The N-acetyltransferase arrest defective 1 (ARD1) is an important regulator of cell growth and differentiation that has emerged recently as a critical molecule in cancer progression. However, the regulation of the enzymatic and biological activities of human ARD1 (hARD1) in cancer is presently poorly understood. Here, we report that hARD1 undergoes autoacetylation and that this modification is essential for its functional activation. Using liquid chromatography-tandem mass spectrometry and site-directed mutational analyses, we identified K136 residue as an autoacetylation target site. K136R mutation abolished the ability of hARD1 to promote cancer cell growth in vitro and tumor xenograft growth in vivo. Mechanistic investigations revealed that hARD1 autoacetylation stimulated cyclin D1 expression through activation of the transcription factors β-catenin and activator protein-1. Our results show that hARD1 autoacetylation is critical for its activation and its ability to stimulate cancer cell proliferation and tumorigenesis. Cancer Res; 70(11); 4422-32. ©2010 AACR.

Objective We analyzed the longitudinal profile of Alzheimer's disease (AD) cerebrospinal fluid (CSF) biomarkers in early Parkinson's disease (PD) compared with healthy controls (HCs) and tested baseline CSF biomarkers for prediction of clinical decline in PD. Methods Amyloid‐β 1 to 42 (Aβ42), total tau (t‐tau) and phosphorylated tau (p‐tau) at the threonine 181 position were measured using the high‐precision Roche Elecsys electrochemiluminescence immunoassay in all available CSF samples from longitudinally studied patients with PD (n = 416) and HCs (n = 192) followed for up to 3 years in the Parkinson's Progression Markers Initiative (PPMI). Longitudinal CSF and clinical data were analyzed with linear‐mixed effects models. Results We found patients with PD had lower CSF t‐tau (median = 157.7 pg/mL; range = 80.9–467.0); p‐tau (median = 13.4 pg/mL; range = 8.0–40.1), and Aβ42 (median = 846.2 pg/mL; range = 238.8–3,707.0) than HCs at baseline (CSF t‐tau median = 173.5 pg/mL; range = 82.0–580.8; p‐tau median = 15.4 pg/mL; range = 8.1–73.6; and Aβ42 median = 926.5 pg/mL; range = 239.1–3,297.0; p < 0.05–0.001) and a moderate‐to‐strong correlation among these biomarkers in both patients with PD and HCs (Rho = 0.50–0.97; p < 0.001). Of the patients with PD, 31.5% had pathologically low levels of CSF Aβ42 at baseline and these patients with PD had lower p‐tau levels (median = 10.8 pg/mL; range = 8.0–32.8) compared with 27.7% of HCs with pathologically low CSF Aβ42 (CSF p‐tau median = 12.8 pg/mL; range 8.2–73.6; p < 0.03). In longitudinal CSF analysis, we found patients with PD had greater decline in CSF Aβ42 (mean difference = −41.83 pg/mL; p = 0.03) and CSF p‐tau (mean difference = −0.38 pg/mL; p = 0.03) at year 3 compared with HCs. Baseline CSF Aβ42 values predicted small but measurable decline on cognitive, autonomic, and motor function in early PD. Interpretation Our data suggest baseline CSF AD biomarkers may have prognostic value in early PD and that the dynamic change of these markers, although modest over a 3‐year period, suggest biomarker profiles in PD may deviate from healthy aging. ANN NEUROL 2020;88:574–587

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In Korean subjects, CFH polymorphism appears to be a considerable hereditary contributor to exudative AMD. Y402H polymorphism which has been suggested to be a major risk factor of AMD in Caucasians was found to be only marginally associated with exudative AMD with low frequency, whereas three adjacent SNPs in the CFH gene were significantly associated with AMD in Koreans.

Angiogenesis, the process by which new blood vessels are recruited to existing ones, is essential for tumor development. Insulin-like growth factor (IGF) binding protein-3 (IGFBP-3), which modulates bioavailability of IGF, has been studied for its potential role in angiogenesis during tissue regeneration and cancer development. In this study, we assessed the role of IGFBP-3 in tumor angiogenesis in head and neck squamous cell carcinoma (HNSCC) and human umbilical endothelial cells (HUVECs) using adenoviral (Ad-BP3) and recombinant (rBP3) IGFBP-3. Utilizing an in vivo orthotopic tongue tumor model, we confirmed that both Ad-BP3 and rBP3 suppress the growth of UMSCC38 HNSCC cells in vivo. Ad-BP3 inhibited vascularization in tongue tumors and chorio-allantoic membrane, and suppressed angiogenesis-stimulating activities in UMSCC38 cells. In HUVECs, Ad-BP3 decreased migration, invasion, and tube formation. rBP3 also suppressed production of VEGF in HUVECs and UMSCC38 cells. IGFBP-3-GGG, a mutant IGFBP-3 with loss of IGF binding capacity, suppressed VEGF production. In addition, we found that IGFBP-3 suppressed VEGF expression, even in mouse embryonic fibroblasts from an IGF-1R-null mouse. Finally, we demonstrated that IGFBP-3-GGG inhibits tumor angiogenesis and growth to the same degree as wild-type IGFBP-3. Taken together, these results support the hypothesis that IGFBP-3 has antiangiogenic activity in HNSCC, at least in part due to IGF-independent suppression of VEGF production from vascular endothelial cells and cancer cells.

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Drug resistance is a major impediment in medical oncology. Recent studies have emphasized the importance of the tumor microenvironment (TME) to innate resistance to molecularly targeted therapies. In this study, we investigate the role of TME in resistance to cixutumumab, an anti-IGF-1R mAb that has shown limited clinical efficacy. We show that treatment with cixutumumab accelerates tumor infiltration of stromal cells and metastatic tumor growth and decreases overall survival of mice. Cixutumumab treatment stimulates STAT3-dependent transcriptional up-regulation of IGF-2 in cancer cells and recruitment of macrophages and fibroblasts via paracrine IGF-2/IGF-2R activation, resulting in the stroma-derived CXCL8 production and thus angiogenic and metastatic environment. Silencing IGF-2 or STAT3 expression in cancer cells or IGF-2R or CXCL8 expression in stromal cells significantly inhibits the cancer-stroma communication and vascular endothelial cells’ angiogenic activities. These findings suggest that blocking the STAT3/IGF-2/IGF-2R intercellular signaling loop may overcome the adverse consequences of anti-IGF-1R mAb-based therapies.

Exosomes are extracellular vesicles that contain molecules that regulate the metabolic functions of adjacent or remote cells. Recent in vitro, in vivo and clinical studies support the hypothesis that exosomes released from various cell types play roles in the progression of metabolic disorders including type 2 diabetes. Based on this concept and advances in other diseases, the proteins, mRNA, microRNA and lipids in exosomes isolated from biological fluids have been proposed as biomarkers in metabolic disorders. However, several problems with the development of clinically applicable biomarkers have not been resolved. In this review, the biologic functions of exosomes are briefly introduced, and we discuss the technical and practical pros and cons of different methods of exosome isolation for the identification of exosomal biomarkers of metabolic disorders. Standardization of preanalytical variables and isolation of high-purity exosomes from fully characterized biological fluids will be necessary for the identification of useful exosomal biomarkers that can provide insights into the pathogenic mechanisms of complications of metabolic syndrome and of whole-body metabolism.