The adipocyte-rich microenvironment forms a niche for ovarian cancer metastasis, but the mechanisms driving this process are incompletely understood. Here we show that salt-inducible kinase 2 (SIK2) is overexpressed in adipocyte-rich metastatic deposits compared with ovarian primary lesions. Overexpression of SIK2 in ovarian cancer cells promotes abdominal metastasis while SIK2 depletion prevents metastasis in vivo. Importantly, adipocytes induce calcium-dependent activation and autophosphorylation of SIK2. Activated SIK2 plays a dual role in augmenting AMPK-induced phosphorylation of acetyl-CoA carboxylase and in activating the PI3K/AKT pathway through p85α-S154 phosphorylation. These findings identify SIK2 at the apex of the adipocyte-induced signaling cascades in cancer cells and make a compelling case for targeting SIK2 for therapy in ovarian cancer.
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AMP-Activated Protein Kinases, Acetyl-CoA Carboxylase, Adipocytes, Animals, Female, Heterografts, Humans, Mice, Mice, Inbred C57BL, Mice, Nude, Neoplasm Metastasis, Oncogene Protein v-akt, Ovarian Neoplasms, Phosphatidylinositol 3-Kinases, Protein-Serine-Threonine Kinases, Signal Transduction