Regulators of mitosis have been successfully targeted to enhance response to taxane chemotherapy. Here, we show that the salt inducible kinase 2 (SIK2) localizes at the centrosome, plays a key role in the initiation of mitosis, and regulates the localization of the centrosome linker protein, C-Nap1, through S2392 phosphorylation. Interference with the known SIK2 inhibitor PKA induced SIK2-dependent centrosome splitting in interphase while SIK2 depletion blocked centrosome separation in mitosis, sensitizing ovarian cancers to paclitaxel in culture and in xenografts. Depletion of SIK2 also delayed G1/S transition and reduced AKT phosphorylation. Higher expression of SIK2 significantly correlated with poor survival in patients with high-grade serous ovarian cancers. We believe these data identify SIK2 as a plausible target for therapy in ovarian cancers.
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Antineoplastic Agents, Phytogenic, Cell Cycle, Centrosome, Female, Humans, Ovarian Neoplasms, Paclitaxel, Phosphorylation, Protein-Serine-Threonine Kinases, Proto-Oncogene Proteins c-akt, RNA, Small Interfering, Spindle Apparatus, Transplantation, Heterologous