CTBP1 and lung cancer: While binding of nicotine to nAChRs is the principal mode of its biological action, nicotine has also been found to trigger the production of β-AR ligands, for example, adrenaline and noradrenaline, that act via the β-ARs, activating a number of oncogenic and mitogenic signaling pathways, leading to cell proliferation and the development of lung cancer [24,28].