By Activating Akt/eNOS Bilobalide B Inhibits Autophagy and Promotes Angiogenesis Following Focal Cerebral Ischemia Reperfusion.

BACKGROUND/AIMS: Ischemic stroke is a leading cause of long-term disability. To date, there is no effective treatment for stroke. Previous studies have shown that Ginkgo biloba extract has protective effects against neurodegenerative disorders. In this present study, we sought to test the potential protective role of an active component of Ginkgo biloba extract, bilobalide, in a rat model of middle cerebral artery occlusion (MCAO). METHODS: A rat model of MCAO was used to test the potential protective effects of Bilobalide B on stroke protection. TTC staining was performed to evaluate infarct size of the brains. Neurological deficit score was measured to reveal the effects of the treatments on animal behavior and cognition. Immunohistochemical staining and transmission electronic microscope analysis were performed to measure the cellular responses to drug treatment. Western blotting and ELISA were performed. The expression of Cleaved- Casepase 3, Beclin-1, p62 and LC3I/II were quantified, and the Phosphorylation of eNOS and Akt were evaluated. The ratio of Bcl-2/ Bax was determined to reveal the molecular pathways that are involved in the drug treatment. RESULTS: We found that intraperitoneal delivery of various Bilobalide doses during ischemia can protect against brain injury, as evidenced by reduced infarct size and improved neurological scores after surgery. Histochemical analysis revealed that treatment with bilobalide can significantly reduce apoptosis, autophagy, and promote angiogeneis following ischemia/reperfusion injury to the brain. The performence of increased phosphorylation of eNOS and Akt suggested that bilobalide can activate Akt prosurvival and eNOS pathways to promote cell survival and angiogenesis, respectively. CONCLUSIONS: Our results suggested that bilobalide benefits stroke symptoms by reducing cell death pathways and promoting angiogenesis. As such, bilobalide may be a potential agent for improving self-repair after ischemic stroke.

UCH-L1 promotes invasion of breast cancer cells through activating Akt signaling pathway.

As a de-ubiquitin enzyme, ubiquitin C-terminal hydrolase (UCH)-L1 has been shown to be overexpressed in several human cancers. However, the function of UCH-L1 in invasion of breast cancers is still unclear. Here we report that the expression of UCH-L1 is significantly higher in cancer cells with higher invasive ability. While ectopic UCH-L1 expression failed to alter cell proliferation in MCF-7 cells, it caused a significant upregulation of cellular invasion. Furthermore, siRNA mediated knockdown of UCH-L1 led to suppression of invasion in UCH-L1 overexpressing MCF-7 cells. In order to identify molecular mechanisms underlying these observations, a novel in vitro proximity-dependent biotin identification method was developed by fusing UCH-L1 protein with a bacterial biotin ligase (Escherichia coli BirA R118G, BioID). Streptavidin magnetic beads pulldown assay revealed that UCH-L1 can interact with Akt in MCF-7 cells. Pulldown assay with His tagged recombinant UCH-L1 protein and cell lysate from MCF-7 cells further demonstrated that UCH-L1 preferentially binds to Akt2 for Akt activation. Finally, we demonstrated that overexpression of UCH-L1 led to activation of Akt as evidenced by upregulation of phosphorylated Akt. Thus, these findings demonstrated that UCH-L1 promotes invasion of breast cancer cells and might serve as a potential therapeutic target for treatment of human patients with breast cancers.

PTRF suppresses the progression of colorectal cancers.

As a key component of caveolae structure on the plasma membrane, accumulated evidence has suggested that Polymerase I and Transcript Release Factor (PTRF) plays a pivotal role in suppressing the progression of human malignances. However, the function of PTRF in the development of colorectal cancers is still unclear. Here we report that the expression of PTRF is significantly reduced in tumor tissues derived from human patients with colorectal cancers, and that the downregulation of PTRF correlates to the advanced stage of the disease. In addition, we found that the expression of PTRF negatively regulates the tumorigenic activities of colorectal cell lines (Colo320, HT29 and CaCo2). Furthermore, ectopic PTRF expression caused significant suppression of cellular proliferation, and anchorage-independent colony growth of Colo320 cells, which have the lowest expression level of PTRF in the three studied cell lines. Meanwhile, shRNA mediated knockdown of PTRF in CaCo2 cells significantly promoted cellular proliferation and anchorage-independent colony growth. In addition, in vivo assays further revealed that tumor growth was significantly inhibited in xenografts with ectopic PTRF expression as compared to untreated Colo320 cells, but was markedly enhanced in PTRF knockdown CaCo2 cells. Biochemical studies revealed that overexpression of PTRF led to the suppression of the AKT/mTOR pathway, as evidenced by reduced phosphorylation of AKT, mTOR, and downstream MMP-9. Thus, these findings, for the first time, demonstrated that PTRF inhibits the tumorigenesis of colorectal cancers and that it might serve as a potential therapeutic target for human colon cancer patients.

EUS-Guided FNA for Diagnosis of Pancreatic Cystic Lesions: a Meta-Analysis.

BACKGROUND: Preoperative diagnosis of pancreatic cystic lesions (PCLs) must be reliable as the current standard treatment, major or total pancreatectomy, dramatically affects quality of life. Additionally, early diagnosis of malignancy is essential to an improved prognosis. The diagnostic accuracy of fluid analysis using endoscopic ultrasonography-guided fine-needle aspiration (EUS-FNA) has been demonstrated in pancreatic solid lesions. The utility of this technique in the diagnosis of PCLs is still unknown. METHODS: A comprehensive search was performed in multiple databases. Studies differentiating benign and malignant PCLs via EUS-FNA were included in this meta-analysis. The quality of diagnostic accuracy studies (QUADAS) was adopted to evaluate the selected studies. Pooled sensitivity, specificity, likelihood ratio, diagnostic odds ratio, and summary receiver operating characteristic (sROC) curve analyses were conducted. Two main classification types of malignancy were characterized and analyzed. We also generated a subgroup analysis of available clinical factors. Publication bias was evaluated by Begg's and Egger's tests. RESULTS: Sixteen studies containing 1024 subjects have been published. The pooled sensitivity for malignant cytology according to classification 1 was 0.51 (95% CI, 0.45-0.58), and pooled specificity was 0.94 (95% CI, 0.92-0.96). When the detected PCLs were identified as classification 2, suspicious malignancy or potential malignancy, sensitivity and specificity were similar, 0.52 (95% CI, 0.46-0.57) and 0.97 (95% CI, 0.95-0.98) respectively. CONCLUSION: This meta-analysis demonstrates that EUS-FNA is a reliable clinical tool for the diagnosis of PCLs. However, a more accurate algorithm is needed to reduce various biases and to improve the sensitivity of EUS-FNA in the detection of malignant PCLs.