Expression patterns for nicotinic acetylcholine receptor subunit genes in smoking-related lung cancers.
Oncotarget
; 8(40): 67878-67890, 2017 Sep 15.
Article
in En
| MEDLINE
| ID: mdl-28978081
ABSTRACT
Cigarette smoking is associated with increased risk for all histologic types of lung cancer, but why the strength of this association is stronger for squamous cell carcinoma than adenocarcinoma of the lung (SQC-L, ADC-L) is not fully understood. Because nicotine and tobacco-specific nitrosamines contribute to carcinogenesis by activating nicotinic acetylcholine receptors (nAChRs) on lung tumors and epithelial cells, we investigated whether differential expression of nAChR subtypes in these tumors could explain their different association with smoking. Expression of nAChR subunit genes in paired tumor and non-tumor lung specimens from 40 SQC-L and 38 ADC-L patients was analyzed by quantitative PCR. Compared to normal lung, both tumors share i) transcriptional dysregulation of CHRNA3/CHRNA5/CHRNB4 (α3, α5, ß4 subunits) at the chromosomal locus that predisposes to lung cancer; and ii) decreased expression of CHRFAM7A (dupα7 subunit); this last subunit negatively modulates α7-nAChR activity in oocytes. In contrast, CHRNA7 (α7 subunit) expression was increased in SQC-L, particularly in smokers and non-survivors, while CHRNA4 (α4 subunit) expression was decreased in ADC-L. Thus, over-representation of cancer-stimulating α7-nAChR in SQC-L, also potentiated by smoking, and under-representation of cancer-inhibiting α4ß2-nAChR in ADC-L could explain the different tobacco influences on the tumorigenic process in each cancer type.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Language:
En
Journal:
Oncotarget
Year:
2017
Document type:
Article
Affiliation country: