Targeted knock-in of the polymorphism rs61764370 does not affect KRAS expression but reduces let-7 levels.
Hum Mutat
; 35(2): 208-14, 2014 Feb.
Article
in En
| MEDLINE
| ID: mdl-24282149
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 rs61764370T>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.
Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Colorectal Neoplasms
/
Genes, ras
/
Proto-Oncogene Proteins
/
Ras Proteins
/
Polymorphism, Single Nucleotide
/
MicroRNAs
Type of study:
Risk_factors_studies
Limits:
Humans
Language:
En
Journal:
Hum Mutat
Journal subject:
GENETICA MEDICA
Year:
2014
Type:
Article
Affiliation country:
Italy