Cloning of a G‐protein‐coupled receptor that shows an activity to transform NIH3T3 cells and is expressed in gastric cancer cells

Abstract

The present study was directed towards the identification of novel factors involved in the transformation process leading to the formation of gastric cancer. A cDNA library from human gastric cancer cells was constructed using a retroviral vector. Functional cloning was performed by screening for transformation activity in transduced NIH3T3 cells. Six cDNA clones were isolated, including one encoding the elongation factor 1α α α α subunit, which was already known to play a role in tumorigenesis. One cDNA (clone 56.2), which was repeatedly isolated during the course of screening, encoded a protein identical to a G-protein-coupled receptor protein, GPR35. In addition, another cDNA clone (72.3) was found to be an alternatively spliced product of the GPR35 gene, whereby 31 amino acids were added to the N-terminus of GPR35. Hence, the proteins encoded by clones 56.2 and 72.3 were designated GPR35a and GPR35b, respectively. RT-PCR experiments revealed that GPR35 gene expression is low or absent in surrounding non-cancerous regions, while both mRNAs were present in all of the gastric cancers examined. The level of 72.3-encoded mRNA was consistently significantly higher than that of 56.2 encoded mRNA. An expression pattern similar to that observed in gastric cancers was detected in normal intestinal mucosa. Based on the apparent transformation activities of the two GPR35 clones in NIH3T3 cells, and the marked up-regulation of their expression levels in cancer tissues, it is speculated that these two novel isoforms of GPR35 are involved in the course of gastric cancer formation. (Cancer Science 2004; 95: 131-135)

Isoleucine, an Essential Amino Acid, Induces the Expression of Human <i>β</i> Defensin 2 through the Activation of the G-Protein Coupled Receptor-ERK Pathway in the Intestinal Epithelia

“…This is supported by the reduction of the effect of Ile on the induction of HBD2 when cells were treated with an inhibitor of the Gi subunit, Pertussis toxin. mGluR, GPR35 and the extracellular Ca the intracellular calcium ion concentration and activate the ERK signaling pathway, might therefore be candidates for sensing Ile [17][18][19]34]. Further analysis with knockout models for such GPCRs is needed to determine the specific GPCR responsible for the effects of Ile.…”

“…For example, glutamic acid is absorbed into the epithelia, and is also bound to a taste receptor which is one of the GPCRs. Many types of GPCRs, such as taste receptor and GPR35, are expressed in the intestinal epithelia [18][19][20]. In addi- tion, the functions of some GPCRs are associated with the expression of anti-microbial peptides in neutrophils and gingival cells [21,22].…”

Mycoplasma hyorhinis and Mycoplasma fermentans induce cell apoptosis and changes in gene expression profiles of 32D cells

“…It interacts with TGFB1I1 (KimKaneyama et al, 2005). G protein-coupled receptor 56 is involved in the development of gastric cancer (Okumura et al, 2004). Suppression of tumorigenicity 7 may act as a tumor suppressor (Hooi et al, 2006).…”

The emerging pharmacology and function of GPR35 in the nervous system

“…and GPR35b, which is identical in sequence apart from containing a 31 amino acid N-terminal 285 extension (Okumura et al, 2004). Although the majority of literature on human GPR35 focusses on 286 the short (GPR35a) isoform, it is important to note that there is limited information currently available 287 on whether GPR35a and GPR35b are differentially regulated and/or provide different functionalities 288 in vivo.…”

“…Although the majority of literature on human GPR35 focusses on 286 the short (GPR35a) isoform, it is important to note that there is limited information currently available 287 on whether GPR35a and GPR35b are differentially regulated and/or provide different functionalities 288 in vivo. In human gastric cancer, there does appear to be some differences between the two transcripts 289 with GPR35b being identified from tumours and non-tumorous surrounding regions whilst GPR35a 290 was found in the tumorous regions only, at a level lower than GPR35b, but with a higher transforming 291 capability (Okumura et al, 2004). Such differences were not observed in primary cardiomyocytes 292 where GPR35a and GPR35b mRNA transcripts were found to be expressed to similar levels and to 293 respond in a similar manner to stimuli (Ronkainen et al, 2014).…”