Generation of a human induced pluripotent stem cell line (VRFi001-A) from orbital adipose tissue of a bilateral retinoblastoma patient with heterozygous RB1 gene deletion.

Retinoblastoma (RB) is a pediatric intraocular tumor caused by mutations in retinoblastoma (RB1) gene. We have generated induced pluripotent stem cell line VRFi001-A from a bilateral retinoblastoma patient with heterozygous RB1 gene deletion. The iPSC line VRFi001-A retained the mutation and expressed pluripotency markers, had a normal karyotype and was capable of trilineage differentiation.

EpCAM knockdown alters microRNA expression in retinoblastoma--functional implication of EpCAM regulated miRNA in tumor progression.

The co-ordinated regulation of oncogenes along with miRNAs play crucial role in carcinogenesis. In retinoblastoma (RB), several miRNAs are known to be differentially expressed. Epithelial cell adhesion molecule (EpCAM) gene is involved in many epithelial cancers including, retinoblastoma (RB) tumorigenesis. EpCAM silencing effectively reduces the oncogenic miR-17-92 cluster. In order to investigate whether EpCAM has wider effect as an inducer or silencer of miRNAs, we performed a global microRNA expression profile in EpCAM siRNA knockdown Y79 cells. MicroRNA profiling in EpCAM silenced Y79 cells showed seventy-three significantly up regulated and thirty-six down regulated miRNAs. A subset of these miRNAs was also validated in tumors. Functional studies on Y79 and WERI-Rb-1 cells transfected with antagomirs against two miRNAs of miR-181c and miR-130b showed striking changes in tumor cell properties in RB cells. Treatment with anti-miR-181c and miR-130b showed significant decrease in cell viability and cell invasion. Increase in caspase-3 level was noticed in antagomir transfected cell lines indicating the induction of apoptosis. Possible genes altered by EpCAM influenced microRNAs were predicted by bioinformatic tools. Many of these belong to pathways implicated in cancer. The study shows significant influence of EpCAM on global microRNA expression. EpCAM regulated miR-181c and miR-130b may play significant roles in RB progression. EpCAM based targeted therapies may reduce carcinogenesis through several miRNAs and target genes.

Homocysteine induces oxidative stress in young adult central retinal vein occlusion.

OBJECTIVES: High levels of plasma homocysteine have been reported to be toxic to the vascular endothelium, thereby creating an environment of hypercoagulability and occlusion. Elevated homocysteine has been reported as a risk factor for young adult central retinal vein occlusion (CRVO) cases. This study aimed to see if oxidative stress is an independent risk factor or is homocysteine dependent. METHODS: 23 young adult CRVO patients and 54 age and sex-matched controls were included in the study. Oxidative stress markers thiobarbituric acid-reacting substance (TBARS), superoxide dismutase (SOD), total thiols, glutathione peroxidase and total antioxidant capacity (TAC) were estimated. The effect of homocysteine (25-200 µM) on cultured bovine retinal endothelial cells (BREC) on oxidative stress parameter TBARS was measured. RESULTS: There was a significant increase in the plasma TBARS in CRVO cases compared with controls (p=0.000). SOD and TAC were significantly lower in CRVO cases than controls (p=0.000, p=0.022). There was a significant negative correlation between TAC and TBARS (p=0.00) and a significant positive correlation between homocysteine and TBARS (p=0.029). Nominal regression analysis showed that TAC and homocysteine influence TBARS significantly. The in-vitro study in BREC cells revealed that homocysteine increased the TBARS dose and time dependently. CONCLUSION: TBARS and homocysteine are known to be independent risk factors for CRVO. TBARS can be influenced by both homocysteine and TAC, thereby contributing to the aetiopathology of CRVO by increasing oxidative stress.