Downregulation of retinoic acid receptor-β_z expression is linked to aberrant methylation in esophageal squamous cell carcinoma cell lines

AIM:To study the role of hypermethylation in the loss of retinoic acid receptor β2(RARβ2) in esophageal squamous cell carcinoma (ESCC).METHODS:The role of hypermethylation in RARβ2 gene silencing in 6 ESCC cell lines was determined by methylation-specific PCR (MSP),and its methylation status was compared with RARβ2 mRNA expression by RT-PCR.The MSP results were confirmed by bisulfite sequencing of RARβ2promoter regions.RESULTS:Methylation was detected in 4 of the 6 cell lines,and the expression of RARβ2 was markedly downregulated in 3 of the 4 methylated cell lines. The expression of RARβ2 was restored in one RARβ2-downregulated cell line with the partial demethylation of promoter region of RARβ2 after 5-aza-2′-deoxycytidine (5-aza-dc) treatment.CONCLUSION:The methylation of the 5′ region may play an important role in the downregulation of RARβ2 in some ESCC cell lines, suggesting that multiple mechanisms contribute to the loss of RARβ2expression in ESCC cell lines.This study may have clinical applications for treatment and prevention of ESCC.

Loss of myeloid-related proteins 8 and myeloid-related proteins 14 expression in human esophageal squamous cell carcinoma correlates with poor differentiation

AIM:To study the expression of myeloid-related proteins (MRP)8 and myeloid-related proteins(MRP)14 in human esophageal squamous cell carcinoma and to investigate if there was any correlation between MRP8 and MRP14 expression level and histopathological grade in these tumors. METHODS:In this study,65 cases of advanced esophageal squamous cell carcinoma were assessed for MRP8 and MRP14 expression using immunohistochemistry.Statistical analysis was performed for the comparison of MRP8 and MRP14 expression in normal and tumor tissues,and their relationship with clinicopathological features. RESULTS:Reduced or absent expression of MRP8 and MRP14 was observed in esophageal squamous cell carcinoma,with a significant difference between tumor tissues and normal tissues (P<0.01 and P<0.01 for MRP8 and MRP14,respectively). Poorly differentiated tumors presented a greater decrease than well and moderately differentiated tumors,with a correlation between their protein level and histopathological grading (P<0.001 and P<0.001,respectively).However,no significant association was found between MRP8 and MRP14 expression and age or gender (P>0.05). CONCLUSION:These findings suggest that the decreased expression of MRP8 and MRP14 might play an important role in the pathogenesis of human esophageal squamous cell carcinoma,being particularly associated with poor differentiation of tumor cells.

Transglutaminase 3 expression in C57BL/6J mouse embryo epidermis and the correlation with its differentiation

Epidermal-type transglutaminase 3 (TGM3) is involved in the cross-linking of structural proteins to form the cornifiedenvelope in the epidermis. In the present study, we detected the expression of TGM3 in the mouse embryo using RT-PCR.TGM3 mRNA is weakly presented from E11.5 to E14.5 and increases significantly from E15.5 to birth. Then wedetermined the spatial and temporal expression pattern of TGM3 in the skin and other organs by in situ hybridization. Wefound a deprivation of TGM3 in skin at E11.5, while a rich supply in periderm cells and a weak expression in basal cellsfrom E12.5 to E14.5. From the period of E15.5 to E16.5, after keratinization in the epidermis, TGM3 was expressed inthe granular and cornified layers. The electron microscopic observation of the C57BL/6J mouse limb bud skin develop-ment provided several morphological evidences for the epidermal differentiation. The above findings suggest that theexpression of TGM3 plays a important role in the epidermis differentiation in embryogenesis.

Cytotoxic effect of a non-peptidic small molecular inhibitor of the p53-HDM2 interaction on tumor cells

AIM: To investigate if non-peptidic small molecular inhibitors of the p53-HDM2 interaction could restore p53 function and kill tumor cells.METHODS: A series of non-peptidic small HDM2 inhibitors were designed by computer-aided model and synthesized by chemical method. Syl-155 was one of these inhibitors. Cytotoxic effect of syl-155 on three tumor cell lines with various states of p53, HT1080 (wild-type p53), KYSE510 (mutant p53), MG63 (p53 deficiency) was evaluated by MTT assay, Western blot and flow cytometry.RESULTS: Syl-155 stimulated the accumulation of p53 and p21 protein in HT1080 cells expressing wild-type p53, but not in KYSE510 and MG63 cells. Consequently, syl-155 induced cell cycle arrest and apoptosis in HT1080 cells.CONCLUSION: Non-peptidic small molecular inhibitors of the p53-HDM2 interaction show promise in treatment of tumors expressing wild-type p53.

Expression patterns of esophageal cancer deregulated genes in C57BL/6J mouse embryogenesis

AIM:To investigate the expression patterns of esophageal squamous cell cancer deregulated genes in mid to late stages of C57BL/6J mouse embryogenesis,and the correlation between these genes in embryonic development and tumorigenesis of esophageal squamous cell cancer. METHODS:Reverse northern screening was performed to examine the expression patterns of esophageal cancer deregulated genes in C57BL/6J mouse embryogenesis.To confirm the gene expression patterns,semi-quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) was carried out for 3 of the randomly picked differentially expressed genes. RESULTS:Within these esophageal cancer deregulated genes,4 patterns of expression were observed at 3 stages embryonic d 11.5 (E11.5),embryonic d 13.5 (E13.5) and postnatal d1 (P1).(1) Up-regulation during the E11.5 period, down-regulation during the E13.5 and P1 period (up-down- down),the 10 up-regulated genes during the E11.5 period could be classified into 6 known genes and 4 unknown genes. The known genes included differentiation related genes (S100A8),immunity related gene (IGL),translation and transcription regulation genes (RPL15,EEF1A1),cytoskeletal protein (TUBA1),cysteine protease inhibitor (cystatin B). (2) Up-regulation during the E13.5 and P1 period (down- up-up),such as the SPRR2A which was down-regulated at E11.5.(3) Down-regulation during the E11.5 and E13.5 period (down-down-up),such as RHCG and keratin 4.(4) Fluctuating expression,down initially,up at E13.5,and then down again (down-up-down).EMP1 belonged to such a gene,which was highly expressed at E13.5. CONCLUSION:The results will be helpful for understanding the function of esophageal squamous cell carcinoma (ESCC) deregulated genes in embryonic development and tumorigenesis.S100A8 and S100A9 may play different roles in early embryonic development.IGL may be an oncofetal protein,and EMP1 relates with neurogenesis at E13.5.The genes identified pertinent to embryonic development may serve as candidate susceptibility genes for inherited esophageal cancer disorders as well as for various heritable disorders of embryonic development.