Open AccessIdentification of transforming activity of free fatty acid receptor 2 by retroviral expression screening
Author(s) -
Hatanaka Hisashi,
Tsukui Mamiko,
Takada Shuji,
Kurashina Kentaro,
Choi Young Lim,
Soda Manabu,
Yamashita Yoshihiro,
Haruta Hidenori,
Hamada Toru,
Ueno Toshihide,
Tamada Kiichi,
Hosoya Yoshinori,
Sata Naohiro,
Yasuda Yoshikazu,
Nagai Hideo,
Sugano Kentaro,
Mano Hiroyuki
Publication year - 2010
Publication title -
cancer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.035
H-Index - 141
eISSN - 1349-7006
pISSN - 1347-9032
DOI - 10.1111/j.1349-7006.2009.01348.x
Subject(s) - biology , complementary dna , cdna library , carcinogenesis , microbiology and biotechnology , rapid amplification of cdna ends , cancer , cancer research , gene , biochemistry , genetics , molecular cloning
Gallbladder cancer (GBC) is a highly fatal malignancy in humans. Genetic alterations in KRAS or TP53 as well as overexpression of ERBB2 have been shown to contribute to the development of certain types of GBC. However, many cases of GBC do not harbor such genetic changes, with other transforming events awaiting discovery. We here tried to identify novel cancer‐promoting genes in GBC, with the use of a retroviral cDNA expression library. A retroviral cDNA expression library was constructed from a surgically resected clinical specimen of GBC, and was used to infect 3T3 fibroblasts in a focus formation assay. cDNA incorporated into the transformed foci was rescued by PCR. One such cDNA was found to encode free fatty acid receptor 2 (FFAR2), a G protein‐coupled receptor for short‐chain fatty acids. The oncogenic potential of FFAR2 was confirmed both in vitro with the focus formation assay and by evaluation of cell growth in soft agar as well as in vivo with a tumorigenicity assay in nude mice. The isolated FFAR2 cDNA had no sequence alterations, suggesting that upregulation of FFAR2 expression may contribute to malignant transformation. Indeed, all of quantitative RT‐PCR, in situ hybridization, and immunohistochemical analyses showed that the amount of FFAR2 mRNA and its protein product was increased in digestive tract cancer specimens. Furthermore, short‐chain fatty acids potentiated the mitogenic action of FFAR2 in 3T3 cells. Our data thus, for the first time, implicate FFAR2 in carcinogenesis of the digestive tract. ( Cancer Sci 2009)