PURPOSE:Studying the multidrug resistance(MDR) phenotype occurring in retinoblastoma and its mechanism. METHODS:Using the procedure of stepwise increase in drug concentrations to obtain a retinoblastoma subline which resistant to 600ng/ml vincristine (HXO-RB/VCR). Characteristics of this drug-resistant cell line were investigated by cell counting,drugcontents determinatin,drug sensitivity evaluation and radiation sensitivity test. RESULTS:This cell line was cross-resistant to VDS,MMC VP16，ADM ,DDP,CBP,but not resistant to BCNU and 5-Fu. It was proved to be collaterally sensitive to MTX,and the response to 60Co gamma;-ray was modified slightly in HXO-RB/VCR cell line. Intracellular levels of VCR was much higher in HXO-RB44 cells than in the resistant subline. Those cross-resistances can be reversed by verapamil partly. CONCLUSIONS:MDR and radiation resistance of retinoblastoma can be induced by exposing to VCR and reversed by verapamil partly. （Chin J Ocul Fundus Dis,1997,13: 6-9）
Microparticles are small vesicles that are released by budding of the plasma membrane during cellular activation and apoptotic cell breakdown. A spectrum of cell types can release microparticles including endothelial cells, platelets, macrophages, lymphocytes and tumor cells. Biological effects of microparticles mainly include procoagulant activity, inhibition of inflammation and cancer progression. The present study shows that vitreous microparticles isolated from proliferative diabetic retinopathy (PDR) stimulated endothelial cell proliferation and increased new vessel formation, promoting the pathological neovascularization in PDR patients. Oxidative stress induces the formation of retina pigment epithelium-derived microparticles carrying membrane complement regulatory proteins, which is associated with drusen formation and age related macular degeneration. Microparticles from lymphocyte (LMP) play an important role in anti-angiogenesis by altering the gene expression pattern of angiogenesis-related factors in macrophages. Besides, LMP are important proapoptotic regulators for retinoblastoma cells through reduction of spleen tyrosine kinase expression and upregulation of the p53-p21 pathway which ultimately activates caspase-3. However, how to apply the microparticles in the prevention and treatment of retinal diseases is a major challenge, because the study of the microparticles in the fundus diseases is still limited. Further studies conducted would certainly enhance the application of microparticles in the fundus diseases.
With the method of PCR-SSCP combined sequencing,we analysed the mutations in the RB1 gene of 10 retinoblastoma samples. All 27 exons of RB1 gene have been examined. The PCR products were digested with some restriction endonuclease to the size of about 200 bp and then denatured into single strands. Loading the single strands of DNA into the 6% polyacrilamide gel,we followed the technology named SSCP to f/nd the abnormal bands in the SSCP gel. After that, the samples found with the abnormal bands in the SSCP gel were amplified again and sequenced to confirm the types and locations of the mutations in the RB1 gene. We have fonnd some kinds of mutations in the RB1 gene. （Chin J Ocul Fundus Dis,1994,10:17-20）
ObjectiveTo evaluate the pathological features of bilateral retinoblastoma (RB) and the relationship between different treatments and high-risk histopathologic features (HHF). MethodsRetrospective series of case studies. From 1999 to 2018, 73 patients with binocular RB diagnosed by pathological examination in Department of Ophthalmology, Peking University People's Hospital were included in the study. Among them, 50 patients were male (68.5%, 50/73), 23 patients were females (31.5%, 23/73); 11 patitents had a family history of RB. The mean age at the first diagnosis was 14.8±15.6 months. The average time between first diagnosis and first intervention was 3.97±4.74 months. According to the international classification standard of intraocular RB staging, among the 73 eyes, C, D and E stages were 2 (2.7%, 2/73), 15 (20.5%, 15/73), and 56 (76.7%, 56/73) eyes, respectively. Ocular images for each patient were obtained using a wide-angle contact fundus camera during examination under general anaesthesia. The treatment protocol (globe salvaging or enucleation) depended on the result of several clinical features. Globe salvaging treatment included chemotherapy combined with local therapy such as intra-arterial chemotherapy (IAC), intravitreal chemotherapeutics injection, cryotherapy, laser, transpupillary thermotherapy and radiotherapy. If globe salvaging failed, enucleation was offered and histopathologic analysis was conducted of the enucleated eye, the ophthalmic pathologist read and evaluated the presence of HHF. Independent samples t-test was performed to compare the continuous variables. The pathological features and the relationship between different treatments and HHF were analyzed. Group difference was calculated with chi-square. Results Among the 73 eyes, the first treatment was enucleation in 21 eyes (28.8%, 21/73); 52 eyes (71.2%, 52/73) were treated with eye protection. After enucleation, 9 cases (12.3%, 9/73) had recurrence and metastasis, and 7 cases (9.6%, 7/73) died. The intervention time of patients with recurrence and metastasis and those without recurrence and metastasis were 7.4±7.3 and 3.5±4.1 months respectively; the first intervention time of patients with recurrence and metastasis was significantly later than that of patients without recurrence and metastasis, but the difference was not statistically significant (t=－1.561, P=0.154). The pathological examination results showed that there were 26 eyes (35.6%, 26/73) with HHF, 4 (26.7%, 15/26) and 22 (39.3%, 22/56) eyes were in stage D and E, respectively. Those who received other treatments before enucleation had lower HHF percentages after enucleation than those who did not receive corresponding treatments, but the difference was not statistically significant (χ2=1.852, 0.074, 0.000, 1.007, 0.007, 2.729; P＞0.05). Among the 26 eyes, 5 (83.3%, 5/6) and 21 (31.3%, 21/67) eyes were treated with systemic chemotherapy combined with and without IAC, respectively, and there was a significant difference in the percentage of HHF (χ2=4.422, P=0.035). ConclusionsIAC eye-preserving therapy before enucleation has a significant effect on HHF.
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.
Objective To investigate inhibited effects of melatonin (MLT) on proliferative activity of retinoblastoma cell line HXORB44 and its related mechanism. Methods HXO-RB44 cells were treated by MLT of different concentration (10-10, 10-9, 10-8, 10-7 mmol/L. Cell counting and tetrazolium dyereduction assay (MTT) were used to determine the effect of MLT on the survival and proliferation of HXO-RB44 cells. Apoptotic nuclei were further analyzed by HoechstPI fluorescence staining. Flow cytometry was used to measure the fluorescent intensity of ROS, cell cycle distribution and apoptosis. Results 10 -6 mmol/L (or exceed) of MLT could inhibit the proliferation of HXO-RB44cells in vitro while 10-7 mmol/L (or below) of MLT couldn't. With the increase of MLT concentration from 10-10 mmol/L to 10-7 mmol/L, HXO-RB44 cells gradually increased the expression of ROS. Hoechst staining showed that 4, 8, 12 and 24 hours after the incubation with MLT, the nuclear pyknosis and nuclear fragmentation increased in HXORB44 cells. The extent of apoptosis was proportional to the concentrations of MLT. Flow cytometry revealed that with the increasing of MLT concentration, G0/G1 and G2/M phase cells increased, S phase cells decreased. The apoptotic rate was also increased. Conclusion 10 -6 M of MLT could inhibit the proliferation of HXO-RB44 cells. This effect may relate to the increased ROS expression, cell cycle arrest at G0/G1 phase and apoptosis of HXO-RB44 cells.
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.