α5 Nicotinic acetylcholine receptor mediates nicotine-induced HIF-1α and VEGF expression in non-small cell lung cancer

Xiaoli Ma; Yanfei Jia; Shanshan Zu; Ruisheng Li; Ying Jia; Yun Zhao; Dongjie Xiao; Ningning Dang; Yunshan Wang

doi:10.1016/j.taap.2014.04.023

α5 Nicotinic acetylcholine receptor mediates nicotine-induced HIF-1α and VEGF expression in non-small cell lung cancer

Toxicol Appl Pharmacol. 2014 Jul 15;278(2):172-9. doi: 10.1016/j.taap.2014.04.023. Epub 2014 Apr 30.

Authors

Xiaoli Ma¹, Yanfei Jia¹, Shanshan Zu¹, Ruisheng Li², Ying Jia¹, Yun Zhao¹, Dongjie Xiao¹, Ningning Dang³, Yunshan Wang¹

Affiliations

¹ Central Laboratory, Jinan Central Hospital Affiliated to Shandong University, Jinan 250013, China.
² Institute of Infectious Diseases, 302 Military Hospital, Beijing 100039, China.
³ Department of Dermatology, Jinan Central Hospital Affiliated to Shandong University, Jinan 250013, China.

PMID: 24793809
DOI: 10.1016/j.taap.2014.04.023

Abstract

By binding to nicotinic acetylcholine receptors (nAChRs), nicotine induces the proliferation and apoptosis of non-small cell lung cancer (NSCLC). Previous studies have indicated that α5-nAChR is highly associated with lung cancer risk and nicotine dependence. However, the mechanisms through which α5-nAChRs may influence lung carcinogenesis are far from clear. In the present study, we investigated the roles of α5-nAChR in the nicotine-induced expression of hypoxia-inducible factor-1α (HIF-1α) and vascular endothelial growth factor (VEGF). Immunohistochemistry was used to detect the expression of α5-nAChR and HIF-1α in 60 specimens of lung cancer and para-carcinoma tissue. The correlations between the expression levels of α5-nAChR and HIF-1α and other clinicopathological data were analyzed. In a cell line that highly expressed α5-nAChR, the loss of α5-nAChR function by siRNA was used to study whether α5-nAChR is involved in the nicotine-induced expression of HIF-1α and VEGF through the activation of the ERK1/2 and PI3K/Akt signaling pathways. Cell growth was detected using the cell counting kit-8 (CCK-8). α5-nAChR (78.3%) and HIF-1α (88.3%) were both overexpressed in NSCLC, and their expression levels were found to be correlated with each other (P<0.05). In the A549 cell line, α5-nAChR and HIF-1α were found to be expressed under normal conditions, and their expression levels were significantly increased in response to nicotine treatment. The silencing of α5-nAChR significantly inhibited the nicotine-induced cell proliferation compared with the control group and attenuated the nicotine-induced upregulation of HIF-1α and VEGF, and these effects required the cooperation of the ERK1/2 and PI3K/Akt signaling pathways. These results show that the α5-nAChR/HIF-1α/VEGF axis is involved in nicotine-induced tumor cell proliferation, which suggests that α5-nAChR may serve as a potential anticancer target in nicotine-associated lung cancer.

Keywords: HIF-1α; Nicotine; Non-small cell lung cancer; VEGF; α5-nAChR.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Adult
Aged
Carcinoma, Non-Small-Cell Lung / metabolism*
Carcinoma, Non-Small-Cell Lung / pathology
Cell Line, Tumor
Down-Regulation / physiology
Female
Gene Expression Regulation, Neoplastic
Humans
Hypoxia-Inducible Factor 1, alpha Subunit / biosynthesis*
Hypoxia-Inducible Factor 1, alpha Subunit / genetics
Hypoxia-Inducible Factor 1, alpha Subunit / metabolism
Lung Neoplasms / metabolism*
Lung Neoplasms / pathology
Male
Middle Aged
Nicotine / toxicity*
Receptors, Nicotinic / metabolism
Receptors, Nicotinic / physiology*
Vascular Endothelial Growth Factor A / biosynthesis*
Vascular Endothelial Growth Factor A / genetics

Substances

HIF1A protein, human
Hypoxia-Inducible Factor 1, alpha Subunit
Receptors, Nicotinic
VEGFA protein, human
Vascular Endothelial Growth Factor A
nicotinic receptor alpha5 subunit, human
Nicotine