miR-18b attenuates cerebral ischemia/reperfusion injury through regulation of ANXA3 and PI3K/Akt signaling pathway.

Recent, research has displayed that the disorders of miR-18b are related to ischemic stroke. Here, we aimed to investigate the underlying neuroprotective mechanism of miR-18b in cerebral ischemia/reperfusion (I/R) injury. Oxygen-glucose deprivation/reperfusion (OGDR) model in vitro and middle cerebral artery occlusion (MCAO) model in vivo were established to simulate cerebral I/R injury. RT-PCR, western blotting, CCK-8, TUNEL, and TTC staining assays were applied in this study to explore the effect of miR-18b on cerebral I/R injury. Results displayed that miR-18b expression was reduced after cerebral I/R injury. Besides, miR-18b showed neuroprotective effects on cerebral I/R injury both in vitro and in vivo, These neuroprotective effects included promoting cell viability, decreasing cell apoptosis, reducing the production of inflammatory cytokines in SH-SY 5Y cells after OGDR and depressing MCAO-induced infarct size, neurological deficits and apoptotic cells in mice. Moreover, miR-18b negatively regulated ANXA3 expression, and its neuroprotection on cerebral I/R injury was overturned by ANXA3. Additionally, increasing miR-18b or decreasing ANXA3 promoted the activation of the PI3K/Akt signaling pathway in SH-SY 5Y cells after cerebral I/R injury. In conclusion, these data indicate that miR-18b protects against cerebral I/R injury by inhibiting ANXA3 and activating PI3K/Akt pathway, which provides a promising therapeutic target for ischemic stroke therapy.

Annexin A3 gene silencing promotes myocardial cell repair through activation of the PI3K/Akt signaling pathway in rats with acute myocardial infarction.

Acute myocardial infarction (AMI), as a severe consequence of coronary atherosclerotic heart disease, always contributes to the loss of myocardial cells. Mounting evidence shows that annexin protects the myocardium from ischemic injury. In this study, we examine the inhibition of annexin A3 (ANXA3) on AMI through the phosphatidylinositide 3-kinase/protein kinase B (PI3K/Akt) signaling pathway. We selected rats to build an AMI model which was then assigned into different groups. The hemodynamic parameters after transfection were detected by using enzyme-linked immunosorbent assay. The effect of silencing of ANXA3 on inflammatory reaction and the PI3K/Akt signaling pathway was assessed. Rats transfected with ANXA3-short hairpin RNA had alleviated hemodynamics, inflammatory reaction, decreased infarct size, α-smooth muscle actin, Collagen I, and Collagen III as well as an increased vascular endothelial growth factor. Silencing ANAX3 would promote repair and healing of myocardial tissue by activation of the PI3K/Akt signaling pathway. Collectively, our study provides evidence that the downregulation of ANXA3 promotes the repair and healing of myocardial tissues by activating the PI3K/Akt signaling pathway.

MiR-340-5p is a potential prognostic indicator of colorectal cancer and modulates ANXA3.

OBJECTIVE: MicroRNAs (miRNAs) are increasingly recognized as oncogenes or tumor suppressors in colorectal cancer (CRC). The aim of this study was to explore the expression and functions of miR-340-5p in CRC. PATIENTS AND METHODS: The expression of miR-340-5p in CRC tissues and cell lines was detected by quantitative RT-PCR. Associations of miR-340-5p expression with clinicopathological factors and overall survival (OS) and progression-free survival (PFS) were statistically evaluated. Luciferase assay, RT-PCR, and Western blot were performed to verify the precise target of miR-340-5p. MTT assay, colony formation and transwell assay were performed to determine the proliferation, migration and invasion, respectively. RESULTS: Our results showed that miR-340-5p was significantly down-regulated in CRC tissues and cell lines, and was associated with histological grade (p=0.020), lymph nodes metastasis (p=0.003) and TNM stage (p=0.007). Furthermore, Kaplan-Meier and log-rank tests revealed that patients with low expression of miR-340-5p had a shorter OS (p=0.0110) and PFS (p=0.0032) than those with high expression of miR-340-5p. We further validated Annexin A3 (ANXA3) was a direct target of miR-340-5p in CRC. The functional assay showed that up-regulation of miR-340-5p or down-regulation of ANXA3 can both inhibit CRC cell proliferation, migration, and invasion. Besides, the re-expression of ANXA3 reversed the miR-340-5p induced suppression of cell proliferation, migration and invasion. CONCLUSIONS: Our data demonstrated that miR-340-5p exerted its tumor-suppressive function by directly targeting ANXA3 in CRC, suggesting that miR-340-5p might represent a novel prognostic biomarker and therapeutic target for CRC.

Efficacy of annexin A3 blockade in sensitizing hepatocellular carcinoma to sorafenib and regorafenib.

BACKGROUND & AIMS: Advanced hepatocellular carcinoma (HCC) is a lethal malignancy with limited treatment options. Sorafenib is the only FDA-approved first-line targeted drug for advanced HCC, but its effect on patient survival is limited. Further, patients ultimately present with disease progression. A better understanding of the causes of sorafenib resistance, enhancing the efficacy of sorafenib and finding a reliable predictive biomarker are crucial to achieve efficient control of HCC. METHODS: The functional effects of ANXA3 in conferring sorafenib resistance to HCC cells were analyzed in apoptotic and tumorigenicity assays. The role of ANXA3/PKCδ-mediated p38 signaling, and subsequently altered autophagic and apoptotic events, was assessed by immunoprecipitation, immunoblotting, immunofluorescence and transmission electron microscopy assays. The prognostic value of ANXA3 in predicting response to sorafenib was evaluated by immunohistochemistry. The therapeutic value of targeting ANXA3 to combat HCC with anti-ANXA3 monoclonal antibody alone or in combination with sorafenib/regorafenib was investigated ex vivo and in vivo. RESULTS: ANXA3 conferred HCC cells with resistance to sorafenib. ANXA3 was found enriched in sorafenib-resistant HCC cells and patient-derived xenografts. Mechanistically, overexpression of ANXA3 in sorafenib-resistant HCC cells suppressed PKCδ/p38 associated apoptosis and activated autophagy for cell survival. Clinically, ANXA3 expression correlated positively with the autophagic marker LC3B in HCC and was associated with a worse overall survival in patients who went on to receive sorafenib treatment. Anti-ANXA3 monoclonal antibody therapy combined with sorafenib/regorafenib impaired tumor growth in vivo and significantly increased survival. CONCLUSION: Anti-ANXA3 therapy in combination with sorafenib/regorafenib represents a novel therapeutic strategy for HCC treatment. ANXA3 represents a useful predictive biomarker to stratify patients with HCC for sorafenib treatment. LAY SUMMARY: This study represents the most extensive pre-clinical characterization of anti-ANXA3 monoclonal antibodies for the treatment of hepatocellular carcinoma to date. These results support the clinical trial development of anti-ANXA3 antibodies in combination with sorafenib/regorafenib. Further studies will optimize patient target selection and identify the best treatment combinations.

The MiR-495/Annexin A3/P53 Axis Inhibits the Invasion and EMT of Colorectal Cancer Cells.

BACKGROUND/AIMS: More and more reports have shown that the dysregulation of miRNAs can contribute to the progression and metastasis of human cancers. Many studies have shown that the down-regulation of the miR-495 level occurs in a variety of cancers, including colorectal cancer (CRC). However, the precise molecular mechanisms of miR-495 in CRC have not been well clarified. In the current study, we investigated the biological functions and molecular mechanisms of miR-495 in CRC cell lines. METHODS: qRT-PCR was used to determine the level of miR-495 in CRC cell lines and tissues. A miR-495 mimic and inhibitor were transfected into CRC cells, and the effects of miR-495 on the invasion and EMT were explored by qRT-PCR as well as transwell and Western blot assays. Meanwhile, luciferase assays were performed to validate Annexin A3 as a miR-495 target in CRC cells. RESULTS: In our study, we found that miR-495 is down-regulated in CRC tissues and cell lines. Moreover, the low level of miR-495 was associated with increased expression of Annexin A3 in CRC tissues and cell lines. The invasion and EMT of CRC cells were suppressed by the overexpression of miR-495. However, the down-regulation of miR-495 promoted the invasion and EMT of CRC cells. Bioinformatics analysis predicted that Annexin A3 was a potential target gene of miR-495. Next, the luciferase reporter assay confirmed that miR-495 could directly target Annexin A3. Consistent with the effect of miR-495, the down-regulation of Annexin A3 by siRNA inhibited the invasion and EMT of CRC cells through the up-regulation of p53. The introduction of Annexin A3 in CRC cells partially blocked the effects of the miR-495 mimic. CONCLUSION: The introduction of miR-495 directly targeted Annexin A3 to inhibit the invasion and EMT of CRC cells by up-regulating p53, and the down-regulation of Annexin A3 was essential for inhibiting the invasion and EMT of CRC cells by overexpressing miR-495. Overall, the re-activation of the miR-495/Annexin A3/ p53 axis may represent a new strategy for overcoming metastasis of CRC.

Overexpression of ANXA3 is an independent prognostic indicator in gastric cancer and its depletion suppresses cell proliferation and tumor growth.

BACKGROUND: Gastric cancer (GC) is one of the most common malignancies worldwide. Tumour metastasis is one of the leading causes of death in GC patients. This study aims to investigate the significance of ANXA3 expression and the mechanism by which ANXA3 is involved in the epithelial-mensenchymal transition (EMT) of gastric cancer cells. RESULTS: Our results confirmed that ANXA3 was high expression at the mRNA and protein level in GC cancer tissues and the majority of GC cell lines. In clinicopathological analysis, we found that increased expression of ANXA3 in tumors was closely associated with a poor prognosis. Xogenous ANXA3 transduction promoted proliferation, clone formation, migration, and invasion. Small interfering RNA silencing of ANXA3 inhibited these processes. Silence of ANXA3 inhibited tumorigenicity in vivo. Additionally, ANXA3 expression is associated with the epithelial-mesenchymal transition. METHODS: Firstly, we investigated the ANXA3 expression on mRNA and protein level with RT-PCR and Western blot. Secondly, 183 GC patients tissues were used the to evaluate the clinicopathological characteristics and prognosis through immunohistochemistry. Furthermore, The functions of ANXA3 were analyzed in the cell proliferation, Colony Formation, migration, invasion and apoptosis of GC cell lines. CONCLUSIONS: Our research suggests that ANXA3 plays important roles in gastric cancer carcinogenesis and metastasis, and provides a valuable prognostic marker and potential target for treatment of gastric cancer patients.

Annexin A3 Regulates Early Blood Vessel Formation.

Annexins are a large family of calcium binding proteins that associate with cell membrane phospholipids and are involved in various cellular processes including endocytosis, exocytosis and membrane-cytoskeletal organization. Despite studies on numerous Annexin proteins, the function of Annexin A3 (Anxa3) is largely unknown. Our studies identify Anxa3 as a unique marker of the endothelial and myeloid cell lineages of Xenopus laevis during development. Anxa3 transcripts are also detected in endothelial cells (ECs) of zebrafish and mouse embryos, suggesting an important evolutionary function during formation of blood vessels. Indeed, Anxa3 loss-of-function experiments in frog embryos reveal its critical role during the morphogenesis of early blood vessels, as angioblasts in MO injected embryos fail to form vascular cords. Furthermore, in vitro experiments in mammalian cells identify a role for Anxa3 in EC migration. Our results are the first to reveal an in vivo function for Anxa3 during vascular development and represent a previously unexplored aspect of annexin biology.

Proteomic investigation of 5-fluorouracil resistance in a human hepatocellular carcinoma cell line.

Multi-drug resistance (MDR) is a major obstacle towards a successful treatment of hepatocellular carcinoma (HCC). The mechanisms of MDR are intricate and have not been fully understood. Therefore, we employed a cell-line model consisting of the 5-fluorouracil (5-FU) resistant BEL7402/5-FU cell line and its parental BEL7402 cell line. Using relative and absolute quantification (iTRAQ)-coupled 2D LC-MS/MS, a successfully exploited high-throughput proteomic technology, in total, 660 unique proteins were identified and 52 proteins showed to be differentially expressed in BEL7402/5-FU compared with BEL7402. Several differentially expressed proteins were further validated by Western blot and real-time quantitative RT-PCR analysis. Furthermore, the association of MDR with ANXA3, one of the highly expressed proteins in BEL7402/5-FU, was verified. Our study represents the first successful application of iTRAQ technology for MDR mechanisms analysis in HCC. Many of the differentially expressed proteins identified had not been linked to MDR in HCC before, which provide valuable information for further understanding of MDR.

Expression of annexin A3 in primary cultured parenchymal rat hepatocytes and inhibition of DNA synthesis by suppression of annexin A3 expression using RNA interference.

Annexin A3 is a member of the lipocortin/annexin family, which binds to phospholipids and membranes in a Ca(2+)-dependent manner. Although annexin A3 has various functions in vitro, its cellular significance is completely unknown. Annexin A3 is not found in rat liver in vivo. In the present study, we investigated the expression of annexin A3 in primary cultured parenchymal rat hepatocytes. Annexin A3 protein was detected in 48-h, but not 2.5-h, cultured hepatocytes using Western blot analysis. The annexin A3 level further increased after an additional 24 h of culture. Annexin A3 mRNA was not detected in 2.5-h cultured hepatocytes but was detected 22 h after the start of culture by RT-PCR analysis, reaching a maximum value after 48 h of culture. To define the role of Annexin A3 in DNA synthesis, RNA interference was used to reduce annexin III gene expression in hepatocytes. The transfection of small interfering RNAs targeting annexin A3 in the hepatocytes reduced the corresponding mRNA and protein expression by approximately 80% and more than 90%, respectively, at 24 h after transfection. In the annexin A3 small interfering RNAs-transfected cells, DNA synthesis, as assessed by [3H]thymidine incorporation, decreased by approximately 70% not only in the control cultures, but also in the hepatocyte growth factor- or epidermal growth factor-treated cells. These findings show that annexin A3 is expressed in primary cultured parenchymal rat hepatocytes and that the suppression of annexin A3 expression using RNA interference inhibits DNA synthesis.