Cyclin-dependent kinase 1-mediated AMPK phosphorylation regulates chromosome alignment and mitotic progression.

AMP-activated protein kinase (AMPK), a heterotrimeric serine/threonine kinase and cellular metabolic sensor, has been found to regulate cell cycle checkpoints in cancer cells in response to energetic stress, to harmonize proliferation with energy availability. Despite AMPK's emergent association with the cell cycle, it still has not been fully delineated how AMPK is regulated by upstream signaling pathways during mitosis. We report, for the first time, direct CDK1 phosphorylation of both the catalytic α1 and α2 subunits, as well as the ß1 regulatory subunit, of AMPK in mitosis. We found that AMPK-knockout U2OS osteosarcoma cells have reduced mitotic indexes and that CDK1 phosphorylation-null AMPK is unable to rescue the phenotype, demonstrating a role for CDK1 regulation of mitotic entry through AMPK. Our results also denote a vital role for AMPK in promoting proper chromosomal alignment, as loss of AMPK activity leads to misaligned chromosomes and concomitant metaphase delay. Importantly, AMPK expression and activity was found to be critical for paclitaxel chemosensitivity in breast cancer cells and positively correlated with relapse-free survival in systemically treated breast cancer patients.

Construct validity of the ASAS health index in psoriatic arthritis: a cross-sectional analysis.

OBJECTIVES: The Assessment of SpondyloArthritis international Society health index (ASAS-HI) was designed to assess the global health of patients with spondyloarthritis, but its performance in psoriatic arthritis (PsA) is hardly known. We addressed the clinimetric properties of this instrument in patients with PsA. METHODS: This was a cross-sectional observational study that included 90 consecutive patients with PsA. The measurement properties of ASAS-HI were analysed against the Disease Activity index for PSoriatic Arthritis (DAPSA) and the Psoriatic Arthritis Impact of Disease (PsAID) questionnaire. A multivariate analysis was performed to weigh the ASAS-HI items associated with DAPSA active disease and PsAID high impact. RESULTS: Mean ASAS-HI was 5.8 (4.3). Convergent validity was high both against DAPSA (ρ 0.78, P < 0.0001) and PsAID (ρ 0.80, P < 0.0001). ASAS-HI showed a high discriminant capacity for both DAPSA remission [optimal criterion ≤ 2, area under the receiver operating characteristic curve (AUC) 0.92 (95% CI: 0.85, 0.97), P < 0.0001], and low activity [optimal criterion ≤6, AUC 0.87 (95% CI: 0.79, 0.94), P < 0.0001]. The ASAS-HI items significantly associated with DAPSA active disease were: 'I find it hard to stand for long' (ß 4.48, P < 0.0001), 'I find it hard to concentrate' (ß 2.94, P = 0.042) and 'I sleep badly at night' (ß 1.86, P = 0.044). As for PsAID, the only item significantly associated with a high impact was 'I sleep badly at night' (ß -3.29, P = 0.015). CONCLUSION: We demonstrated construct validity of ASAS-HI, a spondyloarthritis instrument, for the assessment of global health in patients with PsA.