Inactivation of the E‐Cadherin Gene in Primary Gastric Carcinomas and Gastric Carcinoma Cell Lines

Abstract

We investigated the E (epithelial)‐cadherin gene for mutations and loss of heterozygosity (LOH) in 24 primary gastric carcinomas (12 differentiated and 12 undifferentiated types, including 3 signet‐ring cell carcinomas), as well as 4 gastric carcinoma cell lines of the undifferentiated type (MKN‐45, GCIY, HGC‐27 and GT3TKB). We utilized PCR‐SSCP and RT‐PCR followed hy direct sequencing to detect gene mutations and skipped exons, and RT‐PCR‐SSCP to examine LOH. In primary carcinomas, gene mutations or skipped exons, were detected in 4 of 9 (44%) undifferentiated carcinomas of the scattered type, including 2 signet‐ring cell carcinomas, and in none of the 3 undifferentiated carcinomas of the adherent type and 12 differentiated carcinomas. Demonstrated mutations of the E‐cadherin gene included an 18 bp deletion (codon 418‐423) and a 3 bp deletion (codon 400, calcium‐binding domain), both located in exon 9. Skipping of exon 9 with a 1 bp insertion at codon 337, and skipping of exon 8 with a 1 bp deletion at codon 336, also were detected. LOH was confirmed in all of the carcinomas in which gene mutations or skipped exons (3/3 informative cases) were demonstrated. The MKN‐45 cell line exhibited an 18 bp deletion at the exon 6‐intron 6 boundary with loss of the wild‐type allele, and 2 of the remaining 3 cell lines (HGC‐27 and GT3TKB) had lost expression without detectable structural alteration of the E‐cadherin gene. These data provide support for classic two‐hit inactivation of the E‐cadherin gene in a high percentage of undifferentiated carcinomas of the scattered type.

Screening E-cadherin in gastric cancer families reveals germline mutations only in hereditary diffuse gastric cancer kindred

“…To date, we have identified 14 HDGC fami- [Berx et al, 1996;Guilford et al, 1998] Exon 13 692 2076C>T 15/27 (55.6%) 29/100 (59.0%) 72/136 (52.9%) [Berx et al, 1995[Berx et al, , 1996Becker et al, 1995;Tamura et al, 1996] Exon 14 751 2253C>T 1/34 (2.9%) Not done 22/233 (9.4%) [Risinger et al, 1994;Berx et al, 1995Berx et al, , 1996] Exon 14 764 2292C>T 1/34 (2.9%) Not done 3/135 (2.2%) [Risinger et al, 1994] Exon 16 878 2634c>T 1/34 (2.9%) Not done 1/27 (3.7%) [Soares et al, 1997] lies without CDH1 mutations (66.7%), and in these kindred other genes besides CDH1 are probably involved, although in some we might also have missed a CDH1 mutation because of insensitivity of our screening methodology. One may speculate that genes found inactivated in diffuse sporadic tumors would be good candidates.…”

Differential gene expression profiles of gastric cancer cells established from primary tumour and malignant ascites

“…KATO-III, GT3TKB and MKN 7 were purchased from Riken Cell Bank (Tsukuba, Japan) (Hojo, 1977;Sekiguchi et al, 1978;Tamura et al, 1996). NUGC-3 cells were purchased from Health Science Research Resources Bank (Osaka, Japan).…”

“…SNU cell lines have been studied both extensively and intensively. cMET is amplified in SNU-16, overexpression of TGF-b type II receptor, CEA, CA19-9, and c-erbB 2 has been confirmed in SNU-1, SNU-5 and SNU-16, KATO-III cells have K-sam amplification (Katoh et al, 1992), and GT3TKB reduced expression of E-cadherin (Tamura et al, 1996). But their common changes of gene expression have not yet been clarified.…”

Combined analysis of Rac1, IQGAP1, Tiam1 and E-cadherin expression in gastric cancer

“…10 Somatic E-cadherin mutations that impair the adhesive function of the protein have been described in diffuse type gastric carcinomas. [11][12][13][14][15][16] The predominant type of mutations in gastric cancer were splice-site mutations and in-frame deletions and most of the mutations were located in exons 8 or 9. 16,17 Although a number of in vitro investigations have established the significance of Rac1, IQGAP1 and Tiam1 as regulators of E-cadherin-mediated cell adhesion, little is known about the relevance of these markers in gastric cancer.…”