001).Patients with high OLFM3 expression showed a significantly lower overall survival probability compared to those with low OLFM3 expression(P<0.05).Analysis with Depmap database revealed that the expres?sion level of OLFM3 was higher in NB than that in other kind of tumor.The expression level of OLFM3 was signifi?cantly higher in the MYCN?amplified cell lines than in the MYCN?non?amplified cell lines(P<0.01).In MYCN?am?plified NB cells,knockdown of OLFM3 inhibited cells proliferation(P<0.001)and colony formation(P<0.001),but there was no noticeable changes observed in MYCN?non?amplified cells.Conclusions OLFM3 specifically pro?motes the proliferation of MYCN?amplified NB cells,but has a less effect on MYCN?non?amplified cells,indicating it is a potential biomarker for high?risk MYCN?amplified NB.

Objective To explore the effect of open reading frame 66(C12ORF66)located at chromosome 12 on the viability of MYCN amplified NB cell lines.Methods DDatasets GSE16476 and GSE49710 in R2 database were analyzed for expression level of C12ORF66 in MYCN amplified and MYCN non-amplified NB cells and its potential correlation with the prognosis of pediatric patients.C12ORF66 mRNA expression level in normal tissue immortalized cell lines,MYCN amplified and MYCN non-amplified cell lines were detected by RT-qRCR.Transient or stable knockdown of C12ORF66 cell lines were constructed to compare the difference in real time cellular analysis(RTCA),colony formation,Ki67 positive cells between the control group and the C12ORF66 knockdown group.Results By analyzing R2 datasets,C12ORF66 level in MYCN amplified samples was significantly higher than that in MYCN non-amplified samples,and the expression of C12ORF66 was negatively correlated with the prognosis of pediatric patients(P＜0.05).C12ORF66 highly expressed in MYCN-amplified BE(2)-C and SK-N-BE(2)cell lines than in MYCN non-amplified CHLA-255 and SH-SY5Y cell lines(P＜0.001).Transient or stable knockdown of C12ORF66 resulted in significant slow down of proliferation of MYCN amplified NB cells(P＜0.001),the colony formation ability was significantly reduced(P＜0.001),and the proportion of Ki67 positive cells was significantly decreased(P＜0.05).Conclusions C12ORF66 was highly expressed in MYCN amplified clinical NB samples and cell lines which is believed to be correlated with poor prognosis of pediatric patients.C12ORF66 knockdown signifi-cantly inhibits cell viability of NB cells.

Objective:To investigate the function and underlying mechanism of cysteine and glycine-rich protein 2(CSRP2)in neuroblastoma(NB).Methods:The correlation between the expression level of CSRP2 mRNA and the prognosis of NB children in NB clinical samples was analyzed in R2 Genomics Analysis and Visualization Platform.The small interfering RNA(siRNA)targeting CSRP2 or CSRP2 plasmid were transfected to NB cell lines SK-N-BE(2)and SH-SY5Y.Cell proliferation was observed by crystal violet staining and real-time cellular analysis.The ability of colony formation of NB cells was ob-served by colony-forming unit assay.Immunofluorescence assay was used to detect the expression of the proliferation marker Ki-67.Flow cytometry analysis for cell cycle proportion was used with cells stained by propidium iodide(PI).Annexin V/7AAD was used to stain cells and analyze the percentage of cell apoptosis.The ability of cell migration was determined by cell wound-healing assay.The level of protein and mRNA expression of CSRP2 in NB primary tumor and NB cell lines were detected by Western blot and quantitative real-time PCR(RT-qPCR).Results:By analyzing the NB clinical sample databases,it was found that the expression levels of CSRP2 in high-risk NB with 3/4 stages in international neuroblas-toma staging system(INSS)were significantly higher than that in low-risk NB with 1/2 INSS stages.The NB patients with high expression levels of CSRP2 were shown lower overall survival rate than those with low expression levels of CSRP2.We detected the protein levels of CSRP2 in the NB samples by Western blot,and found that the protein level of CSRP2 in 3/4 INSS stages was significantly higher than that in 1/2 INSS stages.Knockdown of CSRP2 inhibited cell viability and proliferation of NB cells.Overexpression of CSRP2 increased the proliferation of NB cells.Flow cytometry showed that the proportion of sub-G1,G0/G1 and S phase cells and Annexin V positive cells were increased after CSRP2 deficiency.In the cell wound-healing assay,the healing rate of NB cells was significantly attenuated after knockdown of CSRP2.Further mechanism studies showed that the proportion of the proliferation marker Ki-67 and the phospho-rylation levels of extracellular signal-regulated kinases 1/2(ERK1/2)were significantly decreased after CSRP2 knockdown.Conclusion:CSRP2 is highly expressed in high-risk NB with 3/4 INSS stages,and the expression levels of CSRP2 are negatively correlated with the overall survival of NB patients.CSRP2 significantly increased the proliferation and cell migration of NB cells and inhibited cell apoptosis via the activation of ERK1/2.All these results indicate that CSRP2 promotes the progression of NB by activating ERK1/2,and this study will provide a potential target for high-risk NB therapy.