Format

Send to

Choose Destination
Hum Mutat. 2014 Feb;35(2):208-14. doi: 10.1002/humu.22487. Epub 2013 Dec 27.

Targeted knock-in of the polymorphism rs61764370 does not affect KRAS expression but reduces let-7 levels.

Author information

1
IRCC, Institute for Cancer Research at Candiolo, SP142 Km 3.95, Torino, Italy.

Abstract

Understanding the role of single-nucleotide polymorphisms (SNPs) in the pathological process represents a unique experimental challenge especially when the variants occur outside of coding regions. The noncoding SNP rs61764370 located in the 3'-untranslated region of Kirsten rat sarcoma viral oncogene homolog (KRAS) has been implicated as a risk factor for the development of cancer and the response to targeted therapies. This cancer-associated variant is thought to affect the binding of the microRNA let-7, which allegedly modulates KRAS expression. Using site-specific homologous recombination, we inserted the rs61764370:T>G KRAS gene variant in the colorectal cancer cell line SW48 (SW48 +SNP) and assessed the cellular and biochemical phenotype. We observed a significant increase in cellular proliferation, as well as a reduction in the levels of the microRNA let-7a, let-7b, and let-7c. Transcriptional and biochemical analysis showed no concomitant change in the KRAS protein expression or modulation of the downstream mitogen activated kinase or PI3K/AKT signaling. These results suggest that the cancer-associated rs61764370 variant exerts a biological effect not through transcriptional modulation of KRAS but rather by tuning the expression of the microRNA let-7.

KEYWORDS:

3′ untranslated region; KRAS; cancer; genetics; let-7; miRNA; single-nucleotide polymorphism

PMID:
24282149
DOI:
10.1002/humu.22487
[Indexed for MEDLINE]

Supplemental Content

Full text links

Icon for Wiley
Loading ...
Support Center