Yuksel Yildiz

Protective Effects of Caffeic Acid Phenethyl Ester on Intestinal Ischemia-Reperfusion Injury

Aim Intestinal ischemia reperfusion (IR) causes tissue injury in two ways, starting a pro-inflammatory cascade and oxidative stress. The aim of this study was to investigate the possible protective effects of caffeic acid phenethyl ester (CAPE), which has antioxidant and anti-inflammatory properties, against intestinal IR injury in rats. Materials and Methods Forty male Wistar-Albino rats were divided into five groups: Sham, IR, IR plus ethanol (vehicle), IR plus 10 mg/kg (IR + 10CAPE), and 30 mg/kg CAPE (IR + 30CAPE) at the 30-min ischemic period. Intestines were exteriorized and the superior mesenteric artery was occluded for 45-min ischemia and then the clamp was removed for 120-min reperfusion. After the experiment, the intestines were removed for biochemical and light microscopic examinations. Additionally, blood samples were taken for plasma TNF-α measurement. Results The TBARS levels of the IR and IR + Ethanol groups were higher than the Sham group (P < 0.05). Both CAPE treatments decreased TBARS levels in comparison with the IR group (P < 0.05). In both CAPE-treated groups, while the superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activities were increased compared to all other groups, which was similarly the case for the CAT activity compared to the Sham and IR + Ethanol groups (P < 0.05). There were no significant differences between GSH levels of all study groups. The TNF-α levels of the IR and IR + Ethanol groups were non-significantly increased compared to the Sham group (P > 0.05). The TNF-α levels of 10 and 30 mg/kg CAPE groups were non-significantly decreased compared to the IR group (P > 0.05). The tissue MPO activities of the IR and IR + Ethanol groups were higher than the Sham group (P < 0.05). The MPO activities of the IR + 10CAPE and IR + 30CAPE groups were not significantly different from the Sham group (P > 0.05). There was necrosis of mucosa in the IR and IR + Ethanol groups in light microscopic evaluations. Those changes were significantly reversed by 30 mg/kg CAPE treatment. Conclusion The intestinal IR injury may be reversed by anti-inflammatory and antioxidant actions of the CAPE. However, 30 mg/kg CAPE treatment may be more efficient in preventing intestinal IR injury in rats.

Effect of experimentally induced hypothyroidism during gestation period on activity dependent neurotrophic factor (ADNF) in newborn rat brain tissue

Abstract Purpose The aim of the study was to evaluate the effects of prenatal hypothyroidism on neonatal rats by the way of activity-dependent neuroprotective factor (ADNF) expression. Methods Twenty-one Wistar albino neonatal rats were divided into two subgroups; a control group and neonatal rats with experimental maternal hypothyroidism. Hypothyroidism was induced by using propylthiouracil (PTU). Neonatal rats obtained PTU from breast milk continuously for 1 week after birth. The rats from the control group were fed only normal feed and water. After birth, body weight and blood thyroid hormone levels were tested. Glial fibrillary acidic protein (GFAP), Slug, Numb, Notch-1 and ADNF antibodies were used for immunohistochemical analysis. Real-time polymerase chain reaction (RT-PCR) and Western blotting analyses were used to evaluate ADNF gene expression levels from 1-week-old rat’s brain. Results There was no difference between the two groups for birth weights. The thyroxine (T4) level from the experimental group was <0.4 ng/mL, and it was 0.8 ng/mL for the control group. It was shown that, the results from the experimental group samples had significantly lower ADNF mRNA levels than control group (p < 0.05). The increase from GFAP and Numb expression and decrease from Slug expression were shown in the experimental group. Local differences were identified for ADNF and a decrease was shown in both sides of brain. There was no difference for Notch-1 expression for both groups. Conclusion In this study, decreasing ADNF expression might contribute to developing neurological problems in congenital hypothyroidism.

Mapping the STK4/Hippo signaling network in prostate cancer cell

Dysregulation of MST1/STK4, a key kinase component of the Hippo-YAP pathway, is linked to the etiology of many cancers with poor prognosis. However, how STK4 restricts the emergence of aggressive cancer remains elusive. Here, we investigated the effects of STK4, primarily localized in the cytoplasm, lipid raft, and nucleus, on cell growth and gene expression in aggressive prostate cancer. We demonstrated that lipid raft and nuclear STK4 had superior suppressive effects on cell growth in vitro and in vivo compared with cytoplasmic STK4. Using RNA sequencing and bioinformatics analysis, we identified several differentially expressed (DE) genes that responded to ectopic STK4 in all three subcellular compartments. We noted that the number of DE genes observed in lipid raft and nuclear STK4 cells were much greater than cytoplasmic STK4. Our functional annotation clustering showed that these DE genes were commonly associated with oncogenic pathways such as AR, PI3K/AKT, BMP/SMAD, GPCR, WNT, and RAS as well as unique pathways such as JAK/STAT, which emerged only in nuclear STK4 cells. These findings indicate that MST1/STK4/Hippo signaling restricts aggressive tumor cell growth by intersecting with multiple molecular pathways, suggesting that targeting of the STK4/Hippo pathway may have important therapeutic implications for cancer.

Abstract 4401: Disclosing the Hippo signaling networks in castration-resistant prostate cancer

Prostate cancer often evolves as a metastatic castration-resistant disease, which is lethal. Despite recent advances, the molecular mechanisms contributing to this lethal disease are largely unknown. Our initial studies have indicated that the loss-of-function of the STK4-encoded MST1 protein kinase, a key component of the Hippo tumor suppressor pathway, may play a prominent role in the etiology of prostate cancer progression. Here, we establish cytoplasmic-, membrane- or nuclear-localized MST1 cell models to elucidate a possible mode of actions by which MST1 control the disease progression. We show that membrane or nuclear MST1 confers superior growth inhibitory effects on castration-resistant prostate cancer cells ex vivo and in vivo in comparison with cytoplasmic MST1, though they express the similar levels of MST1 protein. Consistently, a number of differentially expressed genes (2-fold with FDR ≤ 0.05) regulated by membrane or nuclear MST1 protein are much greater than cytoplasmic MST1, as assessed by RNA-sequencing and bioinformatics analysis. Functional annotation clustering reveals that genes affected by cytoplasmic MST1 protein are mostly associated with cell-cell interactions and membrane trafficking. However, expression of genes altered by membrane or nuclear MST1 involves much broader cellular biology that includes cell signaling, steroid biogenesis, lipid and cholesterol metabolisms, and developmental processes. In addition, Ingenuity Pathway analysis indicates that several genes effected by ectopic MST1 protein the defined cell location interact with androgen receptor pathway signaling, a critical regulator of prostate cancer pathogenesis. The results of this study suggest that the Hippo pathway signaling restricts prostate cancer progression by modulating the array of signaling networks, indicating important therapeutic implications for human disease. Citation Format: Damien Ready, Yuksel Yildiz, Vincent Funari, Serdar Bozdag, Bekir Cinar. Disclosing the Hippo signaling networks in castration-resistant prostate cancer. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4401.