Chuk, also known as Conserved Helix-Loop-Helix Ubiquitous Kinase or IκB kinase α, is a key component of the nuclear factor-kappaB (NF-κB) signaling pathway [3]. The NF-κB pathway has a central role in coordinating the expression of genes controlling immune responses and is involved in various diseases from inflammation to cancer [1]. Chuk contains a serine-threonine kinase catalytic domain and is highly conserved evolutionarily and ubiquitously expressed [3].

In two independent in vivo lung cancer models, Chuk/IKK-α acts as a major non-small-cell lung cancer (NSCLC) tumor suppressor. In a transgenic mouse strain where IKKα ablation is induced in alveolar type II lung epithelial cells, IKKα loss increases the number and size of lung adenomas in response to urethane. Also, IKKα knockdown in human NSCLC lines enhances their growth as tumor xenografts in immune-compromised mice. Bioinformatics and validation experiments show that IKKα loss up-regulates activated HIF-1-α protein to enhance NSCLC tumor growth under hypoxic conditions in vivo [2].

In conclusion, Chuk plays a crucial role in the NF-κB signaling pathway, which is important for immune responses. The gene knockout mouse models have revealed its significance as a tumor suppressor in NSCLC, providing valuable insights into the molecular mechanisms of NSCLC development and potentially offering new directions for NSCLC treatment.