Frameshift Mutations of Human Gastrin Receptor Gene (hGARE) in Gastrointestinal Cancers with Microsatellite Instability

Division of Gastroenterology, Istituto Clinico Humanitas, Rozzano-Milan, Italy.
Laboratory Investigation (Impact Factor: 3.68). 04/2002; 82(3):265-71. DOI: 10.1038/labinvest.3780420
Source: PubMed


Gastrointestinal tumors with DNA mismatch repair (MMR) defects show microsatellite instability (MSI) and harbor frameshift mutations in coding mononucleotide repeats of cancer-related genes (targets). We assessed MSI status in 233 sporadic gastrointestinal tumors. We classified as MSI-H (high-frequency microsatellite instability) 15 (10%) of 150 colorectal cancers and 13 (16%) of 83 gastric cancers. We searched for frameshift mutations in a coding poly(T)(8) tract within the gastrin receptor gene (hGARE), which has a potential role in gastrointestinal carcinogenesis. To this purpose, we screened 43 unstable tumors (including 15 hereditary nonpolyposis colorectal cancer cases previously classified as MSI-H), 98 stable tumors, as well as 3 MMR-deficient and 4 MMR-proficient gastrointestinal cancer cell lines. We found mutations in 8 (19%) of the 43 MSI-H tumors but in none of the 98 stable cancers. hGARE mutation frequency was similar in gastric (23%) and colorectal cancers, including sporadic (13%) and hereditary (20%) cases. All mutated tumors proved to harbor frameshift mutations in other cancer-related genes that are considered as targets in MSI tumorigenesis. The MMR-deficient and gastrin-sensitive LoVo colorectal cancer cells also showed a hGARE heterozygous frameshift mutation, but expressed only the mutated allele. All detected mutations can be predicted to generate a truncated protein carrying amino acid changes. On the basis of genetic findings, we propose hGARE as a new candidate target gene in MSI tumorigenesis. Functional studies are warranted to elucidate the mechanism by which the hGARE mutation might contribute to gastrointestinal carcinogenesis.

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Available from: Antonio Mori, Apr 09, 2014
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    • "With regard to molecular basis of GC, at least two distinct pathways have been identified: one characterized by the successive accumulation of mutations in oncogenes and tumor suppressor genes, in which p53 plays a relevant role, the other, the MSI pathway, characterized by the accumulation of somatic alteration in the length of simple nucleotide repeats that identify a subset of GC with specific biomolecular features (Fiocca et al., 2001). Reported data (Renault et al., 1996; Halling et al., 1999; Iacopetta et al., 1999; Artunedo et al., 2000; Guo et al., 2000; de Manzoni et al., 2001; Palli et al., 2001; Sud et al., 2001; Czopek et al., 2002; Huiping et al., 2002; Inamori et al., 2002; Laghi et al., 2002; Lee et al., 2002; Takahashi et al., 2002; Yamada et al., 2002) vary considerably with regard to MSI, ranging from 9.5% to 37.8% in GCs. These variations may be partly explained by the differences between susceptible populations and by different etiological factors, and seem to be clearly linked to the number of cases investigated and to the type and number of markers used in the study. "
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    ABSTRACT: The aim of this study was to clarify whether specific p53 mutations may have biological relevance in terms of disease relapse or death in gastric carcinomas (GC). Resected specimens from a consecutive series of 62 patients with GC undergoing potentially curative surgery were prospectively studied. The mutational status of exons 5-8 of the p53 gene was investigated in 62 cases using the PCR-SSCP and sequencing. Presence of microsatellite instability (MSI) was evaluated in 56 cases by analyzing loci highly sensitive of MSI. Twenty mutations of p53 were detected in 17 of the 62 cases analyzed (27%). Ten mutations (50%) occurred in highly conserved domains. According to the p53 specific functional domains: 4/20 mutations (20%) were in the L3 loop and 3/20 (15%) in LSH motif. Eight of the 56 GC resulted MSI-H, 5 (9%) MSI-L, and 43 (77%) MSI stable (MSS). None of the 8 (14%) MSI-H GC showed p53 mutations. p53 mutations were associated with intestinal histotype. Moreover, specific mutations in functional domain (L3 and LSH), together with advanced TNM stage, node involvement, depth of invasion, diffuse histotype, proved to be significantly related to quicker relapse and to shorter overall survival. Specific mutations in p53 functional domains, rather than any mutations in this gene, may be biologically more significant in terms of patients outcome, indicating that these mutations might have biological relevance to identify subgroups of patients at higher risk of relapse or death who might benefit from a more aggressive therapeutic approach.
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    • "Frameshift mutations occurred in 23% of the gastric cancers studied, 13% of sporadic and 20% of hereditary colorectal carriers, and all tumours also had frameshift mutations in other genes (Laghi et al. 2002). The gastrin-sensitive LoVo colorectal cancer cell line also showed a similar frameshift mutation in the CCK B receptor gene (Laghi et al. 2002). The results in this study led the authors to propose that the human CCK B receptor gene is a new candidate target gene possibly playing a role in the tumourigenesis of a fraction of MSI tumours. "
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    ABSTRACT: In this paper the possible roles of cholecystokinin (CCK), gastrin, or gastrin-related peptides and their receptors in human gastrointestinal diseases are reviewed. For CCK/CCK(A) receptors (CCK(A)-R), the evidence for their proposed involvement in diseases caused by impaired CCK release or CCK(A)-R mutations, pancreatic disorders (acute/chronic pancreatitis), gastrointestinal motility disorders (gallbladder disease, irritable bowel syndrome), pancreatic tumor growth and satiety disorders, is briefly reviewed. The evidence that has established the involvement of gastrin/CCK(B)-R in mediating the action of hypergastrinaemic disorders, mediating hypergastrinaemic effects on the gastric mucosa (ECL hyperplasia, carcinoids, parietal cell mass), and acid-peptic diseases, is reviewed. The evidence for their possible involvement in mediating growth of gastric and pancreatic tumours and possible involvement of gastrin-related peptides in colon cancers, is reviewed briefly.
    Pharmacology &amp Toxicology 01/2003; 91(6):333-50. DOI:10.1034/j.1600-0773.2002.910611.x
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    ABSTRACT: To clone genes that may predispose us to human gastric cancer and to analyze it's expression in gastric tissues. Specimens of paired tumor, paratumor and normal gastric mucosa tissues collected from fifteen patients who suffered from stomach antrum adenocarcinoma were used for analysis. Seven out of the fifteen cases were first studied by fluorescent differential display reverse transcription polymerase chain reaction (DDTR-PCR) analysis. The differentially expressed bands of interest were cloned, analyzed by Northern blot, sequencing and RT-PCR. Through BLAST, the sequencing results were compared with GenBank database for homology analysis. In situ hybridization with DIG-labeled cRNA probes was used to analyze the expression of interesting cDNA bands in paraffin embedded paired normal gastric mucosa and cancer tissues isolated from 30 gastric adenocarcinoma patients. DDRT-PCR showed that one of the interesting cDNA bands, which was named W2, expressed much higher in all seven tested tumor and paratumor samples than in their normal counterparts, it was sub-cloned into a pGEM-T Easy vector. Two subclones were subsequently obtained. One of the subclone, GCRG224, was studied further. The sequencing result showed that GCRG224 consisted of 1 159 base pairs and had one open reading frame (ORF). It located at human chromosome 11q14. No homologue was found in GenBank database with GCRG224-ORF. This nucleotide sequence data were submitted to GenBank with accession No. AF438406. RT-PCR showed that GCRG224 expressed higher in 11/15 gastric cancer tissues than in non-tumor tissues. However, the result of Northern blot analysis showed a higher GCRG224 expression in the non-tumor tissue than in the tumor one. Human multiple tissue Northern blot analysis revealed that GCRG224 also expressed in human normal colon tissue, and peripheral blood leukocyte. In situ hybridization analysis showed that only 5/30 adenocarcinoma, 3/18 dysplasia and 6/18 intestinal metaplasia showed higher GCRG224 expression level than the normal gastric glands. However, GCRG224 was over-expressed predominantly in 26/30 cases of normal mucosal epithelium. A novel gene named GCRG224 was identified from human gastric mucosal tissue. It overexpressed in almost all gastric mucosal epithelium but only a small portion of cancer and precancerous leisions. The role of GCRG224 expression in gastric epithelium needs further study.
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