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Meng S.,Harbin Medical University | Su Z.,Harbin Medical University | Liu Z.,Harbin Medical University | Wang N.,The Fourth Hospital of Harbin | Wang Z.,PLA Fourth Military Medical University
Neuroscience | Year: 2015

Background: Cerebral ischemia-reperfusion (IR) injury is a complex pathological process that can cause irreversible brain damage, neuronal injury or death from brain ischemia. Rac1 GTPase is involved in cellular protection from IR injury. However, the mechanism of protection and the molecules affected by Rac1 remain to be defined. Methods and results: C57BL/6 mice were subjected to middle cerebral artery occlusion for 1. h, followed by 24-h reperfusion. In this in vivo model of cerebral IR injury, mice treated with the Rac GTPase inhibitor NSC23766 or Rac1 small interfering RNA (siRNA) had better short-term (72. h) neurologic scores, less infarction volume, higher production of antioxidant enzymes, lower lipid peroxide, and reduced apoptosis compared with a vehicle-treated group or a control-siRNA group. However, long-term (14. day) neurologic scores were worse for the two treatments compared to controls. Microarray and quantitative polymerase chain reaction (PCR) revealed that Notch2 was downregulated under NSC23766 treatment. Notch2 protein levels decreased with NSC23766 and Rac1 siRNA in vitro and in vivo. Cell survival increased with the Notch signaling inhibitor DAPT or Notch2 siRNA and NICD2 attenuated the NSC23766 effect. In addition, immunoblotting showed that DAPT and Notch2 siRNA changed the levels of apoptosis-regulating proteins. NFkB mediated Rac1, which regulated Notch2 in an oxygen glucose deprivation model. Both inhibitors of Notch2 and Rac1 enhanced neural stem cell differentiation. Conclusions: This study demonstrated the importance of Rac1 regulation of Notch2 in mediating cerebral IR-induced production of injurious reactive oxygen species and cell death in vitro and in vivo in the short term. Targeted inhibition of Rac1 or Notch2 is new avenue for in vivo therapy aimed at protecting organs at risk from IR injury. © 2015. Source

Wang C.-K.,The Fourth Hospital of Harbin | Yu X.-D.,The Fourth Hospital of Harbin | Li Q.,The Fourth Hospital of Harbin | Xie G.,The Fourth Hospital of Harbin | Teng Y.,The Fourth Hospital of Harbin
Asian Pacific Journal of Cancer Prevention | Year: 2013

Choroquine (CQ) and valproic acid (VPA) have been extensively studied for biological effects. Here, we focused on efficacy of combined CQ and VPA on osteosarcoma cell lines. Viability of osteosarcoma cell lines (U20S and HOS) was analyzed by MTT assay. Apoptotic assays and colony formation assays were also applied. ROS generation and Western Blotting were performed to determine the mechanism of CQ and VPA combination in the process of apoptosis. The viability of different osteosarcoma cell lines significantly decreased after CQ and VPA combination treatment compared with either drug used alone, and apoptosis was increased significantly. ROS generation was triggered leading to expression of apoptosis related genes being increased and of anti-apoptotic related genes being decreased. From our data shown here, CQ and VPA combination treatment in vitro enhanced cytotoxicy to osteosarcoma cells. Source

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