Objective To investigate the effect of berbamine (BBM) on the proliferation and apoptosis of retinoblastoma (RB) HXO-RB44 cells and its possible mechanism in vitro.Methods RB cells in logarithmic growth phase were divided into BBM treated group and control group. RB cells in BBM treated group were cultured with different concentrations of BBM (2,4,8,16 and 32 mg/L) for 24,48 and 72 hours, respectively. The proliferation was assayed by methyl Thiazolyl tetrazolium (MTT). RB cells were cultured with different concentrations of BBM (4,8 and 16 mg/L) for 24 hours. The early apoptotic rates were detected by flow cytometry; the expression of bcl-2 and Bax were measured by enzyme-linked immunosorbent assay (ELISA) and the activity of Caspase-3 was detected by colorimetric assay.Results BBM could obviously inhibit the proliferation of RB cells in a time and dose dependent manner (24 hours: F=70.547,P＜0.01; 48 hours: F=603.438,P＜0.01; 72 hours: F=577.521,P＜0.01). The IC50 value at 24,48 and 72 hours were 25.26, 10.94 and 6.25 mg/L, respectively. Necrosis rates of control group and BBM treated group were (1.25plusmn;0.45)%, (4.10plusmn;2.95)%, (4.39plusmn;0.21)% and (10.54plusmn;4.38)% respectively; the difference between two groups was statistically significant (F=6.527,P＜0.05). Apoptotic and necrosis rates in advanced stage of control group and BBM treated group were (2.13plusmn;0.71)%, (5.45plusmn;2.31)%, (9.86plusmn;3.18)% and (11.10plusmn;1.70)%, respectively. The difference between two groups was statistically significant (F=10.845,P＜0.05). Early apoptotic rates of control group and BBM treated group were (0.51plusmn;0.26)%, (2.68plusmn;0.35)%, (5.97plusmn;0.50)% and (11.22plusmn;1.17)%, respectively. The difference between two groups was statistically significant (F=144.976,P＜0.01). In addition, BBM dose-dependently reduced bcl-2 level and increased Bax expression, causing the reduction of the bcl-2/Bax protein ratio as well as increased the Caspase-3 activity in RB cells remarkably (bcl-2: F=835.726,P＜0.01; bax: F=111.963, P＜0.01;Caspase-3:F=298.058,P＜0.01).Conclusions BBM can inhibit the proliferation and induce apoptosis or necrosis of RB cells in vitro, down regulating the expression of bcl-2, up regulating the expression of Bax. Along with increased Caspase-3 activity these may be the apoptotic mechanisms.
Stem cells are crucial for embryonic development and in the maintenance of adult cellular homeostasis. Understanding the regulatory network of stem cells, including embryonic and adult stem cells, will allow us to learn the pathogenesis and possibly design novel approaches to treat many diseases (such as cancer and degeneration). The retinoblastoma (Rb) pathway controls cellular proliferation, differentiation and death. More and more evidences support an important role of Rb activity in the biology of stem and progenitor cells. Transiently inactivating Rb pathway might favor the expanding of functional stem cell populations, thus have values in the future stem cell applications.
Objective To observe the effect of resveratrol on multidrug resistance (MDR) in human retinoblastoma cells treated. Methods RB cells in logarithmic growth phase were divided into experimental group and control group. RB cells in experimental group were cultured with different concentrations of resveratrol (6.25, 12.50, 25.00, 50.00, 100.00 mu;mol/L) for 24 and 48 hours. The proliferation (absorbance value) was assayed using methyl thiazolyl tetrazolium (MTT). RB cells were cultured with 50.00 mu;mol/L resveratrol for 48 hours. The expressions of MDR-1, cyclooxygenase-2 (COX-2)、multidrug resistance-associated protein-1 (MRP-1), glutathione-S-transferases-pi; (GST-pi;) were determined by reverse transcription-polymerase chain reaction (RT-PCR) and Western blot. The RB cells of the control group were cultured with 0.5% dimethyl sulfoxide. Results Compared with the control group, the absorbance value decreased in experimental groups (6.25, 12.50, 25.00, 50.00 mu;mol/L) in a dose dependent manner (F=4.782，P＜0.05). The difference of absorbance value between 50.00 and 100.00 mu;mol/L experimental groups was not significant (F=6.351,P＞0.05). Compared with the control group, the mRNA (t=9.170, 5.758, 4.152, 4.638) and protein (t=3.848, 5.955, 4.541, 3.514) expression levels of MDR-1, MRP1, COX-2, and GST-pi; decreased in the experimental group (P＜0.05). Conclusion Resveratrol can down-regulate the expression of MDR in RB cells.
Objective To observe the expressions of DNA methyltransferases (DNMTs) 1, 3a and 3b in retinoblastoma (RB). Methods Sixty-two RB samples and six normal retinas were studied, including 17 poorly differentiated and 45 well differentiated samples; 16 invasive and 46 non-invasive samples. The expressions of DNMT1, 3a, and 3b, and Ki-67 were detected using immunohistochemical analysis. Brown staining of nuclei was considered to represent the positive stain for DNMT1, 3a and 3b, and ki-67, blue staining as negative. The level of high expression of nuclear staining was, positive cells in DNMT1ge;65%, in DNMT3age;60% and in DNMT3bge;40%. The correlations of DNMT1, 3a and 3b expression in RB samples, and MIB-1 labeling index were analyzed. Results Viewed under the light microscope, negative expressions of DNMT1, 3a and 3b were demonstrated in normal retinas, however, positive expression was observed in RB samples, with 100% in DNMT1, 98% in DNMT3a and 92% in DNMT3b. Comparing well differentiated RB samples with poorly differentiated samples, significant differences were found in high expression of DNMT1 (chi;2=12.57,P＜0.05) and DNMT3a (chi;2=10.54,P＜0.05); also in the positive cells of DNMT1 (U=179,P＜0.05) and DNMT3a (U=198,P＜0.05). No significant difference was found comparing high expression (chi;2=1.5,P＞0.05) and positive cells (U=307,P＞0.05) of DNMT3b. When comparing invasive tumor tissues with non-invasive tumors, significant differences were shown between high expression (chi;2=4.72,P＜0.05) and positive cells comparing DNMT1 (U=236,P＜0.05). No significant difference was shown in high expression (chi;2=3.53,0.84; P＞0.05) in DNMT3a and DNMT3b, or in comparison with positive cells (U=338,257;P＞0.05). The expression of DNMTs was positively correlated with the MIB-1 labeling index in RB tissues (R2=0.554,0.376,0.219;P＜0.05). Conclusion There are high expressions of DNMT1,3a,and 3b in RB.
Objective To observe the expression and relationship of high-mobility group A(HMGA)1, HMGA2, MIB-1 labeling index (LI) and let-7 in retinoblastoma (RB). Methods Forty-four RB samples were studied, including 11 poorly-differentiated samples, 33 well-differentiated samples; eight invasive and 36 non-invasive samples. The expression of HMGA1, HMGA2 and MIB-1 LI in RB were analyzed by immunohistochemitry. The HMGA1, HMGA2 were scored on a scale of 0 to high expression. 0: no expression; low: 1%-10%; medium: 11%-50%; high: ＞50%. The MIB LI were scored on a scale of 0 to high expression. 0: no expression; low: 1%-40%; high: ＞40%. Semiquantitative reverse transcription-polymerase chain reaction was used to assay the let-7 expression level: ge;80% showed no significantly decreased expression; 60%-79% showed medium decrease in expression; ＜60% highly decreased in expression. ResultsIn 44 RB samples, there were 14 cases with no HMGA1 expression (32%), 11 cases with low expression (25%), 10 cases with medium expression (23%), and nine cases with high expression (20%). Expression level of HMGA1 was significantly higher in poorly differentiated RB than in well-differentiated RB (chi;2=11.3,P＜0.01); however, no statistically significant difference was found between invasive tumors and noninvasive tumors (chi;2=5.9,P＞0.05). There were 11 cases with no HMGA2 expression (25%), 11 cases with low expression (25%), nine cases with medium expression (20%), and 13 cases with high expression (30%). Expression level of HMGA2 was significantly higher in poorly differentiated and invasive RB than in well-differentiated and noninvasive RB respectively (chi;2=20.9, 8.7;P＜0.05). There were 4 cases with no MIB-1 LI expression (9%), 18 cases with low expression (41%), and 22 cases with high expression (50%). Expression level of MIB-1 LI was significantly higher in poorly differentiated RB than in well-differentiated RB (t=5.2,P＜0.05). Higher expression of MIB-1 LI was found in invasive tumors than in noninvasive tumors, with no significant difference (t=-1.1,P＞0.05). Twenty-seven cases had no significantly decreased expression of let-7 (61%). There were eight cases with medium decreased expression (18%) and nine cases with highly decreased expression (21%). Correlation analyses revealed that MIB-1 LI expression significantly correlated with HMGA1and HMGA2 proteins (r=0.327, 0.602;P＜0.05). A significantly inverse correlation existed between let-7 expression and HMGA1, HMGA2 proteins and MIB-1 LI respectively (r=-0.247,-0.310,-0.392;P＜0.05). Conclusions Overexpression of HMGA1, HMGA2 and MIB-1 LI and down regulation of let-7 were demonstrated in RB. Supplying let-7 to RB cells can possibly inhibit HMGA1 and HMGA2 expression.
Objective To observe the influence of cisplan on the expression of B7-H1 in retinoblastoma (RB) cells，and to investigate its mechanism. Methods Human RB cell line HXO-Rb44 cells were treated by 6 different concentrations of cisplan (0.000, 0.375, 0.750, 1.500, 3.000, 6.000 mu;g/ml), and their B7-H1 mRNA expression was determined by the reversetranscription polymerase chain reaction (RT-PCR) and fluorescence quantitative PCR (FQ-PCR); the B7-H1 protein expression was determined by immunofluorescence and flow cytometry. HXO-Rb44 cells were treated by 1.5 mu;g/ml cisplan for 0, 15, 30, 60, 120 min, then the phosphorylation of extracellular signal-regulated kinase 1/2 (ERK1/2) was detected by Western blot.Results The expression of B7-H1 mRNA and protein in the 0.375, 0.750, 1.500, 3.000, 6.000 mu;g/ml group were significantly higher than that of the blank control group (F=395.478，112.03; P=0.000）. Western blot showed that cisplan (1.5 mu;g/ml) could activate ERK1/2 by increasing its phosphorylation in HXO-Rb44 cells. After cisplan treatment, the phosphorylation of ERK1/2 increased gradually and reached its peak at 30 min, and then went down gradually.Conclusion Cisplan can promote the expression of B7-H1 and activate ERK1/2 in RB cells.
Objective To observe the expression of matrix metalloproteinase（MMP-2, MMP-9 and vascular endothelial growth factor (VEGF) in retinoblastoma (RB) and its relationship with the differentiation and optic nerve infiltration of RB.Methods Forty paraffin specimens of pathological confirmed RB were studied. They were divided into differentiated group (15 cases) and undifferentiated group (25 cases) , optic nerve infiltration group（13 cases） and without optic nerve infiltration group（27 cases）. The expression of MMP-2, MMP-9 and VEGF were detected by immunohistochemistry, their relationships with the differentiation and optic nerve infiltration were also analyzed.Results The positive rate of MMP-2, MMP-9 and VEGF expression in 40 RB cases were 52.5％，57.5％ and 72.5% respectively．The expression of MMP-2, MMP-9 and VEGF in the undifferentiated group were significantly higher than those in the differentiated group (chi;2=9.037, 9.253, 8.095; P＜0.05). The expression of MMP-2, MMP-9 and VEGF in RB with optic nerve infiltration group were significantly higher than those in RB without optic nerve infiltration group (chi;2=11.045,10.243, 8.956；P＜0.05). The expression of MMP-2，MMP-9 had a positive correlation with the expression of VEGF in RB (r=0.126,0.314；P＜0.05). Conclusions MMP-2, MMP-9 and VEGF expressed in RB tumor tissues. The expression of MMP-2, MMP-9 has a positive correlation with the expression of VEGF. The levels of MMP-2, MMP-9 and VEGF expression are related to optic nerve infiltration of RB cells.
Objective To explore the characteristics and diagnostic values of ultrasound examination of retinoblastoma (RB).Methods The ultrasound and CT features of 210 eyes (162 patients) with pathologically confirmed RB were analyzed retrospectively. Results The ultrasonography image of those RB eyes were all characterized by substantial masses in the posterior segment of the eyeball, shown as spherical, hemispherical and irregular in shape, and even filled the entire eyeball. Calcification within the mass was observed in 197 eyes of 149 patients (92.0%), but not observed in 13 eyes of 13 patients (8.0%).Colorful blood flow signals extended from the central retinal vessels could be seen inside the masses of all patients. Ultrasound diagnosis was consistent with the pathological diagnosis in 92.0% RB cases. CT examination revealed calcified speckles or plaques in 167 eyes from 145 patients (89.5%), consistent with the pathological diagnosis of RB.Conclusions Ultrasonography can show the tumorprime;s shape, size, internal features and the range of orbital involvement. It is a valuable clinical tool in the diagnosis of RB.