53827

FXYD5

FXYD domain containing ion transport regulator 5;FXYD5;FXYD domain containing ion transport regulator 5

FXYD domain-containing ion transport regulator 5|dysadherin|keratinocytes associated transmembrane protein 1

19q13.12

protein-coding

PURPOSE: Dysadherin, a cancer-associated cell membrane glycoprotein, has been reported to down-regulate E-cadherin expression and promote metastasis. To evaluate the role of dysadherin in gastric cancer, we examined dysadherin and E-cadherin expression in gastric cancer patients. EXPERIMENTAL DESIGN: Dysadherin and E-cadherin expression were evaluated in 276 gastric cancer patients by immunohistochemistry, and the results were compared with the clinicopathological findings of the subjects. RESULTS: Dysadherin was not expressed in normal gastric epithelium. Both dysadherin and E-cadherin were localized to the cell membrane. Dysadherin expression was sometimes largely localized to infiltrating tumor cells or cells dissociating. Ninety gastric cancer patients (32.6%) were positive for dysadherin, and 151 patients (54.7%) showed preservation of E-cadherin expression. expression of dysadherin was associated with moderately differentiated carcinoma and hematogenous metastasis, whereas reduced expression of E-cadherin showed an association with poorly differentiated carcinoma and peritoneal dissemination. As a result, dysadherin positivity and reduced E-cadherin expression were associated with a poor prognosis. In addition, patients with both dysadherin positivity and reduced E-cadherin had the worst prognosis. Multivariate analysis revealed that reduced E-cadherin expression was an independent prognostic factor, but dysadherin expression was not. CONCLUSION: Combined analysis of dysadherin and E-cadherin expression may help to predict the prognosis and the mode of metastasis in gastric cancer patients. Patients with dysadherin positivity have a higher risk of hematogenous metastasis, whereas patients with reduced E-cadherin expression have an increased risk of peritoneal dissemination.

Dysadherin is a membrane glycoprotein expressed strongly in several human cancers. Overexpression of dysadherin in tumor cells is closely associated with malignant phenotype (e.g., metastasis) and poor prognosis. In our analysis, six pancreatic cancer cell lines showed a positive correlation between dysadherin expression and cell motility. Introduction of small interfering RNA (siRNA) against dysadherin into the Panc-1 cell line caused reduction of dysadherin expression and suppression of cell motility. In contrast, stable transfection of a dysadherin expression vector into the Capan-1 cell line increased cell motility. In vivo, the metastatic potential of orthotopically transplanted Capan-1 tumor cells in severe combined immunodeficient mice was increased by dysadherin overexpression. Cell morphology and actin organization were also influenced by modulation of dysadherin expression. Cells transfected with dysadherin siRNA tended to have a relatively larger, more spread shape and increased transverse actin stress fibers compared with parent cells and cells transfected with control siRNA. Our study suggests that dysadherin is able to modulate actin structures, stimulate cell motility, and contribute directly to the metastatic potential of human pancreatic cancer cells.

Dysadherin is a cancer-associated cell membrane glycoprotein. Its cDNA encodes 178 amino acids, including a putative signal sequence, a potential O-glycosylated extracellular domain, a single transmembrane domain, and a short cytoplasmic tail. Dysadherin is believed to down-regulate the expression of E-cadherin, the prime mediator of cell-cell adhesion in epithelial cells, by a posttranscriptional mechanism and promote the metastasis of carcinoma cells. To evaluate the association between dysadherin expression and E-cadherin expression in thyroid carcinoma, immunostaining for dysadherin and E-cadherin was performed in 51 papillary, 10 follicular, and 31 undifferentiated carcinomas. Immunoreactivity for dysadherin, localized at cell-cell boundaries, was detected in 39 of the 51 papillary carcinomas and all 31 undifferentiated carcinomas but not in the follicular carcinomas or normal thyroid tissue controls. Dysadherin expression was significantly higher in undifferentiated carcinoma than in papillary carcinoma and follicular carcinoma and showed significant negative correlation with E-cadherin expression. The degree of dysadherin expression was significantly associated with the prognosis, occurrence of secondary undifferentiated carcinomas, size of the primary tumor, and metastasis to the regional lymph nodes and lungs. In conclusion, a process involving increased dysadherin expression may lead to an adverse clinical outcome.