SIK1, short for salt-inducible kinase 1, is a serine/threonine protein kinase belonging to the AMP-activated protein kinase family. It is catalytically activated by phosphorylation via the upstream kinase LKB1. SIK1 is involved in multiple signal regulatory pathways, such as those related to tumor suppression, glucose metabolism, and sodium ion balance [3,6]. Genetic models, especially knockout mouse models, are valuable in studying its functions.

In NSCLC, conditional genetic loss of Sik1 in mouse models led to increased tumor growth in Kras-dependent lung cancer, and this effect was further enhanced by loss of Sik3. This indicates that SIK1, along with SIK3, mediates key tumor-suppressive effects of LKB1 [1]. In breast cancer, AKT-mediated phosphorylation of SIK1 compromises its tumor-suppressive functions, leading to breast cell tumorigenesis [2]. In Alzheimer's disease, SIK1 protein level increases in the presence of Aβ and in AD brains, and knockdown of SIK1 in 3xTG AD mice restores AMPAR expression and rescues cognitive deficits [4]. In colorectal cancer, SIK1 inhibits the TGF-β pathway, suppressing metastasis and oxaliplatin chemoresistance [5].

In summary, SIK1 plays crucial roles in various biological processes and diseases. Mouse knockout models have revealed its significance in cancer, Alzheimer's disease, and other conditions. These findings emphasize SIK1 as a potential therapeutic target, offering new directions for disease treatment and prevention.