oleuropein and Hypoxia

Background Neurological deficits in hypoxic-ischemic encephalopathy, even with therapeutic hypothermia, are partially attributed to white matter injury. We theorized that proteasome insufficiency contributes to white matter injury. Methods and Results Neonatal piglets received hypoxia-ischemia ( HI ) or sham procedure with normothermia, hypothermia, or hypothermia+rewarming. Some received a proteasome activator drug (oleuropein) or white matter-targeted, virus-mediated proteasome knockdown. We measured myelin oligodendrocyte glycoprotein, proteasome subunit 20S (P20S), proteasome activity, and carbonylated and ubiquitinated protein levels in white matter and cerebral cortex. HI reduced myelin oligodendrocyte glycoprotein levels regardless of temperature, and myelin oligodendrocyte glycoprotein loss was associated with increased ubiquitinated and carbonylated protein levels. Ubiquitinated and carbonyl-damaged proteins increased in white matter 29 hours after HI during hypothermia to exceed levels at 6 to 20 hours. In cortex, ubiquitinated proteins decreased. Ubiquitinated and carbonylated protein accumulation coincided with lower P20S levels in white matter; P20S levels also decreased in cerebral cortex. However, proteasome activity in white matter lagged behind that in cortex 29 hours after HI during hypothermia. Systemic oleuropein enhanced white matter P20S and protected the myelin, whereas proteasome knockdown exacerbated myelin oligodendrocyte glycoprotein loss and ubiquitinated protein accumulation after HI . At the cellular level, temperature and HI interactively affected macroglial P20S enrichment in subcortical white matter. Rewarming alone increased macroglial P20S immunoreactivity, but this increase was blocked by HI . Conclusions Oxidized and ubiquitinated proteins accumulate with HI -induced white matter injury. Proteasome insufficiency may drive this injury. Hypothermia did not prevent myelin damage, protect the proteasome, or preserve oxidized and ubiquitinated protein clearance after HI .

Topics: Animals; Animals, Newborn; Asphyxia; Brain Ischemia; Cerebral Cortex; Gene Knockdown Techniques; Heart Arrest; Hypothermia; Hypoxia; Iridoid Glucosides; Iridoids; Leukoencephalopathies; Male; Myelin-Oligodendrocyte Glycoprotein; Proteasome Endopeptidase Complex; Random Allocation; Rewarming; Swine; White Matter

Previously, we reported that high-fat-diet (HFD)-induced obesity stimulates melanoma progression in the B16F10 allograft model. In this study, we examined whether oleuropein (OL), the most abundant phenolic compound in olives, inhibits HFD-induced melanoma progression. Four-week-old male C57BL/6N mice were fed a HFD-diet with or without OL. After 16 weeks of feeding, B16F10-luc cells were subcutaneously injected and the primary tumor was resected 3 weeks later. OL suppressed HFD-induced solid tumor growth. In the tumor tissues, OL reduced HFD-induced expression of angiogenesis (CD31, VE-cadherin, VEGF-A, and VEGFR2), lymphangiogenesis (LYVE-1, VEGF-C, VEGF-D, and VEGFR3), and hypoxia (HIF-1α and GLUT-1) markers as well as HFD-induced increases in lipid vacuoles and M2 macrophages (MΦs). All animals were euthanized 2.5 weeks after tumor resection. OL suppressed HFD-induced increases in lymph node (LN) metastasis; expression of VEGF-A, VEGF-C, and VEGF-D in the LN; and M2-MΦs and the size of adipocytes in adipose tissues surrounding LNs. Co-culture results revealed that the crosstalk between B16F10s, M2-MΦs, and differentiated 3T3-L1 cells under hypoxic conditions increased the secretion of VEGF-A and -D, which stimulated tube formation and migration of endothelial cells (HUVECs) and lymphatic endothelial cells (LEC), respectively. Additionally, OL directly inhibited the differentiation of 3T3-L1 preadipocytes and tube formation by HUVECs and LECs. The overall results indicated that dietary OL inhibits lipid and M2-MΦ accumulation in HFD-fed mice, which contributes to decreases in VEGF secretion, thereby leading to inhibition of angiogenesis and lymphangiogenesis.

Topics: Adipose Tissue; Allografts; Angiogenesis Inhibitors; Animals; Apoptosis; Cell Proliferation; Diet, High-Fat; Dietary Supplements; Hypoxia; Iridoid Glucosides; Iridoids; Lipid Metabolism; Lymphangiogenesis; Lymphatic Metastasis; Macrophages; Melanoma, Experimental; Mice; Neovascularization, Pathologic; Tumor Burden; Vascular Endothelial Growth Factors

Radiotherapy in ovarian cancer frequently invokes resistance; this severely compromises its therapeutic effect and results in poor clinical prognosis. How to overcome the acquired resistance and re-sensitize tumors to radiation is the central question in this clinical setting. Cancer cell survival was evaluated using a clonogenic assay. The microRNA expression profile was analyzed using a microarray. Transcript expression was determined using real time PCR. The expression of protein was determined by immunoblotting. Transcription activation was measured using a luciferase reporter assay. Transcription factor binding was determined using ChIP-PCR. Xenograft model was established and exposed to radiation with the simultaneous administration of oleuropein. Tumor growth was monitored. We demonstrated that treatment of oleuropein-sensitized ovarian cells with radiation altered the microRNA expression profile. The endogenous expression of miR-299 was suppressed by a hypoxia inducible factor and relieved in response to oleuropein, which in turn suppressed HPSE1 expression and consequently led to increased sensitivity to radiation. Our data elucidates an unappreciated mechanism mediating radiotherapy resistance in ovarian cancer and exploits the potential synergistic effect of oleuropein with radiation, which warrants further clinical investigation.

Topics: Animals; Cell Line, Tumor; Female; Gene Expression Regulation, Neoplastic; Glucuronidase; Humans; Hypoxia; Iridoid Glucosides; Iridoids; Mice; Mice, Inbred BALB C; MicroRNAs; Ovarian Neoplasms; Radiation-Sensitizing Agents