[Investigation of the e-cadherin promoter methylation in patients with colorectal cancer in Iran]

E-cadherin is widely down-regulated and tightly associated with tumor invasion and metastasis in multiple human cancer types. Recent studies have shown that aberrant methylation of the E-cadherin gene promoter contributes to its silencing. However, information regarding epigenetic inactivation of E-cadherin in colorectal cancer is insufficient. Herein, we correlate association of the methylation of the ECadherin promoter with pathological features of colorectal cancer as well as history and demographic data. We used methylation specific polymerase chain reaction [MSPCR] to examine methylation status of the 5' CpG island of E-cadherin along with its expression by using RT-PCR following surgical resection of 66 unrelated patients with colorectal cancer. Results showed that 35 out of 66 tumor DNA samples [53%] showed aberrant methylations. In contrast, all normal tissues were unmethylated. The obtained results show a similarity with the Japanese [54.5%] and Greek [55.7%] populations. The results have confirmed methylation of this gene in sporadic colorectal cancer cases [40.8%] in the Iranian population by researchers in Shiraz. These data suggest that epigenetic silencing via aberrant methylation of the E-cadherin promoter plays a critical role in the inactivation of this tumor suppressor gene in colorectal cancer.

[Studying the morphology and growth of human retinal pigment epithelial cells on a thin layer of alginate and alginate/gelatin as a culture substrate]

Human retinal pigment epithelium [hRPE] is a cell monolayer located in the outer part of the retina that is in contact with photoreceptors. In many diseases RPE cells damage. One way for treating this disease is the implantation of intact instead of damaged cells. For this reason different types of substrates have been used for cell cultivation. This study has used alginate and a blend of alginate/gelatin [A/G] to study RPE cell growth. We prepared alginate solutions in concentrations of 1% and 2% [w/v] in water and DMEM/F12. The solutions were infused into each well of 6-well micro plates until a uniform culture substrate that had a 1 mm thickness was generated. Passage-4 hRPE cells were cultivated on the substrate and the cell characteristics studied. hRPE cells did not adhere to alginate in DMEM/F12 and did not exhibit interaction with alginate substrate. For this reason A/G solutions at concentrations of 1% and 2% [w/v] in water were prepared. We prepared A/G blends at weight ratios of: 20:80, 30:70, 40:60, 50:50, 60:40, 70:30, and 80:20. These blends were infused into each well of 6-well plates until the appropriate 1 mm thickness of A/G was achieved. Isolated hRPE cells were cultured on synthetic substrate after which we studied the cells' characteristics. hRPE cell generated adhesive colonies on the A/G substrate. In all studied combinations of A/G, the diffused hRPE cells formed a monolayer under the substrate sheets. However the A/G 20:80 ratio had cell growth in the upper face of the substrate. hRPE survived indefinitely on A/G substrate. After the cells were re-cultured on polystyrene, they showed general morphological features of normal hRPE cells. The A/G blend at a 20:80 ratio was chosen to be used for future studies