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.
OBJECTIVE:To investigate the cytotoxic effects of homoharringtonine(HHT) on HXO-RB44 cell line and the cell death form induced byHHT in vitro. METHODS:MTT assay was adopted to establish survival rate of the tumor cells. Agarose gel electrophores was chosen to detect the genomic DNA from the cells exposed to HHT. RESULTS:In the concentration from 10-9 to10-4 mol/L HHT powerfully inhibited the growth of the cells (P＜0.05). Regular genomic DNA fragmentation from the cells exposed to 10-6mol/L HHT for 48 hours was shown to be typical DNA ladder on agarose gelelectrophoresis. CONCLUSION :HHT can induce retinoblastoma (RB) programmed cell death (PCD),the effects of which has close correlation with incubated period and concentration of HHT.
Objective To compare the differences of chromosome aberration and Rb 1 gene mutation among 3 cloned cells of SO-Rb50 cell line of retinoblastoma. Methods 1.Three cell cloned strains named MC2, MC3, MC4 were isolated from SO-Rb50. 2. Gbanding and karyotype analysis were performed on the llth passage cells of the 3 cell strains.3.All exons and the promoter region of the Rb gene were detected by PCR-SSCP analysis in tumor cell DNA extracted from the 3 cell strains. Results 1.Both numerical and structural chromosomal aberrations could be observed in these 3 cell strains.Several kinds of structural chromosomal aberrations were observed.The chromosome aberrations in the same passage of different cell strains were different.Aberration of chromosome 13 was rare and the aberration feature was different in the 3 cell strains.Five marker chromosomes were identified.M1,t(1;1)qter-p35∷q24-ter could befound in all cell strains.Two of them M4 and M5,have not been reported in SO-Rb50 cell line previously.2.SSCP analysis of exon 24 showed that MC411 and MC3138 had abnormal band. Conclusions The characteristics of heterogeneity of the original tumor cell line SO-Rb50are still kept during a long-term culture in vitro and the cloned strains had dynamic changes during this period.Aberration of chromosome 13 is not the only cause of RB;aberration of chromosome 1,a commom event in some neoplasias as well as in SO-Rb50, plays a meaningful role in the immortalization of this cell line. (Chin J Ocul Fundus Dis, 1999, 15: 146-148)
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.
We have studied the radiosenstivity of retinoblastoma cell [inc: HXO Rb~4,and found that the ceil growth reduced markedly after being treated by 3GyT-ray. From both clone for mation method and MTT assay,we identify that HXO-Rb44 cell is radiosensitive to T-ray.Oxygen can increase the radiosensitivity of HXO-Rb44 cell, but decrease the repair of sublethal damage.Oxygen enchaneement ratio(OER)is 2.77~3.01. （Chin J Ocul Fundus Dis,1994,10:217-219）
Objective To investigate the effect of the 8-bromum-cyclic adenosine monophosphate (8-Br-cAMP) on the telomerase activity and changes of cell cycle in retinoblastoma （RB） cells. Methods The cultured RB cells were divided into the experimental group (8-Br-cAMP) and control group. After cultured for 24, 48 and 72 hours in vitro, the telomerase activity of RB cells was detected by polymerase chain reaction enzyme-linked immunosorbent assay (PCR-ELISA) and the changes of cell cycle were detected by flow-cytometry. Results The difference of telomerase activity was significant between the experimental groups and control group (Plt;0.01). There was a negative correlation between the A value of absorbance and the time in the experimental groups (r=-0.778 9, F=33.936, Plt;0.01). The changes of the cell cycle were that the percentages increased in G1 phase and decreased in S phases. Conclusion 8-Br-cAMP may weaken telomerase activity, affect the cell cycle, and inhibit the proliferation of RB cells. (Chin J Ocul Fundus Dis，2004，20：358-360)
Despite its low incidence, retinoblastoma and its rela ted gene (Rb gene) have attracted some of the most brilliant minds in medicine and biology fi elds over the past years. Great advances have been achieved in the tumoregenesis mechanism and clinical management of retinoblastoma recently. However as always , more questions arise from those results. In order to improve retinoblastoma re search in China, we need to strengthen the communication and cooperation with di ffe rent countries, different institutes and disciplines, and utilize the great reso urces of retinoblastoma patients in China.
Silver staining technique and computer-assisted image analysis system were used in this study to detect,compare and analyse the nuclear organizer regions(NORs)in human normal retina and retinoblastoma(including differentiated and non-differentiated).The results showed that the mean number of AgNOR per nucleus,the average silver staining area per nucleus and retino of silver staining area to nuclear area in non-differentiated retinoblastoma were much higher than that in differentiated retinoblastoma and normal retina.This might suggest that AgNORs technique and computer-assisted image analysis system have important role in the typing,grading and expectation of progression of retinoblastoma. （Chin J Ocul Fundus Dis,1993,9:202-204）
Objective To investigate the relationship of the expression between heat shock protein (HSP) 70 and 90, and Survivin and its effects on the proliferative activity in retinoblastoma (RB) cells. Methods Expression of Survivin, HSP70 and 90, and Ki-67 in conventional paraffin samples from 43 patients with RB and 6 healthy people was detected by streptavidin-biotin peroxidase (SP) immunohistochemical method. Ki67 labeling index was used to evaluate the proliferative activity in RB. Results In 43 cases of RB, positive expression of HSP70 and 90 and Survivin was found in 28 (65.12%), 37 (86.05%) and 27 (62.79%) cases, respectively. None of the 6 normal retinal tissue expressed HSP70, HSP90 or Survivin. Positive expression of Survivin was more frequent in positive expressions of HSP90 than that in negative expressions of HSP90 (P＜0.05). Ki67 labeling index was higher in positive expressions of HSP90 and positive expressions of Survivin than that in their negative expressions respectively (P＜0.05). Meanwhile, higher Ki67 labeling index was found in positive HSP90Survivin expressions than that in negative HSP90Survivin expressions and those cases where only HSP90 or Survivin was found (P＜0.05). Expression of HSP70 did not correlate with that of Survivin, nor had any significant effect on Ki67 labeling index (P＞0.05). Expression of HSPs and Survivin and Ki67 labeling index did not correlate with histological types (P＞0.05). Conclusion Expression of HSP90 correlates with that of Survivin in RB. Co-existence of Survivin and HSP90 probably plays an important role in the genesis of RB.
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.